一年两熟地区保护性耕作深松试验

Sub-soiling Experiment on Double Cropping and Conservation Tillage Adopted Area

为深入了解深松对产量的影响,2013—2017年连续5年进行了深松试验,初步证明小麦玉米一年两熟区,采用保护性耕作免耕后,实施深松能取得明显增产效果。夏深松的效果优于秋深松,5年平均值夏深松比不深松增产5.9%,比秋深松增产2.3%,同时作业费用较低,大面积应用有利农户增产增收。但在夏季干旱严重又缺乏灌溉条件的地区,仍需采用秋深松。深松对作业当季产量影响最大,试验的8季收获中6季为当季产量最高。连续多年深松存在明显的增产效应递减现象,夏深松第1年增产18%,此后逐年降为6.3%、3.9%、3.4%、1.7%。增产效应递减反映出深松对产量影响的两面性:既有疏松土壤、增加田间持水量等正面影响,也有降低播种质量、迟缓土壤有机质积累、减少土壤细菌数量等负面影响,负面影响逐年增大,深松增产效应逐步下降。当增产幅度低于2%时,深松将增产不增收。从本试验看,夏深松第5年、秋深松第3年增产幅度降至投入大于产出的拐点。合理的深松周期需因地制宜,尚需通过进一步试验来确定。

From the sub-soiling experiment during five years （2013—2017）, it is preliminarily approved that the yield was obviously increased by sub-soiling applied in the continual no-tillage field. The highest yield related with sub-soiling would be happened at current season of operation, searching totally eight harvest seasons, and six seasons had the highest yield at current season of sub-soiling. Adoption of sub-soiling in summer had 5.9% higher yield than no sub-soiling, and 2.3% higher than in autumn, besides, summer sub-soiling had better power using efficiency and lower operation cost. Therefore, summer sub-soiling had better prospect on extension, but the autumn sub-soiling would be preferentially adopted in drought summer and poor irrigation area. An outstanding event in the trial was the decline of yield increasing rate, for summer sub-soiling, the first year had 18% of yield increase, since then, the yield increasing rate was quickly declined to 6.3%, 3.9%,3.4% and 1.7% in the second, third, fourth and fifth year. The decline of yield increase rate reflected double aspects of sub-soiling influence. It had positive aspect by loosing soil and holding more water in the field, but also had negative aspect by depressing of sowing quality, reducing of soil organic matter content and soil bacteria. The negative influence would be accumulated year by year, thus yield increase rate was gradually declined. Sub-soiling was an energy consuming operation, from roughly calculation, while yield increase rate was lower than 2% around, adoption of sub-soiling became input larger than output. From the yield decline trend in the trial, at fifth year of continued summer sub-soiling, at third year of continued autumn sub-soiling, the yield increase rate would reach the turnoff point. To reasonably determine the period of sub-soiling, further experiment was necessary.