【作者】 郑建华；

【导师】 黄冠华；

【作者基本信息】 中国农业大学 ， 农业水土工程， 2014， 博士

【摘要】 水资源短缺和生态环境恶化已成为西北内陆旱区农业可持续发展的制约因素。近年来,压缩高耗水作物、增加节水型经济作物种植比例已成为该地区缓解水资源供需矛盾、促进农民增收的重要举措。因此,研究西北内陆旱区经济作物的节水响应机理,并建立水分高效利用的灌溉制度对促进当地水资源可持续利用、保障生态安全和农业可持续发展具有重要的理论意义和实用价值。本文通过2008-2011年在农业部作物高效用水武威科学观测实验站开展的田间试验研究和土壤水氮迁移转化与作物生长耦合模型(SWNCM)的数值模拟,研究土壤水分和洋葱生理生态、耗水、产量、品质及水分利用效率对亏缺灌溉的响应规律,并建立了三种经济作物(洋葱、辣椒和西红柿)水分高效利用的灌溉制度。主要研究内容和取得成果如下：(1)于2008-2009年开展了洋葱膜上畦灌亏缺灌溉试验,采用称重式蒸渗仪定量研究了洋葱的耗水规律,及水分亏缺对洋葱产量和水分利用效率的影响,得到了洋葱的作物系数。膜上畦灌条件下,洋葱全生育期耗水量可达到358mm,耗水强度和耗水模系数均为鳞茎膨大期>发叶期>苗期>成熟期。洋葱产量可达到62.12t hm-2,鳞茎膨大期水分亏缺使产量显著降低。作物系数在生育期内呈抛物线形变化,在初始生长期、生育中期和成熟期平均分别为0.73、1.28和0.70。(2)于2009～2010年开展了洋葱膜下滴灌调亏灌溉试验,分析了洋葱生理、生态指标对水分亏缺的响应。结果表明洋葱的株高、颈粗、叶片数、叶面积指数、各部分生物量、光合速率、蒸腾速率和气孔导度在灌水量低于0.8ETc时均受到水分亏缺的显著影响而减小；苗期水分亏缺抑制了洋葱生长,但差异不显著；发叶期水分亏缺使各生长指标和生理指标显著降低,鳞茎膨大期水分亏缺显著降低各部分生物量、光合速率、蒸腾速率和气孔导度,成熟期水分亏缺对各生长量无显著影响。(3)膜下滴灌条件下,洋葱全生育期耗水量达到414mm。产量随灌水量(0.4～1.0ETc)的增加而增加,灌水量低于0.8ETc时,减产显著；苗期和成熟期水分亏缺对产量的影响不显著,发叶期和鳞茎膨大期水分亏缺均使产量显著降低。水分亏缺可提高洋葱的水分利用效率。灌水量为0.8ETc时可获得较高的鳞茎可溶性固形物和蛋白质含量,水分亏缺均使鳞茎维生素C含量提高。构建了洋葱全生育期和分阶段的水分生产函数；由Jensen模型分阶段水分生产函数求得洋葱的水分敏感指数为鳞茎膨大期>发叶期>苗期>成熟期。(4)通过田间实测的农田土壤水分动态和作物生长过程数据对SWNCM模型进行率定和验证。结果表明,率定和验证后的SWNCM模型能够较好的模拟试验地区洋葱、辣椒和西红柿等经济作物在亏缺灌溉条件下农田土壤水分动态和作物生长过程,及其对作物产量和耗水的影响,可对该地区此类经济作物的灌溉制度进行模拟优化。(5)基于率定后的SWNCM模型,探讨了不同灌水量和灌水频率对水量平衡组成项、作物产量和水分生产率的影响。得到洋葱、辣椒和西红柿以节水、高产、高效和减少损耗为目标的灌溉制度为：采用膜下滴灌,灌水频率分别为间隔5、5、5～7d灌水,灌水定额分别为0.65ETc、0.73ETc和0.72～0.74ETc(ETc为本模拟中率定后的作物系数Kc与ETo的乘积)。更多还原

【Abstract】 The shortage of water resources and the deterioration of the ecological environment in the arid Northwest China have been the limiting factors for its sustainable development of agriculture. In recent years, reducing the planting area of highly water consumptive crops and increasing the planting proportion of cash crops which are water saving is becoming one of the important strategies to relieve the contradiction between supply and demand of water resources, as well as increase ingatherings of the peasantry. Therefore, study the response of cash crops’growth to water saving practices and establish the irrigation schedules with high water use efficiency is scientifically and practically significant for promoting the sustainable utilization of water resources, and guaranting the ecological security and agricultural sustainable development in this arid region. In this research, field experiments’data analysis and model simulation were combined to study the responses of soil water content, crop ecological and physiological characteristics, crop evapotranspiration, yield and its quality as well as water use efficiency to water deficit, and the irrigation schedules for three cash crops, i.e., onion, pepper and tomato, were established. The field experiments were conducted at the Wuwei Experimental Station of Crop Water Use, Ministry of Agriculture, located in Gansu Province of northwest China in2008-2011. The soil-water-nitrogen-crop growth model (SWNCM) was adopted to predict the dynamics of soil water content and crop growth, as well as optimizing the irrigation schedules. The main results are as follows:(1) Deficit irrigation experiment on onion under border irrigation with plastic mulch were carried out in2008and2009, nine weighing lysimeters were used to estimate onion evapotranspiration. The effects of water deficit on onion yield and water use efficiency (WUE) were investigated, and the crop coefficient was obtained. The seasonal evapotranspiration of onion was up to358mm, water consumption rate and percentage at different growth stages ranked as bulbification stage>development stage>establishment stage>ripening stage. Onion yield can be up to62.12t hm-2, water deficit during bulbification stage can significantly reduce onion yield. The crop coefficients of onion at initial, mid-season and late season stage were0.73,1.28and0.70, respectively.(2) Regulated deficit irrigation experiment on onion under drip irrigation with plastic mulch were conducted in2009and2010, the response of crop growth and physiological indexes to different water saving practices were analysed. The results showed that onion growth indexes (i.e., plant height, neck thickness, number of leaves, leaf area index and dry matter of different parts) and physiological characteristics (i.e., photosynthesis, transpiration and stomatal conductance) were significantlty affected by water deficit when irrigation depth less than0.8ETC. Water deficit at the establishment stage can restrain the crop growth of onion in a certain degree, but the effect was not remarkable. Water stress significantly reduced the growth and physiological indexes when water deficit imposed at the development stage. Water deficit occurred at the bulbification stage can remarkably reduce the dry matter of different parts and the physiological indexes. No significant effects were found in crop growth indexes when water deificit imposed at the ripening stage.(3) Seasonal evapotranspiration of onion can be up to414mm under mulched drip irrigation. Onion yield increased with the increase of irrigation depth significantly when irrigation depth less than0.8ETc. Water deficit during the development and bulbification sages reduced bulb yield significantly, while during establishment and ripening stages, the effects of water deficit on bulb yiled were not well marked. All water deficit treatments improved the water use efficiency of onion. Higher total soluable solids and protein content in onion bulb can be obtained under treatment with irrigation depth of0.8ETc, and water deficit can improve the vitamine C content. The water sensiticity indexes of water production function indicated that bulbification stage is the most critical stage for onion irrigation.(4) The SWNCM model was calibrated and validated by the observed soil water content and crop growth data. The results indicated that the model can be used to simulate the effects of deficit irrigation on the soil water dynamics, crop growth processes, crop yield and evapotranspiration of onion, chili pepper and tomato in this study area. And then, the appropriate irrigation management for the cash crop can be evaluated by the model.(5) Based on the calibrated model, various scenarios of different irrigation amounts and frequencies were studied on the water balance, crop yield and water productivity. With the consideration of water saving, high crop yield and water productivity, the appropriate irrigation schedules for onion, chili pepper and tomato are irrigating with intervals of5,5,7days and the irrigation quota are0.65ETc,0.73ETc and0.72～0.74ETc, respectively, under mulched drip irrigation.更多还原