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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]

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]

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]

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]

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]