The Status and Sediment Reduction Effects of Level Terrace in the Loess Plateau

Level terrace is one of the most important measures of developing soil and water conservation and efficient agriculture in the Loess Plateau,which has the dual role of agriculture efficiency and ecological restoration. This paper analyzed the level terrace status: including scale,distribution,quality,planting structure and sediment reduction effects,based on remote sensing image of the ZY- 3 Satellite and field survey. The results show that there have level terrace 3. 71 million hm2 by the end of 2012,mainly distributed in the Yellow River basin in Gansu Province and adjacent areas and Hekouzhen- Longmen reaches of the Yellow River in Shanxi Province,where the terraced area accounts for around 54. 3% of the total terrace area in the Loess Plateau; Level terrace in Weihe River,Jinghe River and Zulihe River has a high quality rank and is dominated by farming,however,there have mainly narrow terraces with width 4- 6 m in He- Long reaches,and Terrace for Farmland is commonly appearing. In the future,terrace construction in the Yellow River of Gansu Province should give priority to damaged terrace reconstruction,the development space maybe 5% ~ 15%,however,He- Long reaches has a higher development potential,expect to increase new terrace by as much as 25%. Based on the terrace sediment reduction calculation method,the existing level terraces in the area upstream Tongguan can reduce sediment about 500 million tons.