不同耕作方式对内蒙古旱作农田土壤性状及作物产量的影响

Effects of different tillage modes on soil properties and crop yield in a rain-fed field of Inner Mongolia

2005—2008年在内蒙古清水河县进行了定位试验,研究了不同耕作方式下土壤微生物量及土壤营养指标、作物产量的年际变化。结果表明:免耕有利于提高土壤微生物量碳、氮、磷含量,2007和2008年不同耕作方式0～10cm土层土壤微生物量均表现为免耕留高茬覆盖>免耕留低茬覆盖>免耕留高茬>免耕留低茬>传统耕作;免耕有利于提高土壤有机质和土壤养分含量,2007和2008年不同耕作方式0～10cm土层土壤有机质和养分含量均表现为免耕留高茬覆盖>免耕留低茬覆盖>免耕留高茬>免耕留低茬>传统耕作,实施免耕的前3年,玉米产量不稳定,甚至造成玉米减产,第4年免耕增产效应有所显现;不同保护性方式下土壤指标与玉米产量之间的相关度较好,通径分析得知土壤全氮、全磷、速效磷及微生物量碳对玉米产量起直接作用,其中尤以土壤微生物量碳的作用最大;免耕有利于改善内蒙古农田旱作区的土壤生态环境,提高土壤肥力。

A 4-year （2005-2008） field experiment was conducted on a typical slope field in Qingshuihe County of Inner Mongolia to study the effects of no tillage with low stubble （NL）,no tillage with high stubble （NH）,no tillage with low stubble and residues （NLS）,no tillage with high stubble and residues （NHS）,and conventional tillage （CT） on the soil properties and maize yield. No tillage increased soil microbial biomass C,N,and P,and soil organic matter and nutrient contents. In 2007 and 2008,the microbial biomass and the organic matter and nutrient contents in 0-10 cm soil layer were in order of NHS〉NLS〉NH〉NL〉CT. During the first three years of no tillage,maize yield was unstable; but in the 4th year,the yield was increased. Path analysis showed that soil total nitrogen,total phosphorus,available phosphorus,and especially microbial biomass carbon had direct effects on maize yield. The results indicated that no tillage was advantageous to the improvement of soil ecological environment and soil fertility in rain-fed farmlands of Inner Mongolia.