耕作土壤可蚀性及不同耕作方式的水土保持机理

Soil Erodibility and Soil and Water Conservation Mechanism of Different Tillage Methods

黑土地保护是保障我国粮食安全的重要举措,水土保持是黑土地保护的关键技术环节。吉林农业大学水土保持科研团队通过田间试验、人工降雨试验、野外调查等方法陆续开展了黑土地主要土壤类型的可蚀性研究、秸秆不同还田方式的水土保持机理研究等,丰富了黑土地水土保持理论,并为黑土地保护措施体系的建立提供理论支撑。相关研究成果表明,主要耕作土壤可蚀性因子K值表现为黑土最大,黑钙土和白浆土次之,暗棕壤最低,典型黑土耕地土壤易被侵蚀;垄沟秸秆覆盖可使9°以下坡面减流84.8%~97.9%,减沙88.3%~92.9%,土壤分形维数降低,水稳性团聚体含量显著提高;秸秆深还、碎混及免耕覆盖的3种还田方式下,土壤流失防治率分别为84.9%、90.3%、96.8%;留茬免耕使土壤结构稳定,半整地具有疏松耕层土壤且提高保水率的作用。

Black land protection is an important measure to ensure China’s food security,and soil and water conservation is the key technical link of black land protection.The soil and water conservation research team of Jilin Agricultural University has successively carried out the research on the erodibility of main soil types of black land and the mechanism of soil and water conservation of different ways of returning straw to the field through field experiments,artificial rainfall,field investigation and other means.It enriches the soil and water conservation theory of black land,and provides theoretical support for the establishment of black land protection measure system.Relevant research results show that K value of the main cultivated soil erodibility factor is the largest in black soil,followed by chernozem and albic soil,and the lowest in dark brown soil.The typical black soil arable soil is easy to be eroded;Straw mulching in ridge and furrow can reduce the flow and sediment of slope below 9°by 84.8%-97.9% and 88.3%-92.9%,reduce the fractal dimension of soil and significantly increase the content of water stable aggregates;The control rates of soil loss were 84.9%,90.3% and 96.8% respectively under the three ways of straw deep returning,broken mixing and no tillage mulching;No tillage with stubble can stabilize soil structure,and half preparation can loosen topsoil and improve water retention rate.