Sistemas de produção para milho segunda safra consorciado com Urochloa ruziziensis, envolvendo rotação de culturas com plantas de cobertura, arroz e soja
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Data
2019-02-20
Autores
Portugal, José Roberto
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Universidade Estadual Paulista (Unesp)
Resumo
O sistema de produção baseado na sucessão de culturas, assim como a sucessão entre soja e milho no Brasil, não se sustenta ao longo dos anos. Assim, a inserção de plantas de cobertura, bem como o cultivo do arroz substituindo parte da área de soja, podem ser opções para beneficiar o sistema agrícola no Cerrado. O objetivo foi avaliar a adoção de plantas de cobertura no cultivo do arroz de terras altas, da soja e o efeito no milho segunda safra consorciado com Urochloa. O projeto foi constituído por três subprojetos. Subprojeto 1: Sistemas de produção para arroz de terras altas com o uso de plantas de cobertura. Subprojeto 2: Sistemas de produção para soja com o uso de plantas de cobertura. Subprojeto 3: Milho segunda safra consorciado com Urochloa ruziziensis, cultivado sobre palhada de arroz e soja, em função de plantas de cobertura. Foram utilizadas seis plantas de cobertura [milheto (Pennisetum americanum), crotalária (Crotalaria juncea), guandu (Cajanus cajan), milheto + crotalária, milheto + guandu e pousio] semeadas na primavera. O delineamento experimental para o arroz e soja foi o de blocos casualizados, com seis tratamentos e 4 repetições. O delineamento para o milho foi o de blocos casualizados, com esquema em faixas, com 4 repetições. O estudo foi realizado no município de Selvíria – MS, na região de Cerrado, sobre um Latossolo Vermelho Distrófico, conduzido no período de setembro de 2014 a setembro de 2016, com o uso de irrigação suplementar. Subprojeto 1 – No cultivo do arroz de terras altas, o consórcio milheto + crotalária, propicia maior acúmulo de palhada, macronutrientes, além de manter maior quantidade de palhada sobre o solo e promover maior liberação de nutrientes no período de 120 dias após a semeadura do arroz. O cultivo de crotalária, no inverno/primavera, favorece o maior número de espiguetas totais e granadas por panícula, além de beneficiar a produtividade de grãos de arroz. A condição física do solo, em 2015/16, é melhorada com o cultivo do guandu anteriormente à cultura do arroz. Subprojeto 2 – O acúmulo de palhada e de nutrientes pela crotalária, bem como a manutenção de cobertura do solo e a liberação dos nutrientes são prejudicadas pela sucessão com a soja, enquanto que a soja beneficia o cultivo do milheto. O cultivo de guandu, anteriormente à cultura da soja, favorece as condições físicas do solo em relação ao milheto e ao pousio. Subprojeto 3 - O acúmulo de palhada de soja e a ciclagem de N, P, Ca e Mg são superiores a palhada de arroz. A cultura do arroz de terras altas pode ser uma alternativa para entrar em rotação no verão com a soja, obtendo produtividade média de 4.071 kg ha-1 e potencial para produção de 5.619 kg ha-1 de palhada sobre o solo. Na região de Cerrado de baixa altitude, com o uso de irrigação suplementar, o sistema de produção com plantas de cobertura, no inverno/primavera, arroz/soja no verão e milho em consórcio com U. ruziziensis no outono/inverno, possibilita aporte de aproximadamente 20 t ha-1 ano-1 de palhada sobre solo e aproximadamente 9.350 kg ha-1 ano-1 de grãos.
The production system based on the succession of cultures as well as the sequence between corn and soybean in Brazil, does not hold up over the years. Thus, the inclusion of cover crops, and rice cultivation by replacing part of the soybean area may be options to benefit the agricultural system in the Cerrado. The objective was to evaluate the adoption of cover crops in the cultivation of upland rice, soybean and the effect on maize second crop intercropped with Urochloa. The project consisted of three subprojects. Subproject 1: Production systems for upland rice with the use of cover crops. Subproject 2: Soybean production systems with the use of cover crops. Subproject 3: Maize second crop intercropped with Urochloa ruziziensis cultivated on rice and soybean straw, as a function of cover crops. Six cover crops were used [millet (Pennisetum americanum), sunn hemp (Crotalaria juncea), pigeon pea (Cajanus cajan), millet + sunn hemp, millet + pigeon pea and fallow] soothed in the spring. The experimental design for rice and soybean was randomized blocks, with six treatments and 4 replications. The design for maize was randomized blocks, with a scheme in strips, with 4 replications. The study was conducted in Selvíria - MS in the Cerrado region, on a Oxisoil, conducted from September 2014 to September 2016, with the use of supplemental irrigation. Subproject 1 – In the cultivation of upland rice, the consortium millet + sun hemp provides greater accumulation of straw, macronutrients, besides keeping larger amount of straw on the ground and promote greater release of nutrients within 120 days after sowing rice. The sun hemp cultivation in the winter/spring, favors the largest total number of spikelets per panicle and grenades, as well as benefit the productivity of rice grains. The physical condition of the soil in 2015/16, is improved by the cultivation of pigeonpea before the rice crop. Subproject 2 - The accumulation of straw and nutrients by sun hemp and soil cover maintenance and release of nutrients are hampered by succession to soybeans, while soybeans benefits millet cultivation. The pigeon crop, prior to soybean favors the physical conditions of the soil in relation to fallow and millet. Subproject 3 - The accumulation of straw and soybean cycling of N, P, Ca and Mg are higher than rice straw. Cultivation of upland rice can be an alternative to the summer into rotation with soybeans, resulting average productivity of 4,071 kg ha-1 and the potential to produce 5,619 kg ha-1 of straw on the soil. In the region of low altitude Cerrado, with the use of supplementary irrigation, the production system with cover crops, rice/soybean and corn in intercropped with U. ruziziensis, enables input of approximately 20 t ha-1 yr-1 of ground straw and about 9,350 kg ha-1 yr-1 of grains.
The production system based on the succession of cultures as well as the sequence between corn and soybean in Brazil, does not hold up over the years. Thus, the inclusion of cover crops, and rice cultivation by replacing part of the soybean area may be options to benefit the agricultural system in the Cerrado. The objective was to evaluate the adoption of cover crops in the cultivation of upland rice, soybean and the effect on maize second crop intercropped with Urochloa. The project consisted of three subprojects. Subproject 1: Production systems for upland rice with the use of cover crops. Subproject 2: Soybean production systems with the use of cover crops. Subproject 3: Maize second crop intercropped with Urochloa ruziziensis cultivated on rice and soybean straw, as a function of cover crops. Six cover crops were used [millet (Pennisetum americanum), sunn hemp (Crotalaria juncea), pigeon pea (Cajanus cajan), millet + sunn hemp, millet + pigeon pea and fallow] soothed in the spring. The experimental design for rice and soybean was randomized blocks, with six treatments and 4 replications. The design for maize was randomized blocks, with a scheme in strips, with 4 replications. The study was conducted in Selvíria - MS in the Cerrado region, on a Oxisoil, conducted from September 2014 to September 2016, with the use of supplemental irrigation. Subproject 1 – In the cultivation of upland rice, the consortium millet + sun hemp provides greater accumulation of straw, macronutrients, besides keeping larger amount of straw on the ground and promote greater release of nutrients within 120 days after sowing rice. The sun hemp cultivation in the winter/spring, favors the largest total number of spikelets per panicle and grenades, as well as benefit the productivity of rice grains. The physical condition of the soil in 2015/16, is improved by the cultivation of pigeonpea before the rice crop. Subproject 2 - The accumulation of straw and nutrients by sun hemp and soil cover maintenance and release of nutrients are hampered by succession to soybeans, while soybeans benefits millet cultivation. The pigeon crop, prior to soybean favors the physical conditions of the soil in relation to fallow and millet. Subproject 3 - The accumulation of straw and soybean cycling of N, P, Ca and Mg are higher than rice straw. Cultivation of upland rice can be an alternative to the summer into rotation with soybeans, resulting average productivity of 4,071 kg ha-1 and the potential to produce 5,619 kg ha-1 of straw on the soil. In the region of low altitude Cerrado, with the use of supplementary irrigation, the production system with cover crops, rice/soybean and corn in intercropped with U. ruziziensis, enables input of approximately 20 t ha-1 yr-1 of ground straw and about 9,350 kg ha-1 yr-1 of grains.
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Palavras-chave
Oryza sativa L., Glycine max L. Merrill, Zea mays L., Adubação verde, Agricultura conservacionista, Sistema plantio direto, Green manure, Conservationist agriculture, No-tillage system