Irrigation and drainage development of deserts in China

本研究由以下三个研究课题组成。沙漠开发利用水资源：在沙坡头沙漠试验研究站试验田，采用滴灌系统条件下的排水式溶渗仪，采用水分平衡法估算了大豆的蒸散量。用黄河泥沙覆盖沙田土壤，提高了土壤含水量、大豆产量和蒸散量。频繁的少量水的施用减少了沙田的深层渗透损失。通过4年的大豆和玉米栽培试验，证明了处理后的农村居民点废水农业利用的可行性。沙漠化土壤管理：对平落旱田土壤化学性质进行了分析。在地下水位高的情况下，田间盐的积累与小麦的低收获是一致的。2、收获季节后施用大量地表水降低了土壤电导率。沙坡头木本树种的耐旱性和径向生长。采用p-v曲线法研究了9种木本植物的耐旱性差异。所有树种的耐旱性均较好，其中沙棘、中间锦鸡儿和黄柳的耐旱性较好。对五种木本植物在周期性灌溉条件下的径向生长进行了解剖学研究。在Elaeagnus中观察到径向生长的周期性循环。而白杨则表现出稳定的生长趋势。在生长季中，西洋松和松柳的生长停滞只发生一次。

This research is composed of the following three subjects of study.1. Water resources utilization for development of sandy deserts :In the experimental field at the Shapotou Desert Experiment and Research Station, evapotranspiration from soybeans was estimated by the water balance method using the drainage type lysimeters under the condition of drip irrigation system. The water holding in the soil, soybean yield and evapotranspiration in a sandy field increased by covering the soil surface with silt contained in the Yellow river. Application of the small amount of water at frequent intervals decreased the deep percolation losses in a sandy field. Feasibility of agricultural utilization of treated wastewater from a rural settlement was proved by the experiments of soybean and corn culture during four years.2. Soil management for cultivation of sandy deserts :The chemical properties of soil at Pingluo upland field were analyzed. In the case of high groundwater level, the salt accumulation of the field was recognized with lower harvesting of wheat. Application of the, large amount of surface irrigation water after the harvesting season decreased the value, of electric conductivity in the soil.3. Drought tolerance and radial growth of woody species in Shapotou.Differences of drought tolerance among nine woody plants were investigated using the p-v curve method. The drought tolerance of Ammopitanthus mongolicus, Caragana intermedia, and Salix gordejevii was remarkable in all of the species. Anatomical studies on radial growth of five woody species maintained by periodic irrigation were also investigated. The periodic cycle of radial growth was observed in Elaeagnus. angustifolia : and Thuja orientalis, whereas Populus alba showed constant growth. In Pinus sylvestris and Salix matsudana the stagnation of growth occurred once in growing season.