Distribution of natural quality of agricultural land in prefecture-level cities

Summarize the natural quality areas of agricultural land from county (district) level to prefecture-level cities, and the results are shown in Table 4-2. Combined with the analysis in Table 4-2, the agricultural land with the lowest natural quality in Jiangsu Province (15 hectares) and 16 hectares (2308 hectares) are all located in Yancheng City. 17 and other agricultural land are distributed in six prefecture-level cities in the province, and the largest prefecture-level city is Yancheng (80269 hectares); Agricultural land such as 18 is not distributed in Suzhou. In other prefecture-level cities, Yancheng has the largest distribution area (263,926 hectares). 19, 20, 2 1 and other agricultural land are distributed in various prefecture-level cities, among which Yancheng 19 is the largest (393,680 hectares), Xuzhou 20 is the largest (306,686 hectares) and Suzhou 2 1 the largest (65,430 hectares). Grade 22 agricultural land with the highest natural quality is mainly distributed in Suzhou (26 1 10 hectare), but it is not distributed in most prefecture-level cities in the province.

Table 4-2 Statistics of Natural Quality of Agricultural Land in Cities of Jiangsu Province: hectares

Figure 4-2 Scale map of natural quality grade area of agricultural land in cities of Jiangsu Province

In order to intuitively reflect the distribution of natural quality grades of agricultural land in prefecture-level cities, compare the scale map (Figure 4-2). It can be seen that all prefecture-level cities in the province take 19, 20 or 2 1 as the grade with the largest area ratio. Among them, Nanjing, Nantong, Lianyungang, Huai 'an, Yancheng and Suqian have the largest proportion of natural quality agricultural land, which is19; Wuxi, Xuzhou, Changzhou, Yangzhou and Taizhou have the largest proportion of agricultural land with a natural quality of 20; Suzhou and Zhenjiang have the largest proportion of agricultural land, and the natural quality is 2 1.

Based on the analysis of cities, Jiangsu Province is divided into three regions: southern Jiangsu, central Jiangsu and northern Jiangsu, and the natural quality of agricultural land is analyzed. The summary results are shown in Table 4-3 and Figure 4-3. Generally speaking, the natural quality of agricultural land in southern, central and northern Jiangsu is gradually decreasing, with low-grade agricultural land accounting for the vast majority, and high-grade agricultural land in southern Jiangsu is more. The agricultural land area with natural quality of 20 is most evenly distributed in the three regions.

Table 4-3 Statistical Table of Natural Quality Grade Area of Agricultural Land in Southern Jiangsu, Central Jiangsu and Northern Jiangsu Unit: hectare

Figure 4-3 Distribution of Natural Quality of Agricultural Land in Southern Jiangsu, Central Jiangsu and Northern Jiangsu

Southern Jiangsu is located in the Yangtze River Delta and Taihu Lake Basin, with superior natural and socio-economic conditions. The climate is mild and humid, winter is short and summer is long, spring is early and autumn is late, the growth period is long, the precipitation is moderate, the heat is the richest area in the province, the light and hot water match synchronously, and there are vast plains and fertile soil, lakes and rivers crisscross into a network, which is convenient for irrigation and drainage and developed in transportation. Canals, railways and highways connect large and small cities and market towns in China, providing very favorable conditions for agricultural production, and the natural fertility of agricultural soil is high. Agricultural land with high natural quality, such as 2 1, is mainly distributed in southern Jiangsu, and the area of agricultural land over 20% accounts for 75% of the total regional area, and the natural quality of agricultural land in southern Jiangsu is relatively optimal.

Suzhong area is located in the middle of Jiangsu Province, between the Yangtze River and Huaihe River, with the main irrigation canal in the north, the old Toarey Yang Canal in the south, the hilly area in the west and Tongyu Canal and Chuanchang River in the east. Moderate rainfall, coordination of light, heat and water, crisscross of inland rivers and lakes, extremely dense water network, abundant water, easy to flood, good cultivated land quality and high natural fertility. The natural quality of agricultural land in central Jiangsu is between southern Jiangsu and northern Jiangsu.

The hydrothermal conditions in northern Jiangsu are still good, but they are often affected by disastrous weather such as typhoon and rainstorm. Landform is a coastal plain that landed late, and it is one of the main distribution areas of beaches in China and even the whole province. The terrain is low and flat, generally 2 ~ 3 meters above sea level. Soil is generally salty, and its salt content is related to the distance from the coastline. The closer to the sea, the heavier the soil salinity, and the farther away from the sea, the lighter the soil salinity. The soil is sandy and the fertility is average. The main limiting factors of agricultural production are salt and irrigation and drainage conditions. The agricultural land below 19 with low natural quality in the whole province is mainly distributed in northern Jiangsu, and the agricultural land below 19 accounts for 70% of the agricultural land area in this area; The natural quality of agricultural land in northern Jiangsu is the worst.