| An experiment was established in apple orchard under subsurface irrigation and flood irrigation. The experiment site was chosen in hilly area of Xintaicity of Shandong province. The study contents included the meteorological effects, soil physics characteristics, soil water content changes, effects of water saving and yield increase, economic benefits of subsurface irrigation project. It aimed to find out the water saving principle and technique effects of subsurface irrigation. It also can provide scientific basis and theory instructor for application of subsurface irrigation in orchard construction, improving water using and yield increase. The results showed by the research were as follows:1. Subsurface irrigation improve the benefits of the meteorological effects.The air average temperature of subsurface irrigation was 0.95℃higher than that of flood irrigation above 20cm earth's surface and 0.33℃higher above 200cm earth's surface. At 6:00, the lowest air temperature was 26.5℃of flood irrigation above 200cm earth's surface; At 14:00, the highest air temperature was 35.6℃of subsurface irrigation above 20cm earth's surface. The air absolute humidity of subsurface irrigation was 4.40% lower than that of flood irrigation above 20cm earth's surface and 1.67% lower above 200cm earth's surface. At 6:00, the highest air absolute humidity was 64.6% of flood irrigation above 20cm earth's surface; At 14:00, the lowest air absolute humidity was 37.0% of subsurface irrigation above 20cm earth's surface.In 5cm,10cm,15cm and 20cm soil depth, the soil average temperature of subsurface irrigation was 1.40℃, 0.71℃, 0.37℃and 0.37℃higher than that of flood irrigation. The soil temperature of subsurface irrigation was difference significantly from flood irrigation in 5cm, 10cm, but not difference significantly in 10cm, 15cm.2. Subsurface irrigation improves soil physics characteristics. The soil particle Content in 1~0.05mm extension, subsurface irrigation for one year was much more than flood irrigation for one year, subsurface irrigation for two years was much more than flood irrigation for two years. With the passage of time, the soil particle content was reduced in 1~0.05mm extension, but the changes of subsurface irrigation wasn't obvious than flood irrigation. It was difference significantly between subsurface irrigation and flood irrigation in soil density, soil porosity, capillary porosity and non-capillary porosity. Irrigation for one year, the soil density of subsurface irrigation was lower by 2.76% than that of flood irrigation. Subsurface irrigation's soil porosity, capillary porosity and non-capillary porosity was higher by 3.81%,3.60% and 5.24% than that of flood irrigation respective. Irrigation for two years, the soil density of subsurface irrigation was lower by 2.63% than that of flood irrigation. Subsurface irrigation's soil porosity, capillary porosity and non-capillary porosity was higher by 2.54%, 2.22% and 5.07% than that of flood irrigation respective. The soil physics characteristic of subsurface irrigation was better than that of flood irrigation.3. The discharge characteristics of subsurface irrigation porous pipe and the rule of soil water content change. Results show that the emission rates of the pipe decline with time first and then reach a relative stable value. One day after irrigation, in 5cm, 10cm, 15cm and 20cm soil depth, the soil water content of subsurface irrigation was 17.49%, 18.21%, 18.64% and 18.07%, the soil water content of flood irrigation was 19.17%, 18.89%, 17.95% and 16.31% in the same soil depth. The best soil water content of flood irrigation was in 0~10cm, and the least soil water content was in 30~50cm. But the best soil water content of subsurface irrigation was in 20~30cm, and the least soil water content was in 0~10cm. Seven days after irrigation, in 5cm, 10cm, 15cm and 20cm soil depth, the soil water content change of subsurface irrigation was 5.83%, 5.11%, 5.30% and 4.88%, but flood irrigation's was 6.29%, 5.92%, 5.77% and 4.46% in the same soil depth. The best change was in 0~10cm of flood irrigation.Before the next irrigation, the soil water content of subsurface irrigation was higher by 9.74%, 8.56%, 35.80% and 50.40% than that of flood irrigation in 5cm, 10cm, 15cm and 20cm soil depth. The average soil water content of surface irrigation was 8.12% in 0~50cm, but flood irrigation's was6.49%.After irrigation the soil water content was declined with the time passage. The soil water content of flood irrigation was always higher than that of subsurface irrigation in 0~10cm soil depth. At the beginning of flood, the soil water content of flood irrigation was higher than that of subsurface irrigation in 10~20cm soil depth, after seven days they were no difference significantly. In 20~30cm and 30~50cm soil depth, the soil water content of subsurface irrigation were always higher than that of flood irrigation. Subsurface irrigation could keep higher soil water content than flood irrigation in a long tine in 0~50cm soil depth.4. Subsurface irrigation saving water and increasing yield. The consumption of water subsurface irrigation was 800-1200m~3/(hm~2·a) less than that of flood irrigation, reduction ratio was 55.6%. The water irrigation efficiency of subsurface irrigation was increased by 6.51~11.19kg/m~3·hm~2 than that of flood irrigation. The fruit yield of subsurface irrigation was 10329.2-12057.3kg/hm~2,which was increased by 10.94%, and the one-level of fruit increases by 607.25kg/hm~2, rate of increase production is 15.5%.5. The benefit of orchard with subsurface irrigation. Subsurface irrigation was invested about 8710.54 yuan/(hm~2·a), which is more than 3971.14 yuan/(hm~2·a) that of flood irrigation. Beneficial of subsurface irrigation and flood irrigation were 53198.98 yuan/(hm~2·a), 43119.91 yuan/(hm~2·a), former is more than 10079.07 yuan/(hm~2·a) than latter; Pay back period of subsurface irrigation which increased investment were 0.054a.
|
PDF Full Text Request