Tillage and straw retention in rice-wheat cropping system influences on soil aggregation, aggregate carbon and water balance under irrigated conditions: An overview

Abstract

Soil organic carbon (SOC) is the most often reported attribute and is chosen as the most important indicator of soil quality and agricultural sustainability. In this review, we summarized how cultivation, residue and tillage management and monoculture affect soil quality, soil organic matter (SOM) and carbon transformation. The results confirm that SOM is not only a source of carbon but also a sink for carbon sequestration. Cultivation and tillage can reduce soil SOC content and lead to soil deterioration. Tillage practices have a major effect on distribution of C and N, and the rates of organic matter decomposition and N mineralization. Proper adoption of tillage and residue can increase or maintain the quantity and quality of soil organic matter, and improve soil chemical and physical properties.Tillage significantly reduced the proportion of macro-aggregate fractions (>2.00 mm) and thus aggregate stability was reduced by 35% compared with (ridge with no tillage) RNT, indicating that tillage practices led to soil structural change for this subtropical soil. The highest SOC was in the 1.00-0.25 mm fraction (35.7 and 30.4 mgkg-1for RNT and CT, respectively), while the lowest SOC was in micro-aggregate (