| With the northwest Loess Plateau as an interesting study area, the paper was based on the experimental study on in-situ rainwater harvesting and the supplementary irrigation study on spring wheat, watermelon, broccoli and cucumber. The experiments were conducted at the ecological experiment station (Gaolan County, Gansu Province), Chinese Academy of Science, in 2000-2001. The paper was designed to explore the rate of runoff and the catchment's cost of various catchments, analyze the storage cost of various water cellars, and investigate the soil water dynamics, regular of water consumption, yield and its content, water use efficiency (WUE), water irrigation efficiency (WIE) or economic benefit per cubic water, and output value of various crops. Based on the above studies, a catchments-water utilization model for solar greenhouse in the region of precipitation 300mm was proposed.The results of rainwater harvesting experiment are listed as follow: The rates of runoff per year were the surface of solar greenhouse>the road surface>waste plastic catchments>the house surface>the red-sand catchments>the catchments cleaned weeds; the average annual rate of runoff was 57.9%. The catchment's costs were the catchments cleaned weeds>the red-sand catchments>the waste plastic catchments>the surface of solar greenhouse>the house surface>the road surface; the average catchment's cost was 1.07 Yuan.m"J. The average storage cost of various water cellars was 5.08 Yuan.m"3; the storage cost was significantly higher than the catchment's cost.The results of the soil water dynamics of various crop's growth period are listed as follow: Due to influence of precipitation, irrigation and crop's water consumption, the soil water dynamics appeared fluctuated decreasing. Besides, the soil water dynamics of watermelon in gravel-mulched field were subjected to the way of mulching.The results of the regulation of water consumption of various crops are listed asfollow: With irrigation quantities increased, the water consumption of crops was increasing. The wheat and broccoli experiments showed that the water consumption of crops don't change with the ways of irrigation. The average water consumptions of wheat, watermelon, broccoli and cucumber were respectively 2.08mm, 1.65mm, 3.91mm and 1.91mm.The results of yields and theirs contents are listed as follow: About wheat, the differences among irrigation quantities treats and among interaction were very significant; with irrigation quantities increased, the yields were increasing; the yields of the ways irrigation were micro-sprinkle irrigation> pipe-irrigation> drip-irrigation>CK; with irrigation quantities increased, the contribution of 1000 grain weight was decreasing, but the contribution of the number of ears per heliometers was increasing. The differences among irrigation quantities of watermelon were significant; with irrigation quantities increased, the yields, the weight of per fruit and the number of watermelon were increasing. About broccoli, the plant height, crown, the fruit weight, the weight of stem and leaves and the yield of drip-irrigation was superior than of pipe-irrigation and micro-sprinkle irrigation; with irrigation quantities increased, the yields and theirs contents were increasing. About cucumber, the treat of drip-irrigation 180mm had significant supper in yield, the number of cucumber and the fruit weight.The results of WUE of crops are listed as follow: The WUE of irrigation's treats were higher than of CK; the WUE of micro-sprinkle irrigation were higher than of pipe-irrigation and drip-irrigation; the WUE of micro-sprinkle irrigation 67.5mm was highest. The WUE of watermelon was increasing with irrigation quantities increased; the highest WUE was drip-irrigation 67.5rrrn. About broccoli, the WUE of drip-irrigation were higher than of pipe-irrigation and micro-sprinkle irrigation. The WUE of drip-irrigation 180mm was highest about cucumber.The results of WIE of crops (economic benefit per cubic water) are listed as follow: The WIE of micro-sprink... |
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