覆膜滴灌条件下土壤改良剂对土壤导气率的影响

为研究覆膜条件下土壤改良剂对土壤导气率的影响,进行田间对照试验分析。结果表明:施加改良剂对土壤颗粒机械组成没有明显改变,但使土壤容重明显减小、饱和含水率升高、田间持水率升高;覆膜条件有保水保墒作用,但阻碍了土壤空气与外界气体的交换,使土壤导气率降低;改良剂的施加改善了土壤结构和土壤物理性状,促进了土壤孔隙内气体流通,使土壤导气率增大;石膏对导气率的改善效果最显著,聚丙烯酰胺(PAM)次之,旱地龙的改善效果最低;PAM和旱地龙的中、高施量比低施量改善效果更显著,石膏的中、低施量对导气率的改善效果相近,高施量处理下导气率为低施量处理的1.12倍。说明土壤改良剂对土壤导气率有较好的改善效果。

Effects of Soil Amendments on Soil Air Permeability in Film Mulched Drip Irrigation Field

A field experiment was conducted in order to evaluate the effects of soil amendments on soil air permeability under plastic mulching condition. The results showed that soil texture kept slight changes after applying soil amendments; however, it resulted in significant decrease of soil bulk density and increase of saturated water content and field capacity. Although plastic sheet mulch was helpful for soil water storage and heat preservation, it prevented air exchange at soil-atmosphere interface which led to decrease of soil air permeability. Meanwhile, soil structure and physical properties were improved through the application of soil amendments, resulting in clear air flow in soil pores, which led to increase of soil air permeability. Furthermore, the improvement of three types of soil amendment on soil air permeability were ranked in the order of phosphogypsum (PG) > polyacrylamide (PAM) > Handilong. As for PAM and Handilong treatments, high application rate had better effect on soil air permeability than that of low application rate. As for PG treatment, the value of soil air permeability under high application rate was 1.12 times as high as that under low application rate, and moderate and low application rates had similar effects on soil air permeability. The results indicated that soil amendments could obviously improve soil air permeability, which certainly provided new methods for improving soil air permeability during field crops growth.