Evaluating the Irrigation Requirement at a Cornfield in the Yellow River Basin Based on the "Dynamic Field Capacity"
Evaluating the Irrigation Requirement at a Cornfield in the Yellow River Basin Based on the "Dynamic Field Capacity"
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基于“动态田间容量”的黄河流域玉米田灌溉需求评价
DOI：
10.3178/jjshwr.18.663
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
HE WANGWenjun
中科院分区：
文献类型：
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作者：
Risa Iwanaga Tetsuo;HE WANGWenjun
在内蒙古黄河流域的一个玉米试验田进行了灌溉试验，以研究该地区灌溉节水的潜力。根区分为两层;第一层40 cm厚，第二层60 cm厚，灌溉要求，W a（mm），假设表示为其中W i是第i层中所含的水量（mm）（i = 1，2），Wi FC为土层的“动态田间持水量”（mm），αα为根区控制盐分和水分均匀分布的淋溶部分。动场容量Wi FC定义为第i层底表面的水元素上的力平衡时的Wi值，并使用两层BBH模型来计算。这个临界点不是静态的，而是动态的，取决于地下水位的深度和植物根系的潜在吸水量。2004年正常灌溉条件下，试验田的αα平均值为0.75。很明显，这个值太大，不是最佳的，过度灌溉发生，因为地下水水位上升到根区后不久，该区域的下部几乎饱和了很长一段时间。
An irrigation experiment was conducted at an experimental cornfield established in the Yellow River basin, Inner Mongolia, China, in order to investigate the potential for a saving of irrigation water in this region. The root zone was divided into two layers; the first layer 40 cm thick and the second layer 60 cm thick, and the irrigation requirement, W a （mm）, was assumed to be expressed as where W i is the amount of water contained in the i th layer （mm）（ i = 1, 2）, W i FC is the "dynamic field capacity" of the layer （mm）, and αα indicates a leaching part for salinity control and uniform distribution of water in the root zone. The dynamic field capacity W i FC is defined as the value of W i when a balance of forces is made on an element of the water at the bottom surface of the i th layer, and is evaluated using the two-layer BBH model. This critical point is not static but dynamic in nature and depends on the depth of water table and the potential water extract by plant roots. The mean value of αα for the experimental cornfield was evaluated to be 0.75 from the irrigation practiced as usual in 2004. It is apparent that this value was too large to be optimum and over-irrigation occurred, because the groundwater level rose up to within the root zone just after the irrigation and the lower part of the zone was almost saturated for a long time.