Studies On Sustainable Utilization And Management Of Land And Water Resources In The Middle And Lower Reaches Of Yangtse River And The South Of China

Based on the expounding the characteristics of land and water resources and the status of land use in the Middle and Lower Reaches of Yangtse River and the South of China. Factors and problems affecting the sustainable utilization of land and water resources were pointed out, then some countermeasures on sustainable use and management were put forward in these areas, combining with the analysis on potential of land and water utilization. The followings are the main contents and some results:1. Results obtained from the analysis on status of land and water resources and its utilization.China possesses a vast territory, but the per capita amount of land and water resources is very little, And the ratio of land cultivated is high in whole state, while the reserve resources are very poor.The situations on status of land and water resources are more serious in the Middle and Lower Reaches of Yangtse River and the South of China, which respectively had only 0.11 hm~2 and 0.09 hm~2 of cultivated land per capita with the lowest place in the whole state. The amount of water resource per capita is also very poor, and the reclamation of the land with and lower yield in these areas are the main task in the future.The average land utilization ratio are 90.89% and 93.68% in the above two areas respectively, and 31.2%, 18.26 for ratio of land cultivated, 200.5%and 201.9% for multiple crop index. And these areas are the main part of the output of Aquatic product in China, the percentage of cultivated inland water areas to the cultivatable areas are 86.0% and 97.4% in the two areas respectively.2. Results obtained from the analysis of the factors and problems affecting the sustainable utilization of land and water resourcesThe cultivated area had been decreasing very rapidly in the Middle and Lower Reaches of Yangtse River and the South of China with the speed more rapid than the state average. The coastal provinces play the main role in the procedure of decreasing of cultivated land, while the paddy field is the main type of land decreasing. The reserve resources of cultivated land are serious short.In the areas of the Middle and Lower Reaches of Yangtse River, the nutrient of N in cultivated land reached balance, the index of nutrient balance is lower than 1 for P in partial provinces, and the index is lower than 0.66 for K. The situation of nutrient balance are better in the South of China than that in the above area.The percentage of the area of soil erosion to the total land area are 24.63% and 8.78% in the above two areas respectively, the water erosion are all the main type of soil erosion in these areas, just 99.9% and 99.5% to the whole area of soil erosion in the two areas.Pollution in farm land & water areas are very serious in these areas, such as in Taihu Lake in the south of Jiangsu province, over the standard of eutrophication have been happened in the farm land and lake.In the past 4 decades, the percentage of Drought Areas covered and affected to the whole Drought disaster areas in the state are 22.0% and 19.2% in the Middle and Lower Reaches of the Yangtse River respectively. And 5.2% and 4.4% for the areas in the South of China. Due to the destroy of forest, soil erosion, deposit in river and lakes and the poor quality of water conservancy facilities which couldn't meet the real demand, floods were happened frequently in the Middle and Lower Reaches in Yangtse River, specially in 1998.3. Results obtained from the analysis on potential of sustainable utilization of land and water resources.There are huge potential in the development on the mountain and hillside grassland, the percentage of the cultivatable grassland in mountain and hillside to the total cultivatable grassland in the Southern red soil areas are 26.7% and 18.2% in these two areas respectively.The accumulated increasing potential in grain are 3446.77×10~4t and 4520.97×10~4t in the two areas respectively according to the prediction of potential per cultivated area.The percentage of cultivated land of areas with middle and lower yield to the total same areas in the whole state are 20.9% and 7.1% respectively in the two areas, 36.5% and 8.9% for the water areas with lower yield. So the potential in yield are still very promising by increasing investment and management.By the way of controlling of soil erosion and the transforming of hillside cultivated land, the grain will be increased 9.58×10~5 t and 12.05×10~5 t in the two areas respectively.And the potential to increase the multiple crop index still exist in the areas.4. Results obtained from the analysis of strategies for sustainable use and management.Due to the present situation, the production system of resource saving and pollution control should be chosen in these areas.The social and economic countermeasure is to control population, build an improving system, do management according to law and the market regulation.Followings are the some technology strategies: to improve eco-environment, to enhance the construction of water conservancy, to strengthen the capacity to withstand natural calamities, to bring soil erosion, deterioration and pollution under control, to take full use of mountain and hillside grassland to develop livestock husbandry, to expand agriculture in winter et al..