Determination of index area of grading factor

According to the previous adjustment of the grading index area, Jiangsu Province is divided into six grading factor index areas. On the premise of ensuring the integrity of the township administrative region, the scope of each index region is shown in Table 3-2.

Table 3-2 Division of Agricultural Land Classification Index Areas and List of Covered Areas in Jiangsu Province

sequential

(1) Xuhuai Plain

This area is located in the north of Huaihe River and main irrigation canals, and belongs to the southern edge of Huang-Huai-Hai Plain, bordering the Yellow Sea in the east, Anhui in the west, Shandong in the north and He Lixia agricultural area in the south. The climate in this area is characterized by rapid warming in spring, early cooling in autumn, abundant sunshine in spring and autumn, and large temperature difference between day and night. Hot rain is concentrated in summer and cold and dry in winter; There are many droughts in spring, summer and autumn. The lighting condition is the best in the whole province, with annual total solar radiation 1 14 ~ 126 kcal/cm2 and annual sunshine hours of 2233 ~ 263 1 hour. The heat is the lowest in the whole province, with an annual average temperature of 13.2℃ ~ 14.4℃. The landform is mainly the Yellow River Plain, with flat terrain and deep soil layers. The water system belongs to the lower reaches of Huaihe River, yi river River, Shuhe River and Sihe River, with abundant water resources. However, due to the influence of monsoon climate, it is unevenly distributed in time and space. About 70% of the annual rainfall and nearly 95% of the runoff are concentrated in the flood season from June to September. Soil fertility is generally low, including saline-alkali land, ginger, ginger, flying sand and other soils. In the history of agricultural production, triple cropping in two years is the main crop in dry valley, and now it has developed to double cropping in one year. It is the production base of rice, wheat, cotton, oilseeds, beans, tobacco and other important commodities in Jiangsu Province.

(2) He Lixia Plain

This area is located in the middle of Jiangsu Province, between the Yangtze River and Huaihe River, bordering the main irrigation canal in the north, the old Toarey Yang Canal in the south, the hilly area in the west, the Tongyu Canal and the Chuanchang River in the east. Located in the northern part of the north subtropical zone, this area is superior to Taihu Plain in light energy resources and Xuhuai Plain in heat resources. The rainfall is moderate, the three elements of light, heat and water are coordinated, and its peak period coincides with the growth demand of rice, which is very beneficial to the growth and development of rice. It is not too cold in winter, the rainfall in spring is less than that in Taihu Lake, and the meiyu period is also late, which is beneficial to wheat growth. Therefore, rice and wheat are suitable for this area. Except for the high terrain to the west of the canal, the whole region has formed a dish-shaped shallow depression plain with little height difference, with criss-crossing rivers and lakes, dense water network and abundant water, which is prone to floods. Paddy soils formed by lacustrine deposits and alluvial deposits of Huanghuai and Yangtze River are widely distributed in this area, among which there are some paddy soils formed by marine deposits in the Hexi area of Chuanchang, which have strong water and fertilizer conservation functions, good cultivated land quality and high natural fertility. The characteristics of agricultural natural conditions determine that this area is a planting structure of rice and wheat, and there is great potential for developing aquatic production. It is an important grain and aquatic product producing area in Jiangsu Province.

(3) Coastal plain areas

The area is bordered by the Yellow Sea in the east, Chuanchang River in the west, Rudong in the south and the main irrigation canal in the north. It belongs to subtropical humid monsoon climate, because it is close to the Yellow Sea, so it has typical coastal climate characteristics, with slow heating in spring, no heat in summer, late temperature drop in autumn and less cold in winter. The hydrothermal conditions 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 generally contains salt, and the content of soil salt 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 factor of agricultural production in this area is salt. Since the founding of New China, both water conservancy facilities and agricultural improvement measures have been paid equal attention to, and water, fertilizer, forest, seeds and pipes have been comprehensively managed, and the salt content of soil and groundwater has been greatly reduced. The farming system is two crops a year, and the crops are mainly rice, wheat, cotton and corn.

(4) Plain areas along the Yangtze River

This area is located on both sides of the Yangtze River in Jiangsu Province, mainly in Jiangbei. Located in the middle of the north subtropical zone, near the river, the climate is mild and humid, belonging to the relatively flat Yangtze River Delta plain. The conditions of light and heat resources in this area are good, with the annual average sunshine hours of 2040 ~ 2280 hours and annual solar radiation 108 ~ 1 17 kcal/cm2, which is better than Taihu Plain, slightly better than Ningzhenyang Hilly Area and slightly worse than He Lixia Plain. The land types are complex, including Toarey Yang high sandy soil, polder fields along the river, Jiangbei Plain and Jiangnan high plains. There are two kinds of soil: fluvo-aquic soil and paddy soil. The polder fields, surrounding fields and Gaoping fields along the Yangtze River south are mostly muddy soil, mostly loam soil, which has good water and fertilizer conservation performance and belongs to high-yield soil. In addition to paddy soil, Jiangbei is mostly calcareous fluvo-aquic soil with medium fertility. The soil in the high sandy soil area of Toarey Yang is mostly high sandy soil species and mixed sandy soil species in calcareous fluvo-aquic soil, with poor soil quality and average fertility level. Coastal areas are mostly fluvo-aquic soil with moderate fertility. The farming system is two crops a year, and the crops are mainly rice, wheat, cotton and corn.

(5) Taihu Plain

This area is located in the southeast of Jiangsu Province, bounded by the Yangtze River, Zhangjiagang, Yantietang and the plain area along the river in the north and northeast, and bounded by the10m contour line and Ningzhenyang hilly area in the west and southwest. This area belongs to the southern edge of the northern subtropical zone, 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, light and hot water are collocated synchronously, and there are vast plains and fertile soil, lakes and rivers crisscross into a network, which is convenient for irrigation and drainage, and the traffic is developed. Canals, railways and highways connect large and small cities and market towns in China, thus providing very favorable conditions for agricultural production. Agricultural soil is mainly paddy soil with high natural fertility. The farming system is two crops a year, which is an important producing area of rice, wheat, aquatic products, sericulture and so on in Jiangsu Province.

(VI) Hilly area of Ningyang Town

This area is located in the southwest of Jiangsu Province, bordering Huaihe River, Hongze Lake and Xuhuai Plain in the north, He Lixia, Jiangyan and Taihu Plain in the east, and Zhejiang and Anhui provinces in the southwest. The landform types are complex, with low mountains, hills, hills, gullies, plains and depressions interlaced, among which mountains, hills and hills occupy a large area. The annual average temperature is 14.6℃ ~ 16.0℃, and the accumulated temperature ≥0℃ is 5500℃ ~ 5800℃. The heat condition is one of the richest areas in the province, with annual precipitation 1000 ~ 1200mm. The development of water system is closely related to topography, with the Yangtze River, Huaihe River, Chuhe River and Qinhuai River as the main trunk lines. Because the area is long and narrow from north to south and narrow from east to west, the change trend of hydrothermal conditions from south to north is obvious; Due to the complex terrain, the non-zonal difference of climate is also obvious, which often forms a unique water microclimate and topographic microclimate along the river, lake and mountain. Restricted by topography, the utilization rate of precipitation is low, the drought resistance in hilly areas is weak, and there are floods in polder areas. Agricultural soil is mainly paddy soil, with some dry soil, and the area of low-yield soil is large. Dead loess, small white soil, pulp clay and green soil with poor nutrients or poor structure account for a large proportion of the soil area in the whole area. The farming system is two crops a year, mainly rice, and there is a certain proportion of dry food.