洞庭湖区不同耕种方式下水稻土壤有机碳、全氮和全磷含量状况

在洞庭湖区的2km2典型样区内,按3个/hm2的密度采集土样,分析不同耕种方式下(水稻、水旱轮作油菜、水改旱种苎麻1~5年)水稻土壤的有机碳、全氮和全磷含量状况。结果表明,水稻田土壤有机碳、全氮和全磷含量水平均较高,水田改为旱地后土壤有机碳、全氮含量及C/N比值有较大幅度的下降,但全磷含量变化不大。土壤有机碳、全氮及C/N比值均以水稻田土壤>油菜地土壤>苎麻地土壤,与水稻田相比,油菜土壤有机碳平均下降了11.19%、全氮下降了10.33%,而苎麻土壤有机碳平均下降了35.57%、全氮下降了31.61%。土壤有机碳与全氮之间呈线性关系,相关性均达极显著水平(P<0.01)。

Contents of Paddy Soil Organic Carbon, Nitrogen and Phosphorus under Different Cultivation Ways in Dongting Lake Region

Paddy soil organic carbon(SOC),soil total nitrogen(STN) and soil total phosphorus(STP) in different cultivation ways(rice,rape,and ramie)were studied in region of Dongting Lake.The results showed that the content of SOC, STN and STP had a high level in the paddy soil,but SOC and STN(except STP) decreased greatly after being changed to arid land.The content of SOC and STN and the ratio of C/N ranged as follow: rice soil>rape soil>ramie soil.Compared with rice soil,SOC content of rape soil decreased by 11.19% and STN content decreased by 10.33%,while SOC content of ramie soil decreased by 35.57% and STN content decreased by 31.61%.In addition,SOC had linear relation with STN(P<0.01).