Experimental Research And Application On Deep-Pit Irrigation For Mature Grape In Extremely Arid Region

TuHa Basin, which belongs to XinJiang Uigur aotonomous region, located in extremely arid region where has plenty of gravel in soils, and has serious water shortage problem. However, a lot of water resources had been wasted by traditional irrigation method. Water saving irrigation has a great significance for sustainable development of social economy as well as harmonious development between social economy and ecological environment in this area. Nevertheless, there were many problems about the application of traditional water-saving irrigation technology in this particular environment. In order to study the water-saving irrigation technique that is new and applicable to this environment, deep-pit irrigation was proposed on basis of various water-saving irrigation techniques both at home and abroad. In this paper, water infiltration characteristics and water consumption law of grape were studied through combining national scientific and technological supported program and major projects in Xinjiang autonomous region "Study and Demonstration on Key Technology of Micro-irrigation for Mature Grape in Extremely Arid Region" and combining laboratory principle test and field application test. Major findings are as follows:(1) By the infiltration experiment of homogeneous soil with different soil bulk density, both philip infiltration model and kostiakov infiltration for deep-pit irrigation was established with parameter of bulk density. In addition, based on equation of unsaturated soil water movement, effective numerical simulation model on deep pit irrigation was established.(2) The effects of different irrigation amount on physiological characters of grape was studied by field measured data lasted for two years. Then following models were established: the model of fruit sugar content and fruit-shape index affected by irrigation amount, the model of canopy temperature affected by irrigation amount and growth model of fruit longitudinal diameter. It was found that irrigation amount mainly affects the cumulative amount of the first peak of net photosynthetic rate, adaptability to light intensity change and the peak current time.(3) Different growth traits of grape at different growth stages were analyzed through "analytic method of traits boundary". Optimum range of irrigation amount during each growth stage was determined and optimal irrigation scheduling of deep pit irrigation for grape was proposed. What's more, the rationality of optimal irrigation scheduling was verified by water production function.(4) The water consumption, evaporation and transpiration, which increased with the increase of irrigation amount, were calculated at different growth stages. The value reached minimum in blooming stage and maximum in fruit expanding stage. Relevant analysis indicated that there were a good relevance between water consumption intensity and average humidity, evaporation intensity and average net radiation, as well as transpiration rate and humidity.(5) Deep-pit irrigation technology was preliminary evaluated, results showed that:greatly reducing evaporation, saving water resources, improving irrigation water use efficiency and comprehensive quality of grape. While there is a larger one-time investment, but with longer serviced life, the investment can be relatively small.From above all, deep pit irrigation was a new micro-irrigation technology suitable for mature grape in extremely arid region.