水旱轮作对冷浸田土壤碳、氮、磷养分活化的影响

Effects of Paddy-upland Rotation on the Nutrient Activation of Soil Carbon,Nitrogen and Phosphorus in Cold Waterlogged Paddy Field

有机碳活性低、微生物生物量氮含量低和磷素养分缺乏等是冷浸田土壤重要的养分障碍因子。通过连续3a的定位试验,研究油菜—水稻、玉米—水稻、紫云英—水稻和蚕豆—水稻等4种水旱轮作方式对冷浸田土壤碳、氮、磷养分活化及稻谷产量的影响。结果表明：与冬闲—水稻相比,实行水旱轮作,土壤微生物生物量碳含量提高60.54%～195.57%,微生物商增加0.24～0.81个百分点;土壤微生物生物量氮含量提高107.51%～162.90%,微生物生物量氮/总氮比增加0.71～0.91个百分点;土壤全磷、有效磷及微生物生物量磷增幅分别为14.29%～40.00%,31.42%～105.61%和63.76%～83.22%;稻谷产量提高23.64%～55.49%,不同轮作模式以玉米—水稻产量最高。土壤全磷、有效磷、微生物生物量碳、微生物生物量氮和微生物生物量磷等与稻谷产量、有效穗均呈显著或极显著正相关关系。说明潜育化程度较轻的冷浸田通过水旱轮作,土壤有机碳、氮、磷养分得到活化,其中影响冷浸田稻谷产量的养分限制因子顺序为有效磷〉微生物生物量氮〉微生物生物量磷〉微生物生物量碳〉全磷。

Low activity of organic carbon,low content of microbial biomass nitrogen and the lack of phosphorus are the important limiting factors of soil nutrients in cold waterlogged paddy field.Based on a 3-year located field experiment,we studied the effects of 4different paddy-upland rotation patterns（oilseed rape-rice rotation,maize-rice rotation,milk vetch-rice rotation and broad bean-rice rotation）on the nutrient activation of soil carbon,nitrogen and phosphorus and rice yield in cold waterlogged paddy field.The results showed that compared with winter fallow field-rice rotation,4paddy-upland rotation patterns increased soil microbial biomass carbon by 60.54%—195.57%,soil microbial quotient by 0.24—0.81 percentage point,soil microbial biomass nitrogen by 107.51%—162.90% and soil microbial biomass nitrogen/total nitrogen by 0.71—0.91 percentage point.Besides,paddy-upland rotation also increased the contents of soil total phosphorus,available phosphorus and microbial biomass phosphorus by 14.29%—40.00%,31.42%—14.29%and 63.76%—83.22%,respectively,and increased rice yield by 23.64%—55.49%,with the highest crop yield in maize-rice rotation system.The contents of soil total phosphorus,available phosphorus,microbial biomass carbon,microbial biomass nitrogen and microbial biomass phosphorus showed significantly positive correlations with rice yield and productive ear.In conclusion,for cold waterlogged paddy field in which soil gleization level was quite low,paddy-upland rotation could lead to activation of soil organic carbon,nitrogen and phosphorus,and the nutrient limiting factors listed in the following order：available phosphorus〉microbial biomass nitrogen〉microbial biomass phosphorus〉micro biomass carbon〉total phosphorus.