北方旱区保护性耕作对农田土壤水分的影响

Effects of conservation tillage on soil water content in northern arid regions of China

土壤水分是中国北方旱区农业生产的主要限制因子,研究保护性耕作技术体系下土壤水分的动态变化,明确不同耕作模式下的水分平衡规律,对于选择适宜的保护性耕作技术,提高北方旱区土壤水分的利用效率具有重要的指导意义。该文在2a田间试验的基础上采用DSSAT模型对4个不同保护性耕作处理的土壤体积含水量、水分平衡以及水分利用效率进行了模拟和检验。结果表明干旱年份保护性耕作处理土壤体积含水量较传统耕作高,RMSE误差在0.025～0.063;干旱年份传统耕作土壤储水量减少最多,为144.6mm,降水较多年份减少也最多,为46.1mm;干旱年份水分利用效率1.52～1.78kg/m3,免耕覆盖水分利用效率最高,降水较多年份水分利用效率1.70～1.71kg/m3,各处理间差异并不显著。研究结果为保护性耕作技术对农田土壤水分的影响研究提供了理论依据。

Soil water content is the key factor that affect the agriculture production in northern arid regions of China. It is helpful to select proper tillage methods and improve water productivity based on the study of soil water content changing. Soil water content, water balance and water use efficiency were simulated and checked used the DSSAT model based on two-year field experiment. The results show that in dry year the soil water content of conservation tillage is higher than the conventional tillage, RMSE is 0.025-0.063. In dry year, and the largest decrease of soil water storage is conventional tillage （144.6 mm）, and the same in normal year （46.1 mm）. Water use efficiency in dry year is 1.52-1.78 kg/m^3, the largest is no tillage with residue cover treatment, in the normal year is 1.70-1.71 kg/m^3. The differences between different treatments are not obvious. The results provide theoretical foundation for the research of effects of conservation tillage on soil water in the field.