| Drought,water shortage and soil salinization are key factors to inhibit the development of agriculture in arid and semi arid areas.Hetao Irrigation District has some problems,such as irrigation water resources shortage,agricultural labor shortage,soil salinization and short frost free period.This experiment took spring wheat,sunflower,maize monoculture as control,the effects of spring wheat-sunflower multiple cropping on the dynamic change of soil moisture,soil salinity and land productivity in Hetao irrigation district had been monitored and investigated,and drew the following conclusions:1)Before spring wheat harvest,soil moisture in 0-100 cm soil layer of and spring wheat were relatively lower.After spring wheat harvest,soil moisture of spring wheat – sunflower and sunflower,maize in top layer(0-20 cm soil layer)was higher than that in spring wheat,and the soil moisture of 20-80 cm soil layer was lower than that of spring wheat.In the crop growing season,the water consumption of spring wheat,maize,sunflower and spring wheat-sunflower was 562.87 mm,532.34 mm,344.84 mm and 750.09 mm;throughout the growing season,the water consumption was 604.76 mm,611.38 mm,448.84 mm and 750.09 mm.During the growing season,the average soil water evapotranspiration intensity of spring wheat-sunflower and spring wheat was higher,maize and sunflower were lower;and spring wheat-sunflower was the highest and sunflower was the lowest in the whole growth season.2)The different planting methods mainly affected the soil salinity in 0-40 cm soil depth layer,and the soil salinity of different planting methods changed vigorly before spring wheat harvest,and changed slowly after spring wheat.Compare with spring wheat,maize and sunflower,the soil salinity in top soil of spring wheat-sunflower were reduced by 32.52%,16.70% and 24.92%,respectively,and in 0-100 cm soil layer were reduced by 13.32%,8.88% and 12.07% in multiple sunflower harvest period,respectively.3)The equivalent yield of spring wheat-sunflower was 126.01%,3.86% and 3.21% higher than that of spring wheat,maize and sunflower,respectively.Equivalent water use efficiency and equivalent water productivity of spring wheat-sunflower were higher than that of spring wheat,but lower than sunflower and maize.The yield of spring wheat-sunflower was 143.55%,102.33% and 3.19% higher than that of spring wheat,maize and sunflower respectively,and the net output value was 176.15%,116.55% and-13.26% respectively.4)The heat energy of seeds of spring wheat-sunflower was significantly higher than that of maize,and very significantly higher than that of spring wheat and sunflower.The total net heat of spring wheat-sunflower was significantly lower than that of maize and sunflower,but significantly higher than spring wheat.5)The total output value of spring wheat-sunflower was slightly higher than that of sunflower,and significantly higher than that of spring wheat and maize.The net output value of spring wheat-sunflower was significantly higher than that of spring wheat and maize,but was significantly lower than that of sunflower. |
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