RESEARCH ARTICLE


Decomposition and Carbon Dynamics of Crop Residue Mixtures in a Semiarid Long Term No-Till System: Effects on Soil Organic Carbon



N. Casado-Murillo*, A. Abril
Facultad de Ciencias Agropecuarias. Universidad Nacional de Cordoba. Cc 509, 5000, Cordoba, Argentina


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Casado-Murillo et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: https://creativecommons.org/licenses/by/4.0/legalcode. This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Facultad de Ciencias Agropecuarias. Universidad Nacional de Cordoba. Cc 509, 5000, Cordoba, Argentina; Tel: 54 351 4334105/03; Fax: 54 351 4334105/03; ncasadomurillo@yahoo.com


Abstract

Plant residues decomposition transfers organic matter and nutrients to soil, and plays a decisive role in carbon (C) cycling. The aims of our study were to analyze under realistic field conditions the annual decomposition and C dynamics of crop residues mixtures under long-term no-till management and their effect on soil organic carbon (SOC). Three treatments were evaluated: soybean monoculture, soybean rotation (maize as preceding crop), and maize rotation (soybean as preceding crop). In each treatment soil samples and crop residue samples were collected. In crop residues samples we determined: total residue mixture biomass, soybean residue biomass, maize residue biomass, non identifiable residue biomass, total C, soluble C, insoluble fiber. In soil samples, SOC were analyzed. Decomposition rates were calculated for residues mixture, soybean and maize residue before and after deposition of fresh residue. Decomposition rates of all residues analyzed showed a high variability between treatments. Total C, soluble C and insoluble fiber concentrations of the residues mixtures showed a great similarity among treatments. Contrarily, their annual dynamics differed between sampling dates in all treatments. We concluded that decomposition and C dynamics of crop residues mixtures in longterm no-till systems in the semiarid central Argentina are strongly influenced by: the interaction of the chemical quality of the residues, the proportion of the residues from different crops and/or with different decomposition degree,and the seasonal effect. The greater C amount in residues mixture of rotation was not reflected in SOC contents, and further studies are recommended.

Keywords: Soybean, maize, decomposition rates, soluble C, insoluble fibers.