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O objetivo deste trabalho foi avaliar o efeito do preparo e não preparo do solo, de doses de N aplicadas em cobertura e da irrigação na produtividade do feijoeiro cv. IAC Carioca Eté. O delineamento experimental foi o de blocos casualizados em esquema fatorial com quatro repetições. Os tratamentos constituíram-se da combinação de três lâminas de água, com preparo do solo com arado de aiveca, com grade pesada e sem preparo (plantio direto) e com 0, 30, 60, 90 e 120 kg ha-1 de N aplicados em cobertura aos 15 dias após a emergência das plantas. A irrigação foi realizada com um sistema fixo de irrigação convencional por aspersão e no manejo de água foram utilizados diferentes coeficientes de cultura (Kc) distribuídos em períodos compreendidos entre a emergência e a colheita. A menor lâmina de água propiciou produtividade de grãos semelhante à das outras lâminas, mas com menor custo. O preparo do solo com arado de aiveca não diferenciou do preparo com grade aradora e proporcionou maior produtividade de grãos em relação ao plantio direto. A adubação nitrogenada não afetou a produtividade de grãos.

O presente trabalho teve por objetivo estudar três espaçamentos entre fileiras (30, 40 e 50 cm) e três densidades de semeadura (100, 150 e 200 sementes viáveis/m2) quanto a fenologia da planta, os componentes da produção e a produtividade de grãos do arroz de sequeiro cv. IAC 201. Desta forma, foi instalado um experimento em condições de campo, em um Latossolo Vermelho escuro, epi-eutrófico, textura argilosa, em Selvíria, MS. A redução do espaçamento entre fileiras aumentou o número de colmos e de panículas. O aumento da densidade de semeadura reduziu o perfilhamento por planta. A densidade de 100 sementes/m2 é mais adequada para o cultivar IAC 201. Em cultivo de sequeiro sob alta precipitação e boa distribuição pluvial, o espaçamento de 30 cm entre fileiras de plantas, proporcionou maior produtividade de grãos do cultivar IAC 201 de arroz.

This research analyzed the effects of inoculation with Rhizobium tropici, combined with beneficial microorganisms, on the reduction of NPK fertilization and its impacts on common beans. Conducted in two types of soil (clayey Oxisol and sandy Ultisol), the experimental design was a randomized block design under a factorial scheme 4 × 4, with different combinations of inoculation (Rhizobium tropici alone or in combination with Azospirillum brasilense, Bacillus subtilis, and Trichoderma harzianum) and fertilization doses (0%, 33%, 66%, and 100% of the recommended dose). The results showed that inoculation with R. tropici, especially in combination with Trichoderma harzianum, increased nodule formation and improved agronomic parameters such as leaf chlorophyll, dry matter of the plant, number of pods, and grains. Co-inoculation with Azospirillum brasilense resulted in a significant increase in grain yield, particularly in clayey soil with 33% NPK. Inoculation with lower doses of NPK was sufficient for good yield, suggesting the feasibility of reducing the use of mineral fertilizers. This study indicates that soils with corrected fertility, in a no-tillage system, can contribute to the reduction of fertilizer use due to the cycling of organic matter and improvement of soil health. Additionally, the use of microorganisms is an effective ally for the sustainability of agroecosystems. [ABSTRACT FROM AUTHOR]

In tropical regions, maintaining crop residues in the soil is challenging. Silicon (Si) may increase the persistence of these residues in the soil, as it is a precursor to lignin, providing a gradual release of nutrients for subsequent crops. Therefore, the objective of this study was to evaluate the influence of different doses of calcium silicate (Ca2SiO4) (0, 1, 2, and 3 Mg ha⁻1) and limestone (0, 1, 2, and 3 Mg ha⁻1) on the lignin content, residue decomposition, and nutrient release of four cover crops—Pennisetum glaucum, Urochloa ruziziensis, Crotalaria spectabilis, and Cajanus cajan—at various decomposition stages following cover crop management (0, 30, 60, 90, and 120 days). The experiment was conducted in the field at the experimental area of the Faculty of Engineering at Ilha Solteira-UNESP, located in the municipality of Selvíria, state of Mato Grosso do Sul, on Ferralsol. The decomposition rate of the residues was assessed using the decomposition bag method, which was installed after cover crop management. The concentrations of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), Si, lignin, and cellulose were determined. Silicate application did not affect the accumulation of nutrients by cover crops and their release into the soil. There was no relationship between the remaining Si in the dry matter of plants and more persistent residues. The most persistent plants had higher final dry matter lignin content. Using pearl millet and pigeon peas resulted in more persistent residues in the soil. [ABSTRACT FROM AUTHOR]

The cultivation of maize is one of the most important crops for the the Brazilian Agribusiness, representing 6.4% of world production. It should be noted that world production is almost 800 million tons and the United States is responsible for 42% of total production. Nitrogen fertilization is a very important step for the production system of maize, both in the aspect of quantification of doses, and in defining the time of application. The use of portable chlorophyll meter has been widely used, especially in tests of calibration and evaluation of deficiency, on the other hand, there is no literature on using the chlorophyll meter to indicate the amount of N to be applied. The experimental design was the randomized completely blocks with four replications and 6 treatments with nitrogen fertilization by coverage (0, 60,100, 120, 140 and 160 kg N ha-1) using urea. There is verified positive relationship between N rates and nitrogen content and it was affected by increasing doses of this nutrient, until 120 kg N ha-1. The curve of nitrogen fertilization using the Chorophyll meter was possible by the excellent correlations between doses and readings, doses and N content, and doses and grain yield. It was concluded that there was a good correlation between levels of nitrogen applied in coverage, with ICF readings, nitrogen content and and grain yield. Is possible to establish a curve for the nitrogen fertilization by the ICF readings at the time of covering.

Cereals and green manures intercropping contributes to sustainable agriculture as it combines food production with biomass for soil cover formation. This study aimed to evaluate the intercropping of rice and green manures effects on the agronomic and qualitative performance of rice, as well as dry mass yield for the no-tillage system. A two-year experiment with 8 treatments: rice as sole crop or intercropped with Arachis pintoi, Calopogonium mucunoides, Crotalaria breviflora, Crotalaria spectabilis, Stylosanthes capitata and macrocephala, Canavalia ensiformis, and Cajanus cajan was conducted in the Brazilian Cerrado region. The results showed that the shoot dry mass and height of plants was affected by the cultivated species. Rice intercropped with A.pintoi, C.mucunoides, C.breviflora, C.spectabilis and S.capitata and macrocephala promoted yield and grain quality similar to those found with rice as sole crop. Intercropping systems of rice with C.spectabilis, C.ensiformis and C.cajan increased the number of unfilled spikelets and reduced the number of filled spikelets and yield by 33, 24 and 58%, respectively. Intercropping systems with A.pintoi, C.mucunoides, C.breviflora, C.spectabilis, C.ensiformis and C.cajan produced adequate dry mass for the maintenance of soil cover in quality no-tillage system. [ABSTRACT FROM AUTHOR]

Composted sewage sludge (CSS) is an organic fertilizer that can be used as a source of micronutrients in agriculture. However, there are few studies with CSS to supply micronutrients for the bean crop. We aimed to evaluate micronutrient concentrations in the soil and their effects on nutrition, extraction, export, and grain yield in response to CSS residual application. The experiment was carried out in the field at Selvíria-MS, Brazil. The common bean cv. BRS Estilo was cultivated in two agricultural years (2017/18 and 2018/19). The experiment was designed in randomized blocks with four replications. Six different treatments were compared: (i) four increasing CSS rates, i.e., CSS5.0 (5.0 t ha−1 of applied CSS, wet basis), CSS7.5, CSS10.0, CSS12.5; (ii) a conventional mineral fertilizer (CF); (iii) a control (CT) without CSS and CF application. The available levels of B, Cu, Fe, Mn, and Zn were evaluated in soil samples collected in the 0–0.2 and 0.2–0.4 m soil surface horizons. The concentration, extraction, and export of micronutrients in the leaf and productivity of common beans were evaluated. The concentration of Cu, Fe, and Mn ranged from medium to high in soil. The available levels of B and Zn in the soil increased with the residual rates of CSS, which were statistically not different from the treatments with CF. The nutritional status of the common bean remained adequate. The common bean showed a higher requirement for micronutrients in the second year. The leaf concentration of B and Zn increased in the CSS7.5 and CSS10.0 treatments. There was a greater extraction of micronutrients in the second year. Productivity was not influenced by the treatments; however, it was higher than the Brazilian national average. Micronutrients exported to grains varied between growing years but were not influenced by treatments. We conclude that CSS can be used as an alternative source of micronutrients for common beans grown in winter. [ABSTRACT FROM AUTHOR]