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Salinization reduces the osmotic potential of soil solutions and promotes the accumulation of toxic ions (Na+ and Cl-) in plants, causing nutritional imbalance and yield reductions. Thus, the objective of the present study was to evaluate foliar concentrations of nutrients and Na+ and stalk yields in sugarcane RB92579 under different electrical conductivities of irrigation water and leaching fractions (LF). The experiment was conducted in drainage lysimeters in a 5 × 2 factorial scheme with five electrical conductivities of irrigation water - ECw (0.5, 2.0, 4.0, 6.0, and 8.0 dS m-1) without (LF1 = 0) or with a leaching fraction (LF2 = 0.17), and four replicates. Increased ECw decreased the concentrations of N, P, K, Mg, S, Fe, Mn, Cu, and Zn and increased those of Ca, Cl, and Na, reducing the biomass production in two cycles (plant-cane and first ratoon). The use of a leaching fraction of 0.17 mitigated the deleterious effects of salinity on nutrient concentration and yield.

Weed competition in southern Brazil is one of the main limiting factors for Oryza sativa L. (flooded rice) yield. Echinochloa spp. (barnyardgrass) occurs at a high frequency. Although the potential for weed interference in this cereal is well known, there is little information available about the impact of nutrient competition on rice. Thus, this study aimed to evaluate the relationship between the increase of the barnyardgrass population and the development and nutrition of flooded rice plants at different stages of development. The treatments consisted of growing populations of barnyardgrass competing with the crop from stage V4, which were: 0, 1, 6, 13, 100 and 200 plants · m−2. The experimental design was randomized blocks with two replications, and the experimental units were plots 1.53 m wide by 5 m long. Plant biomass, nutrient uptake and loss of productivity were determined with three replications. An increase in the barnyardgrass population reduced the dry mass of rice leaves and stems, regardless of the evaluation period and the vegetative or reproductive period. Barnyardgrass plants had a significant impact on the reduced grain yield of a flooded rice crop, mainly due to high nutrient competitiveness, especially N in the vegetative period and K in the reproductive period. Barnyardgrass caused a loss of yield by unit · m−2 of 1.13%. The competition for N between rice and barnyardgrass plants was higher in the vegetative period, while for K, Ca and Mg the highest competition occurred in the reproductive period.

Adequate mineral fertilization and staking are necessary to obtain good productivity in yam cultivation. The objective of this study was to determine the increase in yield and quality of yams subjected to nitrogen doses and staking methods. This study was carried out under field conditions using a randomized block design in a 5 × 3 factorial scheme, with five nitrogen doses (0, 50, 100, 150 and 200 kg ha-1) and three staking methods (wire trellises, single staking, and without staking) with four replicates. Nitrogen doses were applied in topdressing, and split into equal parts at 60 and 90 days after seed tuber planting. Tuber length and weight, starch and leaf nitrogen concentrations, and total and marketable yields were determined. Staking promoted higher total yield, mass, length, and leaf nitrogen concentration, but no changes were observed in starch concentration among the staking methods. Commercial productivity was higher with single staking. Planting yam with staking and a nitrogen dose of 120.70 kg ha-1 is recommended to promote maximum productivity. RESUMO No cultivo do inhame a adubação mineral e o uso de tutoramento proporciona boa produção. O objetivo deste trabalho foi avaliar a produção e a qualidade do inhame submetidos a doses de nitrogênio e tipos de tutoramento. O trabalho foi realizado em condições de campo no delineamento experimental em blocos casualizados em esquema fatorial 5 × 3, com cinco doses de nitrogênio (0, 50, 100, 150 e 200 kg ha-1) e três tipos de tutoramento (espaldeiramento, vara e sem tutor), com quatro repetições. Na adubação em cobertura foram aplicadas as doses de nitrogênio parceladas em partes iguais aos 60 e 90 dias após o plantio. Foram avaliados comprimento, massa média, teores de amido e N foliar, produtividades total e comercial de túberas. O tutoramento promoveu maior rendimento total, massa média, comprimento e teor de nitrogênio foliar, entretanto não foram observadas alterações no teor de amido entre os tipos de tutoramento. A produtividade comercial é maior com a utilização do tutor em vara. Recomenda-se o plantio do inhame com tutoramento e dose de nitrogênio de 120,70 kg ha-1 para promover a máxima produtividade.

The aim of this study was to determine the content of physiologically active potassium (K2O) in the soil in the territory covered by the work of the Agricultural Advisory and Expert Service of Smederevo (PSSS Smederevo). Research was carried out on three locations: Velika Plana, the City of Smederevo and Smederevska Palanka, for the purpose of ensuring the optimal use of mineral and organic fertilizers, to preserve soil resources. The paper presents the results of testing the content of physiologically active potassium – K2O. The territory of Velika Plana had most areas with harmful content, while the lowest content of K2O was recorded in the territory of Smederevska Palanka. The results indicate that the obtained values were greatly influenced by different types of soil on the examined plots, and an anthropogenic factor was also evident. All the plots from which soil samples were taken for analysis of potassium content were mapped, and based on the obtained results farmers were given advice on the necessary remedial measures and optimal use of organic and mineral fertilizers to improve agricultural production and preserve biodiversity. Mineral nutrition is extremely important for growth, development and reaching maximum yields of cultivated plants.foliar mass were higher in the PSB version (without fertilizers), and in the treatment with the use of P. polymyxa - with the use of N20P40 fertilizers.

The present study evaluated the effect of arbuscular mycorrhizal fungi (AMF) inoculation on growth and nutrition of Euterpe edulis seedlings, supplemented or not with phosphate fertilization. The experiment was conducted in a greenhouse. The randomized block design, consisted of a 3x2 factorial arrangement and 4 replicates, with two phosphorus doses (0 and 50 mg dm-3 of soil), two microbiological treatments (Rhizophagus clarus; laroideoglomus etunicatum; R. clarus + C. etunicatum) and control (without fungus). Sowing and inoculation occurred concurrently in 2 kg plastic bags. Height, collar diameter, leaf area, dry shoot mass, macronutrient content and mycorrhizal colonization percentage were determined after 226 days. Regarding mycorrhizal colonization percentage, R. clarus resulted significantly beneficial for the production of E. edulis seedlings. In the absence of phosphate fertilization, R. clarus and mixed inoculum increased all biometric variables and macronutrient contents in seedlings. Therefore, it is concluded that AMF inoculations provide beneficial effects for growth and nutrition of E. edulis seedlings, resulting in more vigorous plants at a low-cost strategy. Highlights: Rhizophagus clarus resulted significantly beneficial for the production of E. edulis seedlings and in the absence of phosphate fertilization, and mixed inoculum ( clarus + Claroideoglomus etunicatum) increased all biometric variables and macronutrient contents in seedlings. The AMF inoculations provide beneficial effects for growth and nutrition of E. edulis seedlings, resulting in more vigorous plants at a low-cost strategy. The AMF, a biological agent of mutualistic associations with plants, constitutes an innovative approach to sustainable agriculture, contributing to increase plant survival rate, a key-factor for the successful reintroduction and conservation of E. edulis, as well as for its commercial exploitation.

The nitrogen (N) supplying capacity of common bean plants through biological fixation is still questioned by farmers. This study aimed to investigate the nodulation, growth and production of common bean cultivars under field conditions, when subjected to topdressing Rhizobium tropici reinoculation applied at different rates, combined or not with Azospirillum brasilense. A randomized blocks design was used, in a 2 × 4 × 2 + 2 factorial arrangement, with four replications. The treatments consisted of two common bean cultivars (BRS-Estilo and BRS-Esteio) reinoculated with four R. tropici rates (0-, 1-, 2- and 4-fold the reference rate), combined or not with A. brasilense in co-inoculation. The additional treatments consisted of nitrogen fertilizer applications (20 and 50 kg ha-1 at planting and as topdressing, respectively) for both cultivars. The variables evaluated at the R6 stage were nodulation (number of active nodules and nodule dry weight) and morphological plant characteristics (root length and dry weight, plant height, shoot dry weight and N content), while, at harvest, the number of pods per plant, number of grains per pod, 100-grain average weight and grain yield were evaluated. The topdressing reinoculation of R. tropici combined with A. brasilense at the V4 stage affected the nodulation process and agronomic characteristics of the common bean plants. When performed in addition to seed inoculation, it may totally replace the supply of mineral N in the crop, allowing the achievement of high yield levels. RESUMO A capacidade de fornecimento de nitrogênio (N) para o feijoeiro por meio de fixação biológica ainda é questionada por agricultores. Objetivou-se investigar a nodulação, crescimento e produção de cultivares de feijão comum em condições de campo, submetidas à reinoculação de Rhizobium tropici em cobertura aplicado em diferentes doses, em mistura ou não com Azospirillum brasilense. Empregou-se o delineamento de blocos casualizados, em esquema fatorial 2 x 4 x 2 + 2, com quatro repetições, sendo duas cultivares (BRS-Estilo e BRS-Esteio) reinoculadas com quatro doses de R. trocipi em cobertura (0; 1; 2; e 4 vezes a dose referência), em mistura ou não com Azospirillum em co-inoculação. Como tratamentos adicionais, utilizou-se adubação nitrogenada (20 e 50 kg ha-1 na base e em cobertura, respectivamente) para ambas as cultivares. No estádio R6, foram avaliadas as características de nodulação (número de nódulos ativos e massa seca de nódulos) e morfológicas das plantas (comprimento e peso seco de raiz, altura de planta, peso seco da parte aérea e teor de N), e, na colheita, o número de vagens por planta, número de grãos por vagem, peso médio de 100 grãos e rendimento de grãos. A reinoculação em cobertura de R. tropici com A. brasilense realizada no estádio V4 infuenciou no processo de nodulação e características agronômicas do feijoeiro. Quando realizada em complementação à inoculação nas sementes, pode substituir totalmente o fornecimento de N mineral na cultura, permitindo a obtenção de elevados patamares de rendimento.

Iron (Fe) toxicity is a major constraint to rice yields in much of the world due to the greater solubility of reduced ferrous Fe in paddy soils compared with ferric Fe in aerobic soils and resulting excess uptake into the plants. There is genotypic variation in tolerance in Oryza gene pools, but so far only weak-effect alleles have been identified, largely because multiple critical physiological processes determine the tolerance. Most past research has been done in nutrient solution screens at the seedling stage, and not under field conditions over the full life cycle. We investigated tolerance mechanisms in a diverse set of genotypes under field conditions in a highly iron toxic soil in the Central Highlands of Madagascar. We made repeated plant samplings of young and old tissues throughout the growth period until maturity. Multiple mechanisms were involved, and the importance of different mechanisms changed between growth stages. Higher grain yields were mainly due to healthy vegetative growth, achieved either by reducing Fe uptake (exclusion) or by minimizing the effect of excess uptake through compartmentalization in older tissues and tissue tolerance. Exclusion mechanisms were relaxed during reproductive growth, leading to increased Fe accumulation in shoots. But tolerant genotypes were nonetheless able to grow well through a combination of Fe compartmentalization and tissue tolerance, so that grain filling could proceed relatively unimpeded. Tissue phosphorus (P) and potassium (K) concentrations were close to or below deficiency limits throughout growth. Exclusion by ferrous Fe oxidation in the rhizosphere will impede access of P and K ions to roots, but the differences in their tissue concentrations were much smaller than differences in growth rates, so growth rates evidently drove the uptake differences and responses to Fe toxicity were the more important constraints. There was no relation between grain yield and visual symptoms. To identify useful donors and markers for breeding it is important to develop screening protocols that capture the individual tolerance mechanisms, allowing for the effects of growth stage on their relative importance and expression, and possible interactions with other factors such as mineral nutrition. Selection for tolerance based on visual symptoms, particularly at the seedling stage, is overly simplistic, though it can be useful in the study of specific tolerance mechanisms.

Resumo Com o objetivo de avaliar os efeitos da salinidade do solo sobre a nutrição mineral da cultivar de milho UFVM 100, conduziu-se um experimento em lisímetros de drenagem sob condições de casa de vegetação, montado em delineamento inteiramente casualizado com sete tratamentos e três repetições. Os tratamentos foram constituídos de irrigação com água doce, sem lixiviação, e seis irrigados com água salina de 1,2 dS m-1, com frações de lixiviação de 40, 30, 20, 15, 10 e 5% da lâmina de irrigação aplicada. Avaliaram-se os efeitos da salinidade do solo sobre a nutrição mineral da cultura do milho, determinando-se o teor foliar dos macronutrientes catiônicos e suas relações com o Na+, aos 120 dias após o plantio, na fase fenológica correspondente à maturação fisiológica. O aumento da salinidade do solo reduziu os teores dos macronutrientes cálcio, magnésio e potássio e elevou os teores foliares de sódio e as relações Na+/Ca2+, Na+/Mg2+ e Na+/K+. Abstract To evaluate the effects of soil salinity on the mineral nutrition in the maize, UFVM 100 cv., an experiment was carried out in drainage lysimeters under greenhouse conditions. An completely randomized experimental design was used, with seven treatments. The treatments consisted of irrigation with freshwater, without leaching, and the other six ones irrigated with saline water (1.2 dS m-1) with leaching fractions of 40, 30, 20, 15, 10 and 5% of the applied irrigation depth with three replications. The effects of the soil salinity upon mineral nutrition of the maize crop were evaluated, by determining the leaf content of the cationic macronutrients and their relationships with Na+ at 120 days after planting and at the phenological phase corresponding to physiological maturation. The increased soil salinity elevated the leaf sodium contents and the relationships Na+/Ca2+, Na+/Mg2+ and Na+/K+ rations, as well as reduced the contents of the calcium, magnesium and potassium macronutrients.

Made available in DSpace on 2022-05-01T07:58:49Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 Purpose: As soil acidity is a recurring constraint for Arabica coffee (Coffea arabica L.) yield and the application method can interfere with the liming efficiency, a field experiment was performed to evaluate the effect of broadcast- and band-applied limestone rates on amelioration of soil profile chemical characteristics and coffee nutrition, growth, and yield. Methods: The experiment took place from 2015 to 2020 on a sandy clay loam Acrisol (20% clay at 0–0.2-m depth) of southeastern Brazil. It was arranged in a randomized complete block design with three replications. The treatments comprised two limestone rates (2100 and 4200 kg ha−1), both uniformly broadcast-applied all over the area or applied as a surface band under the canopy projection of the plants, and an unamended control. Results: Liming efficiently improved soil chemical attributes up to the depth of 0.1–0.2 m, but only slightly affected the 0.2–0.4-m layer. Band-applied limestone was more efficient in reducing the acidity and increasing the concentrations of Ca2+ and Mg2+ in the soil beneath the plant canopy, while greater effects between the rows were obtained with the broadcast application. When band-applied, limestone rates higher than those currently recommended did not cause an excessive increase in soil pH or micronutrient deficiency in coffee trees and increased bean yield by 42% (589 kg ha−1). Conclusions: Concentrated (band) application of limestone was more efficient than its broadcast application to ameliorate the soil acidity in depth and over time beneath the plant canopy, as well as to increase plant growth and coffee yield. Department of Crop Science College of Agricultural Sciences São Paulo State University (UNESP), Av. Universitária, 3780 São Paulo Agency of Agribusiness Technology (APTA/SAA) Midwest Regional/SAA Department of Agricultural Sciences and Technology School of Agriculture and Enterprise Development Kenyatta University Department of Crop Science College of Agricultural Sciences São Paulo State University (UNESP), Av. Universitária, 3780

Key message Root-specific expression of a cytokinin-degrading CKX gene in maize roots causes formation of a larger root system leading to higher element content in shoot organs. Abstract The size and architecture of the root system is functionally relevant for the access to water and soil nutrients. A great number of mostly unknown genes are involved in regulating root architecture complicating targeted breeding of plants with a larger root system. Here, we have explored whether root-specific degradation of the hormone cytokinin, which is a negative regulator of root growth, can be used to genetically engineer maize (Zea mays L.) plants with a larger root system. Root-specific expression of a CYTOKININ OXIDASE/DEHYDROGENASE (CKX) gene of Arabidopsis caused the formation of up to 46% more root dry weight while shoot growth of these transgenic lines was similar as in non-transgenic control plants. The concentration of several elements, in particular of those with low soil mobility (K, P, Mo, Zn), was increased in leaves of transgenic lines. In kernels, the changes in concentration of most elements were less pronounced, but the concentrations of Cu, Mn and Zn were significantly increased in at least one of the three independent lines. Our data illustrate the potential of an increased root system as part of efforts towards achieving biofortification. Taken together, this work has shown that root-specific expression of a CKX gene can be used to engineer the root system of maize and alter shoot element composition.

This study analyzed the genetic diversity in Coffea canephora genotypes by univariate and multivariate statistical analysis, based on concentrations of macro- and micronutrients in coffee leaves in the stages of pre-flowering and grain filling. The experiment was arranged in randomized blocks with three replications, in a 42x2 factorial design, in which factor one represented the evaluated genotypes and factor two the periods of leaf sampling, i.e., pre-flowering and grain filling. The data of leaf nutrient concentrations were subjected to analysis of variance by the F test (p

HIGHLIGHTS The salinity of the water reduces the number and diameter of the fruits and, the total weight of West Indian cherry fruits. Potassium-phosphorus fertilization attenuates the deleterious effects of salt stress on West Indian cherry production. The effect of water salinity on West Indian cherry fruit varies with salt stress intensity and expo-sure time to salinity. RESUMO Os recursos hídricos no Nordeste brasileiro comumente apresentam elevadas concentrações de sais, o que limita a produção das culturas. Assim, o fornecimento de nutrientes, como o K e P de forma combinada pode reduzir a absorção dos íons Na+ e Cl- nas plantas, tornando viável o uso de águas salinas. Nesse contexto, objetivou-se, avaliar a produção de aceroleira cv. BRS 366 Jaburu sob irrigação com águas salinas e adubação com potássio-fósforo em dois ciclos produtivos no segundo ano de cultivo. Os tratamentos foram distribuídos em blocos casualizados, em esquema fatorial 5 x 4 com três repetições, relativos a cinco valores de condutividade elétrica da água de irrigação (0,6; 1,4; 2,2; 3,0 e 3,8 dS m-1), e quatro combinações de potássio/fósforo (100/100, 85/85, 60/60 e 45/45% da recomendação para a cultura). No primeiro ciclo produtivo, as plantas irrigadas com águas de 1,4 e 1,9 dS m-1, obtiveram o maior peso médio e total de frutos, respectivamente, enquanto que no segundo a irrigação com águas a partir de 0,6 dS m-1 reduziu a produção. A adubação com 45/45% da recomendação de K2O/P2O5 resulta em maior número e peso de frutos de acerola no primeiro ciclo produtivo, independentemente do nível salino.

HIGHLIGHTS Electrical conductivity of water of 3.0 dS m-1 reduces the chlorophyll synthesis and production of custard-apple. NPK recommendation of 100-125-125, 125-125-100 and 125-125-125% cause more damage to the cell membrane. Reduction in the quantum efficiency of custard-apple under salt stress is indicative of photoinhi-bitory damage. RESUMO No semiárido do Nordeste brasileiro, a alta concentração de sais encontrada nas águas destaca-se como um fator limitante para agricultura irrigada. Assim, a adubação com nitrogênio (N), fosforo (P) e potássio (K) é uma estratégia capaz de amenizar o estresse salino sobre as plantas. Neste contexto, objetivou-se com esta pesquisa avaliar os teores de pigmentos cloroplastídicos, a fluorescência da clorofila, o dano na membrana celular e a produção de pinha irrigadas com água de diferentes condutividades elétricas e adubadas com nitrogênio, fósforo e potássio. Os tratamentos foram distribuidos em blocos ao acaso, em esquema fatorial 2 x 8, com três repetições, sendo dois níveis de condutividade elétrica da água de irrigação - CEa (0,8 e 3,0 dS m-1) e oito combinações de adubação NPK (100-100-100; 100-100-125; 100-125-100; 100-125-125; 125-100-100; 125-100-125; 125-125-100 e 125-125-125% das doses recomemdadas de N-P2O5-K2O). A CEa de 3,0 dS m-1 diminuiu os teores de clorofila a e total, o número de frutos por planta, e eficiência fotoquímica, e aumentou os teores de carotenoides e o dano na membrana celular de pinha. A adubação com 100-125-125; 125-125-100 e 125-125-125% das dose recomendada de N-P2O5-K2O resultou em maior dano na membrana celular de pinha.

Phosphorus is a major limiting nutrient for crops in tropical regions. In addition, another major challenge for the future agriculture will be to maintain water levels in the soil to ensure satisfactory crop development. This study inserted in this context aimed to evaluate the conditioning caused by phosphorus fertilization and water availability in the soil over the biomass production and nutritional efficiency of plants of crambe (Crambe abyssinica Hochst). To this end, the experiment was conducted in a greenhouse, with four levels of phosphorus fertilization and three levels of water availability, along of 45 days, in order to obtain information about the production of biomass, nutritional contents, and the patterns of the nutritional efficiency of crambe plants. The results show that increasing the phosphorus supply in the soil promotes greater biomass production in crambe plants. In addition, the increase in water availability and levels of phosphorus fertilization near the recommended level promotes greater nutritional efficiencies in absorb, translocate and use the phosphorus available in the soil.

Made available in DSpace on 2021-06-25T15:05:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-05-06 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) The aim of this study was to evaluate the variability, partition, and correlation of Fe, Mn, and Zn in the leaves and fruit components (pod husk, pulp, tegument, and cotyledons) of cacao trees. These contents were also correlated with chemical attributes of the soils in regions classified as humid (H), humid to sub-humid (SH), and sub-humid to dry (SD) in the South Bahia, Brazil. Soils samples were collected, along with leaves and fruits from the PH16 clone of the cacao tree, for analysis of Fe, Mn, and Zn. Descriptive statistics and Pearson's correlation were applied, as well as Shapiro Wilk's normality test and Tukey's test for comparison of the climate regions. The accumulation order for Fe and Zn in the fruit components was tegument > pod husk > leaf > cotyledons; and for Mn the order was pod husk > leaf > tegument > cotyledons. The increase in hydric restriction, from the most humid region to the driest, causes natural bioconcentration of Fe, Mn, and Zn in the fruit components used to produce food (cotyledons and pulp). The Mn contents in the leaf can be used as indicators of its accumulation in the cotyledon and cacao pulp. Univ Estadual Santa Cruz, Dept Agr & Environm Sci, Ilheus, BA, Brazil Sao Paulo State Univ, Dept Soil & Fertilizer, Jaboticabal, SP, Brazil Univ Estadual Santa Cruz, Dept Exact & Technol Sci, Ilheus, BA, Brazil Sao Paulo State Univ, Dept Soil & Fertilizer, Jaboticabal, SP, Brazil CAPES: 001

Genetic characteristics and their interaction with environmental conditions, including nutritional management, determine coffee productivity and quality. The objective of this study was to evaluate fruit traits and nutrient accumulation in the fruit, husk, and bean, as well as in the leaves of different Coffea arabica cultivars cropped in the Gorongosa National Park, Mozambique. The experiment evaluated nine coffee cultivars in a randomized block design, with four replicates. Fruit and leaf samples were collected over two months (June and July 2021), in the fruit maturation phase, oven-dried and analyzed, namely, through a clustering unweighted pair group method with arithmetic mean (UPGMA). The characterization of ripe and dried coffee bean indicated differences in the performance of the cultivars. The accumulation of the macronutrients N, K, and Ca and micronutrients Fe, Mn, and B was highest in the bean, husk, fruit, and leaves of the evaluated cultivars. Nutrient concentrations and accumulation in the different evaluated organs have a direct influence on the nutritional crop management. This is crucial for a nutritional diagnosis that ensures high yields, but such mineral levels are also a result of the existing genetic diversity among cultivars, which must be taken into account for management and breeding purposes info:eu-repo/semantics/publishedVersion

Glyphosate-resistant (GR) maize is dominant in countries where it is grown. Significant, adverse effects of glyphosate application to GR maize have been reported, but few data from robust studies exist to determine if such effects are common. In this study, the effects of recommended application rates (single and sequential applications) were used on GR maize grown at two locations for one season and for two seasons in a third location. No significant effects of glyphosate on mineral content (N, P, K, Ca, Mg, S, Cu, Fe, Mn, and Zn) in leaves or grain, plant height, stem diameter, ear parameters, or yield were found at any location or in any growing season. Likewise, harvested grain quality, as determined by percent starch, protein, and total lipids, was unaffected by glyphosate treatment at any location. Neither glyphosate nor aminomethylphosphonic acid, the primary degradation product of glyphosate, were found in grain from any treatment at any location, except for 20 ng g−1 of glyphosate found in grain from one season at one location. These results support the view that recommended applications of glyphosate have no significant effects on growth, grain composition, mineral content, grain quality, nor yield of GR maize.

Arbuscular mycorrhizal fungi (AMF) are widely present in heavy metal-polluted soils, but their effects on straw degradation and plant growth of rotated crops are poorly understood. In this study, a pot experiment was used to simulate the return of fore-rotating crop (Brassica napus L.) straw to farmland with a subsequent planting of maize in a lead–zinc mining area on the Yunnan Plateau, Southwest China, which included four treatments: control (CK), addition of rape straw (SR), inoculation of AMF (AMF), and both AMF inoculation and straw addition (AMF + SR). The effects of AMF on the degradation and nutrient release of the fore-rotating rape straw and the growth, mineral nutrition and the cadmium (Cd) and lead (Pb) contents of the subsequent maize were investigated. Compared with the CK treatment, AMF significantly promoted the degradation of rape straw and the release of mineral nutrients (nitrogen, phosphorus and potassium) as well as the Cd and Pb, increased the content of available nutrients in soil, and improved the mineral nutrient contents in the maize. AMF + SR significantly increased the maize height and biomass by 32–35% and decreased the available Cd and Pb contents in soil and the Cd and Pb contents in the maize by 20–30% and 18–25%, respectively. Moreover, the available Cd and Pb contents in the soil presented significant positive correlations with their contents in the maize but negative correlations with the height and biomass of the maize. Thus, AMF played an important regulatory role in the nutrient cycling and heavy metal accumulation of the crop rotation.

The determination of nitrogen in plants by techniques that allow a fast diagnosis, based on plant growth characteristics, can be a useful tool for the nutritional management of coffee plants. Thus, this study evaluated growth and yield characteristics of irrigated conilon coffee in response to different nitrogen levels, resulting in the determination of the minimum N levels required to achieve the maximum yield, here called critical levels. The experiment was carried out in Colatina, Espirito Santo, Brazil, on plantations of conilon coffee, clonal variety Emcapa 8111, genotype 02. Six nitrogen levels were applied (0, 110, 220, 440, 880 and 1320 kg N ha-1) and the response in growth and yield characteristics periodically evaluated. There was a positive effect of the increasing N levels on yield, in that the N levels that provided 95% of the maximum yield (137.4 bags ha-1 and 108.5 bags ha-1) in the 2012/2013 and 2013/2014 growing seasons, respectively, were 420.7 and 543.1 kg N ha-1. There was also a positive effect of N levels on the growth characteristics and nitrogen contents, indicating their use as tools for a rapid nutritional diagnosis, with a view to optimizing the nitrogen management in Conilon coffee. RESUMO: A determinação do nitrogênio nas plantas por técnicas que permitem um diagnóstico rápido, baseado nas características de crescimento das plantas, pode ser uma ferramenta útil para o manejo nutricional das plantas de café. Assim, o objetivo deste estudo foi avaliar as características de crescimento e rendimento do café conilon irrigado em resposta à diferentes níveis de nitrogênio, resultando na determinação dos níveis mínimos de N necessárias para atingir o rendimento máximo, aqui chamadas de níveis críticos. O experimento foi realizado em Colatina, Espírito Santo, Brasil, em plantações de café conilon, variedade clonal Emcapa 8111, genótipo 02. Foram aplicados seis níveis de nitrogênio (0, 110, 220, 440, 880 e 1320 kg N ha-1) e a resposta em características de crescimento e rendimento foi periodicamente avaliada. Houve um efeito positivo do aumento dos níveis de N sobre o rendimento, na medida em que os níveis de N que forneceram 95% do rendimento máximo (137,4 sacos ha-1 e 108,5 sacos ha-1) nas estações de crescimento 2012/2013 e 2013/2014, respectivamente, foram de 420,7 e 543,1 kg de N ha-1. Houve também um efeito positivo dos níveis de N sobre as características de crescimento e conteúdo de nitrogênio, indicando seu uso como ferramentas para um diagnóstico nutricional rápido, com o objetivo de otimizar o manejo de nitrogênio no café Conilon.

The objective of this study was to evaluate nutrient concentrations in the flowers, leaves (pre-flowering and grain-filling period), grains, and husks of Robusta coffee genotypes cultivated in the Amazon region, as well as to identify their genetic diversity. This experiment was carried out in Alta Floresta D’Oeste, Rondônia, Brazil, in randomized blocks with three replications; for the leaves, a factorial experimental design of sampling periods was included. The nutrient concentrations of the different evaluated organs were subjected to analysis of variance by the F test (p < 0.01), and the genetic parameters were estimated. To determine the genetic diversity, the genotypes were grouped by the UPGMA hierarchical method, and to predict it the relative importance of traits was analyzed. Genetic divergence among Coffea canephora genotypes was indicated by the leaf nutrient concentrations. At a maximum dissimilarity threshold of 82% for the genotypes, the UPGMA method formed six groups. Concentrations of nitrogen (N) and phosphorus (P) in the leaf sampling periods of pre-flowering and grain filling were not influenced by genotypes. The leaf and flower iron (Fe) concentrations contributed most to genetic divergence. For a nutritional diagnosis of Robusta coffee, it is important to take into account the comparisons of genetic diversity as well as the nutritional requirements during the flowering and grain-filling periods.

Substrate cultivation has been gaining interest from vegetable producers, however technical information for many crops is still recent, such as the gherkin, especially regarding the nutrient solution. This study was developed with the objective of evaluating the performance of three gherkin cultivars (Do Norte, Liso de Calcutá and Liso Gibão) grown in coconut fiber and fertigated with nutrient solutions of different concentrations (50, 75, 100 and 125% of the recommendation for melon), using a randomized block design, in a 3 x 4 factorial scheme, with four repetitions and plots composed of three plants. Growth and production variables were evaluated. In general, cv. Liso de Calcutá produced heavier fruits (35.69 g fruit-1), however cv. Liso Gibão produced an average of 21.6 fruits plant-1, being more productive (542.19 g planta-1). The cultivars Do Norte and Liso de Calcutá were less demanding on nutrients. In order to obtain the highest production of gherkin fruits cultivated in coconut fiber, fertigations must be carried out using nutrient solutions diluted in 50% for the cultivars Do Norte and Liso de Calcutá, while for cv. Liso Gibão it is recommended to use nutrient solution diluted in 75% of the concentration of nutrients recommended for the cultivation of melon.

Made available in DSpace on 2021-06-25T12:19:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-09-19 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Increasingly intensive cropping systems and the introduction of new genetically modified cultivars can lead to a distinct demand for nutrients in soybean crops. This study aims to evaluate the response of two soybean cultivars [with and without tolerance to glyphosate (RR)] to sulfur (S) rates. The experimental design was completely randomized in a 6 x 2 factorial arrangement with four replicates. The treatments consisted of six S rates (0, 10, 20, 40, 80, and 120 mg kg(-1)) and two soybean cultivars from the same breeding program (BRS 317 and BRS 360RR). The increase in S rates resulted in the herbicide sensitive cultivar (BRS 317) having the best physiological indexes (water use efficiency and chlorophyll content) when compared with those of herbicide tolerant cultivar (BRS 360RR), and an increased grain yield (GY), shoot dry weight yield (SDWY), calcium (Ca), boron (B), NO2-N, and iron (Fe) concentration in the leaf tissues. This indicates that the RR gene can cause significant differences in S uptake responses. Univ Estadual Londrina, Dept Crop Sci, Londrina, Parana, Brazil Embrapa Soja, Dept Plant Physiol & Mineral Plant Nutr, Londrina, Parana, Brazil Sao Paulo State Univ, Dept Soil Sci, Dracena, Brazil Sao Paulo State Univ, Dept Crop Sci, Botucatu, SP, Brazil Sao Paulo State Univ, Dept Soil Sci, Dracena, Brazil Sao Paulo State Univ, Dept Crop Sci, Botucatu, SP, Brazil

The objective of this study was to evaluate the efficiency of the use of phosphorus by maize cultivars for the production of green ears. Two experiments were carried out, one in the rainy season (March to June) and the other in the dry period (August to December), both at the Rafael Fernandes Experimental Farm, in the community of Alagoinha, belonging to the Universidade Federal Rural do Semiárido, in the municipality of Mossoró, RN, Brazil. The treatments consisted of a combination of three levels of phosphorus (low, medium and high) and eight corn cultivars (Dona Josélia, Carrapateira, Pontinha, Cruzeta, Potiguar, BRS 2022, Status and AG 1051). A randomized block design was used in a 3 × 8 factorial scheme, with four repetitions. The evaluated characteristics were: number and total mass of green ears, number and mass of tradable, stuffed and depleted green ears, agronomic and physiological efficiency of production of recovery and use of phosphorus. The cultivars showed better productive performance when fertilized with phosphorus. The cultivars Cruzeta, Potiguar, BRS 2022, Status, AG 1051 and Carrapateira were the most efficient in the use of phosphorus to produce green maize. RESUMO Objetivou-se avaliar a eficiência da utilização de fósforo por cultivares de milho para produção de espigas verdes. Foram conduzidos dois experimentos, um no período chuvoso (março a junho) e outro no período seco (agosto a dezembro), ambos na Fazenda Experimental Rafael Fernandes, na comunidade de Alagoinha, pertencente à Universidade Federal Rural do Semiárido, no município de Mossoró, RN. Os tratamentos foram constituídos pela combinação de três níveis de fósforo (baixo, médio e alto) e oito cultivares de milho (Dona Josélia, Carrapateira, Pontinha, Cruzeta, Potiguar, BRS 2022, Status e AG 1051). Foi utilizado o delineamento experimental em blocos ao acaso, em esquema fatorial 3 × 8, com quatro repetições. As características avaliadas foram: número e massa total de espigas verde, número e massa de espigas verdes comercializáveis (empalhadas e despalhadas), eficiências agronômica, fisiológica, de produção de espigas, de recuperação e de utilização do fósforo. As cultivares apresentaram melhor desempenho produtivo quando adubadas com fósforo. As cultivares Cruzeta, Potiguar, BRS 2022, Status, AG 1051 e Carrapateira foram as mais eficientes na utilização do fósforo para a produção de milho verde.

Made available in DSpace on 2020-12-12T02:15:04Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-06-16 The use of applied phosphorus (P) and the uptake of nutrients from the soil by plants can be improved when the fertilizer is combined with the application of humic substances (HS). However, these beneficial effects are inconsistent and can depend on the type of soil. This study was performed to evaluate the effects of the application of HS (0, 1.25, and 7.50 mL pot–1), as Humic HF®, and fertilizer-P (10, 50, 100, and 200 mg P dm–3), as triple superphosphate, on root morphological characteristics, dry matter accumulation, nutrient uptake, and tuber yield of potatoes grown in sandy and clayey soils. Only under low P supply in the sandy soil did the supply of HS, at the rate of 1.25 mL pot–1, increase the plant growth, yield of tubers, and uptake of macronutrients by the plants, without affecting the efficiency of the P fertilization. In the clayey soil, which had a higher organic matter content, the application of HS did not affect plant growth, tuber yield or nutrient uptake. In both soils, P fertilization increased plant growth, tuber yield, and nutrient uptake. The combined application of HS and P increased the root length of potatoes in sandy soil. Department of Crop Science College of Agricultural Sciences São Paulo State University (UNESP) Center for Tropical Roots and Starches São Paulo State University (UNESP) Department of Crop Science College of Agricultural Sciences São Paulo State University (UNESP) Center for Tropical Roots and Starches São Paulo State University (UNESP)

The aim of this study was to evaluate the growth of atmospheric (tankless-bromeliad) and tank (tank-bromeliad) developmental stages of silver vase bromeliad (Aechmea fasciata) as a function of nutrition with different sources and concentrations of nitrogen. The experiment consisted of the fertilization of atmospheric and tank stages of silver vase bromeliad with 50 mL of Hoagland and Arnon n. 1 (1950) solution, supplemented with 0, 15, 30 or 45 mM N of urea, ammonium nitrate or glutamine as nitrogen sources. After 210 days of experimentation, tank and atmospheric stages of silver vase bromeliad did not show significant differences for the variables plant height, rosette and stem diameter, leaf and total fresh mass, and root, leaf and total dry matter masses. Both stages have grown better with 15 mM N of ammonium nitrate and urea, while 45 mM of all N sources were deleterious. Glutamine in the tank occasioned the presence of a film and dark spots lowing the ornamental quality. The agronomic nitrogen use efficiency showed that tank stage use N more efficiently, when fertilized with inorganic form, while atmospheric stage is indifferent for N source.

Made available in DSpace on 2020-12-12T01:56:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-09-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Potassium (K) supply affects the growth and tuber yield of potato (Solanum tuberosum L.) as well as the uptake and removal of certain nutrients. However, information on this is scarce or inconsistent. Thus, this study was undertaken to evaluate the dry matter (DM) accumulation and the uptake and removal of nutrients by potato ‘Agata’ as affected by K fertilizer management (rates and application timings) in tropical clay soils with varied K availability. In soils with low K availability, K fertilization increased (P ≤ 0.05) the biomass of potato plants without differences among management types; however, in soils with medium and high K availability, K fertilizer did not alter the plant DM accumulation. K fertilization increased (P ≤ 0.05) N, K, Ca, Mg, S, B, Mn, and Zn uptake and removal in the soil with low K availability, while in soils with medium and high K availability, K fertilization had less influence on the uptake and removal of nutrients, except that K uptake and removal increased (P ≤ 0.05) under K fertilization, evidencing luxury uptake. In the soil with medium K availability, K application reduced (P ≤ 0.05) Mg uptake by plants, but this effect was not observed in soils with high K availability. Mn uptake and removal increased (P ≤ 0.05) under K fertilization in soils with low and high K availability. The increases in the uptake and removal of almost all nutrients in response to K fertilization were related to the increase in plant DM accumulation, but changes in the concentrations of K and some other nutrients also contributed to their increased uptake and removal. Department of Crop Science College of Agricultural Sciences São Paulo State University (UNESP), Av. Universitária, 3780 Center of Tropical Roots and Starches São Paulo State University (UNESP) Department of Crop Science College of Agricultural Sciences São Paulo State University (UNESP), Av. Universitária, 3780 Center of Tropical Roots and Starches São Paulo State University (UNESP)

The objective of this study was to evaluate the nutritional status of coriander cultivar Verdão under fertigation depths and pulse and continuous drip irrigation. The experiment was conducted in a protected environment at the Universidade Federal Rural de Pernambuco, Recife, PE, Brazil (8° 1’ 6.50” S, 34° 56’ 46” W and altitude of 6.5 m), in the randomized block design in 2 x 5 factorial scheme, with three repetitions. Treatments consisted of five irrigation depths (40, 60, 80, 100 and 120% of crop evapotranspiration - ETc) and two types of fertigation application (pulse and continuous). At 27 days after sowing, the aerial part of 48 plants per plot was collected for subsequent quantification of nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, iron, manganese, copper and zinc concentrations. Pulse fertigation combined with ETc replacement depths below 100% promoted higher leaf concentrations of phosphorus, sulfur, iron and manganese. Continuous fertigation combined with 100% ETc depth induced sulfur deficiency in the crop and, combined with 40% ETc depth, promoted the highest calcium concentration. Regardless of the type of application, ETc replacement depths from 82.7 and 40% provide adequate leaf concentrations of nitrogen and magnesium, respectively. Regardless of the applied depth, pulse fertigation reduced the leaf concentrations of magnesium.

The objective of this study was to evaluate the the ability of foliar application of potassium nitrate (KNO3) to induce water deficit tolerance in sorghum plants (Sorghum bicolor cv. P898012) subjected to water deficit at pre-flowering. The experiment was conducted under greenhouse conditions with 4 treatments: field capacity (FC), water deficit (WD), field capacity + KNO3 (FC + KNO3), and water deficit + KNO3 (WD + KNO3). Two foliar applications of 3% (m/v) KNO3 were made, the first on day zero of stress and the second on the fifth day. All analyses were performed after 12 days of stress (end of stress). Foliar application of KNO3 to irrigated plants led to increases in relative chlorophyll content, photosynthetic rate, stomatal conductance, transpiration, and carboxylation efficiency. It also induced increases in leaf concentrations of P, Mg, S, Cu, and Fe, in addition to height growth. Under water deficit conditions, plants treated with KNO3 presented higher relative chlorophyll content, leaf area, photosynthetic rate, stomatal conductance, transpiration, carboxylation efficiency, and higher levels of P, K, Mg, S, Cu, and Fe than those not treated with KNO3. The morphometry of the root system was not altered by the treatments. In addition, plants treated with KNO3 under water deficit conditions showed higher growth and a grain yield 32.2% higher than those that did not receive KNO3. These results demonstrated that KNO3 applied to the leaves induced water deficit tolerance in sorghum plants subjected to severe water stress at pre-flowering. The objective of this study was to evaluate the the ability of foliar application of potassium nitrate (KNO3) to induce water deficit tolerance in sorghum plants (Sorghum bicolor cv. P898012) subjected to water deficit at pre-flowering. The experiment was conducted under greenhouse conditions with 4 treatments: field capacity (FC), water deficit (WD), field capacity + KNO3 (FC + KNO3), and water deficit + KNO3 (WD + KNO3). Two foliar applications of 3% (m/v) KNO3 were made, the first on day zero of stress and the second on the fifth day. All analyses were performed after 12 days of stress (end of stress). Foliar application of KNO3 to irrigated plants led to increases in relative chlorophyll content, photosynthetic rate, stomatal conductance, transpiration, and carboxylation efficiency. It also induced increases in leaf concentrations of P, Mg, S, Cu, and Fe, in addition to height growth. Under water deficit conditions, plants treated with KNO3 presented higher relative chlorophyll content, leaf area, photosynthetic rate, stomatal conductance, transpiration, carboxylation efficiency, and higher levels of P, K, Mg, S, Cu, and Fe than those not treated with KNO3. The morphometry of the root system was not altered by the treatments. In addition, plants treated with KNO3 under water deficit conditions showed higher growth and a grain yield 32.2% higher than those that did not receive KNO3. These results demonstrated that KNO3 applied to the leaves induced water deficit tolerance in sorghum plants subjected to severe water stress at pre-flowering.

The aim of this study was to establish DRIS (Diagnosis and Recommendation Integrated System) norms and Nutritional Optimal Ranges (NOR) for ‘Rojo Brillante’ Protected Designation of Origin (PDO) ‘Ribera del Xúquer’. The database contained 800 leaf samples collected in different crop phenological stages [after flowering (AF), fruit enlargement (FE), fruit colouring (FC), and harvesting HV)]. DRIS norms (78) were established for macronutrients: N, P, K, Ca, Mg and S; micronutrients B, Cu, Fe, Mn, and Zn and salinity elements: Na and Cl. The Nutrient Balance Index (NBI; the absolute value of the sum of the DRIS indices) was used to determine the optimal sampling period. Fruit enlargement was the period during which persimmon trees were more nutritionally balanced regardless of sprout origin (vegetative or floral) and irrigation type (drip or flood) in orchards

The nutritional management of the coffee clonal garden influences the production and physiological quality and seedlings production of vegetative propagules. Thus, this study aimed to analyze the seedlings’ production from clonal cuttings taken from Coffea canephora mother plants grown with increasing nitrogen mineral doses. The cuttings were taken from C. canephora var. botany Robusta, from the Embrapa Genetic Improvement Program of Rondônia. The mother plants received nitrogen fertilizer at different doses: 0 (Control); 50; 100; 150; 200; 250 and 300 kg of N per hectare divided into 4 applications, during 150 days of orthotropic stems growth (shoots). The following parameters were evaluated: Dry mass of cuttings, nutritional content of cuttings, and seedlings production, with growth analysis at 0, 48, 61, 80, 101, 122, 143, and 164 days after staking (DAS) and analysis of vegetative characteristics at 122 DAS. The nitrogen fertilization in the mother plant resulted in the variation of macronutrient accumulation in cuttings, but the order K> N> Ca> P> Mg> S was maintained, regardless of N dose. In addition, a positive correlation between nitrogen doses and dry matter accumulation, as well as the physiological quality of seedlings was identified. RESUMO: O manejo nutricional do jardim clonal de cafeeiros influencia a produção e qualidade fisiológica dos propágulos vegetativos e na produção de mudas. Assim, objetivou-se analisar a produção de mudas a partir de estacas clonais retiradas de plantas matrizes de Coffea canephora cultivada com doses crescentes de nitrogênio mineral. As estacas foram retiradas de plantas matrizes de cafeeiros C. canephora var. botânica Robusta, do Programa de Melhoramento Genético da Embrapa-RO. As plantas matrizes receberam adubação nitrogenada nas doses: 0 (Controle); 50; 100; 150; 200; 250 e 300 kg de N por hectare, parceladas em quatro aplicações, durante 150 dias de crescimento das hastes ortotrópica (brotos). Os seguintes parâmetros foram avaliados: massa seca das estacas, conteúdo nutricional das estacas e a produção de mudas, com análise de crescimento, aos zero, 48, 61, 80, 101, 122, 143 e 164 dias após o estaqueamento (DAE) e a análise das características vegetativas, aos 122 DAE. A adubação nitrogenada na planta matriz resultou na variação do acúmulo de macronutrientes nas estacas, mas a ordem K > N > Ca > P > Mg > S foi mantida independente da dose de N. Além disso, foi verificado que há correlação positiva entre as doses de nitrogênio e o acúmulo de massa seca, assim como, a qualidade fisiológica das mudas.

Made available in DSpace on 2022-05-01T11:07:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-01-01 Nitrogen (N) plays a fundamental role in the initial growth of the Arabica coffee plant whereas silicon (Si) is key in enhancing performance of the plant through promoting N-use efficiency (NUE). This study evaluated the effect of N rates (0, 40, 80, and 160 mg dm−3) and Si application methods (no Si, soil-applied soluble Si, and foliar-applied soluble Si) on growth, dry matter (DM) accumulation, N and Si uptake, and NUE of young Arabica coffee plants under greenhouse conditions. Nitrogen fertilization increased the height, number of plagiotropic branches, nodes in plagiotropic branches and leaves, leaf area, root length, DM production, and N and Si uptake of the coffee plant. Results revealed that both soil and foliar application of Si increased plant height. In the presence of the highest N rates, the soil application of Si increased the number of nodes in the plagiotropic branches, length and DM of roots, and Si uptake by coffee plants. In addition, soil application of Si increased NUE indexes, an indication that it can improve performance of the young coffee plants in the field. Department of Crop Science College of Agricultural Sciences São Paulo State University (UNESP), São Paulo ICL América do Sul São Paulo Midwest Regional/SAA São Paulo Agency of Agribusiness Technology (APTA) Bauru Department of Agricultural Sciences and Technology School of Agriculture and Enterprise Development Kenyatta University Department of Crop Science College of Agricultural Sciences São Paulo State University (UNESP), São Paulo

Made available in DSpace on 2022-04-29T08:41:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-01-01 Crop nitrogen (N) status monitoring is required as a decision-making tool to optimize N management of current potato cultivars (Solanum tuberosum L.). Field experiments were conducted to assess the leaf N concentration (LNC) as a diagnostic tool of the N status of potatoes grown in tropical environments of southeastern Brazil. Treatments consisted of two cultivars (Agata and Electra) and five N managements, which varied in rates (0–320 kg N ha−1) and application timings. The LNC was monitored in the most recently matured leaves from 10 to 59 days after emergence (DAE). Total dry matter (DM) biomass and N uptake at vine killing (~ 85 DAE) and fresh tuber yield were also measured. High variation was observed in total DM biomass (3.53–9.75 Mg ha−1), N uptake (41–224 kg ha−1), and tuber yield (14–61 Mg ha−1), with most of the variations ascribed to N management (60–90%). High variation in LNC (68.0–30.8 g kg−1) was attributed to N management and leaf sampling date. Relative tuber yields were positively related to the LNC values across the potato cycle. The threshold value of LNC to reach 95% of maximum tuber yield linearly decreased from 17 to 59 DAE (i.e., from 283 to 999 cumulative growing degree days after emergence) in both potato cultivars. The reference values of LNC to ensure N sufficiency varied from 63.8 g kg−1 (17 DAE) to 52.6 g kg−1 (59 DAE). These outcomes can guide growers to adjust the supply of N according to potato N requirements up to mid-season, preventing the application of excess N fertilizer. Department of Crop Science College of Agricultural Sciences São Paulo State University (UNESP), Av. Universitária, 3780, SP Center of Tropical Roots and Starches São Paulo State University (UNESP), SP Institute of Plant Production and Protection Universidad Austral de Chile, Campus Isla Teja Department of Soil Water and Climate University of Minnesota Rural Development Institute of Paraná - IAPAR-EMATER (IDR-Paraná), PR Department of Crop Science College of Agricultural Sciences São Paulo State University (UNESP), Av. Universitária, 3780, SP Center of Tropical Roots and Starches São Paulo State University (UNESP), SP

Potassium is a mineral nutrient that affects the growth and quality of pineapple fruits. This study aimed to evaluate the quality of ‘Vitória’ pineapple fruits submitted to application of potassium doses. The experiment was carried out from May 2017 to November 2018, in the municipality of São Francisco do Itabapoana (RJ), Brazil. The design was randomized blocks, with four replicates. Treatments were five K2O doses: 0; 6; 12; 18 and 24 g plant-1, applied as KCl, split into two applications after flower induction. Fruit and crown fresh masses, fruit and crown diameters, fruit and crown lengths, titratable acidity, soluble solids, vitamin C, juice pH and soluble solids/titratable acidity ratio were evaluated. Potassium fertilization promoted greater fruit length, diameter and mass. Titratable acidity, soluble solids and vitamin C values increased linearly as a function of potassium doses. Potassium fertilization improves the quality of ‘Vitória’ pineapple fruits under field conditions. Resumo O potássio é um nutriente que afeta o crescimento e a qualidade dos frutos do abacaxizeiro. O estudo objetivou avaliar a qualidade de frutos em abacaxizeiro ‘Vitória’ submetido à aplicação de doses de potássio. O experimento foi realizado de maio de 2017 a novembro de 2018, em São Francisco do Itabapoana (RJ), Brasil. O delineamento foi em blocos ao acaso, com quatro repetições. Os tratamentos foram cinco doses de K2O: 0; 6; 12; 18 e 24 g planta-1, aplicadas na forma de KCl, parceladas em duas aplicações, após a indução floral. As massas frescas do fruto e da coroa, os diâmetros do fruto e do cilindro central,os comprimentos do fruto e da coroa, a acidez titulável, os sólidos solúveis, a vitamina C, o pH do suco e a relação sólidos solúveis/acidez titulável foram avaliados. A adubação potássica promoveu maiores comprimento, diâmetro e massa de fruto. Os valores de acidez titulável, dos sólidos solúveis e da vitamina C aumentaram linearmente em função das doses de potássio. A adubação potássica promove a melhoria da qualidade dos frutos de abacaxizeiro ‘Vitória’ em condições de campo.

The agronomic biofortification of vegetables is a strategy for increasing the concentration of iron (Fe) in food and, consequently, the intake of this micronutrient by the population. When in deficiency, it can cause anemia—a pathology that affects millions of people. Soil-less cultivation is an important cropping system, but there are no studies on how Fe concentrations in a nutrient solution can promote biofortification and affect the quality of collard greens; this is the aim of the present study. For this purpose, five Fe concentrations (2, 4, 6, 8 and 10 mg L−1) were evaluated. Increasing the Fe concentration in the nutrient solution increased the leaf Fe content and decreased the leaf contents of cationic nutrients, without affecting yield. Photosynthetic pigment contents were positively affected by Fe concentrations, while ascorbic acid decreased. There was efficient biofortification of collard greens leaves from 4 mg L−1 Fe, and a higher nutritional quality of leaves was observed at Fe concentrations of 8 mg L−1.

Hairy stork’s-bill (Erodium crassifolium) (HSB) is one of the few Geraniaceae species that produce tubers. While HSB tubers were occasionally used as a food source by desert nomads, they have not yet been taken up in the modern kitchen. Recently, HSB tubers were recognized as harboring potential to become an industrial pharmaceutical crop. The objective of this study was to determine a set of agricultural practices that would maximize the yield of the bioactive compounds of the present HSB genetic material. A generous and consistent irrigation regime of about 700 mm season−1 increased tuber yield and size. The optimal plant density on sandy soils was 16–20 plants m−2. Mineral nutrition, applied through fertigation, increased tuber yield from 0.6 to almost 1 kg m−2. Source-sink manipulations (consistent pruning of the reproductive organs) almost doubled the tuber yield. During 10 years of research, the adopted agricultural practices increased yield by an order of magnitude (from about 0.2–2.0 kg m−2) without any dilution of the bioactive compounds. Nevertheless, further research and development are required to achieve HSB potential as an industrial field crop, including selection and breeding of outstanding infertile clones, optimization of fertigation, and development of various concrete pharmaceutical products.

Understanding the relationship between the levels of nutrients in the soil and those found in the plant is of fundamental importance for site-specific fertility management in mango (Mangifera indica L.) crop fields. This study aimed to evaluate the spatial distribution of macronutrient contents both in the soil and in the leaf and their correlations in commercial mango orchards under semiarid region conditions and to delimit the management zones using soil and leaf data. The experiment was carried out in three commercial areas in San Francisco Valley, Brazil, cultivated with irrigated mango. Soil samples were collected in 0-0.2 and 0.2-0.4 m depths as well as leaf samples following sample grids. Ca, Mg, K, P, and N contents from soil and leaf samples were determined. Descriptive and geostatistics analyses were performed. Co-kriging was used for the delimitation of management zones. Positive spatial correlations were obtained between soil Ca2+ and leaf Ca contents (R2 = 0.80-0.93), soil K+ and leaf K contents (R2 = 0.35-0.61), and soil Mg2+ and leaf P contents (R2 = 0.51). Negative correlations were observed for soil Mg2+ and leaf Ca contents(R2 = 0.79-0.93) and soil Mg2+ and leaf K contents (R2 = 0.98). The soil 0-0.2 m depth had the greatest influence on mango Ca and K uptake. The negative correlation between soil Mg2+ and leaf Ca shows the competition existing in the plant uptake process. It was possible to delimit specific management zones using co-kriging for the three areas using soil and leaf data. Resumo Compreender a relação entre os níveis de nutrientes no solo e aqueles encontrados na planta é de fundamental importância para o manejo específico da fertilidade em áreas de cultivo de mangueira (Mangifera indica L.). O objetivo deste estudo foi avaliar a distribuição espacial dos teores de macronutrientes no solo e na folha, e suas correlações em pomares comerciais de manga, em condições de região semiárida, e delimitar as zonas de manejo utilizando dados de solo e de folha. O experimento foi realizado em três áreas comerciais do Vale do São Francisco, Brasil, cultivadas com manga irrigada. Amostras de solo foram coletadas nas profundidades de 0-0,2 e 0,2-0,4 m, bem como amostras de folhas, seguindo malhas amostrais. Foram determinados os teores de Ca, Mg, K, P e N das amostras de solo e de folha. Foram realizadas análises descritivas e geoestatísticas. A co-krigagem foi usada para a delimitação de zonas de manejo. Correlações espaciais positivas foram obtidas entre Ca2+ no solo e Ca foliar (R2 = 0,80-0,93), K+ no solo e K foliar (R2 = 0,35-0,61) e Mg2+ no solo e P foliar (R2 = 0,51). Correlações negativas foram observadas para o Mg2+ no solo e Ca foliar (R2 = 0,79-0,93) e Mg2+ no solo e K foliar (R2 = 0,98). O solo de 0-0,2 m de profundidade teve a maior influência na absorção de Ca2+ e K+ pelas plantas. A correlação negativa entre Mg2+ do solo e Ca foliar mostra a competição existente no processo de absorção das plantas. Foi possível delimitar zonas de manejo específicas utilizando cokrigagem para as três áreas, usando dados de solo e de folha.

Resumo Com objetivo de avaliar os efeitos da salinidade do solo sobre a nutrição mineral da variedade de milho UFVM 100, conduziu-se um experimento em lisímetros de drenagem sob condições de casa de vegetação, montado em delineamento inteiramente casualizado com sete tratamentos, sendo um irrigado com água doce e sem lixiviação e seis irrigados com água salina de 1,2 dS m-1, com frações de lixiviação de 40, 30, 20, 15, 10 e 5% da lâmina de irrigação aplicada, e três repetições. Os efeitos da salinidade do solo sobre a nutrição mineral da cultura do milho foram avaliados, determinando-se o teor foliar dos macronutrientes aniônicos e suas relações com o Cl aos 120 dias após o plantio, na fase fenológica correspondente à maturação fisiológica. Na variedade avaliada, o aumento da salinidade do solo elevou os teores foliares de cloro e as relações Cl/N, Cl/P, Cl/S, seguidos da redução dos teores de nitrogênio, fósforo e enxofre. Abstract Aiming at the evaluation of the soil salinity effects upon the mineral nutrition of the maize (UFVM 100 cv.), an experiment was conducted in drainage lysimeters, under greenhouse conditions. A completely randomized design was used with seven treatments: one irrigated with fresh water without leaching and six irrigated with saline water of 1.2 dS m-1 with leaching fractions of 40, 30, 20, 15, 10 and 5% of the irrigation depth applied, and three replicaticns. The effects of the soil salinity upon the mineral nutrition of the maize crop were evaluated, by determining the leaf content of the anionic macronutrients and their relationships with Cl at 120 days after planting, at the phenological phase corresponding to the physiological maturation. For the evaluated variety, the increase in the soil salinity elevated the leaf contents of chloride and the relations Cl/N, Cl/P and Cl/S, followed by reduction in the contents of nitrogen, phosphorus and sulfur.

The use of raw materials of Jatropha curcas L. to produce bio-fuel is of increasing interest in Colombia; little information is available on this species as a crop. This research evaluated plant height (Hp) and basal stem diameter (BSD) of J. curcas as affected by different rates of nitrogen (N) and potassium (K) during the first 435 days of growth (DAP). The experiment involved a repeated measures design with inter-subject factors of fertilization (N dose, K2O dose nested in N dose) and an intra-subject factor of evaluation time. The Hp varied both as a function of N dose and the K2O dose nested in the N dose. The tallest plants were obtained with 150 kg ha-1 N and 180 kg ha-1 K2O treatment. With simultaneous confidence intervals of Bonferroni, we compared the evaluation times indicating for Hp non-overlapping intervals at 435 DAP (150 kg ha-1 N and remaining levels of this factor) and at 255 DAP (180 kg ha-1 K2O and remaining levels of this factor). The application of N fertilizers resulted in thicker stems as compared to control plants. Mathematical predictive models were obtained for Hp and BSD in J. curcas using a multiple regression analysis. These models permitted future rapid and non-invasive predictions for J. curcas growth in the field. RESUMEN El uso de materias primas vegetales de Jatropha curcas L. para producir biocombustibles es de creciente interés en Colombia, mientras que hay poca información disponible sobre esta especie como cultivo. Este estudio evaluó la altura de la planta (Hp) y el diámetro del tallo basal (BSD) de J. curcas según lo afectado por las diferentes dosis de nitrógeno (N) y potasio (K) durante los primeros 435 días de crecimiento (DAP). El experimento incluyó un diseño de medidas repetidas con factores de fertilización entre sujetos (dosis de N, dosis de K2O anidadas en la dosis de N) y un factor de tiempo de evaluación. La Hp varió tanto en función de la dosis de N como de la dosis de K2O anidada en la dosis de N, obteniéndose las plantas más altas con aplicación de 150 kg ha-1 N y 180 kg ha-1 K2O. Con los intervalos de confianza simultáneos de Bonferroni, se compararon los tiempos de evaluación indicando para Hp intervalos no superpuestos a 435 DAP (150 kg ha-1 N y niveles restantes de este factor) y a 255 DAP (180 kg ha-1 K2O y el resto niveles de este factor). La aplicación de fertilizantes N dio como resultado tallos más gruesos en comparación con las plantas de control. Los modelos de predicción matemática se obtuvieron para Hp y BSD en J. curcas utilizando un análisis de regresión múltiple. Estos modelos permiten en futuro predicciones rápidas y no invasivas del crecimiento de J. curcas en campo.

Salinity is one of the main agricultural problems faced, and may negatively influence plant development. However, studies have shown that in protected environments and under the application of organic fertilizers, deleterious effects are mitigated. In this context, the objective of this study was to evaluate the effects of irrigation water salinity on mineral nutrition in noni plants grown in two environments and bovine manure application. The statistical design was a randomized block design arranged in split-split plot scheme, with five repetitions. The plots consisted of the cultivation environments (greenhouse and open field), the subplots formed by salinity levels of irrigation water (ECw: 0.3, 1.5, 3.0, 4.5 and 6.0 dS m-1), and the subsubplots were represented by the absence and presence of organic matter, with experimental unit consisting of three pots totaling 300 pots. The nitrogen, potassium, calcium, magnesium, sodium and chloride concentrations were determined in plant leaves. It was verified that the foliar concentrations of Ca2+, Mg2+, Na+ and Cl- and the ratio Na/K was increased with increasing salinity of the irrigation water, being the largest increments observed in the open field. Organic matter is not much relevant in attenuating the deleterious effects of irrigation water on the concentration of leaf nutrient in noni plants. The maintenance of lower values of Na/K ratio in the treatment with organic matter is a positive factor that can attenuate the effects of salt stress on cell metabolism. RESUMO A salinidade é um dos principais problemas agrícolas enfrentados, podendo influenciar negativamente o desenvolvimento vegetal. Porém, estudos têm demonstrado que em ambientes protegidos e sob aplicação de adubos orgânicos, os efeitos deletérios são amenizados. Nesse contexto, objetivou-se avaliar os efeitos da salinidade da água de irrigação sobre a nutrição mineral em plantas de noni, cultivadas em dois ambientes sob adubação com esterco bovino. O delineamento experimental foi em blocos ao acaso, disposto no esquema de parcelas subsubdivididas com cinco repetições. As parcelas foram constituídas pelos ambientes de cultivo (céu aberto e telado), as subparcelas pelas salinidades da água de irrigação (0,3; 1,5; 3,0; 4,5 e 6,0 dS m-1) e as subsubparcelas pela ausência e presença de matéria orgânica, com a unidade experimental consistindo de três vasos, totalizando 300 vasos. Foram determinados as concentrações foliares de nitrogênio, potássio, cálcio, magnésio, sódio e cloreto. Verificou-se que os teores foliares de Ca2+, Mg2+, Na+ e Cl- e a razão Na/K aumentaram com o aumento da salinidade da água de irrigação, sendo os maiores incrementos observados no ambiente a céu aberto. A matéria orgânica não é relevante o suficiente para atenuar os efeitos deletérios da água de irrigação na concentração de nutrientes foliares em plantas de noni. A manutenção de menores valores da razão Na/K no tratamento com matéria orgânica é um fator positivo que pode atenuar os efeitos do estresse salino no metabolismo celular.

Made available in DSpace on 2019-10-06T16:12:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-02-07 Silicon (Si) can increase phosphorus (P) use efficiency (PUE) by increasing P availability in the soil and altering P metabolism in the plant, thus resulting in improved yield under low soil P conditions. The objective was to evaluate the effect of P (10, 50, 100, and 200 mg dm −3 ) and Si (0, 50, and 200 mg dm −3 ) interrelationship on P and Si uptake by plants, forms of P in leaves and tubers, plant growth, and tuber yield of potato plants. Silicon supply increased organic and inorganic P in the leaves. At low soil P rates, Si also increased organic P in the tubers. However, alterations in the P metabolism of potato plants with Si supply did not promote significant changes in dry matter (DM) production and tuber yield. Phosphate fertilization increased growth and yield of plants. Silicon uptake by the plants were also increased by phosphate fertilization with soil Si supply. Department of Crop Science College of Agricultural Sciences São Paulo State University (UNESP) Center for Tropical Roots and Starches São Paulo State University (UNESP) Department of Crop and Soil Sciences University of Georgia Department of Crop Science College of Agricultural Sciences São Paulo State University (UNESP) Center for Tropical Roots and Starches São Paulo State University (UNESP)

Biomass sorghum [Sorghum bicolor (L.) Moench] is a very promising renewable source to produce energy obtained by cogeneration and fermentation processes. However, some aspects of the fertilizer management for this crop should be better understood. This study aimed to determine the accumulation progress of dry matter and macro and micronutrients in phenological stages of the biomass sorghum (Palo Alto 2562) crop, as well as to establish the accumulation order. The experiment was performed in a randomized block design, with four replicates. In order to determine the dry matter and nutrient accumulation curves, the plants were sampled in nine phenological stages (V1, V3, V5, V7, V9, V11, booting, flowering and harvest). Dry matter and N, P, K, Ca, Mg, S, Cu, Fe, Mn and Zn accumulations were analyzed. The maximum dry matter accumulation was 24,853 kg ha-1. K was the nutrient absorbed in the highest amount (447 kg ha-1), what demonstrates the high capacity of the plant to absorb this nutrient. N was the second most accumulated nutrient by the plant (289 kg ha-1) and its absorption pattern suggests that it should be supplied up to the V7 stage. It was also possible to conclude that the order of extraction and accumulation of macro and micronutrients for the biomass sorghum crops is: K > N > Ca > Mg > S > P > Fe > Zn > Mn > Cu. RESUMO O sorgo biomassa [Sorghum bicolor (L.) Moench] é uma fonte renovável muito promissora para a produção de energia obtida por processos de cogeração e fermentação. Alguns aspectos do manejo da adubação para esta cultura, no entanto, devem ser melhor entendidos. Objetivou-se determinar a marcha de acúmulo de massa seca e de macro e micronutrientes em estádios fenológicos da cultura do sorgo biomassa (Palo Alto 2562), bem como estabelecer a ordem de acúmulo. O delineamento experimental utilizado foi o de blocos ao acaso, com quatro repetições. A fim de determinar a curva de acúmulo de massa seca e nutrientes, as plantas foram amostradas em nove estádios fenológicos (V1, V3, V5, V7, V9, V11, emborrachamento, florescimento e colheita). Analisou-se o acúmulo de massa seca e de N, P, K, Ca, Mg, S, Cu, Fe, Mn e Zn. O máximo acúmulo de massa seca foi de 24.853 kg ha-1. O K foi o nutriente absorvido em maior quantidade (447 kg ha-1), o que demonstra a alta capacidade da planta em absorver tal nutriente. O N foi o segundo nutriente mais acumulado pela planta (289 kg ha-1), e o seu padrão de absorção sugere que o seu fornecimento deve ser realizado até o estádio V7. Conclui-se, ainda, que a ordem de extração e acúmulo de macro e micronutrientes para a cultura do sorgo biomassa é a seguinte: K > N > Ca > Mg > S > P > Fe > Zn > Mn > Cu.

HIGHLIGHTS Irrigation using water with electrical conductivity above 2.5 dS m-1 is not adequate for ‘Paulistinha’ cowpea. Increment in phosphorus dose does not increase phosphorus content in cowpea plant. Under salt stress conditions, cowpea plants require lower doses of phosphorus. RESUMO Os problemas de salinização da água e do solo são cada vez mais frequentes em regiões áridas e semiáridas, sendo necessária a adoção de tecnologias que viabilizem o uso desses recursos naturais na agricultura, permitindo que haja desenvolvimento vegetal satisfatório. Com isso, objetivou-se estudar os efeitos da irrigação com água salina associada a doses de fósforo sobre a salinidade do solo e acúmulo de fitomassa e o teor de nutrientes em plantas de feijão-caupi. A pesquisa foi realizada em casa de vegetação usando o delineamento de blocos casualizados em esquema fatorial 5 x 3 constituído de cinco condutividades elétricas da água de irrigação (0,5; 1,5; 2,5; 3,5 e 4,5 dS m-1) e três doses de fósforo (60, 100 e 140% da dose recomendada - 60 kg P2O5 ha-1), com cinco repetições. As plantas foram cultivadas em lisímetros de 8 dm3, até à fase de floração, e nesse período foi avaliado a salinidade do solo, o acúmulo de fitomassa e os teores de nutrientes no tecido vegetal. A irrigação com água com condutividade elétrica acima de 2,5 dS m-1 elevou a salinidade do solo e teor de sódio nos tecidos a níveis tóxicos, reduzindo a fitomassa e os teores de macronutrientes no tecido vegetal do feijão-caupi, com exceção do nitrogênio. A aplicação de 60% da dose recomendada de fósforo para o feijão-caupi melhora a homeostase iônica da cultura, aumentando a absorção de potássio e cálcio, porém sem diminuir os efeitos deletérios da alta salinidade no acúmulo de fitomassa.

An application of a balanced nutrition will improve the soil as well as enhance the yield of naranjilla (Solanum quitoense Lam.) grown in the Ecuadorian Amazon. A field experiment was carried out in Palora, 16 de Agosto (Morona Santiago province) and Fátima (Pastaza province) to find which variables are related with the yield of the naranjilla crop and the yield response when the crop receives complete nutrition with N, P, K, Ca, Mg, and S plus lime and with the omission of each of these nutrients. A Random Complete Block Design with three replications was used in the three environments. The naranjilla crop had higher yields (18.14 Mg ha−1) in the complete treatments (N, P, K, Ca, Mg, and S) and without S and Mg, consequently, these two last nutrients did not limit the production. When N, P, K, and Ca were not applied, the yields fell to 14.62 Mg ha−1. The main environmental effect showed that Palora had the highest fruit yields (19.73 Mg ha−1), followed by 16 de Agosto (13.57 Mg ha−1) and finally Fátima with 11.04 (Mg ha−1). These preliminary results showed that with the treatments without S (18.55 Mg ha−1), without Mg (18.42 Mg ha−1) and complete (17.46 Mg ha−1) the highest yields were obtained, consequently, the production was not affected by the absence of these elements, the opposite happened when N, P, K, and Ca were not present.

The modification of water management in the Conilon coffee (Coffea canephora) crop is a possible strategy to improve nutritional management efficiency and ensure better use of the genotypes for regions of transitional altitude. The objective of this study was to evaluate the nutritional characteristics of 27 genotypes of C. canephora and submit them to two water management schemes in soil. The goal was to find evidence of higher leaf contents, exports, and nutrient recycling potential in the productive branches of various genotypes. The experiment was carried out in a randomized block design with three replications in a split-plot scheme. The treatment consisted of 27 genotypes of C. canephora and two water management schemes in soil (“Irrigated” and “Rainfed”). Nutritional content in leaves, exported by fruits, and pruned (leaves and stem of plagiotropic branches) recyclable contents were evaluated for nitrogen, phosphorus, potassium, calcium, and magnesium. Variations were observed among genotypes for all the parameters evaluated in both water management in soil. However, significant homogeneous groups were formed among the genotypes in the irrigated management. Furthermore, the genotypes showed distinct nutritional characteristics in response to water management in the soil. Genotypes 108 and 302 had higher nutritional content and were exported by fruits, regardless of soil water management. RESUMO A modificação do manejo hídrico na cultura do café Conilon (Coffea canephora) pode ser uma estratégia para melhorar a eficiência do manejo nutricional e garantir um melhor aproveitamento por parte dos genótipos para região de altitude de transição. O objetivo do estudo foi avaliar as características nutricionais de 27 genótipos de C. canephora, submetidos a dois manejos de água no solo, visando identificar genótipos que apresentam evidências de maiores teores foliares, exportações e potencial de reciclagem de nutrientes em seus ramos produtivos. O experimento foi conduzido em esquema de parcelas subdividida, em delineamento de blocos casualizados, com três repetições. Os tratamentos consistiram nos 27 genótipos de C. canephora e dois manejos de água no solo (“Irrigado” e “Suprido apenas pela chuva”). Foram avaliados os teores nutricionais foliares, os conteúdos nutricionais exportados pelos frutos e os conteúdos nutricionais potencialmente recicláveis após a poda (folhas e caule dos ramos plagiotrópicos), dos macronutrientes: nitrogênio, fósforo, potássio, cálcio e magnésio. Houve diferenciação entre os genótipos para todas as características avaliadas em ambos os manejos de água no solo. Porém, houve formação de um maior número de grupos homogêneos entre os genótipos no manejo irrigado. Os genótipos apresentaram distinção nas características nutricionais em resposta aos manejos de água no solo. Os genótipos 108 e 302 acumularam maiores conteúdos nutricionais exportado pelos frutos, independentemente do manejo de água no solo.

We carried out greenhouse experiment to evaluate the effect of silicon (Si) on growth and mineral nutrition of yellow passion fruit (Passiflora edulis) submitted to saline stress in a nutritive solution. The experiment comprised a completely randomized design in a 5x4 factorial scheme: five NaCl concentrations (0; 7.5; 15; 30 and 60 mmol L-1) and four SiO2 concentrations (0; 0.5; 1.0 and 1.5 mmol L-1) with four replicates. At the end of 35 days, we measured stem diameter, leaves, stem, and roots dry matter, as well as the macronutrient, Na, Cl, and Si leaf accumulation in plants. In most cases, the increase in NaCl supply in a nutritive solution reduced the dry matter of roots, stem, and leaves. The SiO2 supply attenuated the effect on higher tested saline stress (30 and 60 mmol L-1 NaCl) on roots and stem dry matter. The application of 0.5 mmol L-1 of SiO2 reduced the deleterious effect of salinity on all macronutrients absorption in yellow passion fruit cultivated in a nutritive solution.

International audience; In Ecuador, oil palm plantations from the Quinindé-Quevedo region are subject to El Niño/Southern Oscillation (ENSO) with a preponderance of La Niña weather conditions. With more than 2,000 mm, the total annual rainfall is theoretically non-limiting but, with only 1,000 h, the total annual sunshine is well below the 1,800 h minimum recommended. Starting in the 1970s, the frequent occurrence of frond yellowing symptoms in the region became a recurrent worry for growers, convinced that they were facing the expression of a mineral deficiency. In this study, we used experimental results to examine the actual role of mineral nutrition in yellowing manifestation. We described the effects of two El Niño events (1982/1983 and 1997/1998) on climate variables and analysed their putative consequences on palm physiological functioning that could explain the observed foliage recovery. Our analysis led us to conclude that a direct mineral deficiency was not involved, as the soil reserves for the main nutrients were not to blame. We rejected the most frequently proposed hypothesis, whereby yellowing is caused by magnesium deficiency. Our study revealed the key role played by nitrogen, the best indicator of yellowing. Variations in N status appear to be linked to the same factors that determine the symptoms and we opted for the hypothesis of physiological disruption generated by low solar radiation levels under normal conditions. The study also reveals the need to consider specific optimum contents for N and Mg and to adjust fertilizer recommendations to local climate conditions.; En Equateur, les plantations de palmiers à huile de la région Quinindé-Quevedo sont soumises au phénomène El Niño/Oscillation australe (ENSO) avec une prépondérance des conditions climatiques de La Niña. Avec plus de 2 000 mm, le total annuel des précipitations est théoriquement non limitant mais, avec seulement 1 000 h, l’ensoleillement total annuel est très inférieur au minimum de 1 800 h recommandé. A partir des années 1970, l’apparition fréquente de symptômes de jaunissement des feuilles dans la région est devenue une préoccupation récurrente des planteurs, convaincus d’être confrontés à l’expression d’une déficience minérale. Dans cette étude, nous avons utilisé des résultats expérimentaux pour examiner le rôle réel de la nutrition minérale dans la manifestation du jaunissement. Nous avons décrit les effets de deux occurrences d’El Niño (1982/1983 et 1997/1998) sur les variables climatiques et analysé leurs conséquences supposées sur le fonctionnement physiologique des palmiers qui pourraient expliquer la rémission observée du feuillage. Notre analyse nous a permis de conclure à l’absence d’une déficience minérale directe, les réserves du sol en éléments majeurs n’étant pas en cause. Nous avons rejeté l’hypothèse la plus fréquemment proposée, selon laquelle le jaunissement serait dû à une déficience en magnésium. Notre étude a révélé le rôle clé de l’azote, meilleur indicateur du jaunissement. Les variations du statut azoté semblent être liées aux mêmes facteurs que ceux qui déterminent les symptômes et nous avons opté pour l’hypothèse d’une perturbation physiologique générée par un faible rayonnement solaire en conditions normales. L’étude révèle également la nécessité de retenir des teneurs optimales spécifiques pour N et Mg et d’ajuster les recommandations de fertilisation aux conditions climatiques locales.

The artificial flowering induction in mango tree is the most important crop management in mango orchards and requires greater attention from growers. The management involves three steps: stoppage of plant growth, branch maturation and flowering induction with nitrates. The first stage starts with the application of paclobutrazol to the soil. However, problems with the use of excessive concentrations are common and lead to the accumulation of residues in the soil. In addition, the use of paclobutrazol is not allowed in organic agriculture. Therefore, this review article aimed to compile information about the updates and efforts to solve these problems in conventional mango crops, as well as identify alternatives for its organic management. In conventional orchards, the application of fulvic acids in association with paclobutrazol, as an alternative to the single use of paclobutrazol, was identified as a way to improve the absorption of the product by plants and, consequently, reduce the concentrations and residues in the soil. Researches involving pruning, girdling, fertilization and irrigation should be developed as an alternative to the use of paclobutrazol for the organic crop system of mango cultivars in tropical and subtropical regions. RESUMO A indução ao florescimento artificial em mangueira é o manejo cultural mais importante em pomares e requer maior atenção dos produtores. O manejo envolve três etapas: paralisação do crescimento das plantas, maturação dos ramos e indução ao florescimento com nitratos. A primeira etapa começa com a aplicação de paclobutrazol ao solo. Porém, são comuns problemas com o uso de concentrações excessivas, que levam ao acúmulo de resíduos no solo. Além disso, o uso de paclobutrazol não é permitido na agricultura orgânica. Objetivou-se, neste artigo de revisão, compilar informações sobre as atualizações e esforços para solucionar esses problemas em lavouras convencionais de manga, bem como identificar alternativas para o seu manejo orgânico. Em pomares convencionais, a aplicação de ácidos fúlvicos em associação a paclobutrazol, como alternativa ao uso exclusivo de paclobutrazol, foi identificada como forma de melhorar a absorção do produto pelas plantas e, consequentemente, reduzir as concentrações e resíduos no solo. Pesquisas envolvendo poda, anelamento, fertilização e irrigação devem ser desenvolvidas como alternativa ao uso de paclobutrazol para o cultivo orgânico de cultivares de manga em regiões tropicais e subtropicais.

The use of Azospirillum brasilense has the potential to improve plant nitrogen (N) use efficiency, while a better understanding of alternative management practices with inoculation is necessary. The aim was to examine the effects of the leaf application of A. brasilense in association with nitrogen fertilization on the wheat crop. The experiment was conducted in Lidianópolis, Paraná, Brazil, in a completely randomized block design with four replications. The treatments included four doses of A. brasilense for leaf application (0, 200, 400, and 600 ml ha-1) and four doses of N (0, 40, 80, and 120 kg N ha-1). The nutritional content, yield components, quality, and yield of the wheat crop were evaluated. There was no interaction among the factors, nor did the treatments have an isolated effect on spike length, the number of spikelets per spike, spikes per m2, thousand grain weight, and test weight. However, doses of A. brasilense increased calcium and magnesium absorption at 283 and 380 ml ha-1, respectively. Similarly, nitrogen application increased the content of calcium, magnesium, and copper in the leaf at 61, 47, and 49 kg N ha-1, respectively. Nitrogen also increased the number of grains per spike and yield at 56 and 54 kg N ha-1, respectively. Yield correlated with the number of grains per spike and the manganese and copper content in the leaf. The results demonstrate that the inoculation of leaves with A. brasilense favored a higher absorption of divalent cationic macronutrients and that N was fundamental to increasing the yield, with the best responses observed between 47 and 61 kg ha-1.

Cowpea (Vigna unguiculata) crops produce a poor yield in northeastern Brazil compared to the other regions. The goal of this study was to assess the effects of irrigated cropping systems and sowing seasons on cowpea yield and profitability in Vitória da Conquista, Bahia, Brazil. Field studies were performed in four experiments during the rainy and dry seasons during 2016/2017 and 2017/2018, which denoted harvests 1, 2, 3, and 4, respectively. A randomized block design was used for each experiment with four replicates and the following treatments for cropping systems: (1) manual weeding; (2) liming and manual weeding; (3) liming and phosphorus (P) fertilization at sowing, nitrogen (N) and potassium (K) topdressing fertilization, and chemical weed control; (4) liming and P fertilization at sowing, K topdressing fertilization, rhizobia inoculation, and chemical weed control; (5) liming and P fertilization at sowing, N and K topdressing fertilization, rhizobia inoculation, and chemical weed control; and (6) seed pretreatment with cobalt (Co) and molybdenum (Mo), liming and P fertilization at sowing, N and K topdressing fertilization, rhizobia inoculation, and chemical weed control. The technology added to cropping systems increased the number of pods per plant, pod length, seeds per pod, and 100-seed weight, irrespective of the rainy or dry sowing season. Economic analysis, in turn, showed that the technology decreased the total operating cost despite increasing the cost of mechanical operations, inputs, and materials because of the replacement of manual weeding by chemical weed control. However, these costs were not influenced by the sowing seasons. We concluded that technologically enhanced cropping systems, especially systems 4 and 6, improved grain yield and provided greater profitability, which translated into improved economic benefits for farmers. Conversely, the sowing season influenced profitability, which was higher for dry season harvests, when there was less product offered and prices became higher. Cowpea (Vigna unguiculata) crops produce a poor yield in northeastern Brazil compared to the other regions. The goal of this study was to assess the effects of irrigated cropping systems and sowing seasons on cowpea yield and profitability in Vitória da Conquista, Bahia, Brazil. Field studies were performed in four experiments during the rainy and dry seasons during 2016/2017 and 2017/2018, which denoted harvests 1, 2, 3, and 4, respectively. A randomized block design was used for each experiment with four replicates and the following treatments for cropping systems: (1) manual weeding; (2) liming and manual weeding; (3) liming and phosphorus (P) fertilization at sowing, nitrogen (N) and potassium (K) topdressing fertilization, and chemical weed control; (4) liming and P fertilization at sowing, K topdressing fertilization, rhizobia inoculation, and chemical weed control; (5) liming and P fertilization at sowing, N and K topdressing fertilization, rhizobia inoculation, and chemical weed control; and (6) seed pretreatment with cobalt (Co) and molybdenum (Mo), liming and P fertilization at sowing, N and K topdressing fertilization, rhizobia inoculation, and chemical weed control. The technology added to cropping systems increased the number of pods per plant, pod length, seeds per pod, and 100-seed weight, irrespective of the rainy or dry sowing season. Economic analysis, in turn, showed that the technology decreased the total operating cost despite increasing the cost of mechanical operations, inputs, and materials because of the replacement of manual weeding by chemical weed control. However, these costs were not influenced by the sowing seasons. We concluded that technologically enhanced cropping systems, especially systems 4 and 6, improved grain yield and provided greater profitability, which translated into improved economic benefits for farmers. Conversely, the sowing season influenced profitability, which was higher for dry season harvests, when there was less product offered and prices became higher.

Resumen Introducción. La productividad del rambután depende de satisfacer su demanda nutricional a través del uso de fertilizantes. Conocer la cantidad y momentos de mayor exigencia de nutrientes por la planta permite al productor mejorar los programas de fertilización. Objetivo. Evaluar el contenido y distribución de macronutrientes en diferentes edades del cultivo de rambután. Materiales y métodos. Se estableció un experimento en el litoral atlántico de Honduras bajo un diseño completamente al azar con seis tratamientos (muestreo a los 2, 3, 4, 8, 10 y 17 años de establecido) y tres repeticiones. El estudio se realizó entre los meses de marzo a diciembre de 2017. En época de cosecha se hizo la recolección de hojas, ramas, cáscaras y semillas para analizar en cada uno las concentraciones de N, P, K, Ca, Mg y S. Resultados. Se registró que la concentración de macronutrientes difirió significativamente entre los órganos y edades de la planta, encontrando la mayor concentración de N, Ca, Mg y S en hojas, P en semilla y K en la cáscara. La concentración total (hoja + rama + cáscara + semilla) de los nutrientes registró fluctuaciones en el tiempo y aumentó la demanda de P, K, Ca y Mg en los años 2 y 3, para luego decaer en los años 8 y 10. Mientras que la exigencia de N y S fue constante durante las etapas de desarrollo. Además, el N (41 %) fue requerido en mayor cantidad, seguido por K (24 %) y Ca (20 %) y, por último, P (6 %), Mg (5 %) y S (4 %). Conclusión. El contenido y distribución de los macronutrientes fue variable conforme a la edad de la planta, lo que permitió identificar cuales nutrientes y en qué momento tuvieron una mayor exigencia y el órgano vegetal donde se acumuló. Abstract Introduction. Rambutan productivity depends on satisfying its nutritional demand through the use of fertilizers. Knowing the quantity and the times of greatest demand for nutrients by the plant allows the producer to improve fertilization programs. Objective. To evaluate the content and distribution of macronutrients in different ages of the rambutan crop. Materials and methods. An experiment was established in the Atlantic coast of Honduras under a completely randomized design with six treatments (sampling at 2, 3, 4, 8, 10, and 17 years of establishment) and three repetitions. The study was carried out between the months of March and December 2017. At harvest time, leaves, branches, shells, and seeds were collected to analyze the concentrations of N, P, K, Ca, Mg, and S in each one. Results. It was recorded that the macronutrient concentration differed significantly among the organs and ages of the plant, finding the highest concentration of N, Ca, Mg, and S in leaves, P in seed and K in the shell. The total concentration (leaf + branch + shell + seed) of the nutrients registered fluctuations over time and increased the demand for P, K, Ca, and Mg in years 2 and 3, to then decline in years 8 and 10. While the demand for N and S were constant during the development stages. In addition, N (41 %) was required in greater quantities, followed by K (24 %) and Ca (20 %) and finally P (6 %), Mg (5 %) and S (4 %). Conclusion. The content and distribution of macronutrients were variable according to the age of the plant, allowing the identification of which nutrients and when they were most required and the plant organ where it was accumulated.