The Contribution of Land to The Economic Growth and Inflection Point of Its Logistic Curve in Anhui Province in Recent 15 Years

China is undergoing rapid advance of industrialization and urbanization. A large number of input in new construction land provide a strong support for the sustained rapid growth of investment in the whole society,and the continuous growth of investment has become an important driving force to spur economic growth. The moderate input in land factor is the basis to guarantee urbanization and economic development. The over-reliance on land for development will inevitably lead to a decline in the amount of arable land,not only endangering food security and the achievement of guard-line objectives for 1.2×103km2of arable land,but also having a major impact on the terrestrial carbon cycle and ecological system changes,which involves compensation,resettlement of landless peasants and other social issues. Accordingly,the accurate control on the contribution of construction land expansion to economic growth can help the management understand the land value in a scientific way as well as correct and abandon the wrong ideas to exaggerate economic value of the land. Based on the statistical data and C-D production function,the economic contribution rate of construction land of Anhui Province from 1997 to 2011 was quantitatively measured with the method of least squares regression,and its Logistic curve was explored. The results showed the findings in the following. 1) In the study period,the elastic coefficients of input factors,i.e.,capital,labor and construction land,against the total output value of secondary and tertiary industries were 0.469,0.801 and 0.369 respectively. 2) The economic contribution rates of input factors,i.e.,capital,labor,construction land and scientific progress,were 52.31%,22.9%,20.74% and 4.05% respectively. 3) The Logistic curve of construction land expansion fitted with economic growth occurs when the total output value of secondary and tertiary industries was 274.4 billion yuan(RMB) in 2002. From 1997 to 2002,the economic contribution rate of construction land increased rapidly. From 2002 to 2011,the rising speed of economic contribution rate of construction land slowed down and tended to be steady. 4) The economic contribution rate of scientific progress tended to increase steadily but in a relatively low value. These results can not only provide a reference for the directional transition of economic development in Anhui Province from land and other factors to technological innovation as well as similar researches at the provincial scale,but also lay a scientific basis for the development of differentiated adjusted land policy and the protection of arable land resources in different stages.