The Soil Ecological Effect Of Wheat Stubble Mulch On Spring Maize Field In Irrigated Oasis Of Hexi Corridor

Conventional tillage is widely used in irrigated area, which led to soil erosion aggravates, soil organic matter content drops, the soil structure stability reduces as well as the water resources waste is serious and so on. Using conventional tillage as control to study the effects of no-tillage with straw cover on sandstorm-preventing in irrigated oasis, the soil water character of spring maize field, soil microbial biomass(SOM) and the probability of soil through field experiment in Zhangye, China. , the results are summed up as below:A. The effects of conservation tillage on preventing sand-stormHigher stubble and adopted stubble standing could increase the wind erosion critical wind speed of the surface significantly.Through observed the threshold wind erosion velocity of different height of stubble left and different stubble retaining styles, the result indicated that leaving higher stubble (40cm) could remarkably increase the wind erosion critical wind speed of the surface. At same stubble retaining amount, sandstorm-preventing effect of stubble standing was better than that of stubble pressed, when the stubble amount was higher (40cm), but under the condition of lower stubble amount (20cm), two kinds of stubble retaining style had no differ. The wind erosion critical wind speed of NS40 (leaving 40cm high stubble at harvest) , NPS40 (leaving 40cm high stubble at harvest, then press), NPS20 (leaving 20cm high stubble at harvest, then press) , NS20 (leaving 20cm high stubble at harvest) and conventional tillage (CT) was 16.0 m·s-1,15.2 m·s-1,14.7 m·s-1,14.5 m·s-1 and 6.3 m·s-1 respectively.Higher stubble not only decreased wind speed but reduced wind erosion rate. Conservation tillage had significant effect on prevent wind erosion when the wind speed lower than 20m·s-1.The wind tunnel experiment shows that, the best effect of sandstorm-preventing was gained at leaving 40cm high stubble at harvest. The wind erosion rate of NS40 reduced 87.84% and 80.77% compared to that of CT, when the wind erosion speed were 16 m·s-1 and 22 m·s-1 respectively.B. The effects of conservation tillage on soil bulk and soil hardnessConservation tillage can reduce soil bulk density (BD) in fallow stage. BD in 0~5cm soil layer of different conservation tillage treatments lower than that in CT, the average...