摘要
在黄土丘陵区坡耕地水土流失特征分析的基础上 ,对坡耕地水土流失与土地生产力的关系进行了研究。采用不同的试验方法 ,以单位面积坡耕地生产某种生物产品的数量为土地生产力指标 ,以生产周期短的农作物为指示植物 ,具体探讨了地表径流损失和土壤流失分别所造成的土地生产力下降幅度。表土人工堆积处理的径流小区试验结果表明 ,坡耕地每损失 1 mm径流 ,供试作物产量平均下降 5 .0 %～ 9.7% ;小区铲土覆土模拟土壤流失的小区试验结果显示 ,每减少 1 cm表土 ,作物产量下降 1 .0 %～ 3.1 % ,每增加 1 cm表层熟化土 ,产量增加 0 .8%～ 1 .7%。在干旱年份 ,半干旱黄土丘陵区坡耕地由于水土流失导致的作物减产每年平均为 2 1 .9%～ 80 .0 % ,其中径流损失的比重占 95 .8%～ 98.2 % ,而土壤流失仅占 1 .8%～ 4.2 %。作物品种不同 ,水土流失对作物产量的影响各异。
Soil and water erosion is probably the most serious ecological environment problem in the Loess Plateau, especially on the slope fields of this semi-arid hilly gully region. It results in decline of top soil thickness, soil nutrients loss, water pollution, flood disaster and land productivity degradation. But the relationship between soil and water erosion and land productivity is not well defined yet. Without an adequate definition, the selection of proper management strategies to optimize perennial crop and biomass production will be impossible. Insufficiently reasonable decisions can easily result in serious damage to land resources. Land productivity may approach zero in many severely eroded areas such as in the steep slope fields of the Loess Plateau. Accurate estimates of future land productivity are essential to make agricultural and soil erosion management policy decisions and to plan the use of land from the field scale to the national level. Such a task is enormous because it requires a method for quantifying land productivity with sediment and runoff date bases. Land productivity is the capacity of a land in its normal environment to produce a particular plant or sequence of plants under a specified management system. Because of the emphasis on a land's capacity to produce crops or other plants, land productivity should be expressed in terms of yields or biomass. Despite limited research efforts have been developed to relationship between the soil and water erosion and land productivity problem specifically in china, considerable effort has gone into most of the important processes involved in middle and upper reaches of the Yellow River. The Yellow River, passing through the Loess Plateau, is the most heavily sediment-laden river in the world, with an average sediment concentration of 37.5 kg/m3 and annual sediment load of 1.6 billion t. The test zone, Xiji county of Ningxia Hui Autonomous Region, is located in hilly gully area of the Loess Plateau and belongs to semi-arid region with average annual
出处
《生态学报》
CAS
CSCD
北大核心
2003年第8期1463-1469,共7页
Acta Ecologica Sinica
基金
国家自然科学基金资助项目 ( 3 0 1 70 779)
国家"九五"科技攻关资助项目 ( 96-0 0 4-0 5 -1 0)~~
关键词
黄土丘陵区
水土流失
坡耕地
土地生产力
hilly gully area of the Loess Plateau
soil and water erosion
slope field
land productivity
