Integrated Evaluation On Water-saving Cropping System In Irrigated Oasis Of Hexi Corridor

Conflicts between crop production of Hexi oasis major grain-producing and severe water scarcity were studied to achieve sustainable agricultural development, we focused on status and trends of agricultural development to coordinate multiple objectives of agricultural production, farmer's income and sustainable use of water resources. Planting system and driven cropping patterns for irrigation in arid oasis were analyzed. By researching the water conditions and efficiency, typical cropping patterns in Liangzhou district were evaluated to select saving-water and high efficiency patterns and its related water-saving technologies for development of planting system in water binding region. The main conclusions were as follows:1. The crop irrigation scale had been reduced following with changes in crop structure and water-saving technologies progress, making farming irrigation water decline and water use economic efficiency increase significantly.Through the structural adjustments as expansion of the autumn crops and pressure of the summer crops, Crop production nearly doubled, water use volume of main crops reduced to 635 million m3 in 2007 from 822 million m3 in 1998, decreased by 22.74%; increasing of crop production and decline of water makes the water consumption per ten thousand yuan GDP decreased from 0.54 in 1998 to 0.21 in 2007, decreased by 61.11%. Cropping patterns as seed corn and vegetable and potato in the large-scale planting saved irrigation water by 750m3/hm2,1275 m3/hm2,1200 m3/hm2 compared with scattered planting.2. Water consumption, Yield, WUE, WEUE of different cropping patterns shown an non-identical relationship, Mid-water consumption patterns such seed corn, corn and peas intercropping had higher water use efficiency, wheat and corn intercropping had but higher water use efficiency even though its high water consumption was much higher.The traditional pattern wheat and corn intercropping's water consumption was 990.79 mm, it still was the high consuming-water of production system. The patterns of low consuming-water such as potato and greenhouse vegetables' water consumption were less than wheat and corn intercropping by 47.1% and 27.3%. Other then, corn and pea intercropping was also the pattern of low consuming-water in mixed groups, it reduced water-consumption by 21.8% compared to wheat and corn intercropping. The WUE of corn and pea intercropping and maize patterns was highest, were14.77Kg/mm·hm2 and 14.31Kg/mm·hm2; that of seed corn was relatively better performance, which was 12.17 Kg/mm-hm2. In the view of WEUE, the high-value pattern greenhouse vegetables showed a high level of 305.7yuan/mm·hm2, it was 10 times more than other patterns, following seed corn was 24.49 yuan/mm-hm2. Yielding a high efficiency but low consumption of water is ideal for water-saving cropping patterns, but the high-yield high-efficiency mode with high water consumption patterns should not be completely abandoned.3.10 kinds of typical cropping patterns in comprehensive economic benefits and social benefits and ecological benefits were evaluated.The results showed that:the greenhouse vegetables and corn and pea intercropping and seed corn had a higher degree of multi-objective requirements with the development of planting system in arid oasis, and these cropping patterns has good prospectives for development.The high value-types of greenhouse vegetables, seed corn, wheat and corn intercropping and corn and peas intercropping had batter economic benefits, in addition, greenhouse vegetables had a high contribution to the income of peasants; spring wheat, winter wheat, beer barley and wheat-rape needed less requirement of labor, showing good social benefits, the patterns of corn had a higher WPEE and long growing period, showing better eco-efficiency. From the comprehensive evaluation results, greenhouse vegetables, corn and pea intercropping, wheat and corn intercropping, seed corn, field corn and potato etc. had better comprehensive benefits.4. Based on the analysis of different water-saving technological projects, saving-water potential, proposed water-saving and efficiency cropping system for the development in area were put forward.The water-saving technological engineering saved 78.83million m3 water in the wheat and corn fields, which accounted 14% for the total irrigation amount in crops field. The saving-water content is 20% of the total irrigation, though the application of various water-saving technologies in field could save total water supply by18.4%. Water-saving and efficiency cropping system for the area were:①Planting patterns for gravity irrigation district landscape;②Planting patterns for groundwater exploitation area;③Hilly regions and high-tech water-saving patterns for suburb planting system.