Soil water content and water balance in rainfed fields in Northeast Thailand
Soil water content and water balance in rainfed fields in Northeast Thailand
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DOI：
10.1016/j.agwat.2008.07.007
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发表时间：
2009
影响因子：
6.7
通讯作者：
T. Moroizumi;H. Hamada;S. Sukchan;M. Ikemoto
中科院分区：
文献类型：
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作者：
T. Moroizumi;H. Hamada;S. Sukchan;M. Ikemoto
泰国东北部是半湿润的热带气候，其特点是旱季和雨季。为了稳定作物生产，可能有必要开发新的水资源，如土壤水分和地下水，而不是现有资源。这是因为该地区的许多地区已经尝试了不成功的农业。在这项研究中，我们调查了在泰国东北部的孔敬，种植水稻和甘蔗，在一个为期1年的期间，包括旱季和雨季，并估计实际蒸散量（ETa）微气象数据。此外，我们还根据土壤含水量调查结果和实际蒸散量评估了水分平衡。在旱季，坡耕地和低耕地0.6m以上土壤含水量逐渐减少，而1.0m以下土壤含水量基本保持湿润。土壤含水量的二维剖面表明，在旱季结束时，0.4m以下的土层显示土壤含水量超过0.10-0.15m3m−3，因此表明水分是从这些土层供应给甘蔗的。Etarates的范围与先前研究中的范围几乎相同。平均ETarates为3.7mmd-1的较低的领域和4.2mmd-1的坡地。在旱季，从剖面外部估算的向上水流为373 mm（相当于1.9mmd−1的通量）。这种向上水流的来源是1 m深度以下的桑迪粘土（SC）层。正是这种来自SC层的土壤水分供应使得甘蔗在没有灌溉的情况下生长。
Northeast Thailand has a semi-humid tropical climate which is characterized by dry and rainy seasons. In order to stabilize crop production, it may be necessary to develop new water resources, such as soil moisture and groundwater, instead of rainfed resources. This is because rainfed agriculture has already been unsuccessfully tried in many areas of this region. In this study, we investigate the soil water content in rainfed fields in Khon Kaen in Northeast Thailand, where rice and sugarcane were planted, over a 1-year period that contained both dry and rainy seasons, and estimate the actual evapotranspiration (ETa) using micrometeorological data. In addition, we assess the water balance from the results of the soil water content investigation and the actual evapotranspiration. Although the soil water content at depths above 0.6m in both the lower and the sloping fields gradually decreased during the dry season, the soil water content at a depth of 1.0m was under almost constant wet conditions. Two-dimensional profiles of the soil water content demonstrated that at the end of the dry season, the soil layers below a depth of 0.4m showed a soil water content of more than 0.10–0.15m3m−3, thus suggesting that water was supplied to the sugarcane from those layers. The range in ETarates was almost the same as that in the previous study. The average ETarates were 3.7mmd−1for the lower field and 4.2mmd−1for the sloping field. In the dry season, an upward water flow of 373mm (equivalent to a flux of 1.9mmd−1) was estimated from outside the profile. The source of this upward water flow was the sandy clay (SC) layer below a depth of 1m. It was this soil water supply from the SC layer that allowed the sugarcane to grow without irrigation.