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Boron (B) is a micronutrient that plays a role in the growth and development of plants. In beetroot (Beta vulgaris L.), B allows increased yield and accumulation of dry mass. This work aimed to evaluate the agronomic performance of beetroot fertigated with B in the municipality of Mossoró, RN. To this end, two field experiments were conducted in Mossoró, RN, Brazil, designed in complete randomized blocks. Five doses of B (0, 1.0, 2.0, 3.0, and 4.0 kg ha−1 of B) were tested, with four replications. The treatments did not influence the plants' height, the number of leaves per plant, or the postharvest quality characteristics of the tuberous root. The maximum total and commercial yield of tuberous roots was 22.22 and 21.29 t ha−1, respectively, fertilizing with 4.0 kg ha−1 of B. This dose also promoted the highest accumulation of B in the plant. Using doses above those evaluated can promote greater yield of tuberous beetroot. Therefore, further studies are necessary to determine the recommended dose of B for beets grown in semi-arid regions. [ABSTRACT FROM AUTHOR]

Vale do Ribeira is one of the largest banana producing regions in Brazil. However, information on soil fertility and nutrient status that could limit fruit production remains scarce. Thus, the present study diagnosed the most limiting nutrient parameters for the Nanica and Prata banana cultivars, in Vale do Ribeira, São Paulo State, based on soil and leaf chemical analyses. The data assessed included samples from commercial plantations in the municipalities of Eldorado, Cajati, Jacupiranga, Pariquera-açú, Registro and Sete Barras, between 2012 and 2020. The results of soil (pH, V, P, K, Ca, Mg, S, B, Cu, Fe, Mn and Zn) and leaf chemical analyses (N, P, K, Ca, Mg, S, B, Cu, Fe, Mn and Zn) were interpreted according to literature values and their maximums, minimums, means, coefficients of variation (CV), and confidence intervals (CI) were calculated at P < 0.05. Parameter classes were assessed according to their frequency distribution. A large part of the samples exhibited pH and V values similar to those recommended for banana plants. Although, average soil nutrient concentrations were considered high, soil K, Mg and S levels did not provide adequate banana plant nutrition, since these nutrients were deficient in the plants. [ABSTRACT FROM AUTHOR]

Managing invasive species is essential for achieving mineland rehabilitation goals and ensuring the long‐term provision of critical ecosystem services while preventing new dispersion sources to neighboring areas. Traditional techniques include chemical and manual weeding, but frequent reinvasion limits their long‐term success. Therefore, additional integrated tools, such as stimulating natural competitors, may become necessary, especially where sensitive ecosystems, e.g. the ferruginous savanna ecosystem (cangas) from the Carajás National Forest, Eastern Amazon, Brazil, are found nearby rehabilitation sites. Here, we investigate the influence of different substrates and fertilization levels on the biotic interactions between two native canga grasses (Axonopus longispicus and Paspalum cinerascens) and the invasive molasses grass (Melinis minutiflora), which is frequently found in anthropized and natural ecosystems in Latin America. Nutrient application significantly influenced the growth, resource use strategies, and competitive outcomes of M. minutiflora. Nutrient application has positive effects on the growth of native species when cultivated in isolation but reduces plant development when subjected to competition with molasses grass, potentiating the invader. Although neither of the tested native species exhibited competitive advantages over M. minutiflora, increased nitrogen availability favored the competitive ability of this invasive grass. Thus, eliminating fertilization during mineland rehabilitation may be important for reducing the cover of M. minutiflora in the Carajás region, as sensitive canga ecosystems lack natural barriers against invasion. This strategic approach mitigates the operational risks and costs associated with combating invasive species from rehabilitating minelands, reducing propagule pressure on neighboring canga areas. [ABSTRACT FROM AUTHOR]

Orchids are valued as ornamental plants, bioindicators, and medicinal plants, which implies that some species may be overcollected. Some inhabit very fragile environments and are under threat by the misuse of habitats and anthropogenic impacts. The search for beautiful plants and flowers has increased the number of facilities for micropropagation either by seeding or by cloning plants using in vitro techniques. However, not all species have appropriate media for growth and development that would help in conservation efforts. Cyrtopodium aliciae is an endemic species of rupestrian grassland in Brazil t. It has appeal as an ornamental plant or for use in hybridisation programs dueo its small size and white brownish-purple dotted flowers. This study compared three different media, namely 1/2 concentration Murashige and Skoog (MS), Vacin and Wendt, and Knudson C, during plant growth and their effect on the acclimatization of Cyrtopodium aliciae. The number and length of shoots and roots, increase in mass, and survival in vitro and ex vitro were analyzed. The experiment was conducted as completely random with a factorial arrangement of treatments (3 Ã--3) with 10 repetitions per treatment containing 10 plants for the in vitro experiment and 3 repetitions of 10 plants for the ex vitro experiment. Cyrtopodium aliciae performed better in the ½ concentration MS medium with a higher increase in mass, plant development, and survival under both in vitro and ex vitro conditions. [ABSTRACT FROM AUTHOR]

Climate change is the main cause of biotic and abiotic stresses on plants and has adverse effects on agriculture in a region. Cassava is fundamental for the socioeconomic development of the region Midwest of Brazil. Establishing the appropriate places for planting in future climate change scenarios collaborates in the planning of public policies and adaptation measures. The objective of the study is to carry out the agroclimatic zoning of cassava (Manihot esculenta Crantz) for the Midwest region of Brazil in future scenarios of climate change. We analyzed information on the relationship of climatic needs with the development of plants and establish the adaptive capacity of cultivation in the region. We used data corresponding to the historical series of 1988–2018 of the National Aeronautics and Space Administration/Prediction of Worldwide Energy Resources—NASA/POWER, referring to average air temperature daily (ºC) and annual rainfall (Rmm). We consider areas suitable when TAIR was between 20 and 27 °C and Rmm between 1000 and 1500 mm. The air temperature was increased by 1.5, 3.0, 4.5 and 6.0 °C, and the rainfall change scenarios at −30, −15, + 15 and + 30% Rmm were carried out as adopted by Pirttioja et al. The potential cultivation area of cassava will be reduced in most scenarios in relation to the current scenario, which has 44% of the suitable region, except in scenario 1 (−30% Rmm) and scenario 2 (−15% Rmm) with an increase of + 12% and + 20% in the adequate area, respectively. It is essential to adapt management systems to mitigate climatic changes' effects on cassava growth, development and productivity, with the introduction of genes tolerant to biotic and abiotic stress in cassava varieties to increase their production, regardless of changes in climatic conditions. It appears that in addition to global awareness of climate change, agriculture must seek criteria based on science that meet the sustainable development of cassava. [ABSTRACT FROM AUTHOR]

Summary: Aphelenchoides besseyi is a concern to Brazilian agriculture, since the losses caused by the green stem and foliar retention syndrome in soybean, especially in hot and humid climates, could reach high levels. However, limited information is available regarding the host-parasite relationship. The objective of this study was to evaluate the capacity of A. besseyi to penetrate soybean roots and its movement in soybean tissues until reaching the top parts. Plants inoculated with 1000 A. besseyi were evaluated for root penetration from 1-28 days after inoculation (DAI), and post-penetration and movement inside tissues by staining them with acid fuchsin. Plant development, chronology of the symptoms and the number of pods were also evaluated at 60 DAI. Aphelenchoides besseyi was found in the cortex and xylem vessels of roots from 1 DAI. During the experimental period, the number of nematodes from roots to shoots increased more than 123, 330 and 430%, respectively, for roots, stems + petioles + inflorescences, and leaves, demonstrating the ascendent movement of A. besseyi. Necrotic lesions in young leaves and apical tissues were observed from 8 DAI; the typical symptom of 'amachamiento' was observed from 10 DAI, with enlargement of nodes and lesions in inflorescences and, at 30 DAI, stunted plants were detected. At 60 DAI, inoculated plants had lower numbers of pods and exhibited severe symptoms including abortion of flowers and tissue splitting and cortical lesions in a few pods and roots. These observations emphasise the importance of A. besseyi for Brazilian soybean production. [ABSTRACT FROM AUTHOR]

Statice is an important cut flower belonging to the Plumbaginaceae family and which has good acceptance among producers and consumers. The construction of a phenological scale for statice that is easy, fast, and non‐destructive can contribute to the improvement of management practices, increase flower yield and quality, increase the knowledge on the plant and facilitate the communication between the scientific and technical personnel. Field and greenhouse experiments with seven sowing dates were carried out during 2019 and 2020 at the Universidade Federal de Santa Maria, in Santa Maria, RS, Brazil, with Assorted Seeds (mix) and two cultivars (QIS Purple and QIS Yellow) of statice to describe the main stages of plant development. The developmental cycle of statice was divided into three phases: germination, vegetative and reproductive. The germination phase includes the stages S0, S1, S2 and SE, the vegetative phase comprises the stages VC, V2, V8, V10, V20, V100 and Vn, and the reproductive phase has the stages R1, R1.1, R1.2, R1.n, R2, R2.1, R2.2, R2.n, R3, R3.1, R3.2, R3.n, R4, R4.1, R4.2, R4.n, R5, R5.1, R5.2, R5.n, R6, R6.1, R6.2, R6.n, R7, R7.1, R7.2, R7.n, R8, R8.1, R8.2, R8.n and R9. Part of the vegetative development overlaps the reproductive development to represent the appearance of new leaves as new floral stems develop. The phenological scale proposed for statice has practical applications and can be easily used in the field by scientists, teachers, students, consultants and farmers. [ABSTRACT FROM AUTHOR]

Brazil's northeast is now the region with the largest installed capacity of renewable energy, predominantly wind and solar power. The purpose of this research is to show the relationship between the installation of renewable energy power plants and the economic development in the northeast of Brazil. The methodology used is the generalized spatial two-stage least-squares regression with a spatial lag of the dependent (GDP per capita and salary growth) and independent variables (presence of solar or wind power plant). The results indicate that the presence of renewable energy power plants is beneficial only in terms of GDP per capita growth and not in terms of salary increases. Moreover, the municipalities that benefit the most in terms of GDP per capita growth are the neighboring ones, meaning that the spillover effect is greater than the direct effect. Consequently, renewable power should be adjusted to economic and social situations to avoid local tensions with traditional resource users and inhabitants. [ABSTRACT FROM AUTHOR]

Currently, high doses of vinasse are employed for the fertigation of sugarcane with positive results on yield. Usually, this effect is related to the presence of mineral nutrients in its composition as well as to its action on soil properties. Consequently, the concentrations of minerals, organic acids, and other metabolites in vinasse are very well characterized. However, considering that cane vinasses are obtained from the treatment of vegetal tissues, it is also possible that they might contain significant concentrations of phytoregulators that could have a relevant role in their beneficial action on yield. To investigate this hypothesis, we analyzed the main plant hormones in 22 samples of vinasse collected in different production sites of Brazil using HPLC–mass spectrometry. The results show that both ABA and IAA present concentrations in vinasse within the micromolar range, thus being potential active ingredients affecting plant development. In conclusion, the beneficial action of cane vinasses on sugarcane yield might involve, among other factors, the action of IAA and ABA on plant growth. [ABSTRACT FROM AUTHOR]

Jatropha curcas is a common species in Brazil, potentially being an option to produce oil for bioenergetic purposes. Around the world, J. curcas has been cultivated in areas of low fertility, in the presence of salts, and with the use of brackish groundwater. Salt stress can hinder the absorption of nutrients and allow entry of ions in toxic concentrations, affecting the development and productivity of plants. This study aimed to evaluate the effect of salinity on the gaseous exchange and the dynamics of some mineral nutrients in the leaves, stems and roots of J. curcas, subjected to two levels of NaCl (0 and 150 mM) in four genotypes: CNPAE183 (tolerant-like), JCAL171 (sensitive-like) and CNPAE133 and CNPAE266 (confused responses to tolerance). Salt treatment promotes a strong reduction in photosynthesis and plant height in all genotypes, although more drastic in CNPAE266 (77.5% and 70% respectively). Additionally, NaCl reduced the content of manganese, calcium, potassium and phosphorus in the leaves, elements linked to gas exchange. The salt-tolerant-like (CNPAE183) and salt-sensitive-like (JCAL171) transcriptome matched the applied sequences, with few chimeric sequences and novel transcripts with no similarities. [ABSTRACT FROM AUTHOR]

Background: Canga is the Brazilian term for the savanna-like vegetation harboring several endemic species on iron-rich rocky outcrops, usually considered for mining activities. Parkia platycephala Benth. and Stryphnodendron pulcherrimum (Willd.) Hochr. naturally occur in the cangas of Serra dos Carajás (eastern Amazonia, Brazil) and the surrounding forest, indicating high phenotypic plasticity. The morphological and physiological mechanisms of the plants' establishment in the canga environment are well studied, but the molecular adaptative responses are still unknown. To understand these adaptative responses, we aimed to identify molecular mechanisms that allow the establishment of these plants in the canga environment. Results: Plants were grown in canga and forest substrates collected in the Carajás Mineral Province. RNA was extracted from pooled leaf tissue, and RNA-seq paired-end reads were assembled into representative transcriptomes for P. platycephala and S. pulcherrimum containing 31,728 and 31,311 primary transcripts, respectively. We identified both species-specific and core molecular responses in plants grown in the canga substrate using differential expression analyses. In the species-specific analysis, we identified 1,112 and 838 differentially expressed genes for P. platycephala and S. pulcherrimum, respectively. Enrichment analyses showed that unique biological processes and metabolic pathways were affected for each species. Comparative differential expression analysis was based on shared single-copy orthologs. The overall pattern of ortholog expression was species-specific. Even so, we identified almost 300 altered genes between plants in canga and forest substrates with conserved responses in the two species. The genes were functionally associated with the response to light stimulus and the circadian rhythm pathway. Conclusions: Plants possess species-specific adaptative responses to cope with the substrates. Our results also suggest that plants adapted to both canga and forest environments can adjust the circadian rhythm in a substrate-dependent manner. The circadian clock gene modulation might be a central mechanism regulating the plants' development in the canga substrate in the studied legume species. The mechanism may be shared as a common mechanism to abiotic stress compensation in other native species. [ABSTRACT FROM AUTHOR]

Papaya is among the main fruit species produced in Brazil, representing high socioeconomic importance in productive regions. Changes in production methodologies aim to meet market demands and sector sustainability. In this sense, the use of organic compounds has been successfully used in the production of seedlings. The objective of the study was to evaluate the potential use of different sources of organic material for the composition of substrates used in the production of papaya seedlings, identifying the effects on the emergence and development of plants. Therefore, the treatments were composed of different substrates, namely: T1 - Soil; T2 - 75% soil and 25% chicken litter; T3 - 75% soil and 25% earthworm humus; T4 - 75% soil and 25% tanned cattle manure. When evaluating the characteristics, it was found that substrates composed of the fractions of earthworm humus and cattle manure allowed increases in the characteristics of shoot length, number of leaves, leaf area and stem circumference, while the presence of chicken litter interfered negatively on all the variables studied. It was concluded that organic compounds have the potential to favor the production of papaya seedlings. In this sense, the composition of the substrate alters the emergence and development of papaya seedlings, and the use of a fraction of 25% of earthworm humus allows the formation of seedlings with greater vigor, while the use of chicken litter in this same proportion should be avoided. [ABSTRACT FROM AUTHOR]

The objective of this study was to characterize the development of chia plants sown at different dates, and to determine the relation between the duration of the development cycle and the final number of leaves and the leaf appearance rate on the main stem. A field experiment was conducted in the agricultural year of 2016/2017 in five sowing dates (09/22/16, 10/28/16, 01/03/17, 02/08/17 and 03/24/17) in the edaphoclimatic conditions of the central region of the RS, Brazil. A randomized block design with four replicates was used. For each sowing date, the duration of the vegetative and reproductive phases in days and in °C day (Tb = 11 °C), the final number of leaves and the phyllochron of the main stem were determined. The duration of the vegetative phase of chia plants in days and in °C day varies between the sowing dates, with shorter duration in late sowings in response to the photoperiod reduction. The vegetative phase represents the largest part of the total development cycle in early sowing dates, being overcome by the reproductive phase in late sowing dates (02/08/17 and 03/24/17). The phyllochron for chia varies from 36.23 (very late sowing) to 59.88 °C day (early sowing). Later sowing has a smaller final number of leaves accumulated in the main stem due to the shorter duration of the vegetative phase. [ABSTRACT FROM AUTHOR]

Copyright of Revista Brasileira de Engenharia Agricola e Ambiental - Agriambi is the property of Revista Brasileira de Engenharia Agricola e Ambiental and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Eucalyptus is the main species for the forestry industry in Brazil. Biotechnology and, more recently, gene editing offer significant opportunities for rapid improvements in Eucalyptus breeding programs. However, the recalcitrance of Eucalyptus species to in vitro culture is also a major limitation for commercial deployment of biotechnology techniques in Eucalyptus improvement. We evaluated various clones of Eucalyptus urophylla for their in vitro regeneration potential identified a clone, BRS07-01, with considerably higher regeneration rate (85%) in organogenesis, and significantly higher than most works described in literature. Endophytic bacteria are widely reported to improve in vitro plant growth and development. Hence, we believe that inclusion of endophytic plant growth promoting bacteria enhanced was responsible for the improved plantlets growth and development of this clone under in vitro culture. Metagenomic analysis was performed to isolate and characterize the prominent endophytic bacteria on BRS07-01 leaf tissue in vitro micro-cultures, and evaluate their impact on plant growth promotion. The analysis revealed the presence of the phyla Firmicutes (35%), Proteobacteria (30%) and much smaller quantities of Actinobacteria, Bacteroidetes, Gemmatimonadetes, Crenarchaeota, Euryarchaeota and Acidobacteria. Of the thirty endophytic bacterial strains isolated, eleven produced indole-3-acetic acid. Two of the isolates were identified as Enterobacter sp. and Paenibacillus polymyxa, which are nitrogen-fixing and capable of phosphate and produce ammonium. These isolates also showed similar positive effects on the germination of common beans (Phaseolus spp.). The isolates will now be tested as a growth promoter in Eucalyptus in vitro cultures. Graphical abstract for the methodology using cultivation independent and dependent methodologies to investigate the endophytic bacteria community from in vitro Eucalyptus urophylla BRS07-01. [ABSTRACT FROM AUTHOR]

The objective of this work was to evaluate seed germination and the initial development of soybean plants with low physiological quality seeds submitted to different doses of phytoregulator. The experiment was carried out from March to April 2018 in Campo Novo do Parecis, MT, Brazil. The experimental design was of completely randomized blocks, in a 3x4 factorial scheme, being three soybean cultivars: Monsoy 7739, Desafio and Monsoy 8372, and four doses of phytoregulator: 0.0; 0.5; 0.75 and 1.0 L ha-1 of Stimulate® composed of cytokinin, indole butyl acid and giberelic acid. Totaling 12 treatments with four replicates. The evaluated variables were: initial germination, final germination, plant height, dry shoot mass, dry root mass and total dry mass. The cultivars responded differently to the phytoregulator doses. The cultivar Monsoy 7739 responded positively to the use of phytoregulator, as it increased germination, presented higher plant height, dry root mass and total dry mass, at the maximum dose of 1.0 L ha-1 .The cultivar Desafio responded negatively to the phytoregulator, as germination presented significant differences compared the other evaluated variables. Monsoy 8372 did not conclusively respond to the use of the phytoregulator conclusively. [ABSTRACT FROM AUTHOR]

Chia is a plant whose seeds are used in cooking and is a natural source of omega-3 fatty acids, fiber and protein, as well as other important nutritional components such as antioxidants. The objective of this work was to estimate the base temperature, plastochron and chia seed yield for different sowing times in Cruz Alta, Rio Grande do Sul, Brazil. The experimental design was completely randomized and the treatments consisted of different sowing times (September, October and November). For the determination of the base temperature for node emission in the main stem of the plants, the method of least mean square error of linear regression between the number of nodes and the accumulated thermal sum was used. Regarding estimation of the plastochron at each sowing time, a simple linear regression was obtained between the number of nodes in the main stem and the accumulated thermal sum. Seed yield was measured at harvest. Sowing in times with air temperature below 19 °C should be avoided so that the development of plants is not impaired. Plastochron ranges from 28.01 °C to 32.26 °C day for successive node emission in the main stem of chia plants and September sowing promotes higher seed yield. [ABSTRACT FROM AUTHOR]

Acromyrmex species primarily attack Pinus taeda plantations during the first months after planting, with more intense damage in the first 30 days.We evaluated potential damage by Acromyrmex crassispinus and Acromyrmex subterraneus in 30‐day‐old P. taeda plantations in southern Brazil by assessing the number of attacked plants and the distance reached by each colony, along with the losses in plant development resulting from different levels of defoliation.Both species were significant pests in newly established pine plantations. A single colony can attack a substantial number of seedlings (up to 453 seedlings). Colonies with larger nests attacked more plants and ranged farther; A. crassispinus reached 59 m and A. subterraneus 87 m.After 10 years, no significant losses in plant development were seen in seedlings defoliated less than 50% at 30 days after planting. But when defoliation of the young plants attained 75%, 100%, and 100%, including the cut of the apical meristem, volume losses reached 32%, 37%, and 43%, respectively.Leaf‐cutting ant controls should be carried out in plantations of P. taeda within 30 days of planting to avoid attacks. When seedlings are defoliated more than 75%, they should be replanted to avoid future losses in final wood volume. [ABSTRACT FROM AUTHOR]

The Physalis genus is composed of species with economic and medicinal importance, its cultivation is expanding in Brazil, and is needed research on the performance of species in different regions of the country. Thus, the objective was to characterize the growth, development and yield of Physalis angulata and Physalis ixocarpa species cultivated in three sowing seasons in Bahia's semiarid region. The days after sowing were determined for the occurrence of vegetative and reproductive stages, and the length and diameter of the main branch were evaluated weekly. At the end of cultivation, the number and total weight of fruits per plant were determined. The plants sown in April showed the best results, as flowering precocity, higher productivity and growth close to other producing regions, which is the best period for the cultivation of species. P. angulata is a more tolerant species and can be sown at different periods without compromising yield. High temperatures combined with scarcity of rainfall compromise the development of plants of both species of Physalis. [ABSTRACT FROM AUTHOR]

The passionfruit has high relevance to Brazilian fruticulture, widely used in the food business. Its seedlings production, might attempt to the utilized substrate characteristics, its organic matter content, adequate nutrients concentration, good aeration, and pathogens agents' absence. Nowadays is increasing the use of renewable fertilizers in detriment to mineral ones, such as the bokashi and the organics compost in agriculture, although few studies are made to test how it affects different plants' metabolism. Due to this circumstance, more studies must test its effectiveness. The bokashi possesses several favourable characteristics as nutrients rapid release, soil structure maintenance, some pests, and disease prevention and control. This study used the bran rice bokashi and the organic compost aiming to verify its effect on passionfruit seedlings germination and initial growth in the tube at the greenhouse. The study area was in the fruticulture sector, on the Instituto Federal de Educação, Ciência e Tecnologia do Sul de Minas Gerais (IFSULDEMINAS), Muzambinho Campus, Brazil. The treatments were different bran rice bokashi doses with organic compost: T1 (0%/100%, respectively bokashi/organic compost), T2 (2%/98%), T3 (4%/96%), T4 (8%/92%), T5 (16%/84%) and T6 (32%/68%). The adopted outline was the RBD, six treatments, and four repetitions, and eight tubes per portion. The obtained data submitted to statistical analysis, the treatments that stood out regarding the germination, were mainly the witness T1, T3, and T5. About the plants' growth treatments T4, T5, and T6; the T5 was the best treatment due to the high seeds germination and plant development rate on this experiment conditions. [ABSTRACT FROM AUTHOR]

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The objective of this research was to evaluate the effect of seeder furrow opening mechanisms on soil physical characteristics, plant growth, and soybean yield in lowland areas with the presence of compacted layer near the surface. An experiment was conducted in the lowland experimental area of the Federal University of Santa Maria-RS, Brazil, during the 2015/16 and 2016/17 growing season. The experimental design was a randomized block with five replications and four treatments: Planter using shank (S) at 0.23 m depth; S at 0.13 m; Planter using double disk at 0.07 m depth and Raised-bed + S at 0.12 m depth. The use of S at 0.23 m depth allowed reduction of penetration resistance and increase of soil macroporosity in the layers 0-0.1 and 0.1-0.2 m depth in the seeding row. Sowing with S at 0.23 m depth and Raised-bed + S at 0.12 m depth allowed a better development of soybean plants in compacted irrigated rice area (higher nodulation, leaf area index and root growth), as well as higher grain yield. [ABSTRACT FROM AUTHOR]

Analyzes of plant growth throughout the crop vegetative cycle are important to know the dynamics of the plant development. Thus the objective of this work was to study the development of potato genotypes throughout the crop cycle, in three environments. Experiments were conducted in Canoinhas-SC, Pelotas-RS, and Brasília-DF, Brazil, in the 2018 crop season. A randomized complete block experimental design with three replicates was used. Traits related to different plant parts of clones F183-08-01 and F50-08-01 and the cv. Asterix were evaluated as a function of time and, at the end of the cycle, for tuber yield. The two clones were found to have high tuber yields, but later development than 'Asterix'; consequently, its management must be adapted to this trait. Leaf mass, leaf number, leaf area index and root mass plus stems were correlated with each other, and leaf area index, leaf number and leaf mass can be quantified through only one of these traits, due to the high correlation between them. There were also positive and significant correlations between the height of the tallest stem and the root plus stem mass and the tuber mass, indicating that more vigorous plants have higher tuber yield. [ABSTRACT FROM AUTHOR]

Eucalyptus (Eucalyptus spp.) is the main tree cultivated for cellulose pulp production in Brazil and is raised in large-scale monocrop plantations based on a two-dimensional system (rows and lines) of trees of the same age and hence height. There are opportunities to incorporate these huge plantations into agroforestry systems to create ecologically designed production systems. Plants respond to environment by modifying their structures, which in turn mediate their relationships with the available solar radiation—the main parameter affecting plant performance, provided other minimum conditions are met. In this way, it is possible to design a new system as a whole in view of maximizing solar radiation absorption and thus productivity. A tridimensional structure intermediated by a planting time scale (the fourth dimension) was designed on a conventional grid system. The Wave Project, which started in 2009, uses this concept to create a canopy with a wave-like appearance and to have production waves spaced in time. Eucalyptus was planted in alleys and monocrop (for comparison purposes) all at the same spacing (3 × 2 m) at different times. The different heights of neighboring Eucalyptus (the third dimension) allowed a much higher solar radiation exposure. With such an arrangement trees were allowed to present architecture modification in relation to those in monocrop conditions. Trees were able to greatly expand their canopies when exposed to increasing solar radiation availability, thus improving their growth rates. The use of the other two dimensions (height and time) is greatly ignored. With the time scale it is possible to design production systems that evolve. The adjustment of the temporal issue to plants' development and systems' architecture management presents a great possibility of increases on production with ecological adjustments—still unexplored. [ABSTRACT FROM AUTHOR]

Lovegrass (Eragrostis plana) is the most important invasive plant in pastures of southern Brazil. The research evaluated the potential of Ruta graveolens (rue) and Schinus terebinthifolius (Brazilian peppertree) essential oils (EOs) to inhibit germination and initial development of lovegrass. The in vitro treatments tested were control (distilled water), alcohol control, 0.001, 0.005, 0.01, 0.05 and 0.1% (v/v) of both EOs. Higher concentrations of these EOs were applied to germinated plants under greenhouse conditions. The EOs of both species were effective in reducing lovegrass germination, with emphasis on rue. Height and shoot dry mass, at greenhouse conditions, were significantly reduced by both EOs, especially when applied at a concentration of 1%. The results point to the potential of rue and Brazilian peppertree EOs for the formulation of natural herbicides. [ABSTRACT FROM AUTHOR]

The damage caused by nematodes has been severe in many crops in Brazil, causing a reduction in agricultural yield. The objective of this work was to evaluate the efficiency of a formulation, elaborated with extract of the rosemary (Rosmarinus officinalis) and cassava bark, on the control of nematode Meloidogyne incognita in soybean. The doses evaluated were 0.0; 25; 50; 100; 150 and 200 mL of the dried formulation per pot of 3 L containing soybean plants. The experiment was conducted in a greenhouse, in a randomized block design, with five replications. We evaluated dried and fresh masses of aerial part, fresh mass of root, and the number of egg mass, galls and second stage juveniles (J2) and eggs in root and soil. The soybean plants showed growth reduction resulting from the interaction of the formulation, maybe due a phytotoxic effect from cassava bark. There was allelopathic effect in soybean plants treated with formulated made with cassava bark + aqueous extract of rosemary, evidenced by inhibition in plant development according to the increase in doses of the formulated. Moreover, the formulated was not efficient in the control and or reduction of M. incognita. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Applied Technology for Agricultural Science / Revista Brasileira de Tecnologia Aplicada nas Ciências Agrárias is the property of Brazilian Journal of Applied Technology for Agricultural Science and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Rhizobia and other plant growth‐promoting rhizobacteria (PGPR) have been broadly used as inoculants in agriculture, resulting in morphofunctional improvements in roots and grain yield. This study was carried out during two cropping seasons under field and greenhouse conditions in Brazil to verify the effects of inoculation of two soybean cultivars with PGPR and secondary microbial metabolites (SMMs) on root activity and nodulation, plant development, and grain yield. Inoculation and co‐inoculation treatments consisted of Bradyrhizobium japonicum strain SEMIA 5079 and B. diazoefficiens strain SEMIA 5080 inoculated together, in combination with Bacillus subtilis strain QST 713, Azospirillum brasilense strains Ab‐V5 and Ab‐V6, and SMMs extracted from B. diazoefficiens strain USDA 110 and Rhizobium tropici strain CIAT 889. Root systems were evaluated by direct (optical reading) and indirect (rubidium nitrate application, 85RbNO3) methods. Increases of up to 1.6% in root diameter (0.01‐ to 0.5‐mm class), 28.5% in length, 19.7% in root volume, 17.8% in root surface area, 29% in the number of nodules, 27.2% in nodule dry weight, 13.5% in root dry weight, and 3.8% in shoot dry weight. Greater exploration and activity within and between rows following inoculation at up to 40 and 10 cm in depth, respectively, were observed in plants co‐inoculated with the standard inoculation (only Bradyrhizobium spp.) + SMMs + A. brasilense, resulting in a yield increase of 485 kg ha−1. The results emphasize the biotechnological potential of using secondary metabolites of rhizobia with inoculants containing rhizobia and PGPR to improve the growth and soybean yield in tropical conditions. [ABSTRACT FROM AUTHOR]

The central-north of Brazil is a region with strong presence of concrectionary soil, whose supposed disadvantages from the agronomic point of view, do not prevent their use in agriculture. However, more in-depth information about the behavior of crops of agricultural interest cultivated in this type of soil is few. Due to the observation of agricultural stands in this type of soil, it was hypothesized that plinthite ironstones concretions negatively interfere in the development of crops of agro-economic interest. The objective was to verify the growth and development of soybean cultivated in soil with the presence and absence of plinthite ironstones. Concretionary Petric Plinthosol were collected in the 0-0,20 m layer and part of the soil was sieved so that concretions larger than 3.10 mm in diameter were removed, thus leaving two treatments, soil with and without plinthite ironstones. Morphological evaluations were performed during their phenological phase. Soybean grown in soil without ironstones showed higher growth at 32 and 48 DAE and more leaflets when compared to soy crop grown in soil with ironstones. As for dry matter, soybean grown in soil without ironstones showed more values for aerial, root and total mass as well for aerial root rate when compared to soybean grown in soil with ironstones. Plinthite ironstones interfere with the growth and/or vegetative development of soybeans. Soybean has less vegetative development when grown in soil with plinthite ironstone concretions. [ABSTRACT FROM AUTHOR]

Mining tailing areas may contain metal minerals such as Cu, Pb, Zn, Cr, and Cd at high concentrations and low nutrients for the growth of plants. This kind of conditions of the area, as well as lack of tailing structure, may limit the development of plants on these areas. Thus, the present study determined the metal, macronutrient, and micronutrient concentrations in the tissues of the roots and shoots of the Solanum viarum Dunal species as well as it evaluated the potential use of the plant for phytoremediation of mining tailing areas contaminated with heavy metals. The macronutrients, micronutrients, and heavy metals in the roots and shoots were determined by the digestion method with nitric and perchloric acid (HNO3-HClO4) and quantified by the ICP-OES. In S. viarum, the average concentrations of the metals presented in the dry biomass varied between the shoots and roots, being higher in the roots for metals such as Cu (229 mg kg−1), Zn (232 mg kg−1), Mn (251 mg kg−1), Cr (382 mg kg−1), Ni (178 mg kg−1), Pb (33 mg kg−1), and Ba (1123 mg kg−1). S. viarum indicates the possibility of a potential application in phytoremediation and treatment of areas contaminated with heavy metals. [ABSTRACT FROM AUTHOR]

Calophyllum brasiliense Cambess. (guanandi) is a native species with medicinal potential and also generates expectation for commercial use (wood) and for recovery of degraded areas. These seeds have physical and mechanical dormancy, requiring techniques for dormancy release; knowledge of seed and seedling morphology that assists laboratory analysis and propagation of the species is also necessary. The objective of this study was to describe the morphological structures of the seeds and normal and abnormal seedlings of guanandi, and also investigate if complete extraction of the endocarp and the seed coat to overcome dormancy will affect the morphology and initial plant development, and consequently production of transplants. Guanandi seeds are large (1000 seed weight of 1480.9 g) with a hard seed coat; cotyledons account for most of the embryo and serve as a reserve; the embryonic axis is small (1.0-2.0 mm) in relation to the seed, yet it is differentiated. The seedlings have hypogeal cryptocotylar germination, with cotyledonary petioles, taproot, and epicotyl developing into a long stem and a tip protected by cataphylls. The main abnormalities in seedlings are related to the root system. Extraction of the endocarp and seed coat does not alter the morphology of seedlings and promotes their greater development, which may be an advantageous strategy. [ABSTRACT FROM AUTHOR]

Copyright of Revista Brasileira de Engenharia Agricola e Ambiental - Agriambi is the property of Revista Brasileira de Engenharia Agricola e Ambiental and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The environmental impact caused by extractive livestock activities is a global concern from the environmental and economic standpoints, since environmental degradation affects plant production directly and animal production indirectly. With a view to lessening environmental damage and adopting more efficient and sustainable production models, the Brazilian government launched governmental policies with financial incentives to their implementation. The Crop-Livestock-Forest integration system (CLFi) consists of simultaneous or successive cultivation for the production of animal- and plant-based foods as well as production of timber and non-timber resources. This system allows for income diversification, increased productivity, benefits to the soil and the system and recovery of degraded areas, in addition to having little environmental impact. However, these may not occur under improper implementation or management of its components, resulting in a scenario of imbalance and competition. Because the forest component remains in the production area for a longer time, the species to be used as well as the arrangement to be adopted must be carefully chosen, since these factors may influence its very development and the development of the other plant components. In view of the complexity of the system and its potential benefits, studies on CLFi are essential for the synthesis of information about the best models to be adopted as a function of the environmental diversity and socioeconomic realities in Brazil. [ABSTRACT FROM AUTHOR]

The vine, when studied in different places and years, allow extensive conclusion on cultural adaptation in a specific region. The objective of this research was to evaluate two rootstocks and three cultivars of rustic grapes under bench grafting at Toledo and Ouro Verde do Oeste (Paraná State, Brazil). Both researches were conducted in a private property, evaluating forming and plant development and of this plants in field. Bench grafting was used for plant forming, by saddle graft. After 90 days grafting root percentage and graft union were evaluated. Then, plants were conducted in field and after 15 days the average sprouting height and number of surviving plants was analyzed. Past 120 days the second phase that consisted of: diameter of horizontal cordon, number of grow plants, number of gems and number of branches than reach the second, and third line of the support system was evaluated. The experiment design was of randomized blocks with factorial arrangement 2x3x2. When the arrangement wasn't significant for triple and double interaction, each experiment was analyzed alone in factorial arrangement 2x3. All parameters did not show influence concerning local. In the first phase only height of sprouting was significantly at Ouro Verde do Oeste. The IAC-766 Campinas rootstock was better than 420-A to Bordô variety. In the second phase, the IAC-766 Campinas rootstock was more vigorous than 420-A to form a vineyard. Both rootstocks and cultivars are indicated to both counties. [ABSTRACT FROM AUTHOR]

Olive crop was introduced in several regions of Brazil in the 19th century, especially in the southern and southeastern regions. Crops were a failure due to lack of studies on soil, climate and other factors that directly affected productivity. Due to low commercial production, Brazil imports all olive oil and olives from producing countries. A bibliographical review has been developed on publications on the development and production of olives, with special reference to Brazil, highlighting those which involve aspects related to the interactions with microorganisms, such as arbuscular mycorrhizal fungi (AMFs) and rhizo-bacteria. They are groups that affect the growth and development of the plants. Several studies have been undertaken abroad on AMFs and rhizo-bacteria in olive trees with significant results on growth and development of co-inoculated plants, improvement in resistance to heavy metals and phytopathogens in the greenhouse and in the field. In spite of the great capacity for the development of olive crops, especially due to the country's extension and climatic and biological richness, few studies have been undertaken on microbiological relationships, and thus retard data on and for the growth of olive crops. [ABSTRACT FROM AUTHOR]

Nutrient concentrations in tree biomass components may vary with the component considered, age and genetic material and its measurement is important to understand forestry nutrient management. Due to it, aboveground biomass production and nutrient accumulation and its potential removal through thinning in two species of five-year-old Eucalyptus with were evaluated in the southern of Brazil. Treatments were arranged in a randomized block design with three replications in a 2 x 4 factorial scheme, being 2 species (E. grandis and E. urophylla) and four diametric classes (C1: 3.0 - 8.8; C2: 8.9 - 14.7; C3: 14.8 - 20.6; C4: 20.7 - 26.5 cm). Average annual accumulation of dry matter in both species was of 16.9 Mg ha². Biomass was mainly allocated in the stem (wood and bark). Trees' canopy (branches and leaves) represent the smallest fractions, with only 14,3% of the total biomass. E. grandis showed highest values of wood and leaf compartments. The highest content of N and K were found in the leaves, with N levels of 33.2 and 30.5 g.Kg² respectively to E. grandis and E. urophylla. Trees bark represent an important Ca and Mg reserve to the development of the plant, with values of 18.02 and 3.24 g.kg² respectively. The average concentration of Ca, N, K, Mg and P in the total biomass of the two species was of 528, 305, 200, 128 and 30 kg ha². [ABSTRACT FROM AUTHOR]

This study aims to evaluate the litterfall of three areas in the tropical rain forest, in different successional stages, in the municipality of Siderópolis, Southern Santa Catarina state. Fifteen collectors of 0.25 m² each were used, distributed in three transects per study area (A1, A2 and AR). The highest litterfall production occurred in AR (8.13 Mg ha-1 yr-1), followed by A2 (4.26 Mg ha-1 yr-1) and A1 (2.74 Mg ha-1 yr-1). The AR area produced significantly more leaves, reproductive material and wastes. This can be explained by its more developed forest structure, with large trees, more closed canopy and greater number of epiphytes. On the other hand, areas A1 and A2 produced significant amounts of thin stems. These areas have a higher proportion of species in early successional stages, a higher density of thin trees and a more open canopy, being subject to winds, which could result in greater production and fall of branches. The results of this study highlight the importance of litterfall production in different successional stages, becoming necessary studies with this emphasis to understand the nutritional dynamics of ecosystems, especially those that have suffered strong impacts in the past, such as open-pit coal mining. [ABSTRACT FROM AUTHOR]

Cement industries located nearby limestone outcrops in Brazil have contributed to the coating of cement dust over native plant species. However, little is known about the extent of the response of tropical woody plants to such environmental pollutant particularly during the first stages of plant development and establishment. This work focused on the investigation of possible alterations in leaf structural and ultrastructural traits of 5-month-old Guazuma ulmifolia Lam. (Malvaceae), 6-month-old Myracrodruon urundeuva Allemão (Anacardiaceae), and 9-month-old Trichilia hirta L. (Meliaceae) challenged superficially with cement dust during new leaf development. Leaf surface of plants, the soil or both (leaf plus soil), were treated (or not) for 60 days, under controlled conditions, with cement dust at 2.5 or 5.0 mg cm. After exposure, no significant structural changes were observed in plant leaves. Also, no plant death was recorded by the end of the experiment. There was also some evidence of localized leaf necrosis in G. ulmifolia and T. hirta, leaf curling in M. urundeuva and T. hirta, and bulges formation on epidermal surface of T. hirta, after cement dust contact with plant shoots. All species studied exhibited stomata obliteration while T. hirta, in particular, presented early leaf abscission, changes in cellular relief, and organization and content of midrib cells. No significant ultrastructural alterations were detected under the experimental conditions studied. Indeed, mesophyll cells presented plastids with intact membrane systems. The high plant survival rates, together with mild morphoanatomic traits alterations in leaves, indicate that G. ulmifolia is more resistant to cement dust pollutant, followed by M. urundeuva and T. hirta. Thus, the three plant species are promising for being used to revegetate areas impacted by cement industries activities. [ABSTRACT FROM AUTHOR]

The nutrients availability can lead to changes on grapevines physiological behavior, which results in a great importance of studies regarding the application of potassium doses. The aim of this research was to evaluate the ecophysiological behavior of grapevine cultivar 'Syrah' growing under different potassium doses by fertigation, according to the determination of gas exchange, chlorophyll a, fluorescence and pigments index. Five years old plants, grafted on 'Paulsen 1103' rootstock, in a trellis system and planted at theBebedouro Experimental Field, located in Petrolina, PE, Brazil, were evaluated. The experiment was composed by five potassium doses (0, 20, 40, 80 and 160 kg ha-1), applied by fertigation. The potassium sources were potassium sulfate, potassium nitrate and potassium chloride. The evaluations of the ecophysiologyical parameters were performed at four different times (07am, 10am, 1pm and 3pm) throughout the day on the flowering stage and the first and second fruit growth stages, determining gas exchange and chlorophyll a fluorescence and the pigments index was evaluated at the same grapevines leaves one time. Considering each evaluation period, it was observed that, according to the magnitude of the results for gas exchange, chlorophyll a fluorescence and pigments index, is not possible to indicate the best potassium dose. The climatic conditions during each period of evaluation influenced most the eco-physiological variables than the applied potassium doses, while the changes on pigments index were due to leaves development during the plant cycle. [ABSTRACT FROM AUTHOR]

Degree-days may be an alternative for predicting the influence of temperature on physiological aspects of plants in a changing climate. The objective of this research was to evaluate the relation between cumulative degree-days index (∑G) and the development, growth, and water consumption of irrigated bean under different soil tillage systems (STS). We developed an experiment in Southeast Brazil in plots managed with the following STS: chisel ploughing (CP), disk ploughing (DP), and revolving hoe (RH). The treatments did not influence the crop phenology when correlated to ∑G. The parameters of canopy ground cover, leaf area index, total dry matter, and the plant height presented a highly significant relationship with ∑G (P<0.05). We also compared the results of field water balance with a simulation developed between the crop coefficient and ∑G and found a strong relationship (R2 = 0.93∗∗; ∗∗: high statistical significance (P<0.01)) between these measurements and the model. The total water consumption measured at the irrigated bean crop reached 383 mm, 386 mm, and 375 mm while that simulated from dual crop coefficient approach based on ∑G reached 378 mm, 373 mm, and 349 mm to CP, DP, and RH, respectively, representing a mean difference of 4.2%. [ABSTRACT FROM AUTHOR]

The origin of lenticels during apple fruit development growing in different altitudes, the physicochemical and physiological fruit features at harvest and storage, were studied in order to correlate these aspects to lenticel breakdown. ‘Gala’ and ‘Galaxy’ apples were harvested from orchards located at three traditional growing regions in Brazil: Vacaria, RS (971 m a.s.l.), Fraiburgo, SC (1048 m a.s.l.) and São Joaquim, SC (1353 m a.s.l.), during the 2008/09 season. The fruit were kept in cold storage (CS) at 0 °C and 90% RH for up to 120 days or at controlled atmosphere (CA) at 1.5% O 2 , 2.5% CO 2 , 0 °C and 90% RH for up to 210 days. Colour index was higher in ‘Galaxy’ apples and in fruit grown in São Joaquim, where the minimum temperatures were approximately 10 °C. The firmness was reduced at CS and CA, but it remained greater than 40 N in all the treatments. Acidity, except for ‘Galaxy’ apples, and sugars were influenced by the climatic conditions of the growing sites. There was no relationship between the lenticels dyeing and the incidence of lenticel breakdown. Contrary to the expectations, higher incidence of the disorder was noticed in ‘Gala’ apples grown in São Joaquim (SC) at the end of the both types of storage. The lenticel breakdown was featured by symptoms such as concentric depression around the lenticels, cell obliteration of the epidermis and subepidermal layers, with wide spaces formed by cell lysis. The origin of lenticels has no influence on the disorder development. It was not possible to establish a relationship among physicochemical, physiological and anatomical features from distinct growing sites and the predisposition to lenticel breakdown disorder. [ABSTRACT FROM AUTHOR]

Increasing the number of species conservedex situin Megadiverse countries is a major task exacerbated by many intricate factors including: biome complexity, wide range of biodiversity and an incomplete knowledge of life cycles, reproductive strategies, adaptations and species interactions. Although, establishing safe reserves is a crucial conservation measure their security and effective maintenance can be unfavourably compromised by climate change and the risks incurred by socioeconomic instability and changes in land use. Anthropogenic impacts, non-sustainable practices and habitat erosion have motivated current international efforts which focused on Brazil as host of ‘Rio+20’ the United Nation's twentieth anniversary conference on sustainable development. The revised targets of the Global Strategy for Plant Conservation (GSPC) are responses to species decline and realizing Target 8, which concernsex situconservation, places the heaviest burdens on countries that are custodians of the highest levels of global biodiversity. At the scientific level,ex situconservation of endemic species in genebanks is often hindered by a lack of information about molecular genetics and problematic (recalcitrant) storage behaviors that restrict the preservation of flora native to Megadiverse countries. The potential for applying the ‘Biospecimen Science’ paradigm in expediting conservation in biodiversity-rich biomes is considered using Brazil as an exemplar of a Megadiverse country. The impacts of process chains on the quality of preserved plant germplasm and using evidence-based research to improve conservation outcomes, risk and quality management systems are appraised. The Biospecimen Science approach is not intended to displace conventional conservation practices but rather, to enhance their effectiveness in terms of the scale and efficiency of their scientific and technical operations. [ABSTRACT FROM AUTHOR]

Abstract: The underground systems of plants show the most varied structures adapted to survival in unfavorable environmental conditions. For instance, long-term droughts may induce the development of either water and reserve substances or vegetative propagation structures. Since Mandevilla atroviolacea is a species found at high altitudes on rocky outcrops, this study aimed to provide information on the morpho-anatomy of the underground system of this species that may assist in understanding the adaptive strategies at play. Samples from the underground system of three young and two mature plants collected in the field were sectioned and processed according to standard plant anatomical techniques. The upper area of the underground system corresponds to a xylopodium, while the lower is a tuberous stem organ. Tuberous roots account for the majority of the underground system. The increase in tuberous root diameter results from the action of a typical cambium. The high shoot-forming potential and storage of water and reserve substances observed in the underground system of this species are important strategies for it to survive in this habitat. [Copyright &y& Elsevier]

Copyright of Biotropica is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The interaction between the Brazilian pioneer legume Sesbania virgata and its microsymbiont Azorhizobium doebereinerae leads to the formation of nitrogen-fixing nodules on roots that grow either in well-aerated soils or in wetlands. We studied the initiation and development of nodules under these alternative conditions. To this end, light and fluorescence microscopy were used to follow the bacterial colonisation and invasion into the host and, by means of transmission electron microscopy, we could observe the intracellular entry. Under hydroponic conditions, intercellular invasion took place at lateral root bases and mature nodules were round and determinate. However, on roots grown in vermiculite that allows aerated growth, bacteria also entered via root hair invasion and nodules were both of the determinate and indeterminate type. Such versatility in entry and developmental plasticity, as previously described in Sesbania rostrata, enables efficient nodulation in both dry and wet environments and are an important adaptive feature of this group of semi-tropical plants that grow in temporarily flooded habitats. [ABSTRACT FROM AUTHOR]

Abstract: In a field experiment performed in Lins County (São Paulo State, Brazil), treated sewage effluent (TSE) irrigation increased sugarcane yield but caused an excessive increase in the exchangeable sodium percentage (ESP) and clay dispersion after 16months due to an intense irrigation regime (2500mm/16months) with sodium rich effluents. After two additional complete cycles with lower TSE irrigation rates (1200mmyear−1), 1700kgha−1 of phosphogypsum was added to a section of the irrigated plots to evaluate its residence time and its implications on Na+ dynamics and other soil properties. Undisturbed soil cores were taken 2years after phosphogypsum application to verify soil physical properties up to 0.2m depth, and disturbed soil samples were taken every year up to 1m depth for chemical analyses. After 5years of consecutive TSE irrigation (2005–2010), soil acidity (pH≈5) and basic cations (Ca≈12, Mg≈6 and K≈2mmolc kg−1) were maintained in adequate conditions for plant development without the necessity of liming, while acidity was increased (pH≈4.5) and Ca (≈9mmolc kg−1), and the Mg (≈4.5mmolc kg−1) concentration decreased in the rainfed without phosphogypsum treatment. An increase in water retention capacity at −30 (from 0.14 to 0.17m3 m−3) and −1500kPa (from 0.08 to 0.12m3 m−3) potentials was also observed in all TSE irrigated treatments. The plots with a phosphogypsum treatment showed average increases of 2mmolc kg−1 of Ca2+ and 7mgkg−1 of S-SO4 2− in all soil profiles and an average reduction of 2mmolc kg−1 of Na+ up to 0.4m from 2008 to 2009. However, the extent of the chemical effects was greater after the first year compared to the second year. The high concentration of Na+ found in previous studies performed in the same area returned to low concentrations after continued TSE irrigation at lower rates, even without the phosphogypsum application. An unusual phosphorus migration was observed to the 0.4–0.8m soil layer as a result of TSE irrigation, most likely due to a high pH and a Na carbonate-dominated TSE. [Copyright &y& Elsevier]

The amount and composition of crop residues added to soil in agroecosystems can influence decomposition processes and soil organic matter levels. This study aimed to evaluate residues (quantity and quality) of different corn cultivars commonly used in Brazilian cropping systems. The experiment was conducted for two seasons (2005/2006 and 2006/2007) in Rolândia, Paraná State, Brazil. Ten corn cultivars that represent five degrees of breeding development (i.e., landrace, commercial variety, double cross, triple cross, and single cross hybrids) were evaluated. At harvest, carbon (C) and nitrogen (N) of non-yield residue and grain were determined. Except for grain C, other measures (grain N concentration, residue C and N concentration, and C:N ratio) varied among cultivars. In general, the hybrids had higher residue C and lower residue N concentrations than the landraces and commercial varieties. Findings suggest that breeding selection may have altered residue production and composition, which may influence soil C dynamics. [ABSTRACT FROM AUTHOR]

Abstract: The impact of plant defoliation on the yield of short-season soybean cultivars was evaluated in five trials carried out in two crop seasons (2008/2009 and 2009/2010) in three states in Brazil (Rio Grande do Sul, Goiás and Mato Grosso). In 2008/2009, defoliation was performed by removing one, two or three leaflets (33.3%, 66.6% and 100% defoliation, respectively) from all leaves at different plant developmental stages (V5, V8, R2, from V5 to R2, and from V5 to harvest). In 2009/2010, the defoliation levels studied were 16.7% (half leaflet) and 33.3% (one leaflet), performed weekly during the vegetative or reproductive period, and during the entire cycle in three trials in Goiás. All tested cultivars tolerated defoliation levels equal and sometimes even higher than current Economic Thresholds (ETs) (30% vegetative stage defoliation threshold and 15% reproductive stage defoliation threshold) without significant yield loss. This indicates that even for the new cultivars belonging to shorter maturity groups or of indeterminate growth habit, soybean plants showed high defoliation tolerance. Thus, we conclude that the currently recommended ET for leaf-lamina consumers in the soybean crop is still valid and should be used by growers, even for the newer cultivars belonging to the lower maturity groups with indeterminate growth habit. [Copyright &y& Elsevier]

The allelopathy is a process for which products of the secondary metabolism, as terpenes phenolic, of a certain vegetal intervene significantly, generally of antagonistic form, in the development of other species of plants. The objective of this work was to chemically characterize the essential oil of Lippia sidoides Cham. Growing in the Cariri cearense region Brazil, and evaluate the allelopathyc effect of this oil on the germination of lettuce (Lactuca sativa L.), arugula (Eruca sativa Mill.), and cauliflower (Brassica oleracea L.), in pre-plantation application. The monoterpene thymol (84.90%) ha been identified as the principal constituent in the essential oil. The experiment was done in randomized complete block, in 4 x 3 factorial; being used four essential oil combinations applied in three different species in pre-plantation applications. Emergence velocity index (EVI) germination percentage and mean time to germination (MTG), had been analyzed through daily counting carried out until the 14th day after sowing. Through qualitative analysis performed by gas chromatograph coupled with mass spectrometry (GC/MS) were identified seven chemical constituents representing 97.82% Of essential oil of L. sidoides, being that the constituent present in greater concentration in oil was the thymol (84.90%). Could be verified the occurrence of the negative allelopathyc effect of lettuce crop, because its present low EVI and greater MTG. for the other vegetable species there were no allelopathic effect. [ABSTRACT FROM AUTHOR]

Copyright of Revista Caatinga is the property of Revista Caatinga and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)