Establishment of soil managements for moisture-nutrients and saline irrigation by drip method in sand fields

根据1986-1988年的研究结果，总结如下.根据滴灌条件下高粱根区水盐运移特征，探讨了滴灌条件下高粱根区水盐运移的三维分布特征、裸沙地水盐运移的二维分布特征和根区水盐运移的一维分布特征.利用蒸渗仪在草棚中进行了棉花田土壤淋溶试验。在淋溶分数为0.16和0.18的条件下，土壤盐分的淋溶率分别为40%和60%。3，500 ppm盐水灌溉的棉花产量比非盐水灌溉的棉花产量减少一半以下.利用生长箱内种植蔬菜的土柱，研究了集中供水和滴灌两种灌溉方式下土壤水分和盐分的运移规律。在蒸腾活跃期，滴灌法的水分利用效率更高，根系盐分浓度也更高.在<45>室内砂柱条件下，应用~（13）Ca同位素自显影技术和图像分析技术研究了土壤盐分的运动。通过这些方法，可以在不取样的情况下对盐分进行定量分析，并在土柱中每小时追踪盐分运动。

From the studies during 1986-1988, the results were summarized as follows.1. Movements of moisture and salts under drip irrigation were discussed on the characteristics of (1) three-dimensional distribution in the dare sand field, (2) two-dimensional distribution in the bare sand field and (3) one-dimensional distribution in the root zone of sorghum.2. Leaching experiments on cotton cultivation were carried out using lysimeters in grass-house. The leaching ratios of soil salts showed 40% and 60% under the conditions of leaching fractions of 0.16 and 0.18, respectively. The cotton yields with the saline irrigation of 3,500 ppm decreased below a half of those obtained with non-saline irrigation.3. The movements of moisture and salts were discussed under the conditions of two irrigation methods of concentrated water supply and drip method, using the soil columns planted with vegetables in the growth cabinets. The drip method showed more efficient water use and higher salts concentration in the main root zones during active transpiration stage in a day.4. The methods of auto-radiography using isotope of^<45>Ca and image analysis were applied to the soil salts movement under the conditons of sand columns in the laboratory. It was established by these methods that salts were analyzed quantitatively without soil sampling and salt movements were traced hourly in the soil colomns.