Abstract:The balance of salt in the groundw after and salt flux and rate of salt accumulation in vadose and forecasted soil salinization of different landforms in Taoer river basin of Jilin province is calculated with soil salinization forecast model. The generalt rend of soil salinizaton will be aggravated in the river basin, but there is much difference in diverse landforms. Soil salinization become more aggravating from the upper reach to the lower of the river basin. The traditional method of forecasting soil salinization with developing rate is not precise.

Abstract:Using the 10 years observed data about runoff and sediment in the loess hilly forest region, the temporal change of soil erosion intensity in the reclaimed lands was analy zed. The results showed that with the increasing of erosion time, the soil erosion intensity in reclaimed lands would be increased apparently, and there had about 10mm soil layer be eroded away every year. In the 10th year, the 100.81mm depth of soil was eroded away, which was almost all the humus layer. At last, it is pointed that the increase of the erosion intensity, the decease of soil quality and the worse of the soil properties would aggravate the soil erosion intensity seriously.

Abstract:The fertility condition and measures of fostering fertility are studied by field-ex periment. The result shows, that all the measures of fostering fertility can increase the whole-nut rients and the quick-acting nutrients obviously, and the exchange capacity of positive-ion and pH of soil decrease. The effect of varied measures to dumpling-structure of soilisex tinct, and the organic fertilizer is the best of all, the capacity of restraining-water increase. Cooperation application of N, P, K can increase the content of organic matter, valid-N, valid-P and valid-K. Cooperation of bio-fertilizer and abio-fertilizer have the better effect compared with singleabio-fertilizer.The intercrossing can be combined by using field with fostering field in production of wine-g rapes, it can increase the accumulation of organic matter extinctly, and increase the content of valid-N, valid-P and valid-K in a shortperiod.

Abstract:Drought is the first limiting factor threatening the sustainable development of flax production in southern Ningxia Hui Autonomous Regivn. In recent years, The technology of mulched hole planting is used on dryland flax, and its yield-increase mechanism and benefit were explored. The results showed that, mulched hole planting could improv e soil temperature, conserve soil moisture, and promote full release and efficient use of soil rapidly-avai lable nutrients. Hole planting could enhance the co-force of breaking th rough the soil off laxseed, so the rate of germination was as high as 79.4%～96.2%, and yield was raised by 37.9%～46. 2%. Meanwhile,w ater-saving supplied irrigation was conducted in the key development stage of flax f rom the latter stage of clumping to the initial stage of budding. The results indicated that the yield could be increased by 30%～44% with 300～450 m³ /hm² irrigation, which is 8%～14.9% greater than the contrast. Hence, this new plantingtechnology should be extensively used on flax in arid and semi-arid areas.

Abstract:A large scale hydrological simulation model was developed from the relation of temperature to melt water as well as varied ratio of run off to rainfall. This model was applied in the upst ream basins of the Yellow river. The testing results were satisfactory by compari son with the observed data for the simulated run off in thosebasins. The tendency of water resource in the upper reaches of the Yellow river was analyzed.

Abstract:Quercus alienavar. acuteserrata forest is one of the most important vegetation types of Qinling mountain. The characteristics of it in Xunhe river basin on the south side of Qinling mountain, such as flora,spectrum of life form, community structure, community types and progress of successionare studied. Quercus alienavar. acuteserrata forest in this region should be protected and ratio nalutilized according to its environmental conditions and characteri stics.

Abstract:It makes the method of reckoning curve of water surface simple to calculate critical and normal water depth by using the alternative method, and then calculate average water depth according to the method. The flow length between the site which water depth equal to the average water depth and the head of steep section is calculated by average water depth. By this, the side wall of steep section of spillway from the head of steep section to the site of average water depth is designed as the height of water depth of head of section adding safety height.The side wall of flow below average water depth is designed as the height of average water adding safety height.This makes the construction convenient and cost smallest. These provided a scientific basis for design,construction and budget cost of side wall of spillway steep section.

Abstract:Sev eral important issues on the comprehensive control engineerings of debris flow are found by investigation in the west of Yunnan province. That is, imbalance of the investment intensity and control scale, weakness of the engineering management and supervision, neglect of the bio-engineering, etc. Lastly, ideas or suggestions a reput forward on the management, supervision, legislation, bio-engineering of comprehensive control engineerings of debris flow.

Abstract:The precipitation regularity on Weibei highland is analyzed, and the results are as follows.(1) The annual precipitation was statist ically in accordance with normal distribution with a probability of 80% in ≥450mm precipitation and eight-year-cycle and twenty-year-cycle in time.(2) The distribution of monthly precipitation follows the equation: Y=0.0291 x ⁵The precipitation regularity on Weibei highland is analyzed, and the results are as follows.(1) The annual precipitation was statistically in accordance with normal distribution with a probability of 80% in ≥450mm precipitation and eight-year-cycle and twenty-year-cycle in time.(2) The dist ribution of monthly precipitation follows the equation: Y=0.0291 x ⁵-0. 8737 x ⁴+8. 9185 x ³-37. 277 x ²+72. 661 x-40. 575, R²=0. 9354.(3) The rainfall events often occurred during May to October a year, the highest rainfall was in July with alow variation. On the basis of the results, four techniques for improving rainfall utilization efficiency are put forward,firstly, basic building of farmland and soil fertiliza ion, secondly, preservation water with less tillage and mulch,thirdly, drop irrigation and micro-irrigation with mulch, fourthly, integrated controls of desolate mountains with rain collect ion planting.-0.8737 x⁴+8. 9185 x ³-37. 277 x ²+72. 661 x-40. 575, R²=0. 9354.(3) The rainfall events often occurred during May to October a year, the highest rainfall was in July with a low variation. On the basis of the results, four techniques for improving rainfall utilization efficiency are put forward,firstly,basic building of farmland and soil fertilization, secondly, preservation water with less tillage and mulch,thirdly, drop irrigation and micro-irrigation with mulch, fourthly, integrated controls of desolate mountains with rain collection planting.

Abstract:The orchard plot selection, good varieties arrangement, sloping fields amelioration, adequate fertilization, drought-resistant cultivation, rational prune and others are the safeguard of apple to have top quality and high production in loess hilly-gully region of northern Shaanxi province. The operational theory and method of these measures are expounded.

Abstract:The natural P.screnkianavar.tianschanica forestation on the lower limit of elevation range of 1450～1800 m. The results showed that the effect was significant by the 3 treatments of cross and straight cutting brushes along the mountain slope with motor chain saw and group planting of P.screnkiana var. tianschanica; by big hole-site preparation and group planting in the brush land and trembling poplar clear cutting slash, the P.screnkiana var.tianschanica sampling(15 a) were 40.0% and 46.5% higher than CK. The excellent and poor consequent succession of spruce sampling growing in the different sitetype was brush land> trembling poplar clear cutting slash> trembling poplar> P. screnkiana var.tianschanica clear cutting slash.

Abstract:Dry and water shortage are the main restrict factor for grain output increasment of non-irrigated slope field in Yuanmou dry and hot valley. In order to utilize soil through-flow moisture fully and reduce seasonal drought, the underg round plastic sheet wall experiment in the non-irrigated slope field in Yuanmou county was carried out in 1999. The result indicates, that the output of the non-irrigated slope field with underground plastic sheet wall is increased by 7. 1%～ 20. 2% compared with the cont rast area.

Abstract:According to the principle of rainfall collection using, some slope field is left as rainfall collection area to provide water to plant area, and to decrease water deficit of wheat in plant area. The result shows, if the ratio of rafall collection area to plant area is 1∶1, the soil water condition of plant area will be improved obviously, single development of wheat in plant area will grow better, the yield will be increased by 51.38%, and WUE is raised 2.27 kg/(mm· hm²) compared with the check plot.

Abstract:Dong sheng city in southw estern Inner Mongolia Autonomous Region, situates on the swelling belt of Ordos plateau. Where animal husbandry plays an important role in village agriculture structure, but the traditional manag ement ways have not been changed for hundreds years. Thus, the eco-environment gradually became worse and the relative benefit of husbandry lowered. The reasons why husbandry was prohibited, the successful experience how to coordinately develop soil-water conservation ecological construction and husbandry after prohibit pasturing in Dong sheng city are into roduced. This set an example for places in semi-farming and semi-husbandry area that the contradiction of farming and husbandry has not been solved for many years.

Abstract:Jiangle county is rich in natural resources, especially in law n, but tracts or odd pieces of them are not exploited. Only 60 percent of the small plots of lawn is opened up. In 1998, the output of the herbivo remeat was 163t, occupying only 2.57 percent of the output of the totallive stocks. And the output of the milk was 264t. It must become one of the important modern estate of Jiangle county to develop the plant-eating animals. For this reason, some suggestions are put forward.

Abstract:In taking measures of comprehensive administ ration, 1 230 000 yuan has been investment. They carried on the project of dry masonry dams for flood ditch prevention, tailings warehouse, mine drainage system and mine vegetation resume according to the characters of soil erosion in Tang quan mining area, and the causes of the harm. By administ ration, it is not only has controlled soil erosion of mining area effectively, but also resumed and improved the eco-environment of the mine stope and Tang quan river progressively, and it has promoted comprehensive administ ration of mine soil erosion in Datian county.

Abstract:There are some problems in the vegetat ion const ruct ion in the loess plateau reg ion, such as the low rate of vegetation cover, the low survivorship and preservation rates of afforestation, and the low economic benefit. It can be done better if only the idea about ecological efficiency and tree species selection is changed. The great problems about vegetation construction are put forward.

Abstract:The balance of original natural environment will certainly be broken during construction of water conservancy engineering. Simultaneously, the balanced system in construction region will be interfered. The const ruction results in the unstablility of regional geology structure, so stable issue of geo-envi ronment is caused.The relevant relation between environmental effect and water conservancy engineering, the relation between water conservancy engineering and unfavorable factors are analyzed, and suggests that deep and detailed investigation and research works for geo-technical environment engineering should be carried out, so as to overcome unfavorable factors and enlarge the environmental effects during the process of design, construction as well as the management of construction.

Abstract:Because of controlling soil and water loss effectively, vegetation construction is regarded as one of the most effective and fundamental methods. The coverage of community is anindicator of measuring the quality of vegetation community for controlling soil and water loss. Effective coverage, critical coverage and potential coverage are three stages in the course of development of vegetation community. The concept and determining methods of “ three coverage” are expounded in detail. It is thought that the coverage of a vegetation community should reach the effective coverage(lower limit) or critical coverage(upper limit) in the construction of vegetation in the soil and water loss region.