耕作措施对黑土农田耕层水分的影响

通过田间长期定位试验，探讨了耕作措施对农田黑土耕层水分的影响．结果表明：平翻和旋松耕作的垄台容重最小，但其持水能力较低；免耕土壤容重最高，饱和含水量较低，易造成土壤积水，不利于机械作业，但可提高4～6月垄沟的土壤含水量2到4个百分点，是抵御春旱的有效耕作措施；少耕夏季垄沟容重较低，持水能力高，可提高土壤有效水含量，进入雨季后，可显著地多蓄纳雨水，提高垄沟土壤含水量，最高可提高4个百务点，为东北雨养农业区高效水分调控措施．

Effects of Different Soil Tillage Systems on Soil Water in the Black Farmland

Tillage systems are considered as the most important measures of water-adjustment. In a longterm experiment in Northeastern China, the bulk density and soil water of the black farmland under different tillage systems were determined. The results showed that the bulk density in the ridge was the lowest with moldboard plough and rotary tillage, resulting in lower water capacity than the other treatments. In the treatment of no-tillage, the soil had the highest bulk density and lower saturated water content, which tended to lead to water accumulation on soil surface and hinder mechanical operation. No-tillage increased soil water content in ridge and furrow by 2-4 % and was thus beneficial to alleviating spring drought. Reduced tillage had a lower bulk density and higher water capacity in summer, and increased water content in furrow by 4 %, which could hold much rainfall during the rainy season. Hence, reduced tillage should be an effective soil water management in northeast of China.