【作者】 孙景生；

【导师】 康绍忠；

【作者基本信息】 西北农林科技大学 ， 农业水土工程， 2002， 博士

【摘要】 干旱缺水严重地制约着社会经济的可持续发展。我国是一个灌溉农业大国，水资源紧缺问题十分严重。然而，由于经济欠发达，我国农田灌溉仍以传统的畦、沟地面灌溉技术为主，水资源浪费现象还比较严重，因此，如何运用新的理论研究和改进地面灌水技术，提高农田水分利用效率和水的生产效率，已成为当今我国农业节水研究的重点课题。 沟灌是大田宽行作物灌溉中比较常见的一种灌水方式。但常规沟灌很难满足灌溉过程中对灌水适时、适量的要求。近年来，根据室内控制性作物根系分区交替灌溉的试验成果，通过对土壤控制水分进入作物根区的物理过程、根系吸水的生理过程、以及根系的动态性质、补偿功能、根冠间信息传递和相互作用等的深入了解，提出的控制性交替隔沟灌溉技术，在大田宽行作物灌溉中已初步表现出节水而不减产的优点，被证明是一种行之有效的灌水方式。然而，目前有关交替隔沟灌溉的研究还主要集中于这种灌水方式对作物水分生理指标、耗水量和产量的影响方面，而对大田采用这种灌水式后的土壤入渗参数变化情况、作物需水量与耗水量计算、以及指导大田灌溉的水分下限控制指标等与大田生产实际密切相关的几个问题基本上还没有进行系统的深入研究，而这些问题如不能得到很好地解决，势必会对这种灌水方式的推广应用产生严重的影响。为此，本文针对上述问题，以夏玉米为试验材料，在大田和防雨棚下测坑内开展了三年的试验研究。 全文共分六章。第一章对地面沟灌技术的改进与发展、控制性交替隔沟灌溉技术的提出与理论依据、国内外相关研究的进展情况等进行了分析和阐述，提出了目前有待进一步研究和解决的主要问题；第二章通过大田灌水试验对控制性交替隔沟灌溉的土壤入渗参数、灌溉水流推进和水分在土壤中的再分布过程进行了研究；第三章利用棚下测坑的实测资料，分析给出了不同沟灌方式夏玉米田棵间土壤蒸发与作物蒸腾的比例关系，并对棵间土壤蒸发与表层土壤含水率和叶面积指数的关系、灌溉后湿沟土面蒸发强度的变化过程进行了研究，最后依据实测的产量资料初步确定了交替沟灌溉的夏玉米需水量和各生育阶段的日平均需水强度；第四章研究了控制性交替隔沟灌溉对夏玉米植株生长发育、根冠比、灌浆速度、叶片水分生理指标、产量及水分利用效率的影响，分析确定了控制性交替隔沟灌溉夏玉米的适宜灌水控制下限；第五章对交替隔沟灌溉条件下夏玉米需水量的估算方法、基础作物系数与土面蒸发系数的确定等且且一．进行了研究和验证；第六章对研究主要结论进行概括总结，并就有关问题进行了讨论。 本文研究得出的主要结论可归纳为如下几点： 门）由于表层土壤干燥程度及水平方向吸力梯度的差异，不同沟灌方式之间土壤入渗参数存在着一定的差异，交替隔沟灌溉的土壤初始入渗速率较大，水流推进速率较常规沟灌和固定隔沟灌的都慢，但其入渗速率随时间的衰减速度较快，在单沟灌水量相同的情况下沟中地表水消退历时更长一些。根据建立的水量平衡方程，采用模式搜索技术中的爬山法，利用 Infilt vs分析软件，计算得到的不同沟灌方式灌溉水流的推进过程与利用实测资料回归分析得到的水流推进过程几乎完全重合，预测精度很高，因此证明本文建立的模型和分析计算方法是合理可行的，完全可用于不同沟灌方式土壤入渗参数和水流推进过程的估算。 u）采用交替隔沟灌溉，灌水沟的水分入渗类似于 GreenAmPt干土入渗的打气筒模型入渗方式，湿润锋面明显且比较陡直，上层剖面同一层次的水平侧渗量比常规沟灌和固定隔沟灌的都大，灌水湿润土层深度不到60cm土层，完全可以避免深层渗漏的发生。与固定隔沟灌相比，交替隔沟灌土沟的干湿交替循环不会使根区部分土壤出现长期极度干燥的情况，因此对作物根系的生长和吸收比较有利。在灌水沟沟长小于50m且在尾端打有土埂的情况下，不同灌水方式对沿沟长方向的灌水均匀度不会产生任何影响。 （3）采用交替隔沟灌溉方式，夏玉米生育期需水量为310二3rum，其中棵间土壤蒸发与作物蒸腾量分别为88．43turn和221．70mm，比常规沟灌的分别减少25．36％、35石2％、20．29％，表明干湿交替循环不仅可以减少每次灌水间隔期间的棵间土壤无效蒸发，而且也抑制了作物的奢侈蒸腾，因此作物需水量明显减少，节水效果非常显著，被证明是沟灌方式中最科学的一种灌水方法。 （4）夏玉米田棵间土壤蒸发主要发生在灌后几天表层土壤比较湿润的时期内，其中表层土壤含水率和叶面积指数是影响土面蒸发的两个基本因素。采用控制性交替隔沟灌溉，通过减少湿润表面面积，缩短表面湿润时间，可在夏玉米生育期各阶段明显减少棵间土壤蒸发，增进土壤贮水向作物根系吸水的转化，使作物蒸腾占阶段耗水量的比例增大。如灌水下限同为L刁0的水分处理，交替隔沟灌溉的夏玉米，在播种～出苗、出苗～拔节、拔节～抽雄、抽雄～灌浆、灌浆～成熟及全生育期的植株蒸腾量占阶段耗水量的比例比常规沟灌的分别增加了4．32％、6．82％、5．26％、3石1％、1．89％和 4．55％。 （5）夏玉米更多还原

【Abstract】 Drought and water shortage are restricting seriously the sustainable development of social economy. China is a large country of irrigated agriculture, in which the shortage of water resources is very serious. Due to the underdevelopment of economy, traditional surface irrigation such as border and furrow irrigation is still taken as the dominant way in farmland irrigation, which leads to the great waste of water resources. Therefore, how to apply a new theory to study and improve surface irrigation technique in order to increase water use efficiency and water productivity in farmland, has become a key project in water-saving research of agriculture today.Furrow irrigation is a common way used in wide-row crops. But conventional furrow irrigation is difficult to meet the demands that crops are irrigated at proper time and with suitable amount of water. In recent years, according to the experimental results of controlled roots-divided alternative irrigation, controlled alternative furrow irrigation technique has been put forward through the deep investigation on the physical process of soil water moving into root zone, physiological process of roots absorbing water, dynamic properties and compensative role of roots, signal transmission and interaction between roots and canopy and so on. Controlled alternative furrow irrigation is proved to be an effective irrigation technique that has an advantage of saving water and not reducing yields in irrigating wide-row crops. At present, the studies about the controlled alternate furrow irrigation are focused on how it affects the water physiological indexes, water consumption and yields of crops. But, some problems such as the soil infiltrative parameters, irrigating water advancing, water redistribution in soil, calculation of crop water requirement and water consumption, and the upper and lower limit indexes of soil moisture, guiding a field irrigation after the controlled alternative furrow irrigation is implemented in field, have notbeen researched systematically and deeply. If these problems could not been solved commendably, the popularization of controlled alternate furrow irrigation will be affected. Therefore, an experimental study has been conducted on summer maize planted in field and lysimeters under a rain shelter for three years to solve the problems.This dissertation is divided into six chapters. In the first chapter, the improvement and development of furrow irrigation technique, theory foundation of controlled alternate furrow irrigation, and related research advance at home and abroad were analyzed and elucidated, and the main problems needing to be studied further and to be solved were put forward. In the second chapter, the soil infiltrative parameters, irrigating water advancing and water redistribution in soil were studied by adopting the controlled alternative furrow irrigation in field. In the third chapter, the ratio of soil evaporation to crop transpiration under different furrow irrigation ways adopted in summer maize field was analyzed by using the measured data in lysimeters. Next, the relationship between soil evaporation, surface soil moisture and leaf area indexes and the variation course of surface soil evaporation intensity in wet furrows after irrigation were studied. Finally, water requirement of summer maize and daily water requirement at each stage were determined based on the yield data under alternate furrow irrigation. In the fourth chapter, the effect of controlled alternative furrow irrigation on the ratio of root to shoot, filling rate, leaf physiological indexes, yield and water use efficiency of summer maize were discussed, and the lower limits of suitable irrigation for summer maize in controlled alternate furrow irrigation were analyzed and determined. The estimation methods of water requirement, and determination of basal crop coefficient and soil evaporation coefficient under the controlled alternative furrow irrigation in summer maize were studied and verified in the fifth chapter. In the last chapter, the m更多还原