Dynamic Changes of Net Primary Productivity of Cultivated Land in Wind-drift Sand Region——A Case of Yuyang Area of Northern Shaanxi Province
【Abstract】 Based on the grain yield of Yuyang area from 1984 to 2003,the authors have chosen a suitable model to estimate net primary productivity of cultivated land of different regions to research the relation between ecological environment and NPP of cultivated land.Study has shown:(1) The total amount of NPP of cultivated land was on the rise generally in Yuyang area during 1984-2003.Its total amount has grown from 21.94×104 t/a in 1984 to 57.98×104 t/a in 2003.The annual increasing degree was 5.24%.(2) The unit area amount of NPP of cultivated land in the north was not only much more than that in the south but also increasing fast during 1984-2001.At the same time,the unit area amount of NPP of the cultivated land changed little in the south.(3) During 1984-2001,the unit area amount of NPP of cultivated land in urban was the highest and that in suburb was the second higher.The total amount of NPP of cultivated land in urban,suburb and outer suburb of Yuyang area was all on the rise generally,and that in outer suburb fluctuated at the largest range.(4)The increasing of the NPP of cultivated land was partly because of increasing investing in agriculture,but mainly because of ecological environment improvement of Yuyang area.
【Key words】 wind-drift sand region； Yuyang area； cultivated land； NPP；
- 【文献出处】 地理科学 ,Scientia Geographica Sinica , 编辑部邮箱 ,2007年04期