秸秆还田方式下黑钙土土壤碳氮磷钾化学计量特征研究

Stoichiometric Characteristics of Soil Carbon,Nitrogen,Phosphorus,and Potassium in Chernozem Soil under Straw Returning

以吉林省西部黑钙土为研究对象,探究土壤C、N、P、K及其化学计量特征对秸秆还田方式的不同响应,为科学进行土壤养分管理及筛选适宜耕作培肥技术提供理论依据。设置秸秆深翻还田(SF)、秸秆富集还田(FJ)、秸秆覆盖还田(FG)、秸秆离田(CK)4种方式,采用常规测定方法测定0~20 cm、20~40 cm土壤C、N、P、K含量。结果表明,黑钙土分解有机质速度较快、磷素转化效率较高,相较于土壤中充足的P含量,植物生长易受N元素的限制,且不同养分之间的比值不仅受直接相关养分的制约,还受其他养分的影响。秸秆还田能减缓有机质的分解速度(FG、FJ)及植物生长可能受到的N素威胁(SF、FJ),建议降少化肥施用量(P、K)以增加黑钙土有机质固持能力。

This study investigates the different responses of soil C,N,P,and K and their stoichiometric characteristics to straw returning methods in chernozem soil in Western Jilin Province,providing a theoretical basis for scientific soil nutrient management and screening of suitable tillage and fertilizer technologies.Four methods were employed:straw deep turning and returning to the field(SF),straw enrichment and returning to the field(FJ),straw mulching and returning to the field(FG),and straw-off field(CK).The contents of C,N,P,and K in 0-20 cm and 20-40 cm soil were determined by conventional methods.The results indicated that chernozem decomposed organic matter faster and had a higher phosphorus conversion efficiency.Compared with sufficient P content in the soil,the N element easily restricted plant growth,and the ratio of different nutrients was not only restricted by directly related nutrients but also affected by other nutrients.Therefore,straw returning to the field can reduce the decomposition rate of organic matter(FG,FJ)and the possible N-element threat to plant growth(SF,FJ).At the same time,reducing the amount of fertilizer(P,K)is recommended to increase the organic matter holding capacity of chernozem soil.