Effects of crayfish on aggregate characteristics and organic carbon distribution of paddy soil under integrated rice-crayfish system
In order to investigate the effects of crayfish on the quantity and stability of paddy soil aggregates,as well as the content and distribution of organic carbon in soil aggregates under a long-term integrated rice-crayfish system,this study utilized a long-term field experiment that was initiated in 2014.Three treatments were set up:winter flooded fallow without straw returning(W),winter flooded fallow + straw returning(WS),and winter flooded fallow + straw returning + crayfish culture(WSC).Surface soil samples were collected from each treatment,and the distribution characteristics of soil aggregates and organic carbon were analyzed.The results showed that the water-stable aggregates were mainly in the＞1-2 mm size range.The WS treatment significantly increased the proportion of＞2 mm aggregates,organic carbon content,and organic carbon contribution rate,and also increased the average mass diameter of aggregates.Compared with the WS treatment,the proportion of aggregates＞2 mm and＞1-2 mm in the WSC treatment significantly increased by 19.8%and 6.5%,respectively,while the proportion of aggregates 0.053-0.25 mm decreased significantly by 9.2%.Moreover,the number of aggregates＞0.25 mm,mean weight diameter,and geometric mean diameter in the WSC treatment increased by 7.8%,20.6%and 37.5%,respectively.The WSC treatment significantly increased the contents of soil total organic carbon,microbial biomass carbon and particulate organic carbon by 6.2%,34.0%and 23.1%,respectively,and the content of organic carbon in＜0.25 mm aggregates was significantly increased compared with that of the WS treatment.These results indicate that crayfish farming in an integrated rice-crayfish system promotes the transformation of small aggregates into large aggregates,improves the stability of soil aggregates,increases the content of soil organic carbon and active components,especially the organic carbon content in micro-aggregates,and enhances the soil carbon sequestration capacity.
integrated rice-crayfish systemcrayfishwater-stable aggregateorganic carbon distribution
万方数据
维普
