SOIL AND WATERCONSERVATION IN CHINA

Present Status and Suggestions on Establishing Soil and Water Conservation Sci-Tech Zones of Sichuan；Some Cognition on Establishing a Big Pilot Area of Soil and Water Conservation in Guang‘an；Ecological Effect of Long-Term Fertilizer Applied Soil；Existing Problems in Applying Poplar into Soil and Water Conservation and Countermeasures;Preliminary Approach to Soil and Water Conservation Modes in Various Kinds of Open Economic Zones and Small Reskdential Districts in Dazhou City.     

QUALITY CONTROL IN SOIL SURVEY

The paper examines 66 Australian soil surveys in a variety of terrains (but not close forest), by several survey procedures, and published at a range of map scales. It relates the Survey Effort (E) of professional staff (in man-days per km²) to (I) survey procedure, (2) the kind of mapping unit, and (3) the intricacy of the soil pattern mapped. Intricacy (I), the average number of mapped soil boundaries crossed by 1 km of random linear traverse, is related to the total length of mapped boundary (km per km²). When the surveys are grouped according to survey procedure and mapping unit, the survey effort for each group may be described by a regression of the form . B could not be shown to differ significantly between groups. D varied in the ratio 0.5: I, according to whether or not surveys used air photograph interpretation, and in the ratio 0.3:0.7:1.o, according to whether they mapped land systems, other compound mapping units, or simple mapping units. Since the choice of survey procedure and mapping unit is usually governed by the intricacy of the soil pattern the effect of these factors can be summarized in a single regression for all 66 surveys: There is a significant (P≤ 0.001) log-log regression between I and map scale.     

SOIL AND WATER CONSERVATION IN CHINA

Effects of Soil Amelioration with Different Soil and Water Conservation Measures of Eroded Red Soil Region YU Rong-gang, ………………………………………………ANG Jie, WANG Nong, et al. （Jiangxi Provincial Research Institute for Soil and Water Conservation, Nanehang, Jiangxi 330029, China）（40） The paper studied the variations of pH value and nutrient content of slope land in eroded red soil region under the conditions of using dif- ferent soil and water conservation measures and analyzed the effects of soil amelioration with different soil and water conservation measures combining with field survey and laboratory analysis. The outcomes show that the different soil and water conservation measures notably affect the pH value and the contents of organic matter, total nitrogen, available nitrogen, total phosphorus and available phosphorus of eroded red soil region, but the influence to the contents of total potassium and available potassium are not remarkable. Planting forage grass and cultiva- tion measures can remarkably increase the pH value and the contents of organic matter, total nitrogen, available nitrogen, total phosphorus and available phosphorus of the soil and improve the conditions of soil fertility, while the influence of terraced fields to the soil fertility status is not obvious. The soil fertility condition of the studied area is not restricted by potassium. It can utilize organic matter as a simplified index to judge the conditions of soil fertility.     

SOIL AND WATER CONSERVATION IN CHINA

Critical Study on Influence of Precipitation and Vegetation Coupling of Typical Area in the Loess Plateau to Erosion and Sediment Yield
The influence of precipitation and vegetation coupling to soil erosion is an important issue of surface erosion process study. The paper analyzed the influence of precipitation and vegetation coupling to soil erosion from microscopic point of view based on the observed data of runoff plots of artificial grassland and natural grassland of Xifeng Soil and Water Conservation Experimental Station in the period of 1954 - 1986. The outcomes show that when the vegetation coverage is smaller than 10% , the extreme erosion modulus is increased along with the in- crease of vegetation coverage. This shows that the coverage should not be lower than 10% for effective anti-erosion. When the vegetation cov- erage is greater than 10%, the extreme erosion modulus shows good power function relationship with vegetation coverage. The vegetation cov- erage should at least reach to 70% if hoping the anti-erosion ability playing a maior role and achieving optimal effect.     

SOIL AND WATER CONSERVATION IN CHINA

Should Pay Attention to the Issues of Mine Vegetation Rehabilitation Works YANG Jian-jie, ZHENG Wen-mei, GUO jiang （ Qian＇ an Forestry Bureau, Qian＇ an, Hebei 064400, China） （33） Mining development has promoted the development of economy, but at the same time, it also has destroyed ecological environment. In order to improve the ecological environment of mining area and realize the sustainable development of mining economy, the paper introduced one by one the government functions and issues of the principal part of a project, overall planning, security, economic benefit, selection of tree species, technique and mode of reforestation and management and protection after vegetation rehabilitation of mine that should pay atten-tion to.