稻田垄作免耕对根际土壤有机碳及颗粒态有机碳的影响

On Effect of Ridge-Cultivation without Tillage on Rhizosphere of Soil Organic Carbon and Particulate Organic Carbon in a Rice-Based Cropping System

以稻田免耕长期定位试验站为平台,分析不同耕作制度对稻田根际土壤有机碳(SOC)和颗粒态有机碳(POC)的影响,并与非根际土壤进行对比分析.结果表明,长期实行垄作免耕(水稻—油菜)的方式下,根际SOC和POC含量显著高于其他耕作方式,而实行水旱轮作(水稻—油菜)方式下二者含量均最低.垄作免耕(水稻—油菜)根际SOC含量高于非根际土壤,而其他耕作处理均为根际低于非根际土壤.另外,垄作免耕(水稻—油菜)根际土壤POC含量高于非根际土壤,差异达极显著水平(p<0.01);常规平作(水稻—冬水田)也为根际大于非根际土壤,但差异不显著;其余耕作处理根际土壤POC含量均表现为非根际大于根际土壤,且差异均不显著(p>0.05).垄作免耕(水稻—冬水田)和垄作免耕(水稻—油菜)SOC和POC含量间存在显著相关性,表明免耕方式有利于土壤有机碳和颗粒有机碳的保护和稳定.

Based on Long-term positioning of fertilization test points in paddy field,the paper deals not only with the analysis of the effects of different farming systems on soil organic carbon（SOC） and particulate organic carbon（POC）,but also with the comparison of the differences between rhizosphere and non-rhizosphere in paddy soil.With this experiment,there come out four cultivation treatments： conventional tillage with rice only（CT-r）,ridge-cultivation without tillage but with rice only（RT-r）,ridge-cultivation without tillage but with rice-rape rotation（RT-rr）,and conventional tillage with rice-rape rotation（CT-rr）.The results show that SOC and POC concentrations of rhizosphere are significantly higher in paddy field under the long-term RT-rr system than other cultivation systems（p0.05）.SOC concentration of rhizosphere under the RT-rr system is higher than that of non-rhizosphere,but other tillage systems are opposite.Moreover,POC concentration of rhizosphere under the RT-rr system is significantly higher than that of non-rhizosphere（p0.01）,and POC concentration of rhizosphere under the CT-r system is higher than that of non-rhizosphere.But this difference is indistinctive（p0.05）.The other cultivation systems are opposite.In conclusion,the significant correlation between SOC and POC indicates that the no-tillage systems are more helpful in protecting and stabilizing the SOC and POC in paddy soil.