Mechanism And Field Application Under Crop Rootzone Non-Pressure Subirrigation

Crop rootzone non-pressure subirrigation was a new water-saving irrigation method. It was no pressure or little pressure or negative pressure on head of water pipe. The douche was imbedded on crop root zone. Water enters into soil by suction of soil and transpiration. Crop rootzone non-pressure subirrigation was local dropping irrigation and grads of water are power of water content.The project study on mechanwasm of irrigation and application of under crop rootzone Non-pressure subirrigation through mechanical experiment and field experiment. We measured the crops physiology ecology targets in different breeding stages,for example, soil water content,photosynthetic rate,stomata,transiration and leaf area index,and measured the parameter of plant heights ,stem diameter, leaf area,root length,try weigh of root. At same time, the wind speed, run radiation, temperature and humidity were measuerd by weather station of automatwasm. We measured the yield and analyzed the fruit quality of tomato, cucumber, apple and pear. We study the movement of water content and dwastribution, technology parameter, irrigation index, require water rule, and effection of fruit quality though these data. The results show as follows:(1) The Crop rootzone non-pressure subirrigation was using the drive power which caused by the function of soil matrix potential and plant transpiration water consumption made the water into the rootzone through the apertures of the pipeline to satisfy the needs of plants. It can improve the water use efficiency by sending water and fertilizer to the crop rootzone at the right time with the suitable amounts of water while reduce the soil wetted surface, ineffective soil evaporation and the loss of deep percolation. It can energy conservation, saving water and improved fruit quality and yield by the water- fertilizer-air-heat and plant coordination.(2)The runoff of douche was less than freedom flow under non-pressure subirrigation. The process and change rule of irrigating water are related with aperture of douche, soil temperature, and soil initial water content and so on. The runoff of douche in positive pressure was bigger than zero and negative pressure under the same aperture, and with the pressure bigger, the water volume larger. The runoff of douche was not same under different aperture in same pressure, with the aperture bigger, the water volume larger.Theoretically speaking, the wetting body of non-pressure subirrigation was sphere; and the concentric spherical surface of the douche was the equipotential surface of soil appearance. It means the soil water content value was equal in each spherical surface.(3)Through studying the effect of non-pressure irrigation and furrow irrigation on tomato, we found the tomato yield increased 9.2%, the irrigation quantity and the water consumption reduced 20%～34.9% and 12.4%～26.9%respectively, the water productivity increased 27.8%.The cucumber yield and water productivity increased 3.6% and 34%respectively, the irrigation quantity and the water consumption reduced 26.9% and 16.4%respectively.They indicated the irrigation methods can saving water and increase yield.(4) Through studying the effect of non-pressure irrigation and furrow irrigation in greenhouse. Compared with furrow irrigation, non-pressure irrigation did not decrease crop yield, but improved water availability and productivity, and in turn significantly raised contents of vitamin C, soluble sugar, total sugar and inorganic phosphorus. Apple and pear increased yield 135kg·667m-2and 88kg·667m-2 respectively. The vitamin C and soluble sugar of pear and apple enhanced 125% ,18.4%and93.2%,17.2% respectively under crop rootzone non-pressure subirrigation. They indicated that the crop rootzone non-pressure subirrigation can enhance the fruit yield and quality.The paper was financially supported by National Natural Science Foundation of China"Study of Index and Parameter about Non-pressure Subsurface Irrigation"(No. 50479051). We applied 4 items of the national monopoly, in which include country invention patent and practical new patent 2 items respectively. At the same time, we presented 7 dissertations in《ACTA PEDOLOGICA SINICA》,《Transactions of the CSAE》,《Transactions of the Chinese Society of Agricultural Machinery》,《Journal of Irrigation and Drainage》,《China Rural Water and Hydropower》. The project brought up Master degree 3 persons and Bachelor degree 2 persons...