The Ecological Restoration And The Technology Of Development For The Waterlogging Land In Jianghan Plain In China

The areas of waterlogging land were about 7.64 X105 hm2 in Jianghan Plain, correspond to 40.6 % of all farming areas. Despite there are the abundance natural resources and the advantage of geographic location, because of a great deal of the waterlogging land, the agricultural productivity was also not high and instability so much as tempestuously undulation, and the degenerate trend of ecological environment was very obvious in this areas. Based on the amount information coming from the plot trials, some field investigations and annals datum, and exerted the methods of microcosmic combining macroscopic and system analysis, the paper studied the characters of agricultural ecosystem in waterlogging area, then discussed the ecological principium of restoration and rebuilding for the waterlogging ecosystem, and put forward the approach and technology model about the ecological restoration and resources utilization for the waterlogging land, so attain to the two aims of preventing and decreasing the disaster and regulating of farming structure. The results were as follows:(1) The formation reasons of the waterlogging land in Jianghan Plain were the special geographical position, not level landforms, the special change of climate and hydrology and the artificial factors, for example, the excessive reclaiming land from the lake and the unreasonable farming system. The mostly characteristic of waterlogging ecosystem in Jianghan Plain were about: the frequency of climate change was becoming big, the distribution of rainfall in a year was becoming more not uniformity; the emergence of waterlogging and be soiled was going with together, and either the waterlogging or aridity were existing in this area; the water was becoming of low quality; the trend of soil gleyization and lake swamping were also continuing, and the availability of nutrient was becoming little; the degraded trend of biology resources was appearing, the .soil productivity was also declining; the amount of relative poor population was increasing, and the Schistosome disease was diffusing in waterlogging area.(2) The succession was driving by both natural and artificial factors. The natural factors were about the geological structure motion and climate change, and the artificial factors were mainly the excessive reclaiming land from the lake, the constructing dam and the agricultural policy. The lakes of this area played the regulating and indication role in the ecological succession course of the waterlogging land. The big scale reclaiming land from the lake of latter-day expedited the formation of waterlogging land greatly.(3) The step diversification rule for the topography, the geological settings, the hydrology, the soils, the climate and the biology was very distinct in waterlogging micro-area in Jianghan Plain. Based on the step diversification rule, the waterlogging area of Qianjiang city was classified as 6 types and 6 reaches. The technologies of exploitation and utilization were tested separately in 6 typical different types of the waterlogging micro-area, the results showed that the exploitation based on the classifying were very effective.(4)It was not perfect that separating the waterlogging process and the being soiled process when drawing up the drainage plan for the waterlogging land in south ChinaThe drainage controlling indexes of the most crops were studied under the conditions of the abidance being soiled and the synthesize role from waterlogging and be soiled, as the waterlogging and being soiled to a continuum process. The results showed that the cumulate value (SEW30) between the exceeded part to the standard of soil water level below the soil surface and the abidance times was correlation to the relative yield (Ry) of the cotton and soybean (or the extent of yield reduce Rf) observably under the conditions of the abidance being soiled, and the cumulate value (SFEW80) of the exceeded part to the standard of soil water level below the soil surface under the synthesize role of waterlogging and being soiled was correlation to...