Organic material decomposition and nutrient dynamics in a mulch system enriched with leguminous trees in the Amazon

Revista Brasileira de Ciência do Solo

José Henrique Cattanio¹  Ronald Kuehne²  Paul L.g. Vlek² 

[1] ,Universidade Federal do Pará Faculdade de Meteorologia Belém PA

关键词: contrasting chemical compositions;    nutrient mineralization;    nutrient immobilization;    litterbags;    composição química contrastantes;    mineralização de nutrientes;    imobilização de nutrientes;    sacos de liteira;   

DOI  :  10.1590/S0100-06832008000300016

来源: SciELO

【 摘 要 】

The new techniques proposed for agriculture in the Amazon region include rotational fallow systems enriched with leguminous trees and the replacement of biomass burning by mulching. Decomposition and nutrient release from mulch were studied using fine-mesh litterbags with five different leguminous species and the natural fallow vegetation as control. Samples from each treatment were analyzed for total C, N, P, K, Ca, Mg, lignin, cellulose content and soluble polyphenol at different sampling times over the course of one year. The decomposition rate constant varied with species and time. Weight loss from the decomposed litter bag material after 96 days was 30.1 % for Acacia angustissima, 32.7 % for Sclerolobium paniculatum, 33.9 % for Iinga edulis and the Fallow vegetation, 45.2 % for Acacia mangium and 63.6 % for Clitoria racemosa. Immobilization of N and P was observed in all studied treatments. Nitrogen mineralization was negatively correlated with phenol, C-to-N ratio, lignin + phenol/N ratio, and phenol/phosphorus ratios and with N content in the litterbag material. After 362 days of field incubation, an average (of all treatments), 3.3 % K, 32.2 % Ca and 22.4 % Mg remained in the mulch. Results confirm that low quality and high amount of organic C as mulch application are limiting for the quantity of energy available for microorganisms and increase the nutrient immobilization for biomass decomposition, which results in competition for nutrients with the crop plants.

【 授权许可】

CC BY   
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