| Because of the main features that the fragile ecosystem, soil erosion and outdated technology in Semi-arid areas of Shaanxi, my experiment in order to ensure the sustainable use of water and soil resources in Loess Plateau, improve public economic benefits in shaanbei, fullfill the need of agricultural modernization and Improve the regional ecological environment. This dissertation is based on the national scientific and technological support project—"research and demonstration of comprehensive water-saving technology on distinctive fruits in semi-arid mountain areas of Shaanxi", and it refers to the relevant bibliography both at home and abroad, additionally it follows the technological route of combining the field experiment and theory analyze to mainly study the water-consuming regularities of drip-irrigation jujube, water use efficiency and crop coefficient, etc., the major results are as follows:(1) We have studied on the soil-water distribution characteristics of drip-irrigation jujube under different irrigation treatments. On the whole, moisture percentage of each treated soil gradually decreases in variation with the increases in depth., The variation of moisture percentage in the soil layer of 0~20cm is the largest in all soil lyers; different treatments of soil moisture variations are mainly centralized in the soil layer of 0 ~ 80cm, while moisture percentage in soil layer of 100~120cm basically remains stable.(2) During its growing period, jujube experiences two stages of significant soil water consumption: flower-fruit stage and fruit-growth stage, during which the moisture percentage of soil dramatically varies. Appropriatelly increasing irrigation ration can increases moisture percentage of soil to some extend, however, if increasing more than a certain value, the moisture percentage of soil cannot be significantly increased.(3) We have analyzed each physiological and growth index of the jujube during its growing period. Increasing the irrigation quantity and frequency can increase the jujube's leaf area index, flower-fruit rate and the hanging length; stomata aperture values change in a day showed a bimodal curve with temperature changes; water potential of leaf is high in the early and late of the day, low in the middle of the day, under the same conditions, the size of leaf water-potential is associated with the soil moisture status.(4) the water consumption of jujube increases with increasing of irrigation, which achieves the maximum in flower-fruite stage and fruit-expand stage, the sum of ET in these two periods accounts for approximately 71.9% of the whole ET during the growth-period, water deficit sensitivity index is the highest, and is most sensitive to water deficit, therefore this is the critical period for water requirement.(5) We have studied on reference crops'water requirement and crop coefficient of the drip-irrigation jujube in the Loess Plateau, and crop coefficient during the crop growth period was ranked from large to small: fruit-expand stage> fruit-mature stage>flower-fruite stage> embryonic-leaf developing stage, respectively, 1.306,0.961., 0.683 and 0.515.(6) Irrigation quantity during jujube fully-growing period, the water consumption and the yield all demonstrate a good quadratic relationship. Water consumption increases with the increase of the yield, however, when water consumption increases to a certain extent, the upward trend slows down to be almost stable, and water input after that makes little influence in the yield(7) We have proposed appropriate irrigation quota and frequency: irrigation five times (two times in initial stage, two times in flower-fruit stage, one time in flower- fruit stage), the drip irrigation quota is 135.0m3/hm2, irrigation water is 675m3/hm2 , which are the most efficient treatment of water production. Furthermore, we have caculated the economic irrigation quota Jujube growth period and calculated the economic use of irrigation quota is M=687.122m3/hm2 during the jujube fully-growing period. |
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