Abstract:Starting from the advantages and disadvantages of the control over soil and water erosion and development of this region along the Yellow River, this paper analyses and sums up the controlling practices of soil and water erosion in recent years, on the basis of which, this paper also suggests the basic guiding thinking, objectives, top priority regions, technical strategies and complementing measures for the further control over soil and water erosion and development of this region.

Abstract:Chiaogou of Santan is at present one of the urgent top-priority to be controlled in the south section of Chenkun Railway line, Based on the analysis of damages caused by the mudrock flow，the worseninig of geological and geomorphological environment and the developing tendency in santan mudrock flow gully, this Paper suggests two plans for controlling over santan mudrook flow gully:(1)the combination of check- ing and drainage; and (2)the construction of open channel aqueduct, Also, the com- parison of two plans is made in this paper.

Abstract:Low benefit forest refers to the stand with total low functions in economic system of forest ecology. Based on the determination data fromthe runoff observation plots in various low benefit forests, this paper discusses the laws of soil and watfr conservation with different benefits.

Abstract:Through 3 years' runoff plot monitoring and measurements, laboratory and field surveys and analysis, it comes to an conclusion that the engineering practices and biological measures adopted in the severely-eroded hilly and gully regions to weaken the process of geologicalization, to accelerate the process of soil formation and to make weathered debrics further weather, whose physical and chemical properties can gradually take the turns for the better.And hence soil and water erosion has been basically controlled,And at the same time, the scientific bases have been provided for the further exploration and utilization of land resources in this region.

Abstract:This paper introduces the situation of water and soil losses and analyses the natural and human factors causing water and soil losses and its behaviors and damage in the purple sand shale areas in Nanxong County of Guangdong Province.Based on the summary of controlling experience and nanlysis of benefits, this paper also suggests some countermeasures for controlling water and soil losses in the areas.

Abstract:Torrential rain with one hundred years' frequency- occured from July 23- 24, 1991 in Zhongnan Prefecture of Shandong Province, causing a serious flood and water logging disasters in this region. After the flood, the authors rushed to go to such three counties as Pingyi, Menying and Yinan to select the typical small watersheds to carry out surverys and comparative analysis, The results indicated that in those bitter comprehensively-controlled small watersheds, esery soil and water conservation practice has brought about the apparent benefit effects upon water storage and soil conservation as well as flood prevention, thus reducing flood threats and damages caused by flood disasters, And at the same time, the authors studied information From comprehensive surveys and presented some suggestions for doing a better work on soil and water conservation.

Abstract:“重点学科发展项目”世界银行贷款——黄土高原土壤侵蚀与旱地农业国家重点实验室,在中国科学院和西北水土保持研究所领导的重视和关心下,经科技人员的努力,现已进入建设实施阶段。该项贷款连同国内配套资金近600万人民币。为了用好这笔贷款,西北水保所的领导和科技、管理人员对项目计划、仪器招标及软投入(合作研究、考察访问、培训及国书、软件等,进行了缜密地论证,作了精心安排。目前,实验室的各项前期工作进展顺利,预计在1993年将全部建成运行。

Abstract:Based on the field experimental observation and lab analytical tests, this paper analyses and studies the biological benefits from the cultivated slopping farmlands after the comprehensive controllin water and soil losses, and its biological benefits are shown in the following aspects: 1.the remarkable reduction of water and sediment losses; 2 .an increase in vegetation cover so as to improve microclimate in the fields; 3 .an obvious enhancement in soil ability to store moisture and con- serve moisture in soils;4 .farmland ecosystem begins to convert into a better cycle， and 5.the diminishment of natural disasters and the enhancement in the hability to resist disasters in agriculture.

Abstract:The trial planting of grain amaranths was introduced in the semiarid area in the southern part of Ningxia in 1987. The results from 4 years' experiments proved that grain amaranths is very drought resistant, very tolerant to poor soil, able to adapt the weather and soil conditions in the introduced areas, grows vigorously and adaptable to livestocks and also a good feed for pigs in particular. When grain amaranth is planted in the current spring, it can flower and bear fruit with fresh yield of 4472 kg per mu on average and the highset frseh yield of 7750 kg per mu. Grain yield can reach 104 kg per mu. As a result, grain amaranths is suitable to be extend for planting in the aird and semiarid areas on the loess plateau.

Abstract:Four kinds of texured soils (i.e. sandy loam, light loam, medium loam and heavy loam) were experimentally oven-dried at four kinds of constant temperatures (105℃，125℃，140℃，and 150℃)with organic matter contents determined, The results indicate that the laws of their moisture losses are in general that the constant tem- peratures of 125℃is adopted to sandy loam and light loam for two hours; and the constant temperature for medium loam and heavy loam for two hours and 20 minutes, which can replace the conventional me thods of drying soil samples thereby to shorten the oven-drying time of soil samples.In comparison of soil organic matter contents in high-temperature oven-drying with natural airdcying, the absolute error is less than 0.05% so that high-temperature oven drying method will not affect soil organic contents.

Abstract:Based on Wu Putei's Model and information, this paper revises the mathematical model of splash erosion by raindrops for slope surface as follows:S_r=7.459（EI）^0.054S^0.471-150.048