保护性耕作对水-旱轮作土壤有机碳组分的影响——基于密度分组法  

Effects of Conservation Tillage on Soil Carbon Fractions in Paddy-upland Rotation:Based on Density Grouping Method

作　　者：黄雅楠[1] 黄丽[1] 薛斌[1] 成莉娟 李小坤[1] 鲁剑巍[1] HUANG Ya-nan;HUANG Li;XUE Bin;CHENG Li-juan;LI Xiao-kun;LU Jian-wei(Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River),Ministry of Agriculture,Huazhong Agricultural University,Wuhan 430070,China)

机构地区：[1]华中农业大学农业部长江中下游耕地保育重点实验室,湖北武汉430070

出　　处：《土壤通报》2019年第1期109-114,共6页Chinese Journal of Soil Science

基　　金：公益性行业(农业)科研专项(201503123);国家绿肥产业技术体系(CARS-22)资助

摘　　要：以武穴市10年水-旱轮作长期定位试验的传统耕作(CT)、传统耕作+秸秆还田(CTS)、免耕(NT)、免耕+秸秆还田(NTS)4个处理的水稻土为对象,通过密度分组方法研究各组分有机碳(游离态轻组、闭蓄态轻组、重组)含量的变化特征,探讨秸秆还田与免耕对土壤有机碳及其组分的影响。结果表明,游离态轻组、闭蓄态轻组和重组有机碳含量分别为1.25～3.02 g kg^(-1),0.85～3.05 g kg^(-1)和18.46～23.23 g kg^(-1),占总有机碳的4.44%～12.36%、3.53%～10.86%和77.85%～82.73%。NTS处理显著增加土壤闭蓄态轻组和重组有机碳含量;免耕对各组分土壤有机碳的影响不明显。闭蓄态轻组和重组有机碳与总有机碳含量呈极显著正相关,闭蓄态轻组对耕作方式改变的敏感性最强(敏感性指标为4.00),能够敏感地反映不同耕作措施对土壤有机碳库的影响。与常规还田相比,NTS处理促进游离态轻组有机碳向闭蓄态轻组有机碳转化,有利于土壤有机碳的积累,是本研究中提升土壤有机质的最佳保护性耕作措施。Four treatments of traditional tillage(CT),traditional tillage with straw returning(CTS),no tillage(NT)and no tillage with straw returning(NTS)were set up in the 10 years paddy field experiment in Wuxue.The characteristics of soil organic carbon(SOC)fractions(free light fraction,occluded light fraction and heavy fraction)were studied by density grouping method,in order to understand the effects of straw returning and no tillage on SOC fractions.The results showed that the contents of SOC in free light fraction,occluded light fraction and heavy fraction were 1.25-3.02 g kg^-1,0.85-3.05 g kg^-1 and 18.46-23.23 g kg^-1,respectively.The proportion of free light fraction C in total SOC was 4.44%-12.36%,that of occluded light fraction C was 3.53%-10.86%,that of heavy fraction organic C was 77.85%-82.73%.NTS increased the contents of SOC in occluded light fraction and heavy fraction significantly,while NT did not show obvious effect on SOC fractions.Occluded light fraction and heavy fraction both showed significant positive correlations with total SOC.Occluded light fraction was the most sensitive to the change of tillage treatments(the sensitivity index was 4.00),which could sensitively reflect the effects of different tillage measures on SOC pools.As compared with CTS,NTS treatment promoted the conversion of SOC fraction from free light fraction to occluded light fraction,which was of benefit to the accumulation of SOC.NTS treatment was the best conservation tillage measure to enhance soil organic matter.

关 键 词：有机碳分组 游离态轻组 闭蓄态轻组 重组 保护性耕作 

分 类 号：S158[农业科学—土壤学]