Response of soil organic matter in aggregates to long-term straw incorporation in a subtropical paddy field
To explore the changes in soil organic carbon content and carbon sequestration efficiency of soil aggregates under long-term straw return treatment,the paddy red soil in the Jinxian County of Jiangxi Province was selected as the research object,and conventional treatment and conventional treatment combined with straw incorporation were carried out respectively.Carbon and nitrogen content were measured by an element analyzer,and carbon sequestration efficiency of soil was calculated through soil organic carbon(SOC)sequestration amount and accumulated carbon input amount.The results showed that:①The dominant aggregates size of paddy red soil was[0.250,2.000)mm,with a mass proportion of(40.64%-47.04%).Com-pared with the conventional treatment,the conventional treatment conbined with straw incorporation treatment had no signifi-cant effect on the mass proportion of aggregates with different fractions and the stability in dex of soil aggregates.②Com-pared with the conventional treatment,SOC and the total nitrogen(TN)contents increased significantly by 13.60%and 10.17%in the bulk under the conventional treatment combined with straw incorporation,respectively,but C/N in the bulk soil and SOC content,TN content,and C/N in all aggregate fractions didn′t change significantly.③Compared with the convention-al treatment,the SOC sequestration amount and the cumulative carbon input amount were increased by 55.37%and 216.76%under the conventional treatment combined with straw incorporation.However,the carbon sequestration efficiency of the con-ventional treatment combined with straw incorporation was significantly reduced by 50.85%compared with the conventional treatment.In conclusion,straw incorporation is beneficial to SOC sequestration in the southern sub-tropical red-soil double-cropping rice areas,but is not conducive to the improvement of soil carbon sequestration efficiency,and has no significant impact on the stability of soil aggregates.
万方数据
维普
