地膜秸秆双覆盖对免耕种植玉米田土壤水热效应的影响

Effects of plastic mulching on surface of no-till straw mulching on soil water and temperature

针对免耕秸秆覆盖种植在北方旱区导致土壤温度降低，从而造成作物产量下降的问题，该研究依托山西寿阳农业部旱地农业野外科学试验站长期保护性耕作定位试验，在免耕秸秆覆盖（NTSM）的处理上增加了地膜覆盖措施，研究秸秆地膜双覆盖免耕（NTSMP）措施对农田土壤水分、土壤温度、水分利用效率及作物产量的影响。研究结果表明，在玉米生长前期，NTSMP0～20cm土层的土壤含水率分别比NTSM和对照处理（CT）高20.2%和21.5%，差异显著（P〈0.05），但在40～110cm土层，NTSMP处理土壤含水率却分别比NTSM及CT低8.8%～14.0%和12.7%～18.8%，差异显著（P〈0.05）。整个生育期结束后，NTSMP处理的土壤储水量出现了负增长，但与CT处理相比差异并不显著（P〉0.05）。玉米生育期前期（4月～5月）0～10cm土壤平均温度，NTSMP处理比NTSM和CT分别高3.2℃和1.9℃，差异显著（P〈0.05）。NTSMP处理的玉米产量分别比NTSM和CT高50.3%、36.8%（P〈0.05），水分利用效率分别提高了42.5%和30.4%（P〈0.05）。可见，NTSMP在玉米生育前期可以增加表层土壤温度，提高表层土壤含水率，为玉米生长提供了良好的水热条件，并最终实现了玉米产量和水分利用效率的大幅提高。

Concerning the decline of crop yield caused low temperature under no-till with straw mulching in dry farmlands of north China, field experiments were conducted to investigate the effects of plastic mulching on the surface of no-till with straw mulching on soil water and temperature at the Ministry of Agriculture Shouyang Dryland Agriculture Key Field Scientific Observation and Experiment Station. The field management practices including conventional tillage （CT）, no-till with straw mulching （NTSM） and plastic mulching on the surface of no-till with straw mulching （NTSMP） were designed to study their effects on soil water and temperature, water use efficiency （WUE） and crop yield. The results showed that the maize （Zea mays） was able to take a good advantage of soil water in the deep layers in the treatment of NTSMP than in treatments of CT and NTSM in the seeding stage under less rainfall condition. In the early growth stage of maize at the topsoil （0-20 cm）, the soil water content in the treatment of NTSMP was 20.2% and 21.5% higher （p〈0.05） than that of NTSM and CT, respectively. However, the water content in NTSMP treatment was 8.8% to 14.0% and 12.7% to 18.8% lower （p〈0.05） than that in the treatments of NTSM and CT, respectively. The soil water storage declined in the treatment of NTSMP at the end of growing season, but it was not significant （p〉0.05） compared with the treatment of CT. This might attribute to the good water conservation capacity of the soil interface in NTSMP that allowed the use of water from deeper soil layers. The treatment of NTSMP had significant （p〈0.05） effects on soil temperature mostly in the seeding stage and in the decline stage when the crop area covering the soil was smaller than in any other stages. However, the effects soil temperature on the growth of crops was more important in the earlier stages than in middle and late stages. The average soil temperature in NTSMP treatment in the 0-10 cm deep soil layer in the early growth stage of maize （April, May） was 3.2℃and 1.9℃, higher than that of NTSM and CT, respectively. The yield of maize in the treatment of NTSMP was 50.3%and 36.8%higher than that in treatments of NTSM and CT （p〈0.05）. The water use efficiency increased by 42.5% and 30.4%, respectively, compared with the treatments of NTSM and CT. Therefore, it can be concluded that the treatment of NTSMP increased the soil surface temperature and water use by maize in the early growth stage. The NTSMP treatment provided a better water and temperature condition for maize growth. Thus, the method can improve maize yield and the water use efficiency.