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Spatial distribution of surface rock fragment on hillslopes in a small catchment in wind-water erosion crisscross region of the Loess Plateau

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Science china Earth sciences 2008年第6期51卷 862-870页

作者： ZHU YuanJun1,2 & SHAO MingAn1 1 institute of soil and water conservation, chinese academy of sciences and ministry of water resources, Northwest Agriculture and Forestry University, yangling 712.00, china 2.institute of Geographical sciences and Natural resources Research, chinese academy of sciences, Beijing 100101, china 1. institute of soil and water conservation Chinese Academy of Sciences and Ministry of Water Resources Northwest Agriculture and Forestry University Yangling 712100 China 2. institute of Geographical sciences and Natural resources Research Chinese Academy of Sciences Beijing 100101 China

The cover and size distributions of surface rock fragment in hillslopes were investigated by using digital photographing and treating technique in a small catchment in wind-water erosion crisscross region of the Loess Plateau. The results indicated that the maximal cover of rock fragment was pre-sented at mid-position in steep hillslope. Rock fragment presented a general decreasing-trend along the hillslope in gentle hillslope. Rock fragment cover was positively related to gradient, rock fragment size decreased generally along the hillslope, and the size reduced with the gradient. The mean size of rock fragment was at a range of 6―20 mm in the steep hillslope, rock fragment size > 50 mm was rarely presented. The covers of rock fragment at different positions were markedly related to the quantities of rock fragment 2―50 mm accounted for 60% or more of the total area, dominating the distribution of rock fragment in the hillslopes.

关键词： wind-water erosion crisscross region of the Loess Plateau small catchment hillslope surface rock fragment cover and size

soil water characteristics in mountain poplar stand and its benefits to soil and water conservation in loess hilly region

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Journal of Environmental sciences 1994年第3期6卷 347-354页

作者： Wu Qinxiao Liu Xiangdong Zhao Hongyan Northwestern institute of soil and water conservation,chinese academy of sciences and ministry of water Conservancy),yangling 712.00,china)

The soil physical properties,its water characteristics and the benefits to soil and water conservation in mountain poplar stand were determined and studied. The results of the study show that the compaction in soil profile is relatively *** specific gravity and volume weight of soil increase with deepening of soil horizon. The water infiltration rate of soil in the stand is 17,6 times as high as in *** to the intense absorption of water by root system of plants,a drying layer is formed in soil horizon from 2.3 m to 2.7m,showing that the subsoil moisture is in the state of deficit. The annual water storage capacity in 2 m of soil horizon is 360 mm 370mm,or 63% 65% of annual precipitation. Compared with farmland,mountain poplar stand reduces the surface runoff and soil loss by 70% and 99%,respectively,indicating the great benefits to soil and water conservation.

关键词： mountain poplar soil water characteristics soil and water conservation.

Potential soil Erosion Energy Increase of Loess Slop System Caused by Project Construction

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水土保持通报 1997年第2期 34-37页

作者： Zhang Liping Tang Keli (institute of soil and water conservation,chinese academy of sciences and ministry of water resources,712.00,yangling,Shaanxi,PRC)

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ＰｏｔｅｎｔｉａｌＳｏｉｌＥｒｏｓｉｏｎＥｎｅｒｇｙＩｎｃｒｅａｓｅｏｆＬｏｅｓＳｌｏｐＳｙｓｔｅｍＣａｕｓｅｄｂｙＰｒｏｊｅｃｔＣｏｎｓｔｒｕｃｔｉｏｎＺｈａｎｇＬｉｐｉｎｇＴａｎｇＫｅｌｉ（ＩｎｓｔｉｔｕｔｅｏｆＳｏｉｌａｎｄＷａｔｅｒＣｏｎｓｅ...

关键词： loess slope system project construction slope surface of steep slant

Assessing and regulating the impacts of climate change on water resources in the Heihe watershed on the Loess Plateau of china

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Science china Earth sciences 2010年第5期53卷 710-720页

作者： LI Zhi1,2, LIU WenZhao2, ZHANG XunChang3 & ZHENG FenLi2 1 College of resources and Environment, Northwest Agriculture & Forestry University, yangling 712.00, china 2.institute of soil and water conservation, chinese academy of sciences & ministry of water resources, yangling 712.00, china 3 USDA-ARS Grazinglands Research Laboratory, 73036, El Reno, Oklahoma, USA 1. College of resources and Environment Northwest Agriculture & Forestry University Yangling 712100 China2. Institute of Soil and Water Conservation Chinese Academy of Sciences & Ministry of Water Resources Yangling 712100 China3. USDA-ARS Grazinglands Research Laboratory El Reno Oklahoma 73036 USA

Climate change can cause considerable changes in water resources and assessing the potential impacts can provide important information for regional sustainable development. The objectives were to evaluate the possible impacts of climate change during 2010-2039 on water resources (runoff, soil water content, and evapotranspiration) in the Heihe watershed on the Loess Plateau of china and to further explore adaptive measures to cope with the changes. Projections of four climate models (CCSR/NIES, CGCM2, CSIRO-Mk2, and HadCM3) under three emission scenarios (A2, B2, and GGa) were used to estimate future changes in precipitation, maximum and minimum temperature based on Change Factor method. The soil and water Assessment Tool (SWAT) was employed to simulate the hydrologic responses to climate changes. The CA-Markov model was used to develop land use scenarios. Compared with the present climate, the climate models predicted a -2.3% to 7.8% change in annual precipitation, 0.7 to 2.2°C rises in maximum temperature, and 1.2 to 2.8°C rises in minimum temperature. Without consideration of land use change, SWAT predicted a -19.8% to 37.0% change for runoff, -5.5% to 17.2% change for soil water content, and 0.1% to 5.9% increase for evapotranspiration during 2010–2039 under all climate scenarios. Though the change of hydrometeorolocial variables are complex, they would possibly increase with great probability, and the hydrological regime would be influenced such as a decrease in runoff in winter months. With land use changes, the projected land use of 2015 would increase soil water content by 4.0% and surface runoff by 5.7% while slightly decrease evapotranspiration by 0.6% compared with the 2000 land use. This result showed that adjustment of land use patterns was capable of regulating water resources and could be used to mitigate the adverse effects of climate change.

关键词： climate change water resources SWAT the Loess Plateau

Effects of Caragana Korshinskii Kom. cover on runoff, sediment yield and nitrogen loss

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International Journal of Sediment Research 2010年第3期25卷 245-257页

作者： Guan-Hua ZHANG1,Guo-Bin LIU2?, and Guo-Liang WANG31 Ph.D., College of Resource and Environment, Northwest A and F University yangling, Shaanxi 712.00, china, institute of soil and water conservation, chinese academy of Science and ministry of water resources, yangling Shaanxi 712.00, china. 2 Prof., Researcher. institute of soil and water conservation, chinese academy of Science and ministry of water resources, yangling Shaanxi 712.00, china, College of Resource and Environment, Northwest A and F University, yangling, Shaanxi 712.00, china, 3 Assistant Researcher, institute of soil and water conservation, chinese academy of Science and ministry of water resources, yangling Shaanxi 712.00, china. [a] Ph.D. College of Resource Environment Northwest A F University yangling Shaanxi 712100 China Institute of Soil water conservation Chinese Academy of Science ministry of water resources YangLing Shaanxi 712100 China [b] Prof. Researcher. Institute of Soil water conservation Chinese Academy of Science ministry of water resources YangLing Shaanxi 712100 China College of Resource Environment Northwest A F University YangLing Shaanxi 712100 China [c] Assistant Researcher Institute of Soil water conservation Chinese Academy of Science ministry of water resources YangLing Shaanxi 712100 China

soil erosion is serious in the Loess Plateau of china. Deposition of the eroded sediment in lakes or rivers may lead to eutrophication, because the sediment carries a lot of nutrients. Field experiments were conducted to study soil erosion and loss of nitrogen (N) from a 15o hillslope with 30% (low) or 80% (high) coverage of the shrub Caragana korshinskii Kom. A bare soil plot was used for the comparison. The results showed that Caragana korshinskii cover significantly reduced runoff and soil erosion. In comparison to the bare soil plot, the vegetation covered plots had about 20% less runoff and 65% less sediment. In general, the concentration of N in both runoff water and the eroded sediment decreased with time and approached a steady value. However, the species of nitrate nitrogen (NO3) was exceptional which increased with time slightly. The soil erosion caused an N loss of about 250 mg/m2 for the bare soil plot, the low coverage of Caragana korshinskii reduced the N loss by 20% and the high coverage of Caragana korshinskii reduced the N loss by 40%. Moreover, the amount of total N in eroded sediment was 2 to 3 times higher than the value in runoff water. In the total N loss, the organic N was about 75-80%. Nevertheless, inorganic N in runoff water was 5 to 10 times higher than the value in eroded sediment. The species of NO3 was obviously higher than the species of ammonium nitrogen (NH4). NO3 was the main species of inorganic N loss and was about two thirds of total. The organic N was the main species of N in the eroded sediment.

关键词： C. korshinskii cover Runoff Sediment Nitrogen loss Simulated rainfall

Critical slope gradient for compulsory abandonment of farmland on the hilly Loess Plateau

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chinese Science Bulletin 1998年第5期43卷 409-412页

作者： TANG Keli+1, ZHANG Keli 1,2 and LEI Aling 1,3 1. institute of soil and water conservation, chinese academy of sciences, yangling 712.00, china 2. Department of Hydraulic Engineering, Tsinghua University, Beijing 100084, china 3. water resources C institute of soil and water conservation Chinese Academy of Sciences Yangling China Department of Hydraulic Engineering Tsinghua University Beijing China water resources conservation Bureau of Yangtze River Ministry of Water Resources Wuhan China

Scientific evidence for the upper limit of farmland is proposed. Shallow gully erosion is one of erosion types distributed extensively on sloping farmland in the hilly regions of the Loess Plateau. Field observation and aerial photos interpretation, as well as laboratory experiments show that the shallow gully erosion occurring on the steeper farmland in the hilly regions of the Loess Plateau is an important factor leading to intensive erosion on slope, because of its extensive distribution and intensive runoff collection. The data on the formation, development and distribution of shallow gullies on sloping farmland indicate that critical slope gradient for shallow gully initiation ranges from 15 to 20 degrees with an average of 18.2 degrees. Therefore, it is suggested that critical slope gradient for compulsory abandonment of farmland on the hilly Loess Plateau should be kept within the critical slope gradient for shallow gully initiation to prevent shallow gully formation in order to control soil loss more effectively. But as the first step, the cultivation on the slopes with slope larger than 25 degrees where the maximum erosion occurs should be strictly forbidden.

关键词： hilly region of Loess Plateau upper limitation for farmland shallow gully erosion erosion dynamic.

Developmental Tendency of Dry Land Farming Technologies

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Agricultural sciences in china 2002年第8期1卷 934-944页

作者： SHAN Lun(institute of soil and water conservation, chinese academy of sciences and ministry of water resources, Northwest Sci-Tech University of Agriculture and Forestry, yangling 712.00, P. R . china ) institute of soil and water conservation Chinese Academy of Sciences and Ministry of Water Resources Northwest Sci- Tech University of Agriculture and Forestry Yangling 712100 P. R. China

The developmental tendency of dry land farming technologies in the semiarid area of china were reviewed based on the overview of recent progress in dry land farming researches from china and oversea. It was emphasized that conservation tillage, limited irrigation, genetic modification and chemical control are the important aspects for the dry land farming research and development of the future. In addition, some consid-

关键词： Dry land farming conservation tillage Limited irrigation Genetic modification Chemical control

Nitrate Accumulation in soil Profile of Dry Land Farming in Northwest china

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Pedosphere 2003年第4期13卷 367-374页

作者： FAN Jun, HAO Ming-De and SHAO Ming-AnState Key Laboratory of soil Erosion and Dryland Farming on the Loess Plateau, institute of soil and water conservation, the chinese academy of sciences, yangling 712.00 (china). State Key Laboratory of soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water Conservation the Chinese Academy of Sciences Yangling 712100 China

A long-term fertilizer experiment on dry land of the Loess Plateau, northwestchina, has been conducted since 1984 to study the distribution and accumulation of NO_3-N down to adepth of 400 cm in the profile of a coarse-textured dark loessial soilafter continuous winter wheatcropping. Thirteen fertilizer treatments consisted of four levels of N and P applied alone or incombination. Annual N and P (P_2O_5) rates were 0, 45, 90, 135 and 180 kg ha^(-1). After 15successive cropping cycles, the soil samples were taken from each treatment for analysis of NO_3-Nconcentration. The results showed that NO_3-N distribution in the soil profile was quite differentamong the treatments. The application of fertilizer N alone resulted in higher NO_3-N concentrationin the soil profile than the combined application of N and P, showing that application of P couldgreatly reduce the NO_3-N accumulation. With an annual application of 180 kg N ha^(-1) alone, a peakin NO_3-N accumulation occurred at 140 cm soildepth, and the maximum NO_3-N concentration in thesoils was 67.92 mg kg^(-1). The amount of NO_3-N accumulated in the soil profile decreased as thecumulative N uptake by the winter wheat increased. Application of a large amount of N resulted inlowerN recoveries in winter wheat and greater NO_3-N accumulation in soil profile. KO_3-N did notenter underground water in the study region; therefore, there is no danger of underground waterpollution. Amount of NO_3-N accumulation can be predicted by an equation according to annual N and Prates based on the results of this experiment.

关键词： dry land long-term fertilizer experiment NO_3-N accumulation wheat

Study of elemental distribution in soil on the loess plateau of china

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Journal of Environmental sciences 1993年第1期5卷 37-44页

作者： Tian Junliang, Li Yaqi Liu PulingNorthwestern institute of soil and water conservation, chinese academy of sciences, Shaanxi 712.00, china Northwestern Inst. of soil & water conservation Chinese Academy of Sciences Shaanxi 712 100 China

Instrument neutron activation analysis (INAA) has been employed in this study to determine 32 elements in soil on the loess plateau. The preliminary results suggest that geochemical characteristics of elements in the soil mainly retained those in the parent materials (loess). It has been found that fractional deposition among grain sizes in the process of loess transportation as well as the bioclimate in which the soil developed are main factors affecting the regional variations of elemental distribution in soil on the plateau. Contour maps of element concentrations plotted from the trend analyses exhibit the major patterns of the distributions and variations on the plateau. Furthermore, the study also provides evidence for the aeolian theory of the loess transportation in china.

关键词： elements soil loess plateau variation patterns.