Fundamental Studies on Land Improvement in an Orchard Surrounded with the Paddy Field

为制定灌溉、土地改良和果园复垦的未来规划提供基础数据，1990~1993年，采用水箱模型法，对水田环抱果园(梨、葡萄、樱桃、柿)的根系发育、土壤水分波动、地下水位和土壤水分平衡的实际情况进行了调查。取得的结果如下。1.葡萄、梨、柿的根系分布在30 cm土层，占总根重的93%~99%。2.果园10 cm、20 cm、30 cm、50 cm、70 cm土壤吸力白天升高，夜间逐渐减小。这些波动被认为与在每个深度吸收水分的根的深度分布直接相关。3.落叶果树的根冠比葡萄为1.6~1.7，柿为1.4~2.0，梨为2.7~3.1。4.梨园灌溉的灌溉设施是必要的。5.采用水槽模型法和水量平衡法对柿园土壤水分平衡进行了估算。

With a view of obtaining basic data mecessary for making a future plan of irrigation, land improvement project and reclamation of an orchard, the actual conditions of root development, soil moisture fluctuation, ground-water level and soil moisture balance by the tank model method in an orchard (Pear, Grape, Cherry and Persimmon) surrounded with the paddy field, were investigated from 1990 to 1993. The results obtained are as follows. 1. The roots of grape, pear and persimmon were found in the top 30 cm layr from about 93 % to about 99 % of the total root weight. 2. Soil moisture suction at a depth of 10 cm, 20 cm, 30 cm, 50 cm and 70 cm in an orchard rose during the day and decreased gradually during the night. It is considered that these fluctuations are directly related to the depth distribution of roots which absorb water at each depth. 3. The top-root ratio of deciduous fruit trees was 1.6-1.7 (grape), 1.4-2.0 (persimmon) and 2.7-3.1 (pear) respectively. 4. The irrigation facilities for irrigation in a pear orchard is necessary. 5. The estimation of soil moisture balance in the persimmon orchard was made by means of the tank model method as well as the water balance method.