Consórcio de guandu-anão com milheto: persistência e liberação de macronutrientes e silício da fitomassa
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Data
2012-01-01
Autores
Ferrari Neto, Jayme [UNESP]
Crusciol, Carlos Alexandre Costa [UNESP]
Soratto, Rogério Peres [UNESP]
Costa, Claudio Hideo Martins da [UNESP]
Título da Revista
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Editor
Instituto Agronômico de Campinas
Resumo
O consórcio de gramíneas com leguminosas pode ser alternativa interessante para o fornecimento de fitomassa para sistemas de rotação de culturas, porém, pouco se sabe sobre a dinâmica de decomposição e de liberação de nutrientes da palhada. Assim, objetivou-se avaliar a persistência de palhada e a liberação de macronutrientes, carbono e silício da fitomassa do consórcio guandu-anão+milheto com e sem a fragmentação mecânica da mesma. O experimento foi desenvolvido em esquema fatorial 2x6 sob delineamento em blocos casualizados, com quatro repetições. O primeiro fator foi constituído por dois manejos da fitomassa da parte aérea (sem e com fragmentação mecânica) e o segundo por seis épocas de coleta (0, 18, 32, 46, 74 e 91 dias após manejo (DAM)). A fragmentação da palhada não alterou a decomposição e a liberação de N, P, K, Ca, Mg e S e as máximas liberações diárias ocorreram de 0 a 18 DAM. Aos 91 DAM pelo menos 80% de todos os macronutrientes foram liberados ao solo. O K foi o nutriente mais rapidamente liberado, restando aos 91 DAM, apenas 1,4% da quantidade total acumulada, na média dos manejos com e sem fragmentação mecânica. O Si foi o elemento mais lentamente liberado da palhada, restando ainda aos 91 DAM, em média 69% da quantidade total acumulada. A relação C/Si pode ser uma ferramenta para avaliar a degradação de palhada.
Grasses and legumes intercropping can be an attractive alternative for phytomass supply to crop rotation systems; however, information about its decomposition and macronutrient release dynamics is scarce. Thus, the objective of this work was to evaluate the persistence of dry matter, nutrient, carbon and silicon release of pigeonpea and millet intercropping, with and without mechanical fragmentation of straw. The experiment was arranged as a 2x6 factorial in randomized block design, with four replications. First factor consisted of two straw managements (without and with fragmentation) and second consisted of six sampling times (0, 18, 32, 46, 74 and 91 days after management (DAM)). The fragmentation of straw did not alter decomposition and release of N, P, K, Ca, Mg and S, and the maximum daily release of these occurred between 0 and 18 DAM. At 91 DAM at least 80% of all macronutrients were released to the soil. Potassium was released faster, leaving only 1.4% of the total amount accumulated in the straw at 91 DAM, on average of the managements with and without mechanical fragmentation. Silicon was the most slowly released from the straw, still leaving 69% of the total amount accumulated in the straw at 91 DAM. The C/Si ratio is suggested as a tool to evaluate the degradation of straw.
Grasses and legumes intercropping can be an attractive alternative for phytomass supply to crop rotation systems; however, information about its decomposition and macronutrient release dynamics is scarce. Thus, the objective of this work was to evaluate the persistence of dry matter, nutrient, carbon and silicon release of pigeonpea and millet intercropping, with and without mechanical fragmentation of straw. The experiment was arranged as a 2x6 factorial in randomized block design, with four replications. First factor consisted of two straw managements (without and with fragmentation) and second consisted of six sampling times (0, 18, 32, 46, 74 and 91 days after management (DAM)). The fragmentation of straw did not alter decomposition and release of N, P, K, Ca, Mg and S, and the maximum daily release of these occurred between 0 and 18 DAM. At 91 DAM at least 80% of all macronutrients were released to the soil. Potassium was released faster, leaving only 1.4% of the total amount accumulated in the straw at 91 DAM, on average of the managements with and without mechanical fragmentation. Silicon was the most slowly released from the straw, still leaving 69% of the total amount accumulated in the straw at 91 DAM. The C/Si ratio is suggested as a tool to evaluate the degradation of straw.
Descrição
Palavras-chave
Cajanus cajan, Pennisetum glaucum, reciclagem, taxa de decomposição, manejo da palhada, cobertura vegetal, Cajanus cajan, Pennisetum glaucum, recycling, decomposition rate, straw management, cover crop
Como citar
Bragantia. Instituto Agronômico de Campinas, v. 71, n. 2, p. 264-272, 2012.