塔里木河沿程水量流失的分析及防治措施

塔里木河是我国著名的内陆河流,其水资源的合理开发利用对沿程的生产发展和生态环境的变化起着重要作用。特别是塔里木河下游长491km的绿色走廊,它是水草丰美、林木丰茂的条带绿州,是抗御风沙浸蚀的绿色屏障,是国家生态环境重点保护的绿色走廊。但是,近二十年来,塔里木河下游水量急剧减少,形势是严峻的。本文根据1986年6月至12月对塔里木河干流沿程水情的考察资料,对塔里木河沿程水量流失原因进行了详细的分析,并提出如下防治措施:(1)修建拦河分水枢纽,恢复“渭干塔里木河”主流;(2)采取截弯取直或改道措施,缩短河道流程,减少水量损失;(3)建罗乎罗克水渠,减少自乌斯满河来水量损失;(4)扩建卡尔其克和塔里木水库,解决尉犁东河滩地区在枯水期的用水问题;(5)全面规划巴州境内河段的农、牧业用水和草场、林场建设;(6)统筹好巴州境内塔里木河的来水用水,以保证铁干里克以下2.0～2.5亿m^3的水量。

八钢生活区流失水量问题的监测与分析

通过对八钢生活区各主要供水管线供水量的监测，分析生活区总流失水量及主要流失途径和原因，提出了减少流失水量的措施。

四川坡耕地的水土流失与农业生产

四川省现有旱地5000余万亩,占总耕地面积的50.5％,产粮占全省粮食总产的42％左右。这些旱地中,有63.5％是坡耕地,约92％的旱地面积分布在丘陵山区,其特点是雨量充沛,气候温和,无霜期长,宜于农作物生长,是全省粮、经作物的主产区.据调查:这些坡耕地的地面坡度在10°以下的占14.7％,10°～20°占36.4％,20°～30°占26.7％,30°以上的占22.2％;加之人为的不合理生产活动,造成和加剧了水土流失,致使土层瘠薄,土壤肥力下降,抗旱力弱,产量低而不稳。

Nutrient Losses in Soils on Loess Plateau

The soil nutrient losses due to excessive soil loss on Loess Plateau were studied by means of runoff plotsand systematical determination of soil nutrients both in sediments and runoff.The results show that theamounts of nutrient losses depended on the amounts of erosion sediments. Along with sediment, 11-197 kgnitrogen/hectare and 9-174 kg phosphorus/hectare were lost, accounting for 92.46-99.47 percent of the totalamount of nitrogen loss and 99.85-99.99 percent of the total amount of phosphorns loss respectively. Thenutrient losses, very small in runoff, were mainly attributed to erosion of a few rainstorms during a year. Thenutrient level in sediment was mostly higher than that in the original soil. Planting grass evidently reducedthe losses of soil nutrients. The N level was lower in runoff than in rainfall so that the N loss from runoffconld be made up by rainfall. Fertilizer application to crops raised the nutrient level in runoff.

The Suitability of Using Leaf Area Index to Quantify Soil Loss under Vegetation Cover

Soil erosion by water under forest cover is a serious problem in southern China.A comparative study was carried out on the use of leaf area index(LAI) and vegetation fractional coverage(VFC) in quantifying soil loss under vegetation cover.Five types of vegetation with varied LAI and VFC under field conditions were exposed to two rainfall rates(40 mm h-1 and 54 mm h-1) using a portable rainfall simulator.Runoff rate,sediment concentration and soil loss rate were measured at relatively runoff stable state.Significant negative exponential relationship(p < 0.05,R2 = 0.83) and linear relationship(p < 0.05,R2 = 0.84) were obtained between LAI and sediment concentration,while no significant relationship existed between VFC and sediment concentration.The mechanism by which vegetation canopy prevents soil loss was by reducing rainfall kinetic energy and sediment concentration.LAI could better quantify such a role than VFC.However,neither LAI nor VFC could explain runoff rate or soil loss rate.Caution must be taken when using LAI to quantify the role of certain vegetation in soil and water conservation.

Development of a New Index for Integrating Landscape Patterns with Ecological Processes at Watershed Scale

Understanding the relationship between landscape pattems and ecological processes has been a central yet challenging research theme in landscape ecology. Over the past decades, many landscape metrics have been proposed but few directly incorporated ecological processes. In this paper, we developed a landscape index, namely, location-weighted landscape index （LWLI） to highlight the role of landscape type in ecological processes, such as nutrient losses and soil erosion. Within the framework of the Lorenz curve theory, we develop this index by integrating land- scape pattern and point-based measurements at a watershed scale. The index can be used to characterize the contribution of landscape pattern to ecological processes （e.g. nutrient losses） with respect to a specific monitoring point in a watershed. Through a case study on nutrient losses in an agricultural area in northeastern China, we found that nutrient losses tended to be higher for a watershed with a higher LWLI value, and vice versa. It implied that LWLI can be used to evaluate the potential risk of nutrient losses or soil erosion by comparing their values across watersheds. In addition, this index can be extended to characterize ecological processes, such as the effect of landscape pattern on wildlife inhabitation and urban heat island effect. Finally, we discuss several problems that should be paid attention to when applying this index to a heterogeneous landscape site.

Impacts of precipitation variation and soil and water conservation measures on runoff and sediment yield in the Loess Plateau Gully Region, China

The Loess Plateau of China has experienced a lengthy drought and severe soil erosion.Changes in precipitation and land use largely determine the dynamics of runoff and sediment yield in this region. Trend and mutation analyses were performed on hydrological data(1981–2012) from the Yanwachuan watershed in the Loess Plateau Gully Region to study the evolution characteristics of runoff and sediment yield. A time-series contrasting method also was used to evaluate the effects of precipitation and soil and water conservation(SWC) on runoff and sediment yield. Annual sediment yield declined markedly from 1981 to 2012 although there was no significant change in annual precipitation and annual runoff. Change points of annual runoff and annual sediment yield occurred in 1996 and 1997,respectively. Compared with that in the baseline period(1981–1996), annual runoff and annual sediment yield in the change period(1997–2012)decreased by 17.0% and 76.0%, respectively, but annual precipitation increased by 6.3%. Runoff decreased in the flood season and normal season, but increased in the dry season, while sediment yield significantly declined in the whole study period. The SWC measures contributed significantly to the reduction of annual runoff(137.9%) and annual sediment yield(135%) and were more important than precipitation. Biological measures(forestland and grassland) accounted for 61.04% of total runoff reduction, while engineering measures(terraces and dams) accounted for 102.84% of total sediment yield reduction. Furthermore, SWC measures had positive ecological effects. This study provides a scientific basis for soil erosion control on the Loess Plateau.

Study on water loss of the surface stream affected by iongwali mining

In order to study the effect of Iongwall mining on surface stream water, monitoring stations of water flow rate was established. A lot of water flowing data were collected before, during and after Iongwall mining. Based on monitoring data, the effects of Iongwall mining on surface stream water were analyzed. The results demonstrate that Iongwall mining has effects on the surface stream water; and the stream water would be lost and decrease due to Iongwall mining but never go into underground through fractured zone. Also, the mechanism of water loss due to Iongwall mining was presented. The stream water can go into the surface cracks in the intersection of stream and surface cracks, longwall mining subsidence can change the surface stream slope and the downstream water flowing status. The results also show the effects of Iongwall mining on stream water are temporary and about one or two years later, surface stream water can be recovered.

Study on Influence of Soil Erosion for Different Covered Patterns in Karst Slope of Sugarcane Planting Regions

Sugarcane production is mainly slope cultivation, so soil erosion was serious. The results showed that the different coverage methods have a higher production rate of 39.26%-41.22%, than the control treatment （blank） without covering, so yield-increasing effect was significant. As annual rainfall is around 1,250 mm and the control treatment（blank） without covering, the whole year of fertilizer runoff was 175 mm, the average soil content of runoff water was 2.22 g/L, and the total amount of soil loss was 3585.0 kg/ha. The treatment with farmer fertilization practice ＋ plastic film mulching annual runoff water was 153 mm, the average soil content of runoff water was 2.30 g/L, and the total soil loss of volume was 3183.0 kg/ha. The treatment with optimize fertilization ＋ plastic film mulching annual runoff water was 141mm, the average soil content of runoff water was 2.42 g/L, and the total amount of soil loss was 2958.0 kg/ha. Sugarcane leaves covered treatment runoff did not occur throughout the year. The coverage of treatment compared with the control treatment, runoff water reduction is in the range of 12.6-16.0%, is 15.8-23.8% reduction in the amount of runoff soil. Treatment with no fertilization nutrient N loss was 5.760 kg/ha, and P205 loss was 2.565 kg/ha in runoff water. Farmer fertilization treatments the nutrient N loss was 12.435 kg/ha, and the loss P205 was mulching treatment nutrient N loss was 7.755 kg/ha, and P205 loss was 3.960 kg/ha in water runoff. Optimizing fertilization ＋ plastic 3.540 kg/ha in runoff water.

Effects of Bahia Grass Cover and Mulch on Runoff and Sediment Yield of Sloping Red Soil in Southern China

Rainfall,runoff (surface runoff,interflow and groundwater runoff) and soil loss from 5 m × 15 m plots were recorded for 5 years (2001-2005) in an experiment with three treatments (cover,mulch and bare ground) on sloping red soil in southern China.Surface runoff and erosion from the Bahia grass (Paspalum notatum Flugge) cover plot (A) and mulch plot (B) during the 5 years were low,despite the occurrence of potentially erosive rains.In contrast,the bare plot (C) had both the highest surface runoff coefficient and the highest sediment yield.There were significant differences in interflow and surface runoff and no significant difference in groundwater runoff among plots.The runoff coefficients and duration of interflow and groundwater runoff were in the order plot B > plot A > plot C.Effects of Bahia grass cover were excellent,indicating that the use of Bahia grass cover can be a simple and feasible practice for soil and water conservation on sloping red soil in the region.

Approximation of Rainfall Erosivity Factors in North Jordan

Despite being in arid and semi-arid areas,erosion is largely a result of infrequent but heavy rainfall events; therefore,rainfall erosivity data can be used as an indicator of potential erosion risks.The purpose of this study was to investigate the spatial distribution of annual rainfall erosivity in North Jordan.A simplified procedure was used to correlate erosivity factor R values in both the universal soil loss equation (USLE) and the revised universal soil loss equation (RUSLE) with annual rainfall amount or modified Fournier index (F mod ).Pluviometric data recorded at 18 weather stations covering North Jordan were used to predict R values.The annual values of erosivity ranged between 86-779 MJ mm ha ?1 h ?1 year ?1 .The northwest regions of Jordan showed the highest annual erosivity values,while the northeastern regions showed the lowest annual erosivity values.