Abstract:After comparatively researching the typical soil profile series situated in dry and hot valley region of Jinsha river in Yunnan province under the condition of different ecological landscape, the phase of soil degradation process and its characteristics about dry red soil and vertisol series were initially determined. The indexes of thickness in soil humus horizon (A), content of organic matter, soil structure, content of total nitrogen in soil, or including soil fissure, clay activity and so on could be used in showing the phase characteristics of soil degradation process. Furthermore, the soil degradation model with change type in step by step, jump and combination in soil degradation process was put forward.

Abstract:Based on field investigation and indoor analysis,the results showed thatOn the Loess Plateau region, recovering vegetation can improve remarkably the content of soil organic matter and available N,K etc.,and drop soil pH and bulk density,add the quantity of waterstable aggregate of soil,improve the productive capability of land,enhence the process of humification and illimerization;Available nutrients,clay and>0.25 mm aggregate are all rich in high forest land,however,bush grass land shows more acid and>0.05 mm microaggregate and less solidity.The benefit of high forest land is better than that of bush grass land in preventing soil deterioration.

Abstract:农业综合开发通过改变绿洲中的水、土、气、热条件组合对绿洲农业生态环境产生直接影响.农业绿洲生态与环境总体趋势变好,局部问题突出,是当前新疆农业绿洲生态与环境的基本现状.农业综合开发对生态环境既有有利影响,又有不利影响.在正确评估的基础上,提出相关对策,为新疆农业综合开发规划提供决策依据.

Abstract:According to the annual administrative reports of 8 tributary of the Yellow River from Hekou to Longmen,the data of round number sampling in 1985,detail survey in 1989,land use change survey in 1996 and two-stage sampling in 1997,and combining with acceptance check material of the first and the second period national main harness area in the basin of Sanchuan river, the preservation ratio of the water and soil conservation measures and its distribution have been analysed and determined. This work have made a good foundation for the calculation of benefits soil and water conservation measures on large area.

Abstract:土壤水是重要的生态水源和水文要素之一,它与黄土区生态环境建设关系密切.水土保持措施是人类对土壤流失区下垫面性质的综合改造,这种改造会影响土壤水分的静态分布和动态过程.在黄土高原地区,水土保持坡面工程措施能有效地提高土壤含水量.人工林草植被使土壤含水量降低,甚至造成人为干层.天然植被与人工植被对土壤含水量的影响相反,这是黄土高原植被营造及规划中应关注的问题.

Abstract:Both annual and single event's sediment-runoff relations are established on the basis of the long-term records of sediment and discharge at Heiyukou Hydrological Station on Heihe River. At the same time, the causes of some isolated points in the relations are analyzed. Then, the established relations are used to correct construction impact on sediment concentration measured in 1996.

Abstract:The original Green-Ampt equation is further analyzed and some features of the Green-Ampt equation are discussed. The applications of Green-Ampt equation in layered soils with a sand layer, muddy water infiltration, intermit infiltration, rainfall infiltration are summarized and analyzed. The parameters in Green-Ampt equation are discussed to guild in application of Green-Ampt equation in loess area.

Abstract:Applying Geographic Information System (GIS) technology, and adopting Universal Soil Loss Equation (USLE), the potential soil losses and the reality soil losses in Hainan island was estimated, the soil erosion factors (R, K, LS) in Hainan island were analysed, the spatial distribution of soil erosion characteristics in Hainan island was presented. The result shows the potential and reality soil erosion in Hainan mid-mountain area is serious.

Abstract:Preferential flow refers to the rapid transport of water and solute through some small portion of the soil volume which is receiving input over its entire inlet boundary. It is a general phenomena but not exception. Preferential flow is confined to many factors, such as macropore in soil, structure, texture, water content, initial water content, application rate of water and solute as well as application method of solute etc.. There are two mechanisms causing preferential flow one is heterogeneity-driven, another is wetting front instabilities-driven. At present, the most reliable methods observing preferential flow are soil coring, soil column effluent experiment and dye tracers. Although it is very difficult to simulate preferential flow, many models were still suggested. The focus of preferential flow research should be put on doing a number of field experiment, so as to obtain enough data to describe preferential flow, developing new observation techniques to monitor preferential flow and suggesting new models to simulate preferential flow. Furthermore, the environmental problems associated with soil and ground water contamination could be solved.

Abstract:本项研究以河南省作为研究对象,以钾素养分作为研究主线,用养分资源的观点和生态系统平衡理论,以及国内外推荐施肥的常规方法与先进技术,通过宏观调查与统计分析,田间小区与盆栽试验、室内模拟试验与长期定位监测研究相结合的方法,系统研究了河南省钾素养分资源特征及其推荐施钾技术.主要研究结果如下: