The level-trench method is a traditional tillage operation to develop a drainage system on slope land in the Three Gorges region. Before crops are planted, farmers prepare the land with level trenches spaced 3-1o m ap...The level-trench method is a traditional tillage operation to develop a drainage system on slope land in the Three Gorges region. Before crops are planted, farmers prepare the land with level trenches spaced 3-1o m apart, depending on the slope gradient： steeper slopes require shorter distances. Little scientific analysis has been done on the use of traditional level trenches for soil conservation. We conducted a field investigation and simulation experiments, and present a comparison between the spacing of level trenches and the slope length required for rill initiation. The results indicate that the spacing of level trenches in farmland is close to the slope length required for rill initiation in the experimental plots, and regression models of trench spacing with the gradient and the slope length required for rill initiation with the gradient have similar formats; the coefficients of determination （R2） for the two equations are 0.99 and 0.88, respectively. There were some differences between the field survey and experiments, but we conclude that the traditional level-trench method has an important role in preventing rill initiation.展开更多
In the early years of reform and opening up, with the household contract management as the core, the land reform has been adapted to the prevailing agricultural productivity development and management level, achieved ...In the early years of reform and opening up, with the household contract management as the core, the land reform has been adapted to the prevailing agricultural productivity development and management level, achieved to mobilize the peasants＇ production enthusiasm and creativity, to improve production efficiency, basically solved the food and clothing problem; but it has formed small-scale decentralized business model. With the rapid development of the rural economy, along with urbanization and industrialization, it has been further increased the degree of market-oriented agriculture. The contradiction between big market and small-scale production is more prominent; such small -scale decentralized form of management has begun not to meet agricultural development request and the market economy development. It needs changes to moderate scale. Eleventh Five-Year Plan and construction of new socialist village require clearly various forms of appropriate scale.展开更多
基金supported by the Ministry of Science and Technology of China (Grant No.2011BAD31B03)the Ministry of Environment of China (Grant No.2009ZX07104-002-06)
文摘The level-trench method is a traditional tillage operation to develop a drainage system on slope land in the Three Gorges region. Before crops are planted, farmers prepare the land with level trenches spaced 3-1o m apart, depending on the slope gradient： steeper slopes require shorter distances. Little scientific analysis has been done on the use of traditional level trenches for soil conservation. We conducted a field investigation and simulation experiments, and present a comparison between the spacing of level trenches and the slope length required for rill initiation. The results indicate that the spacing of level trenches in farmland is close to the slope length required for rill initiation in the experimental plots, and regression models of trench spacing with the gradient and the slope length required for rill initiation with the gradient have similar formats; the coefficients of determination （R2） for the two equations are 0.99 and 0.88, respectively. There were some differences between the field survey and experiments, but we conclude that the traditional level-trench method has an important role in preventing rill initiation.
文摘In the early years of reform and opening up, with the household contract management as the core, the land reform has been adapted to the prevailing agricultural productivity development and management level, achieved to mobilize the peasants＇ production enthusiasm and creativity, to improve production efficiency, basically solved the food and clothing problem; but it has formed small-scale decentralized business model. With the rapid development of the rural economy, along with urbanization and industrialization, it has been further increased the degree of market-oriented agriculture. The contradiction between big market and small-scale production is more prominent; such small -scale decentralized form of management has begun not to meet agricultural development request and the market economy development. It needs changes to moderate scale. Eleventh Five-Year Plan and construction of new socialist village require clearly various forms of appropriate scale.
