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Zinc oxide nanoparticle (ZnO NPs) has been used as a fertilizer alternative, although some applications technique and metal-microbial effects should be studied. This research evaluated the bioefficiency of synthetic ZnO NPs in soybean seedlings combined with different water status and with or without PcO6 bacteria. ZnO NPs performed in sand inhibited growth and fluorescence parameters. Still, when soybean seeds were exposed to ZnO NPs seed priming the root mass was increased, mainly in non-drought conditions. Soybean plants cultivated in drought conditions will have compromised development, although was demonstrate soybeans seed inoculation with PcO6 may decrease undesired effects from drought. Also, PcO6 soybean inoculation mitigate metal ZnO toxicity. Here, one of the first positive report about soybean interaction with PcO6 by drought and metal mitigation of toxicity. In addition, the best way to apply ZnO was through seed priming, while sand application was toxic and foliar application had no effects. [ABSTRACT FROM AUTHOR]

It is necessary to increase the agronomic use efficiency of urea to reduce ammonia volatilization and increase crop yield. However, relying solely on urea for the enhanced efficiency technologies development could harm fertilizer integrity, resulting in reduced application quality and fertilizer storage time. The authors aimed at developing and characterizing the physical, chemical, and physicochemical quality of a novel enhanced efficiency fertilizers, synthesized from urea plus boron (B), zinc (Zn), nickel (Ni), or molybdenum (Mo) addition, with or without N-(n-butyl) thiophosphoric triamide (NBPT) associated. Hygroscopicity, hardness, salt index (SI), pH, and thermogravimetric decomposition were the parameters evaluated. Fertilizer quality was assessed through microscopic X-ray fluorescence, microtomography, and scanning electron microscopy. Micronutrients were added by coating or granulation; they were homogeneously distributed over the fertilizer’s granules. The fertilizers’ hardness increased up to 86% with Zn coated compared with uncoated. Granulated urea with B, Zn, Ni, or Mo had greater internal porosity, which resulted in lower hardness. Boron and Zn addition to the fertilizers increased the hygroscopicity in average 388% and 473%, respectively, compared with hygroscopicity observed for urea. Moreover, hygroscopicity was increased by an average of 56% with NBPT addition. Micronutrients addition to the urea granules increased the SI, while thermal decomposition stages of urea were unaffected by micronutrients addition. Enhanced efficiency fertilizers require characterization before agronomic efficiency tests due to changes in their physical, chemical, and physicochemical properties. Unfavorable changes could harm granules integrity and application efficiency in the field, resulting in economic losses to the industry and farmers. [ABSTRACT FROM AUTHOR]

It is necessary to increase the agronomic use efficiency of urea to reduce ammonia volatilization and increase crop yield. However, relying solely on urea for the enhanced efficiency technologies development could harm fertilizer integrity, resulting in reduced application quality and fertilizer storage time. The authors aimed at developing and characterizing the physical, chemical, and physicochemical quality of a novel enhanced efficiency fertilizers, synthesized from urea plus boron (B), zinc (Zn), nickel (Ni), or molybdenum (Mo) addition, with or without N-(n-butyl) thiophosphoric triamide (NBPT) associated. Hygroscopicity, hardness, salt index (SI), pH, and thermogravimetric decomposition were the parameters evaluated. Fertilizer quality was assessed through microscopic X-ray fluorescence, microtomography, and scanning electron microscopy. Micronutrients were added by coating or granulation; they were homogeneously distributed over the fertilizer’s granules. The fertilizers’ hardness increased up to 86% with Zn coated compared with uncoated. Granulated urea with B, Zn, Ni, or Mo had greater internal porosity, which resulted in lower hardness. Boron and Zn addition to the fertilizers increased the hygroscopicity in average 388% and 473%, respectively, compared with hygroscopicity observed for urea. Moreover, hygroscopicity was increased by an average of 56% with NBPT addition. Micronutrients addition to the urea granules increased the SI, while thermal decomposition stages of urea were unaffected by micronutrients addition. Enhanced efficiency fertilizers require characterization before agronomic efficiency tests due to changes in their physical, chemical, and physicochemical properties. Unfavorable changes could harm granules integrity and application efficiency in the field, resulting in economic losses to the industry and farmers. [ABSTRACT FROM AUTHOR]

Limestone is the most widely used agricultural input for soil acidity correction and calcium (Ca) and magnesium (Mg) fertilization. However, other materials have the potential to fulfill these purposes, such as steel slags, also known as silicates. Silicates have higher solubility than limestone, serving as agents for increase pH in no‐till, in addition to being a source of Ca, Mg, and silicon (Si). This study aimed to compare the effects of surface application of dolomitic lime and calcium magnesium silicate on soil chemical properties, soybean [Glycine max (L.) Merr.] nutritional status, and grain yield under no‐till. The experiment was installed in the northwest Paraná State, Brazil, on a Rhodic Eutrustox. Lime and silicate rates were applied by broadcasting before the sowing of soybean. Silicate treatment increases soil Ca2+, pH, and base saturation up to a depth of 0.10 m. By contrast, liming effects on soil chemistry were restricted to the 0.05 m top layer after 24 months of application. The acidity correction and Ca2+ supply to greater soil depths and the increased leaf Si as a beneficial element provided by silicate treatment contributed to increasing soybean yield in the 2018/2019 and 2019/2020 seasons. Lime application, regardless of the rate, did not improve soybean yield. Waste from the steel industry can be used as acidity correctives and source of Si, Ca, and Mg, improving the agronomic performance of soybean. Core Ideas: Silicate is more efficient in maintaining soil fertility compared to lime.Changes in soil fertility were observed up to a depth of 0.10 m after 24 months.Silicate increases silicon content in soybean leaf.Surface application of silicate increased soybean yield up to 43%.Soybean yield did not improve with lime. [ABSTRACT FROM AUTHOR]

This study aimed to assess the nutritional status of soybean and wheat and the relationship with grain yield and biometric components after lime and phosphogypsum (GY) reapplication. Treatments consisted of two lime application methods, surface liming and incorporated liming, to different levels of base saturation (BS) (44, 70, and 90%), in addition to surface liming to 70% BS associated with a standard dose (70GY1) or double dose (70GY2) of GY. Treatments were applied in 2012 and reapplied in 2016. The results refer to the 2018/2019 soybean season and the 2019 wheat season. Lime + GY treatment increased leaf area, plant height, leaf dry matter, and stem dry matter in soybean but had no effect on specific leaf area (235.4 cm2 g−1), stem diameter (6.08 mm), number of pods per plant (71.7), grain number per plant (165), or thousand grain weight (117 g). Liming to 90% BS reduced leaf manganese contents in both crops and leaf iron content in soybean. GY application improved the calcium status of both crops and the sulfur status of soybean. However, 70GY2 reduced leaf magnesium contents in soybean and wheat. Soil tillage without lime reduced wheat yield by 12% compared with no-till. Soybean yield correlated positively with leaf nitrogen (0.79), leaf phosphorus (0.91), leaf area (0.62), and thousand grain weight (0.65), whereas wheat yield correlated with leaf phosphorus (0.83), calcium (0.75), and sulfur (0.74). For improved soybean and wheat performance, it is preferable to apply lime and GY to the soil surface (70GY1), permanently maintaining no-till practices. [ABSTRACT FROM AUTHOR]

The yield gain of soybean inoculated with Bradyrhizobium spp. or co-inoculated with Bradyrhizobium spp. and Azospirillum brasilense is variable. Inoculants can be applied in the sowing furrow or via seed treatment. There is a gap in our understanding of the efficacy of different inoculation methods. This study aimed to assess the agronomic efficiency of soybean inoculated and co-inoculated with Bradyrhizobium spp. and A. brasilense by different methods. The study was conducted in Paraná State, Brazil, in two seasons. Five treatments were tested: control; seed treatment with Bradyrhizobium spp. (SBr), seed treatment with Bradyrhizobium spp. + A. brasilense (SBr+Az), in-furrow treatment with Bradyrhizobium spp. (FBr), and in-furrow treatment with Bradyrhizobium spp. + A. brasilense (FBr+Az). Shoot dry weight, grain nitrogen content and grain yield were lower in 2018/19. In 2017/18, FBr+Az increased nodule number and dry weight compared with SBr. FBr+Az promoted a 47% increase in pods per plant compared with the control in both seasons. Regardless of season, grain nitrogen content was higher with FBr+Az (mean relative increase of 27%). FBr+Az was superior to SBr+Az in 2017/18, with a 12% increase in yield. Inoculation and co-inoculation improve morphological traits and soybean yield. In-furrow inoculation is more efficient than seed treatment. [ABSTRACT FROM AUTHOR]

This study aims at assessing the effect of limestone mining by-product from the Irati Formation on soil calcium, magnesium, and sulfur contents, as well as their accumulation in the onion biomass. The study was carried out in a greenhouse. A Eutrophic Haplic Planosol (SXe) and a Eutrophic Yellow Argisol (PAe) soil were used. The treatments included the control, limestone by-product, dolomitic limestone, calcium (Ca) + magnesium (Mg) carbonates, and Ca + Mg carbonates + gypsum. Onions were grown in pots containing 10 dm3 of soil kept at a moisture level close to the field capacity. The onion biomass harvest (bulb + leaves) was performed 77 days after transplanting. Afterwards, the soil macronutrient content and the dry onion biomass were determined, as well as its production. The by-product application increased Mg2+ content in both soils (+74% in SXe and + 182% in PAe) and Ca2+ and sulfate (S-SO42-) contents, respectively, in the PAe (+62%) and SXe (+124%). There was an increase in S accumulation due to the onion biomass cultivated in both soils (about 85%). Regarding Ca and Mg accumulations, no difference was observed in the by-product treatment when compared to the control. Therefore, it is possible to infer that the limestone mining by-product from the Irati Formation is potentially useful as a source of secondary macronutrients and proves to be a clean environmental solution for soil fertilization, increasing the sustainability of the local production system. [ABSTRACT FROM AUTHOR]

Improvements in nitrogen use efficiency (NUE) in corn production systems are necessary, to decrease the economic and environmental losses caused by loss of ammonia volatilization (NH3-N). The objective was to study different nitrogen (N) fertilizer technologies through characterization of N sources, NH3-N volatilization losses, and their effects on the nutrient concentration and yield of corn grown in clayey and sandy soils in south Brazil. The treatments consisted of a control without N application as a topdressing, three conventional N sources (urea, ammonium sulfate, and ammonium nitrate + calcium sulfate), and three enhanced-efficiency fertilizers [urea treated with NBPT + Duromide, urea formaldehyde, and polymer-coated urea (PCU) + urea treated with NBPT and nitrification inhibitor (NI)]. The losses by NH3-N volatilization were up to 46% of the N applied with urea. However, NI addition to urea increased the N losses by NH3-N volatilization by 8.8 and 23.3%, in relation to urea alone for clayey and sandy soils, respectively. Clayey soil was 38.4% more responsive than sandy soil to N fertilization. Ammonium sulfate and ammonium nitrate + calcium sulfate showed the best results, because it increased the corn yield in clayey soil and contributed to reductions in NH3-N emissions of 84 and 80% in relation to urea, respectively. [ABSTRACT FROM AUTHOR]

Urea is the most used nitrogen (N) fertilizer worldwide, but its rapid hydrolysis on the soil surface results in N loss in the form of ammonia (NH3-N). Enzyme inhibitors have been investigated for their ability to reduce NH3-N volatilization, particularly from no-till and surface-limed soils. This study assessed the efficiency of stabilized fertilizers in reducing NH3-N volatilization under different lime rates and application methods. The experiment followed a 2 × 4 × 3 factorial design, with two liming methods (surface application and incorporation), four base saturation levels (50, 60, 70, and 90%), and three urea (45% N) sources: conventional urea, urea + N-(n-butyl)-Thiophosphoric triamide (NBPT), and urea + Boron (B) + Copper (Cu). NH3-N volatilization losses varied from 9.15 to 20.43 kg ha−1, accounting for 11.4 to 25.5% of the applied N rate. Base saturation did not influence NH3-N volatilization. Liming method, however, had a significant effect. Urea + B + Cu was effective in reducing volatilization loss only in soils ameliorated by lime incorporation (23% reduction compared with conventional urea). Urea + NBPT was effective in surface-limed and incorporated soils (up to 55.5% reduction). The results showed that soil management influences the efficiency of stabilized fertilizers and that urea + NBPT provides the best results. [ABSTRACT FROM AUTHOR]

Thousands of chemical analyses are carried out annually with the aim of recommending soil correction; however, these analyses are expensive, destructive, time-consuming, and can be harmful to the environment. As an alternative to conventional analysis methods, diffuse reflectance spectroscopy has been proposed as an option for evaluating the chemical characteristics of soil. The selection of variables has also emerged as an alternative to improve the performance of PLSR (partial least squares regression), as it decreases the root mean square error (RMSE) and increases the accuracy of the models. However, few studies have used a previous selection of variables for the construction of PLSR models to estimate the chemical characteristics of soil. In this context, the hypothesis in this study was that it is possible to calculate the liming recommendation in Oxisol based on the chemical characteristics estimated by PLSR, with a previous selection of variables using iPLS (Interval PLS). The objective was to calculate the need for liming based on chemical characteristics estimated via iPLS selection and PLSR modeling of specific wavelengths of soil reflectance. The experimental area was treated with different application rates of limestone, with and without incorporation, and phosphogypsum was applied in additional treatments. Soil assessments were carried out 5, 12, 24, and 36 months after the application of the treatments, using six layers: 0.00–0.05, 0.05–0.10, 0.10–0.20, 0.20–0.30, 0.30–0.40 and 0.40–0.60 m. Samples were subjected to conventional laboratory analyses, and spectral readings (400–2500 nm) were obtained with a spectroradiometer. The spectral curves were subjected to the iPLS variable selection method to generate PLSR models of the chemical characteristics used to calculate the liming recommendation. The chemical characteristics of the soil, such as Ca2+, sum of bases (SB), effective cation exchange capacity (CTCe), cation exchange capacity (CTC), and base saturation (BS), could be estimated, with values of R2 ranging from 0.83 to 0.92 in the calibration and validation steps, and from 0.84 to 0.90 for the prediction step (in the fourth assessment). The liming recommendation calculated based on the chemical characteristics predicted from the PLSR models showed a strong correlation (r > 0.86) with the liming recommendation calculated by conventional laboratory techniques. The fourth soil assessment yielded the best correlation coefficient (r = 0.95). [ABSTRACT FROM AUTHOR]

Biological nitrogen fixation (BNF) is what makes soybean economically viable. However, the launch of cultivars, with a high-yield potential and abiotic factors that reduce BNF, raised doubts about the need for nitrogen (N) fertilizers for soybeans. The objective of the research was to evaluate the effects of nitrogen supply, in two application times in furrow starter fertilization and top-dressing. The experimental design was in the 3 × 6 factorial scheme. The treatments consisted of three rates of N at in furrow starter fertilization (0, 10, and 20 kg ha−1 of N), and six rates of N in top-dressing, applied at the soybean R1 stage (0, 30, 60, 90, 120, and 150 kg ha−1 of N). The highest rate in furrow starter fertilization of 20 kg ha−1 of N resulted in the increase in the leaf area index (LAI) and specific leaf area (SLA), which are attributes that maximize the absorption of light energy, thus being able to positively influence yield. However, the BNF demonstrated that the strains of the selected Bradyrhizobium are efficient and capable of supplying the required N because the supplementation of nitrogen in furrow and/or top-dressing did not result in significant differences in the yield in relation to inoculated soybean. [ABSTRACT FROM AUTHOR]

Lime (L) and phosphogypsum (GY) are indispensable inputs in acidic soils that can alter the nutritional status of crops. The objective of this study was to evaluate the nutritional status and productivity of maize and wheat after the application of L and GY. The treatments consisted of a 2 x 4 + 3 factorial, with two forms of L application: surface (SL) and incorporated (IL) to obtain different levels of base saturation (BS%): 44, 60, 70 and 90; additionally three treatments involving the use of GY were evaluated: BS% 60 + 3.71 Mg ha−1; BS% 70 + 3.71 Mg ha−1 and BS% 70 + 7.42 Mg ha−1 of GY. The increase in BS% favored the absorption of magnesium (Mg) (SL and IL) and phosphorus (P) (IL) content in maize. IL increased the contents of nitrogen (N) and sulfur (S) and maize yield compared with SL. GY increased the maize yield by 7.6% compared with the control (BS 44%). Maize productivity correlated positively with calcium (Ca) (0.65), S (0.78) and N (0.54) leaf contents. In wheat, the increase in BS% reduced absorption of potassium (K) (SL and IL) and increased leaf Ca and Mg (IL) contents. Wheat yield correlated positively to leaf Ca (0.61) and S (0.62). Lime incorporation decreased wheat yield. High doses of GY (7.42 Mg ha−1) reduced absorption of Mg (maize and wheat) and K (maize). It is better to apply GY than to till the soil, thus maintaining uninterrupted no-till. [ABSTRACT FROM AUTHOR]

Large amounts of waste are produced daily by several industrial branches in Brazil, many of which can be used in agriculture. Applying nutrient-containing waste onto soil might minimize dependence on chemical mineral fertilizers, contributing to sustainable agriculture. Some of this waste increases soil pH, similar or even superior to that of limestone, providing opportunities for use in acidic soils. Different industrial waste may have elements that alter the electric charge of clay surfaces, which may alter soil physical characteristics related to dispersion and flocculation and consequently soil aggregation. Therefore, the presence of sodium may cause the dispersion of clays and calcium-containing waste, as its components may improve aggregation. The application of industrial waste can add heavy metals to the soil and, consequently, environmental problems if performed without strict regulations. Brazil has large industrial and agricultural areas, to which waste can be applied to supply part or all of the nutritional plant demand. To be recommended as economically effective and environmentally safe, a thorough waste analysis, chemical characterization of the soil, and knowledge of the nutritional requirements of the crop to be grown are required. [ABSTRACT FROM AUTHOR]

Emission of nitrous oxide (N2O) can be reduced using enhanced efficiency nitrogen fertilizers (EEFs), such as urease inhibitors and coating technologies. In this study, we evaluated the potential of EEFs to reduce N2O emissions in maize in a clayey Inceptisol subjected to no-till management under summer subtropical conditions, in southern Brazil. The EEF sources used included urea containing N-(n-butyl) thiophosphoric triamide (UR-NBPT), polymer-coated urea (UR-pol), in addition common urea (UR), nitrate (CN) and control treatment without the application of nitrogen fertilizer. N2O emissions were assessed using the static chamber method during one maize season and analyzed through non-linear regression, using a logistic model. The accumulated emission was 0.817, 0.613, 0.457 and 0.393 kg N2O ha−1, for CN, UR, UR-pol and UR-NBPT, respectively. The maximum daily emission of N2O did not vary between amidic forms, however for CN it occurred on the 4th day after application (DAA), while for urea forms it occurred on average at 5.3 DAA. The average N2O emission factor (FE-N2O) was 0.51%, approximately half the standard factor proposed by the Intergovernmental Panel on Climate Change (IPCC), which is 1%. The application of nitrogen increased the maize yield in relation to the control, but the sources of nitrogen did not differ, with an average yield of 10,455 kg ha−1. Based on our findings, the use of UR-NBPT and UR-pol in subtropical agroecosystems provides environmental benefits, by reducing N2O emissions in comparison with conventional nitrogen fertilizers (CN and UR), however, the EEFs did not offer agronomic advantages in maize yield. [ABSTRACT FROM AUTHOR]

Knowing the nutrient removal by soybean grain harvest in different varieties, locations, and over time is essential to correctly adjust agronomic recommendations, update farmers' practices, and increase nutrient use efficiency. A field-based research trial was carried out to assess macronutrients [nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), calcium (Ca), and sulfur (S)] removed in grain by modern soybean varieties from southern Brazil introduced between 2007 and 2016. We examined changes between our set of modern varieties and a dataset of historical values encompassing a wide range of varieties introduced before 2007. Moreover, we undertook a synthesis analysis using scientific literature published after 2007 to investigate nutrient removal by grain among modern Brazilian soybeans and a dataset that included field trials from Argentina, United States, and India. There were no yield gains across the years for modern soybean varieties introduced among 2007 and 2016 in Brazil, although the grain N and Mg concentrations decreased. Modern Brazilian soybeans increased nutrient removal compared with that by soybeans historically planted in Brazil, with 11.1, 26.9, 45.0, and 31.6% more N, P, K, and Mg removed, respectively. Our results indicated that soybean growing in Brazil removed 4.3% less N relative to the values reported in the literature dataset, whereas K removal was 21.4% greater. A significant difference was also recorded for high-yield soybean varieties, and Brazilian varieties removed 11.8% less N and 8.6% more K than varieties in the literature dataset. No differences were found among locations for P removal, averaging 4.9 kg Mg–1 grain. In conclusion, this study indicates that the amounts of nutrients removed by modern soybean varieties were greater relative to the historical values recorded in Brazil, excluding Ca and S. Nonetheless, in the middle to long term (10 years), a significant impact of plant breeding on grain nutrient concentration was recorded only for N and Mg. The difference in nutrient removal patterns between Brazil and other countries indicates an integrated effect of management, genotype, and environment on nutrient removal. These findings provide guidance for optimal nutrient management and specific information for plant breeding programs to understand nutrient variability. [ABSTRACT FROM AUTHOR]

Nanofertilizer application is becoming a sustainable alternative for plants micronutrients supply. Seed nutrient priming before seeding reduces non-target dispersion; although, applying nanofertilizer in correct concentration must be narrowly chosen to prevent germination and development issues. Here, we evaluated corn seedlings development and germination after seed priming with Mn3O4 nanoparticle (NP), Mn3O4 bulk and MnCl2. Sterile seeds were soaked for 8 hours in priming solutions of 0, 20, 40, 80 and 160 mg L−1 for each Mn sources. The seeds vigor and germination were evaluated after 7 days on germination paper. Root, shoot and total lengths were measured as well as root, shoot and total dry biomass. Compared to the control, the Mn3O4 NP and Mn3O4 bulk promoted beneficial effects. Mn3O4 NP seed-priming exhibited a concentration dependent profile in improving seedling growth, with greatest benefit around 20 mg L−1, providing higher germination, vigor, dry biomass and length than control and the other source tested. Particle size plays an important role in the reactivity of Mn3O4 NP. On the other hand, seeds primed with soluble source did not differ from the control. These findings support NP-seed priming as an alternative to delivery micronutrients. [ABSTRACT FROM AUTHOR]

Nutrient leaf application is complementary to soybean nutritional management, mainly at maturity, when plants present high nutritional demand and high nutrients and photoassimilate translocation rates for seed production. The aim of this research was to evaluate the agronomic performance, physiological quality, and nutritional contents of soybean seeds after application of different rates (0, 0.50, 1.0, 1.5, 2.0, and 2.5 kg ha−1) of foliar fertiliser containing calcium (20%) and boron (4%) at the R3 stage (onset of pod formation). This research was carried out in two sites (Guaragi and Floresta) both in Parana State, Brazil, in randomised complete blocks with 4 replicates. Calcium and boron leaf application increased grain sulphur and nitrogen levels (Guaragi) but reduced phosphorus and magnesium (Floresta). Regarding physiological quality, foliar fertilisation increased the index of germination speed. The yield and number of pods increased up to the rate of 0.6 and 1.2 kg ha−1 of leaf fertiliser in Floresta. Foliar fertilisation with calcium and boron showed advantages, however, results depended on the site, indicating different levels of soil fertility and climatic characteristics. [ABSTRACT FROM AUTHOR]

Nanoparticle (NP) use is becoming important alternative in different branches of science such as in agriculture, used as new source of fertiliser. In this study, it was tested iron (Fe) NP, applied as corn seed priming. In order to evaluate the early growth and development of the corn seedling a factorial experiment (5 × 3) was performed in a complete random way design with 4 replications. One of the factors were concentrations of (0, 20, 40, 80, 160 mg L−1) related to iron inside and the factor with three levels were sources (Fe3O4 NP, Fe3O4 bulk and FeCl3). 50 sterile seeds were the plot composition, which were soaked in the different Fe concentration solution containing a total volume of 200 mL for 8 h. Germination and biometric development were evaluated. Fe NPs promoted beneficial responses for seedling growth compared to other Fe sources tested here. It was realised that Fe3O4 NP concentration beneficial effects was lower compared to the other tested sources. Particle size had an important assignment in the bioavailability. The plant response reached in this research indicated iron NPs can consist efficiency for corn seed priming when applied between 50 and 70 mg L−1 concentration based on interpolation. [ABSTRACT FROM AUTHOR]

The application of alternative and sustainable soil correctives to increase soil pH in sowing furrows can promote yield increases in soybean crops. The aim of this study was to characterize two different soil corrective sources in granular and powder forms and to evaluate the agronomic efficiency of their complementary application in a sowing furrow of a soybean crop. Two experiments were conducted. Regarding the first experiment, there were 5 treatments: control, biogenic lime powder, biogenic granular lime, common lime powder, and common granular lime. All applications were performed in a seeding furrow at a dose of 16 kg ha−1. The experiment was carried out in randomized blocks with five replicates. The second experiment involved the characterization of the sources and their forms by means of X-ray diffraction, total chemical analysis and neutralization power. The results showed that in comparison to the control, the application of correctives to increase soil pH in the sowing furrow promoted significantly higher growth and greater soybean yield, although the sources did not differ from each other. The soil pH corrective application in the sowing furrow was important for dissolution in the soil and consequently soybean yield. The neutralizing capacities of the correctives for all the granulometries tested were similar. Therefore, applying these soil pH correctives in granular or powder forms in sowing furrows might be an additional management alternative. [ABSTRACT FROM AUTHOR]

Knowledge on the behavior of cumulative N-NH3 volatilization is important for defining the strategies to reduce the N losses, as well as increasing the efficiency of nitrogen fertilization in different environments. The present study, which uses nonlinear models, aims at assessing the cumulative N-NH3 losses through volatilization by applying different rates of urea over time to two soils cultivated with second-season corn. Two experiments were carried out; one in a clayey Oxisol, and another in a sandy-clay loam Ultisol in a randomized block experimental design. N-NH3 volatilization was quantified by using semi-open static chambers and spectrophotometry (salicylate blue). The cumulative N-NH3 losses were similar at both rates of urea and in both soils assessed, ranging from 34.04% to 43.15% of the N applied. The highest N-NH3 volatilization occurred from 1.03 to 6.48 days after applying the fertilizer, and the highest volatilization rates ranged from 0.90 to 2.91 kg ha-1 d-1. The shortest time to reach the highest volatilization rate, associated with the highest daily rate of N-NH3 volatilization, was seen in the Ultisol. Although the volatilizations accumulated in both soils were similar, this result was only seen due to the climatic conditions after applying the fertilizer, which contributed to minimize the N-NH3 losses. The use of nonlinear models has shown an appropriate data adjustment, providing parameters that help to understand the behavior of N-NH3 volatilization accumulated over time in second-season corn. [ABSTRACT FROM AUTHOR]

The effects of lime and phosphogypsum (GY) on wheat (Triticum aestivum) nutrition are well documented. However, little is known about the influence of these soil amendments on biometric parameters or yield components. This study investigated the effects of lime and GY on wheat crops grown at cation base saturation (BS) levels of 44%, 70%, and 90%, achieved by surface application or soil incorporation of lime. Two additional treatments were included: surface liming to 70% combined with a standard rate of GY (3.71 Mg ha−1) or twice the recommended GY rate (7.42 Mg ha−1). The experiment was conducted during two crop seasons in Southern Brazil. The treatments did not influence dry biomass partitioning between spikes, stems, and leaves and total. In one season, liming increased flag leaf area, which was strongly associated with grain yield. Regardless of the rate, application method, and combined use of GY, liming increased the number of grains per spike in both seasons, which was the variable that most influenced wheat yield. Liming also increased spike length and the number of spikelets per spike in the 2018 season. No benefits were seen when lime was applied by soil incorporation, BS was raised to 90%, or liming was combined with GY application. The results showed a positive effect of liming on wheat yield components that are associated with grain yield. [ABSTRACT FROM AUTHOR]

The objective of the study was to evaluate the effect of foliar application of urea and urea-formaldehyde, triazone-based fertilizers on soybean and corn crops. Four experiments were carried out, two on soybeans, one on first season corn, and the other on second season corn. The experiments were conducted using a randomized block design, with 5 treatments studied: T1—control without application of foliar nitrogen (N); T2—foliar application of conventional urea solution and three treatments with Hexion foliar fertilizers based on urea-formaldehyde and triazone (N-Hexion®), with varying levels of N and slow-release components; T3—Hexion 1; T4—Hexion 2; and T5—Hexion 3. The foliar application of conventional urea showed no statistically significant difference in relation to the control for the yield components and grain yield for the soybean crops in seasons 2018–2019 and 2019–2020. Urea-formaldehyde/triazone treatments showed a significant increase in yield for soybeans in the 2018–2019 season compared to the control and to conventional urea. Nitrogen fertilizers with high percentages of slow-release compounds promote nitrogen release more slowly, which led to no significant increase in yield for Hexion 1. No statistical differences were observed in the corn yield for the first and second crop. [ABSTRACT FROM AUTHOR]

Nanofertilizers are increasingly explored for sustainable micronutrient delivery in agriculture. Pre-treating seeds with nanofertilizers prior to planting (i.e., seed priming) reduces concerns about nanoparticle (NP) fertilizer non-target dispersion; however, priming formulations and concentrations must be carefully selected to avoid germination inhibition and toxicity. Here we investigate changes in corn seed germination and seedling development after seed priming with ZnO NPs, ZnO bulk and ZnCl2. To evaluate the effects sterile seeds were immersed in priming solutions of 0, 20, 40, 80, 160 mg L−1 Zn for the three Zn sources. Following an 8 h priming the seeds were evaluated for germination and vigor for 5 days on germination paper. Root and shoot lengths were measured as well as fresh and dry biomass. Compared to the control, the ZnO NP and ZnCl2 seed priming promoted beneficial effects. ZnO NP seed-priming exhibited a concentration dependent profile in improving seedling growth, with greatest benefit around 80 mg L−1, providing 17%, 25% and 12% higher values than control for germination, root length, and dry biomass production, respectively. In contrast, seeds primed with bulk ZnO did not differ from the control. These findings support NP-seed priming as an alternative to delivery of essential micronutrients, such as zinc, to corn seedlings. [ABSTRACT FROM AUTHOR]

Studies on the use of hyperspectral remote sensing for nutrient prediction in soybean (Glycine max L.) leaves are limited, especially regarding the selection of wavelengths. Therefore, the objective of this study was to estimate macro and micronutrients in soybean leaves by employing reflectance data modeled by Partial Least Squares Regression (PLSR) from bands selected by the iPLS (Interval PLS), method with a script developed for MATLAB R2018a. The experimental area was treated with different doses of limestone, with and without incorporation, also with phosphogypsum application in additional treatments. The soybean crops of 2018/2019 and 2019/2020 had the nutritional status evaluated by a random collection of the third fully developed trefoil in the R2 (full flowering) and R5.5 (76–100% grain filling) reproductive phenological stages. The leaf samples were submitted to conventional laboratory analyses. The Ca, Mg, K, P, S, Cu, Fe, Mn, and Zn elements in the leaves were quantified through spectrometry. A field spectroradiometer performed spectral data acquisition in the visible-near infrared, short-wave infrared spectral range of soybean leaves. The spectral curves were subjected to iPLS, and PLSR models were fitted. After iPLS selection, the coefficient of determination (R2) values of PLSR models were on average 15.3% and 16.6% higher in calibration and validation, respectively, compared to classical methods. The PLSR model for Mn, which obtained R2 above 0.90 in the calibration and validation phases, stood out. The Root Mean Square Error (RMSE) decreased, on average, more than 15.0%, both in calibration and validation, after applying the iPLS selection. The models for Ca and Mn stood out with over a 30.0% decrease in RMSE, in calibration and validation. The iPLS selection was efficient in improving the performance and accuracy of the PLSR models, increasing the R2 and decreasing the RMSE, opening new possibilities for the analysis and prediction of macro and micronutrients in plants. [Display omitted] • The wavelengths selection by iPLS was efficient in improving the PLSR models. • R2 increased on average 15% and 17% in calibration and validation, respectively. • RMSE decreased on average 15% after applying the iPLS selection. • The PLSR model for Mn, which obtained R2 above 0.90 stood out. [ABSTRACT FROM AUTHOR]