中亚热带红壤区不同土地利用土壤田间持水量估测

ESTIMATION OF FIELD CAPACITY FOR VARIOUS LAND USES IN A RED SOIL REGION IN CENTRAL SUBTROPICAL CHINA

田间持水量是衡量土壤保水性的重要指标,也是进行农田灌溉、作物水管理和水文模型的重要参数,但其测定繁琐而耗时,迫切需要一种简捷精确的估测方法。采集了50个来自稻田和旱地的1 m深原状土壤剖面样,然后基于土壤基本理化性质,利用多元逐步回归方法对土壤田间持水量进行模型预测。结果显示:(1)对于稻田土壤,田间持水量主要受容重和有机碳影响,而对于旱地则主要受土壤质地影响;(2)构建的田间持水量传递函数,对于稻田土壤预测精确度较高,调整的确定系数达到0.79,对于旱地则相对较弱。研究表明土地利用方式对田间持水量精确估测影响较大,利用土壤传递函数法对田间持水量的快速获取有一定参考价值。

The parameter of field capacity is an important index to reflect soil water-retaining ability, as well as being crucial for farmland irrigation, water management and hydrological models. However, since the direct measuremem for field capacity is tedious and time-resuming, it is necessary to require a fast and accurate approach to derive it. Hence, fifty undisturbed 1-m depth soil profile samples were collected from paddy fields and dry lands in a subtropical basin in Hunan province. And based on soil basic properties, the estimation of field capacity was derived by multiple stepwise linear regression, the results showed that： （1） field capacity was mainly influenced by soil bulk density and soil organic carbon for paddy soil, but mainly by textures for dry lands; （2） the models for field capacity in paddy field performed the best, with adjusted coefficient of determination of 0.79, and relative bad for dry lands. The conclusion indicated that the assessment of field capacity was greatly affected by land uses, and it was convenient to obtain field capacity with pedotransfer function.