SUN Hui , TANG Ya , CHEN Keming , HE Yonghua
1999(6):1-5.
Abstract:Soil erosion is one of the major factors for land degradation in mountains. Contour hedgerow system, consisting of thickly planted double or single hedgerows of nitrogen-fixing trees or shrubs, shows great potential in soil conservation of cultivated slope lands in the tropics. On-farm research was carried out in Ningnan county of southwest China to assess the effect of hedgerows on soil erosion control in the subtropical region. The research consists of four treatments with three replicates. The results showed that more than 70% soil erosion occurred in the mid-term of monsoon under the traditional cultivation. The 4~7 year old hedgerows of L. leucocephala and T. candida reduced soil loss to be 1%~3% of the control. The erosion is also an accelerating nutrient-loss procedure. The contents of total nitrogen and organic matter in the sediments were more than 2.3 and 2.47 times of those in eroded topsoil. Maintenance of hedgerows can also lead to formation of terrace after normal cultivating in the alleys for several years.
1999(6):6-10.
Abstract:The upper reaches of the Yellow river in Qinghai province is not only a base for industry, agriculture, animal husbandry and fishery production, but also one of source of hydraulic and electric power that will be significantly develop by government, so it play an important role in the economy development of Qinghai province. In recent years, ecological environment protection of Qinghai province, as a major water resource of the Yellow river, has aroused great concern of the whole society with frequent discontinuation of water in the lower reaches. Analysis of water and sediment materials from main hydro-stations in the upper reaches of the Yellow river in Qinghai province showed that, the area in the upper reaches of the Yellow river was only 23.4% of the total Yellow river basin, while its runoff was 47.5%, and sediment yield was only 3.86% of that of the whole basin, so it was a major area of water production and supply. Water resource of the Yellow river in Qinghai province mainly come from the region between Dari in Qinghai and Maqu in Gansu province and the nearby areas, where was a main water flow producing region of the Yellow river in Qinghai province.
YANG Jianqiang , LUO Xianxiang
1999(6):11-15.
Abstract:Taking Qianan county in the west plain of Jilin province as an example, the relation between soil salinization and underground water dynamics is studied deeply with artificial nevral network model and tendency analysis. Combining the result of prediction of salinization, some ways for the prevention and control of soil salinization are put forward.
1999(6):16-19.
Abstract:There are 100 000 silt arresters(SA) and 381 300 hm2 farmlands on the loess plateau that have been built since 1949. The widespread investigation showed that these SA have high effect of economic and social benefit on the soil and water conservation there. However, there were many problems in the SA construction and utilization, it especially showed at five aspects as follows: (1) The distribution of SA system are almost irrational and more weak and dangerous building. (2) Because of the low designing standard, the engineerings are easy to be destroyed and broken down. (3) The quality in specific implement of these structures is worse, and the engineering is not harmonious. (4) The bad management of structure bodies, loose mainte-nance. (5) The low utilization ratio and economical benefit of the filled farmlands.
1999(6):20-22.
Abstract:Slop disintegration erosion of the gully head walls with the pattern of cutting-toppling process occurs commonly in sandshale areas in Guangdong province. This complex erosion including water and gravity erosions differing from that caused mainly by gravity in granitic areas.
1999(6):23-25.
Abstract:Human being is the force at the core in agricultural circulating system. According to the intensity of mans action, the relationship between the two system is divided into three stages. The relationship between ecological system and economic system is second stage in loess plateau region. Through constructing ecological agriculture with commodity, mans behavior duality may be solved and unified.
YAN Changzhen , WANG Yimou , FENG Yusun , WANG Jianhua , WU Wei
1999(6):26-30.
Abstract:Using digital processing method of remote sensing and GIS, TM images in 1996 are interpreted and the database of the sandy land in Gansu province is established. It includes TM image, graph (scale 1∶100 000) and its attributing database. In order to interpret correctly, the interpreting insignia system of sandy land on TM images has been established through analyzing the relative reference and images and then been corrected in the fields. The definition of the sandy land is covered by sand, the vegetation is lower than 5%, and it includes sand desert. Through the study practice and analyzing of sandy land databases, the following conclusions can be gained: (1) In Gansu province, there is as much as 2 750 863 hm2 sandy land occupying 6.054% of the area. And of the 86 county units of the province, there is 32 counties distributed by sandy land. (2) Comparing with traditional methods, there are many advantages using digital processing method to establish the sandy land database such as, mapping rapidly, high accuracy and lower expenses. (3) With the same interpreting insignia and graphical database and attributing database that are well matched with image database, the sandy land can be monitored accurately in large scales.
1999(6):31-35.
Abstract:The thought of spatial structure in landscape ecology is introduced. The patch, cor-ridor, matrix, edge are the main elements according to remote sensing information and material from regional geological mapping in headstream region, and based on the spatial structure features of soil erosion on three scales. Mechanism of soil erosion is put a bridle on spontaneous factor and action of humanity. Measures of soil and water conservation are to enhance consciousness of ecotope and restrain from short-term action paying attention to economy. The specific methods is safekeeping rangeland, safekeeping riverside using plant cover and stockade, resuming plant cover postmining goldmine.
1999(6):36-38.
Abstract:The structure of information system for planing soil and water conservation in a small basin has been analyzed. The database has been built by means of GIS(Geography information system). Further, it require into the fundamental thoughts of developing the information system for soil and water conservation plan in a small basin under the situation of Visual Basic. The development model and some main points of information system for planing soil and water conservation in a small basin has been introduced.
REN Yangjun , QIN Baishun , ZHAO Junxia
1999(6):39-44.
Abstract:According to the principal part of project demand, such as drawing Taohe water irrigation engineering in Gansu province, the distribution and area of afforestation land are discussed. The site type of afforestation land, proposes selection plans of afforestation plant seeds are analyzed, and a feasible afforestation plan in the light of the project special demand for afforestation is put forward by selecting afforestation plans comparatively. The demands and contents of afforestation engineering designs during feasibility study in soil and water conservation scheme are introduced more systematically.
LIU Jing , Ge rile , WANG Guanyu
1999(6):45-48.
Abstract:The Xiaogongwusu village on the hilly land of the north of Yinshan mountain has achieved affect of construction of ecotype agriculture for three years. The effect is analyzed by mathematical model, and some suggestions are put forward for the construction of ecotype agriculture of the north of Yinshan mountain areas.
1999(6):49-53.
Abstract:Experiments on afforestation and grass in Shenmu-Fugu coal mine in the fragile belt had been conducted. The results showed that the suitable plantation time in spring is from 20.March to 5.April. Some technologies of plantation can be used, such as to cover seedling with sandy soil, irrigation 5kg for one plant at one time, and cover land surface with plastic film. By those important measure, the survival and conservation rate can been risen. Grass should been seeded in rain season.
1999(6):54-57.
Abstract:Based on the grade scale of soil erosion intensity issued by the Ministry of Water Resources, relying on the research results of former scholars, soil erosive modulus under different coverage of plants are compared. The results showed that the grade scale of soil erosion intensity was different from the research results of former scholars, and the applicable of the grade scale need be studied further.
1999(6):58-61.
Abstract:The relative theories about the swelling and reduction of swelling soil are introduced. The nature of deformation of swelling soil are explained. Finally, the relative theories are assessed and their differences and identities are pointed out.
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