对6个不同土地利用方式条件下不同侵蚀程度的红壤退化试验小区土壤的物理、化学和生物学性质进行了测定，应用主成分分析法对6个试验小区的红壤肥力退化进行排序和评价。通过对16项土壤参评因子和4项参评因子评价结果的比较，得出土壤有机质、水稳性团聚体、过氧化氢酶、微生物碳量4项肥力因子已基本上反映了土壤肥力退化的综合状况，并建立了红壤肥力退化程度的评价指标方程，从而大大地简化了评价工作。

以低丘缸壤黄赫泥为材料，在测定吴基皋理化性质和水分物理特性的基础上，对不同土壤的持水特性，释水特征厦水分传导性能作了研究，结果表明水田和旱地缸壤的持水量厦非饱和导水率随土壤吸力的增加而快速下降，待水能力差。而下层土壤的特水能力和供水能力要比表土弱。这些性质均影响作物对土壤水分的吸收利用，是造成缸壤作物昌旱的重要原因。

In most cases, rice production is associated with flooding irrigation and the efficiency of irrigated water use (WUEi) is generally lower for production of rice than for other crops. We have examined the effects of various irrigation regimes on water consumption in a well-puddled paddy field, as well as on dry matter production, grain yield and physiological responses of the plants. Four sets of conditions were studied, with two replications, in the well-puddled paddy field: Continuous flooding irrigation treatment (CSF); three intermittent irrigation treatments, designated Ⅱ-0, Ⅱ-1 and Ⅱ-2, in which plants were re-irrigatedwhen the water potential of the soil fell below0, 10, and -20 kPa at a depth of 5 cm, respectively. Water consumption was lower during Ⅱ-0 than during CSF because the percolation rate was reduced by the reduction in the hydraulic head of the ponded water. Intermittent irrigation led to the repeated shrinking and swelling of soil during Ⅱ-1 and Ⅱ-2 and, therefore, soil cracks developed rapidly. Since they became the major routes of water percolation, these soil cracks increased water consumption during Ⅱ-1 and Ⅱ-2 above that during CSF and Ⅱ-0. There were no significant differences in dry matter production and grain yield between CSF and Ⅱ-0, but both were significantly greater than in the case of Ⅱ-1 and Ⅱ-2. Therefore, WUEi increased in the following order: Ⅱ-0, CSF, Ⅱ-2, Ⅱ-1, although the difference was very small between Ⅱ-1 and Ⅱ-2. A lower crop growth rate (CGR) resulted from a decrease in the net assimilation rate (NAR) during II-1 and Ⅱ-2, and there was also a reduction in the leaf area index (LAI) during Ⅱ-2. Early senescence with ripening and water stress around midday decreased the rate of photosynthesis in leaves, causing the lower NAR. These physiological responses of the plants were responsible for the reduction on the dry matter production and grain yield in the intermittent irrigation.

时域反射仪（TDR）测定土壤水分具有自动、连续和原位监测等优点。根据TDR基本工作原理，标定曲线Av=（KV2-DV2）/（KV2-1）中K取值直接关系0到值测定的准确性。而Ks值又与土壤性质（主要考虑质地）相关。因此，尽管TDR生产厂家一般均设定缺省K，值，但为保证测定值的准确性，使用者仍需针对不同土壤类型进行标定和校正。我国南方红壤和水稻土质地粘重，土壤介电常数与砂性土壤和北方潮土等不尽相同，对MP-917型TDR用于测定该地区土壤含水量之基础参数K，值进行标定，并用PVC土柱结合经典称重法加以验证。结果显示，用标定Ks值。测红壤含水量的平均标准差（样本值相对真实值）为0.004 84cm3/cm3，水稻土平均标准差为0.004 68cm3/cm3，表明K，标定值较合理。建议一般红壤的K1=2.92、一般水稻土的K2=2.90。