Soil Physical Properties of Uncultivated Paddy Fields Located in Semi-wet Sloping Land and the Simulation of their Response to Heavy Rain
Soil Physical Properties of Uncultivated Paddy Fields Located in Semi-wet Sloping Land and the Simulation of their Response to Heavy Rain
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半湿坡地未耕稻田土壤物理性质及其对暴雨响应的模拟
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
H. Baba
中科院分区：
文献类型：
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作者：
K. Chiba;K. Koga;H. Baba
通过对半湿润坡地未耕稻田土壤物理性质的调查，研究了半湿润坡地未耕稻田对暴雨的响应。结果表明，未开垦地表层土壤裂隙发育，深度达70 cm，植物根系形成的大孔隙使其具有很高的导水率。X射线立体放射照片还显示了犁层中的小生物形成的大孔隙。在两个未开垦的地块进行了一个小区的摄入率测试。一个是在长期干旱之后，另一个是在长期降雨之后。测量了农田的堤坝高度，发现与普通耕地相比，堤坝高度很低。在野外调查资料的基础上，利用包括农田水分平衡和土壤物理条件的计算机模拟模型，对未开垦农田、普通农田和现代大型农田的水文特性进行了研究。模型以取水量、堤围高度和田间排水口结构为特征。对未开垦和开垦的稻田分别设定两个初始条件，一个是干旱后，另一个是雨后。模型中输入了每天123毫米的大雨。根据模拟结果，未耕种田地中的水在堤坝下部发生快速的表面流出，而耕种田地中的水则通过田地出口逐渐流到排水渠。造成上述差异的原因，本质上是堤防高度的差异。因此，在未开垦稻田防治水患时，田间排水口的管理是十分重要的。
Soil physical properties of uncultivated paddy fields in semi-wet sloping land were investigated in order to study the response of the fields to heavy rain. It was revealed that the upper soil layers of uncultivated fields have very high hydraulic conductivity because of well developed cracks which reach 70 cm deep layer and macropores created by plant roots. The x-ray stereoradiographs showed also macropores made by small creatures in the plow layer. One-plot intake rate tests were carried out in two uncultivated field lots. One was after a long drought and the other was after a long spell of rain. The levee heights of fields were measured and found to be very low compared to ordinary cultivated fields. Based on these data obtained from the field investigation, hydrological properties of uncultivated field, ordinary cultivated field and modern large-sized cultivated field were studied using computer simulation models which include water balance and soil physical condition of field. The models were characterized by intake rate, levee/ bund height and the structure of field outlet. Two initial conditions were given to uncultivated and cultivated paddy fields, respectively, one was after a drought and the other was after rain. A heavy rain of 123 mm per day was inputted to the models. According to the results of the simulation, a rapid surface outflow over a low portion of the levee occurred in uncultivated field whereas water gradually flew out to drainage canal through the field outlet in cultivated fields. The reason for the above difference is essentially the difference in the levee height. It was concluded that the management of field outlet is very important when preventing water disaster in uncultivated paddy fields.