Nowadays the rising of opportunity cost of farm labor comes to the forefront of attention in China. In order to understand its impact on agricultural land-use structure, a theoretical framework of household economics is formulated drawn on Low's model. Under the theoretical framework, the impact of the rising opportunity cost of on-farm on cropping structure is deduced in theory. And then, using statistic and survey data, taking mountain area of southern Ningxia as an example, the theoretical assumes are verified. The results show that the rise of opportunity cost of farm labor leads to less diversified cropping structure.
Based on the data from the Cost-benefit Data of Farm Produce and the China Agricultural Yearbook,this paper aims to examine the spatial and temporal change characteristics of total grain production and its affecting factors.The results show that:1) During 1980 to 2007,total grain production increased from 3.20 × 108 t to 5.02 × 108 t in China,with annual increasing rate of 1.68%.From the regional disparities,most of the regions present increasing trend of total grain production except for several regions with higher level of economic development;2) Grain sown area decreased from 1.17 × 108 ha in 1980 to 1.06 × 108 ha in 2007,which has negative effect on total grain production;3) The increase of grain yield per unit area caused by land use intensity changes contributed to the increase of total grain yield greatly.However,as the land use intensity showed that farmers pay more attention to labor-saving input but not yield-increasing input,the less enthusiasm of farmers in grain production may become an important constraint on fu-ture grain production increase in China;4) Based on the results,this paper proposed different land management poli-cies in different regions,for example,the government should protect cultivated land,promote large scale production.As to the less developed regions,the government should pay more attention to agricultural subsidies to promote farm-ers' enthusiasm in grain production.
