不同耕作处理下冻融对农田黑土硬度的影响

为探讨冻融作用对农田黑土硬度的影响,在吉林省德惠市中层黑土小区上进行了9a的田间定位试验,对不同耕作方式下冻融前后的土壤硬度以及土壤硬度与土壤含水量之间的关系进行了对比分析。结果表明,土壤硬度与土壤水分呈对数显著性负相关关系(R2=0.838 8)。冻融前免耕较秋翻显著增加了土壤硬度(p<0.05),主要表现在2.5-17.5cm深度之间。冻融后免耕较秋翻降低了2.5-17.5cm的土壤硬度,并且在2.5-10cm达到差异显著性水平(p<0.05)。冻融后土壤硬度明显低于冻融前,冻融前后两种处理下玉米连作的土壤硬度均高于玉米-大豆轮作,但最大土壤硬度均对作物的生长没有限制作用。

Impacts of Freezing-Thawing Cycle on Soil Penetration Resistance Under Different Tillage Practices in Black Soil

The effects of freezing-thawing cycle on soil penetration resistance were studied on a black soil in Northeast China.The tillage experiment was established in Dehui City,Jilin Province since 2001.We compared soil penetration resistance before and after the freezing-thawing cycle under both no tillage(NT) and mouldboard plow(MP) treatments.Furthermore,we analyzed the relationship between soil penetration resistance and soil moisture content.The results showed that there was a significantly negative logarithmical correlation between soil penetration resistance and soil moisture content(R₂=0.838 8).Compared with MP treatment,NT led to a significant increase of soil penetration resistance before the freezing-thawing cycle,especially in the layer of 2.5-17.5 cm(p<0.05),while resulted in reduction of soil penetration resistance of 2.5-17.5 cm after the freezing-thawing cycle,especially in the layer of 2.5-10 cm(p<0.05).Soil penetration resistance was obviously less after the freezing-thawing cycle than before(p<0.05).Soil penetration resistance was greater under continuous corn system than under corn-soybean rotation system.However,even with the maximum soil penetration resistance,no restriction was found on the crop growth before and after freezing-thawing cycle of both NT and MP.