Decomposition of ground biomass of secondary forest and yield of annual crops in no tillage

Abstract

RESUMOThe objective of this work was to evaluate the dynamics of decomposition process of chopped secondary forest system, previously enriched with legumes Inga velutina Willd. and Stryphnodendron pulcherrimum (Willd.) Hochr. and the contribution of this process to the nutrient input to the cultivation of corn and bean under no-tillage. The experimental design was a randomized block, split plot with four replications. The plots were two species (I. velutina and S. pulcherrimum) and the subplots were seven times of evaluation (0, 7, 28, 63, 189, 252, 294 days after experiment installation). There was no difference (p > 0.05) between the secondary forest systems enriched and no interaction with times for biomass waste, decomposition constant and half-life time. The waste of S. pulcherrimum trees had higher (p < 0.05) C/N ratio than that I. velutina. However, this one was higher (p < 0.05) in lignin content. Nevertheless, the dynamics of residue decomposition was similar. The corn yield was higher (p < 0.05) in cultivation under I. velutina waste. Meanwhile, the beans planted after corn, shows similar (p > 0.05) yield in both areas, regardless of the waste origin. Key-words: Decomposição da biomassa de capoeira triturada e produtividade de culturas anuais em plantio diretoObjetivou-se, com este trabalho, avaliar a dinâmica do processo de decomposição de resíduos de capoeiras trituradas, anteriormente melhoradas com as leguminosas ingá peluda (Inga velutina Willd.) e baginha (Stryphnodendron pulcherrimum (Willd.) Hochr.) e sua influência na produtividade do milho e do feijoeiro, cultivados sequencialmente em plantio direto. O delineamento experimental foi em blocos casualizados, em parcelas subdivididas, no tempo, com quatro repetições, sendo as parcelas duas leguminosas (ingá peluda e baginha) e as subparcelas sete datas de avaliação (0, 7, 28, 63, 189, 252, 294 dias após a implantação do experimento). Não foi verificada diferença (p > 0,05) entre as capoeiras melhoradas nem efeito da interação destas com as épocas de avaliação sobre os resíduos da biomassa, constante de decomposição e tempo de meia-vida. Os resíduos da capoeira melhorada com baginha apresentaram maior (p < 0,05) relação C/N do que os de ingá peluda, sendo estes últimos superiores (p < 0,05) quanto ao teor de lignina. Porém, a dinâmica da decomposição dos resíduos foi similar para as 569 Decomposition of ground biomass of secondary forest and yield of annual crops in...Rev. Ceres, Viçosa, v. 62, n.6, p. 568-576, nov-dez, 2015 INTRODUCTIONThe traditional system of agriculture in the Amazon is carried out from the clearing and burning of vegetation. Over the years, fire was used as the quickest and most economical way to clean the areas and "fertilize" the soil (Kato et al., 2003).Studies on the slash-and-burn system showed that its main problems are nutrient losses during combustion of biomass and reducing of fallow period (Kato et al, 2006;Sampaio et al., 2008). During the vegetation burning, losses occur both of C, in the form of CO 2 , ...