Evaluation on Dynamic Changes of Landuse and Agricultural Production Structure Before and After Grain for Green Program-Take Two Typical Counties as Examples

摘要

Severe soil erosion is a serious environmental problem in western China.And an effective government program called the Grain for Green Program (GGP) was launched to control soil erosion and ameliorate the ecological environment in western China.Taken two typical counties of the western China as examples,dynamic changes of land use and agricultural production structure had been evaluated before and after Grain for Green Program of Zhongxian county and Ansai county in western China.The cultivated land area was 55000 hm2 in 1989 and was decreased to 51102 hm2 in 2003 in Zhongxian county.The cultivated land per person was 0.095 hm2 in 1999 and reduced to 0.087 hm2 in 2003.There existed negative relation between the cultivated land area and the agricultural production values.The stability index of secondary economic sector was 0.91 during the year of 1990 to 1999 and was 0.94 during 2000 to 2009.Meanwhile,the stability index of tertiary economic sector was 0.88 during 1990 to 1999 and it was 0.92 during 2000 to 2009.And the cultivated land area was decreased from 111,221 hm2 to 94,003 hm2 during 1990 to 1999 in Ansai county.And the soil erosion modulus was decrease from 12000 tkm-2a-1 to 8000 tkm-2a-1 during 1999 to 2006.The stability index of secondary and tertiary economic sectors was 0.86 during 1998 to 2002 in Ansai County.But this stability index decrease 77％ during 2002 to 2007.Several effective strategies of soil and water conservation had been adopted to ameliorate the sustainable development of ecological environment and economy in the Three Gorges Reservoir region and on the Loess Plateau of the western China.