Vinte anos de plantio direto no cerrado: comportamento da soja em função da calagem, gessagem, culturas de cobertura e adubação nitrogenada
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Data
2023-01-09
Autores
Bozada, Hugo Garcia
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
No Sistema Plantio Direto (SPD), a calagem apresenta uma dinâmica diferente dos preparos convencionais. O sistema preconiza o não revolvimento do solo, presença de palha na superfície e rotação de culturas. Diante deste contexto, o presente trabalho teve por objetivo avaliar em uma área com vinte no SPD, a influência dos diferentes modos de aplicação e doses de calcário, gesso, culturas de cobertura no comportamento da soja e no estado nutricional das plantas de cobertura. Na safra 2000/01, após preparo convencional do solo, foi semeada a cultura da soja. Um experimento de longa duração foi iniciado no ano agrícola 2000/01 com a implantação do SPD através da instalação dos tratamentos com modos e épocas de aplicação de calcário e culturas de cobertura na entressafra, tendo a soja, como a cultura principal, cultivada no período de primavera/verão. Os tratamentos compreendiam: T1 - aplicação total da dose recomendada (1,59 t ha-1) em outubro de 2001 e sua incorporação a 0 – 0,20 m; T2 - aplicação total da dose recomendada em outubro de 2001, em superfície; T3 - aplicação de 1/2 da dose recomendada em outubro de 2001 e 1/2 em agosto de 2002, todas em superfície; T4 - aplicação de 1/3 da dose recomendada em março de 2001, 1/3 em outubro de 2001 e 1/3 em agosto 2002, todas em superfície; T5 - testemunha (sem aplicação de calcário). Nos anos agrícolas 2001/02 e 2002/03, a soja foi novamente cultivada na área, sempre no período de primavera/verão, utilizando-se o sistema de semeadura direta. As culturas de cobertura utilizadas foram, em junho de 2001, milho e sorgo, em outubro de 2001, milheto em área total e, em setembro de 2002, capim pé-de-galinha (Eleusine coracana) e sorgo. A partir da safra 2003/04, as culturas de cobertura foram sempre o milheto e a C. juncea, semeadas no período de primavera. A cada 3 anos alterna-se a cultura de soja por milho e vice-versa, como culturas produtoras de grãos. Quando do cultivo do milho, também tem-se avaliado a aplicação de 0, 90 e 180 kg de N ha- anualmente. Durante o período de 2000/01 a 2020, os tratamentos T1, T2, T3, T4 e T5, receberam respectivamente 6,92, 11,44, 7,73, 10,63 e 0,81 t há-1 de calcário, sendo que, os T3 e T4, receberam adicionalmente 1,7 t há- de gesso, em fevereiro/2017. As avaliações realizadas no ano agrícola 2020/21 foram: atributos químicos do solo amostrado a 0-0,10, 0,10-0,20 e 0,20-0,40 m, produção de massa seca e retorno de nutrientes nas culturas de cobertura e características agronômicas e produtividade de grãos da soja.
In the No-Tillage System (SPD), liming presents a dynamic different from conventional tillage. The system advocates non-revolution of the soil, presence of straw on the surface and crop rotation. Given this context, this study aimed to evaluate, in an area of twenty in the NT, the influence of different application modes and doses of limestone, gypsum, cover crops on soybean behavior and the nutritional status of cover crops. In the 2000/01 harvest, after conventional soil preparation, the soybean crop was sown. A long-term experiment was started in the 2000/01 crop year with the implementation of the SPD through the installation of treatments with modes and times of lime application and cover crops in the off-season, with soybean as the main crop, cultivated in the period of spring/summer. The treatments included: T1 - total application of the recommended dose (1.59 t ha-1) in October 2001 and its incorporation at 0 – 0.20 m; T2 - total application of the dose recommended in October 2001, on the surface; T3 - application of 1/2 of the recommended dose in October 2001 and 1/2 in August 2002, all on the surface; T4 - application of 1/3 of the recommended dose in March 2001, 1/3 in October 2001 and 1/3 in August 2002, all on the surface; T5 - control (without lime application). In the 2001/02 and 2002/03 crop years, soybeans were again cultivated in the area, always in the spring/summer period, using the direct sowing system. The cover crops used were, in June 2001, corn and sorghum, in October 2001, millet in total area and, in September 2002, chicken foot grass (Eleusine coracana) and sorghum. From the 2003/04 crop onwards, the cover crops were always millet and C. juncea, sown in the spring period. Every 3 years, soybeans are alternated with corn and vice versa, as grain-producing crops. When growing corn, the application of 0, 90 and 180 kg of N ha-1 annually has also been evaluated. During the period from 2000/01 to 2020, treatments T1, T2, T3, T4 and T5 received respectively 6.92, 11.44, 7.73, 10.63 and 0.81 t ha-1 of limestone, T3 and T4 received an additional 1.7 t ha-1 of gypsum in February/2017. The evaluations carried out in the 2020/21 crop year were: chemical attributes of the soil sampled at 0-0.10, 0.10-0.20 and 0.20-0.40 m, dry mass production and nutrient return in cover crops and agronomic characteristics and soybean grain yield.
In the No-Tillage System (SPD), liming presents a dynamic different from conventional tillage. The system advocates non-revolution of the soil, presence of straw on the surface and crop rotation. Given this context, this study aimed to evaluate, in an area of twenty in the NT, the influence of different application modes and doses of limestone, gypsum, cover crops on soybean behavior and the nutritional status of cover crops. In the 2000/01 harvest, after conventional soil preparation, the soybean crop was sown. A long-term experiment was started in the 2000/01 crop year with the implementation of the SPD through the installation of treatments with modes and times of lime application and cover crops in the off-season, with soybean as the main crop, cultivated in the period of spring/summer. The treatments included: T1 - total application of the recommended dose (1.59 t ha-1) in October 2001 and its incorporation at 0 – 0.20 m; T2 - total application of the dose recommended in October 2001, on the surface; T3 - application of 1/2 of the recommended dose in October 2001 and 1/2 in August 2002, all on the surface; T4 - application of 1/3 of the recommended dose in March 2001, 1/3 in October 2001 and 1/3 in August 2002, all on the surface; T5 - control (without lime application). In the 2001/02 and 2002/03 crop years, soybeans were again cultivated in the area, always in the spring/summer period, using the direct sowing system. The cover crops used were, in June 2001, corn and sorghum, in October 2001, millet in total area and, in September 2002, chicken foot grass (Eleusine coracana) and sorghum. From the 2003/04 crop onwards, the cover crops were always millet and C. juncea, sown in the spring period. Every 3 years, soybeans are alternated with corn and vice versa, as grain-producing crops. When growing corn, the application of 0, 90 and 180 kg of N ha-1 annually has also been evaluated. During the period from 2000/01 to 2020, treatments T1, T2, T3, T4 and T5 received respectively 6.92, 11.44, 7.73, 10.63 and 0.81 t ha-1 of limestone, T3 and T4 received an additional 1.7 t ha-1 of gypsum in February/2017. The evaluations carried out in the 2020/21 crop year were: chemical attributes of the soil sampled at 0-0.10, 0.10-0.20 and 0.20-0.40 m, dry mass production and nutrient return in cover crops and agronomic characteristics and soybean grain yield.
Descrição
Palavras-chave
SPD, Calcário, Produtividade, Limestone, Productivity