Efeito dos sistemas de manejo do solo e da cobertura de entressafra na cultura da soja (Glycine max L.)

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Decomposição de resíduos vegetais de plantas de cobertura e produtividade da cultura de milho

Pós-graduação em Agronomia (Produção Vegetal) - FCAV

Adubação nitrogenada em milho em semeadura direta e cultivo convencional na região Meio-Norte do Piauí

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Plantas de cobertura e doses de nitrogênio em pré-semeadura em algodoeiro

Pós-graduação em Agronomia - FEIS

Consórcio de plantas de cobertura para a cultura de algodoeiro no sistema de semeadura direta

Pós-graduação em Agronomia - FEIS

Absorção de nutrientes e alterações químicas em Latossolos cultivados com plantas de cobertura em rotação com soja e milho

The effects on soil chemical properties brought about by cover crops vary considerably. This study was conducted to evaluate nutrient uptake by five cover crops used for grain, seed and forage production at different seed densities per hectare, as well as uptake by spontaneous vegetation, and their effect on the chemical properties of two Oxisols when grown in rotation with soybean and corn. The experiments were set up in Votuporanga, SP, Brazil and Selvíria, MS, Brazil in March 2008 after conventional soil tillage. A randomized complete block experimental design was used with four replications with the following cover crops at different seed densities: Sorghum bicolor at 6, 7 and 8 kg ha-1; Pennisetum americanum at 10, 15 and 20 kg ha-1; Sorghum sudanense at 12, 15 and 18 kg ha-1; hybrid of Sorghum bicolor with Sorghum sudanense at 8, 9 and 10 kg ha-1; and Urochloa ruziziensis at 8, 12 and 16 kg ha-1. We also used a spontaneous vegetation control. After management of the cover crops, in the first year of study, soybean was sown in no-tillage system and, in the second year, corn was sown, also in a no-tillage system. We evaluated the dry matter yield of different cover crops, nutrient uptake by the cover crops, and the chemical changes in the soil. It was found that in clayey soils with high aluminum content, as in Selvíria, sudan grass at a seed density of 18 kg ha-1, and sorghum at a seed density of 6 kg ha-1, in combination with liming, contributed to reduction of aluminum content and high potential acidity and an increase in base saturation. The different seed densities of each cover crop did not affect the dry matter yield of the cover crop itself, but affected nitrogen uptake of the hybrid Sorghum bicolor with Sorghum sudanense at a seed density of 10 kg ha-1, with lower uptake than at a seed density of 8 kg ha-1. Seed density also affected the organic matter content in the soil with sudan grass, with the seed density of 15 kg ha-1 providing more organic matter content than a seed density of 18 kg ha-1.

Teor de nitrogênio inorgânico no solo em função de plantas de cobertura, fontes de nitrogênio e inibidor de nitrificação

A utilização de plantas de cobertura pode alterar a rela-ção NO3-:NH4+ no solo, proporcionando maiores quantidades de NH4+ e podendo viabilizar o desenvolvimento de culturas que absorvem mais e preferem esta forma de nitrogênio (N), como o arroz. Objetivou-se avaliar a influência da interação de plantas de cobertura e fontes de N, com e sem inibidor de nitrificação (dicianodiamida), em sistema plantio direto (SPD). O experimento foi realizado em 2009/2010, em Botucatu (SP), em Latossolo Vermelho distroférrico cultivado por seis anos no SPD. O delineamento experimental foi em blocos casualizados, em esquema de parcela subdividida, com quatro repetições. As parcelas foram constituídas por seis espécies de plantas de cobertura do solo (Urochloa brizantha, U. decumbens, U. humidicola, U. ruziziensis, Pennisetum americanum e Crotalaria spectabilis) e as subparcelas por sete formas de fertilização nitrogenada, aos 0 e 30 dias após a emergência (DAE) do arroz [1 - controle, sem aplicação de nitrogênio; 2 - nitrato de cálcio (40 + 40 kg ha-1); 3 - nitrato de cálcio (0 + 80 kg ha-1); 4 - sulfato de amônio (40 + 40 kg ha-1); 5 - sulfato de amônio (0 + 80 kg ha-1); 6 - sulfato de amônio + dicianodiamida (40 + 40 kg ha-1); e 7 - sulfato de amônio + dicianodiamida (0 + 80 kg ha-1)]. O uso do inibidor de nitrificação e o cultivo de C. spectabilis proporcionaram maiores teores de amônio no solo. A aplicação da fonte amoniacal sem inibidor em dose total aos 30 DAE e com inibidor tanto parcelada quanto em dose total proporcionaram os maiores teores de nitrato no solo.

Congo grass grown in rotation with soybean affects phosphorus bound to soil carbon

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Crescimento radicular de espécies utilizadas como cobertura decorrente da compactação do solo

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Aplicação de sistemas neuro-fuzzy e espectrometria no infravermelho próximo para a identificação em tempo real do teor de nitrogênio foliar em cana-de-açúcar

Pós-graduação em Engenharia Elétrica - FEB

Doses e épocas de aplicação de potássio na cultura da soja em sucessão a plantas de cobertura

Potassium (K) is the second nutrient that is required in larger amounts by soybean crop. With the use of high doses of that nutrient and increase of no-tillage areas in last years, some changes occurred in ways of this nutrient application, as well as the introduction of cover crops in the system for straw formation. Due those facts, the aim with this work was to study doses and times of potassium application for soybean sowed as succession for cover crops in no-tillage system, in a clayey Distrofic Red Latosol, in cerrado region. The experimental design was a randomized block with treatments arranged in 3x3x5 factorial scheme, with the following factors, cover crops: Pearl millet (Pennisetum glaucum) and Proso millet (Panicum miliaceum) and a control (fallow area), rates of K2O (0, 50 e 100 kg ha(-1)) and K2O application forms (100% in the cover crops; 100% at sowing of soybean; 100% in topdressing in soybean; 50% at sowing cover crops + 50% at soybean sowing; 50% at soybean sowing + 50% in topdressing in the soybean) with four replicates. The Pennisetum glaucum as soybean predecessor crop yields higher dry matter content than the Panicum miliaceum in a short period of time. In clay soil with high content of potassium there was no response to the applied potassium levels. Full doses of potassium maintenance fertilization can be applied in the predecessor cover crop, at sowing or topdressing in soybean crop.

Modos de aplicação e reaplicação de calcário nas culturas de milho e soja em plantio direto: Efeito residual

Pós-graduação em Agronomia - FEIS

Produção de soja e milho cultivados sobre diferentes coberturas

The no-tillage system is an important technique for maintaining and restoring the productive capacity of conventionally managed soils and degraded areas. The aim of this study was to evaluate the production of soy and maize grown on the straw of five cover crops and on spontaneous vegetation. The experiments were carried out in Votuporanga, in the state of Sao Paulo and in Selviria, in Mato Grosso do Sul, Brazil, in March 2008, after conventional soil preparation. The experimental design was of randomised blocks with four replications, using the following cover crops in different amounts of seed per hectare, to make up the treatments: Sorghum bicolor - 6, 7 and 8 kg ha(-1); Pennisetum americanum - 10, 15 and 20 kg ha(-1); Sorghum sudanense - 12, 15 and 18 kg ha(-1); S. bicolor and S. sudanense hybrid - 8, 9 and 10 kg ha(-1); and Urochloa ruziziensis - 8, 12 and 16 kg ha(-1). A control treatment with spontaneous vegetation was also used. After management of the cover crops, soy was planted in the first year of the study, and maize sown in the second, both under a no-tillage system. The dry matter accumulated by the different cover crops, and the agronomic characteristics of the soy and maize were all evaluated. It was concluded that the different cover plants proved to be good options for preceding the soy crop in Votuporanga, SP and the maize in Selviria, MS, and that the different amounts of seed used for each cover crop resulted in differences in relation to the agronomic characteristics of the crops of soy and maize.

Managing soil carbon for multiple ecosystem benefits positive exemplars: Latin America (Brazil and Argentina)

Agriculture provides food, fibre and energy, which have been the foundation for the development of all societies. Soil carbon plays an important role in providing essential ecosystem services. Historically, these have been viewed in terms of plant nutrient availability only, with agricultural management being driven to obtain maximum benefits of this soil function. However, recently, agricultural systems have been envisioned to provide a more complete set of ecosystem services, in a win-win situation, in addition to the products normally associated with agriculture. The expansion and growth of agricultural production in Brazil and Argentina brought about a significant loss of soil carbon stocks, and consequently the associated ecosystem services, such as flooding and erosion control, water filtration and storage. There are several examples of soil carbon management for multiple benefits in Brazil and Argentina, with new soil management techniques attempting to reverse this trend by increasing soil carbon (C) stocks. One example is zero tillage, which has the advantage of reducing CO2 emissions from the soil and thus preserving or augmenting C stocks. Crop rotations that include cover crops have been shown to sequester significant amounts of C, both in Brazilian subtropical regions as well as in the Argentinean Pampas. Associated benefits of zero tillage and cover crop rotations include flood and erosion control and improved water filtration and storage. Another positive example is the adoption of no-burning harvest in the vast sugarcane area in Brazil, which also contributes to reduced CO2 emissions, leaving crop residues on the soil surface and thus helping the conservation of essential plant nutrients and improving water storage.

Early growth of common bean cropped over ruzigrass residues

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)