The Protection Of Cultivated Land Based On Grain Security In Nantong City Of Jiangsu Province

Cultivated land forms the basis to ensure grain security, and the protection of the cultivated land equals to that of grain security. The study mainly includes the following several aspects: analysis of the characteristics of the cultivated land, and the changes of trends and reasons of the cultivated land resources in Nantong city, a municipal city in Jiang Su province; the prediction of the quantity supplied of cultivated land over a period of time in the future; analysis of the features the present situation of grain production in Nantong city and the status quo of grain security by means of the model of the pressure index of cultivated land; the prediction of the demand of cultivated land for the purpose of grain security in the future on the basis of such indexes as total grain yield, per unit area yield of grain, per capita occupancy of grain; the proposal of the principles, goals, the main countermeasures and measures in terms of the cultivated land protection in Nantong city according to above research results. The main conclusions of the present study are as follows:(1)The total and per capita cultivated land resources in Nantong city have shown the trend of reduction in recent years. The cultivated land has annually decreased 3.12133 thousand hectares form 2002 to 2010. Although the total population of Nantong city has reflected a decrease of 19.3 thousand of people each year from 2002 to 2010, per capita amount of cultivated land has reduced from 0.0607 hectare in 2002 to 0.0585 hectare in 2010.The main factors that result in the decrease of cultivated land resources are economic development and the progress of agricultural science and technology.(2)The approaches to increase the cultivated land resource in Nantong city mainly consist of land development, land reclamation and land consolidation of which land development occupies the most important position. And the potential for the land development in Nantong city primarily lies in tidal flat.The decrease of the cultivated land in Nantong city can be attributed to state and rural collective construction land and agricultural production structure adjustment in which the decrease caused by the former accounts for more than 90 percentage of the total reduction. Combined with the factors concerning the increase and decrease of cultivated land, it is estimated that the quantity supply of Nantong city will be 437.388 thousand hectares and 413.082 thousan d hectares respectively by the year of 2020 and 2030 on the basis of the cultivated land at the end of 2009.(3)The total grain yield and per unit area yield of grain Nantong city have increased in a fluctuant way, and the grain supply and demand in Nantong city is basically in a state of balance.The total grain output has been roughly stable at the level of 3.07 million tons in recent years. In this way, per unit area yield of grain has been kept roughly at the level of 5.68386 kilograms per hectare. Providing that the per capita demand of grain is 400 kilograms, the present situation of grain supply and demand in Nantong city is basically in the state of balance.(4)According to the results calculated through the model of the pressure index of cultivated land, the pressure index of cultivated land in Nantong city has been maintained between 1.0 to 0.9 and presented a tendency of reduction on the whole from the year of 2002 to 2010,which means the pressure of cultivated land has been in the light state of alarm. From results of the pressure index of cultivated land, the grain supply in Nantong city is slightly higher than grain demand, which can basically guarantee the grain security.(5)According to the forecast on the basis of the parameters, such as the total population, grain output, the ratio of grain sown area and total sown area, multiple cropping index, per capita demand of grain and grain self-sufficiency rate, it is expected that the demand of cultivated land will be 399.38757 thousand hectares and 391.81615 thousand hectares in 2020 and 2030 separately by means of the model of the demand of cultivated land based on grain security. In comparison with the prediction of the quantity supplied at the corresponding time period, it is be found that just given the demand of grain security, the grain security in Nantong city can be basically guaranteed over a period of time in the future.