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Study on Drip Irrigation under Membrane of Water Demand Regulation and Soil Moisture Lower Limit in

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Tutor: TianJunCang
School: Ningxia University
Course: Water Resources and Hydropower Engineering
Keywords: Dry farming rice,drip irrigation under Membrane,Water demand regulation,soil moi
CLC: S511
Type: Master's thesis
Year:  2014
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Abstract:
Aiming at the practical problems of shortage of water resources in the Yellow-river irrigation district in Ningxia province and lag of irrigation technology, based on experiment base in Pingjipu Yinchan Ningxia. Study on drip irrigation under membrane of increment of ground water and water demand regulation and soil moisture lower limit in Dry farming rice.To determine the reasonable increment of ground water, actual water demand, water demand regulation of rice cultivated in aerobic soil.To find out soil moisture lower limit of different varieties of rice cultivated in aerobic soil.In order to provid theoretical and technical basis for water-saving agriculture and effective utilization of water resource.The main research results are as follows:1. Based on the Penman-Monteith formula the crop potential evapotranspiration quantity formula was derived.Be used the empirical formula by considering the soil water stress coefficient and crop coefficients calculate water requirement of rice.The calculation results indicated that the milk stage require water was minimum, actual water demand of seeding stage was close to the average in the whole stages and from tillering stage to filling stage was the largest. In0.9θfield water treatment was not affected by water stress conditions, film with drip irrigation rice measured water demand was greater than the empirical formula calculated value, the error of8%, at0.8θfield water treatment (initially) water stress conditions, the membrane under drip irrigation rice measured value was almost the same in the crop water requirement and experience formula,0.6θfield water treatment (water stress), membrane under drip irrigation rice measured values in the crop water requirement was lower than the experience formula, the deflection, section3and D10error was12%, ning japonica28error was25%.2. The contrast test method setted up four processing:ZM (drip+coated rice), ZL (drip+open rice), WM (drip+outdoor coated), WL drip irrigation+(open). Using the water balance method to calculate the film with drip irrigation rice recharge of groundwater, the results showed that the groundwater level, irrigation quota (9m3/667m2) and water cycle (2d) cases, the same ZM, WM treatment of groundwater and surface water supplies;ZL, WL treatment of surface water, groundwater recharge membrane under drip irrigation rice ZM treatment of groundwater, surface water supplies supplies every day0.68m3/667m2, accounted for15.1%of irrigation water. Found by calculation,0.8θfield moisture threshold processing for membrane under drip irrigation rice using groundwater critical point,0.8θfield processing (irrigation quota was7.2m/667m2, water cycle for2d), rice by groundwater recharge, supplies a day on average0.18m3/667m2, recharge is19.23m3/667m2in the whole stages;0.9θfield processing (irrigation quota was10.8m3/667m2, water cycle for2d), drip irrigation water recharge of groundwater, supplies a day on average1.26m3/667m2, recharge in the whole stages is131.42m3/667m2, accounted for24.3%of irrigation water;0.6θfield processing (irrigation quota was5m3/667m2, irrigation cycle of4d) rice by groundwater recharge, supplied a day on average1.42m3/667m2, recharge in the whole stages was147.59m3/667m2, accounted for64.73%of irrigation water. Conclusion showed that the appropriate adjust moisture threshold could effectedly use of drip irrigation water and groundwater could not only balance the use of water resources, and keep the local water ecological balance.3. Using the contrast test method, on rice growth index, physiological index and yield were analyzed. The results showed that:(1) with the increasing of soil moisture threshold (O.60field-0.9θfield), the water consumption of rice, plant height, chlorophyll, photosynthetic rate, transpiration rate and yield increased, while stomatal conductance and intercellular CO2concentration was reduced, the three varieties change rule. Under the condition of three kinds of lower limit of soil water, the actual rice water requirement and crop coefficients and convex parabola relationship to the growth period.(2) from the yield difference analysis showed that under0.86&eld processing, production change although not significant, but compared with0.9θfieid processing analysis ning japonica and yield potential in increasing filling period of irrigation, section3affected by mild water stress yield were significant, and D10varieties in each growth period water requirement rule no difference, production potential was not clear, so was the most suitable varieties membrane under drip dry ning japonica28.(3) analysis water floor, suitable for membrane under drip irrigation in the irrigation area of ningxia were dry rice planting soil moisture lower limit of O.9θfield processing, according to the law of water requirement analysis, the water requirement of jointing stage, tillering and booting stage could be carried out in accordance with the lower limit of soil water0.9θfield processing drip irrigation, the water requirement of ratooning buds small could be carried out in accordance with the field processing0.6θfield drip irrigation, seedling stage and filling stage carried out in accordance with the field processing O.80field drip irrigation. To satisfy the requirement of the membrane under drip dry rice water requirement, and achieve the purpose of further saving water.This research results for the rainfed rice membrane under drip irrigation extension provides a theoretical basis and technical support, could apromote development of water-saving agriculture in arid.
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