An Introduction to Chongqing

Chongqing used to be part of Sichuan province. In 1997 it was municipalized and since then it has become the biggest economic centre in the upper reaches of the Yangtze River. Two large rivers (Yangtze River and Jiangling River) flow through Chongqing city and then join together. The capital of Chongqing, however, is named after the abbreviation of Jialing River, Yu. The region covers a land area of 82,403 sq. km and has 29.91 million population in 2014. This region has average annual temperatures between 16 to 18 ⁰C, precipitation between 1,000 to 1,350 mm and frost free days of 325 to 345 days.

Soils and Soil Fertility
The major soil parent materials are those outcrops from the Mesozoic, followed by Paleozoic sea sediments. Developed from these outcrop rocks, eleven soil types including paddy soil (45.6%), purple soil (34.7%), and yellow soil (16.0%) were formed. The results from the national soil-testing based fertilizer recommendations program conducted in recent years showed that the farmlands with medium to low productivity account for 77.4% of the total. There was continuous increase in organic matter and total nitrogen (N), a decrease in potassium (K), and relatively steady in available phosphorus (P) - compared to the second soil survey conducted in 1980’s. Available zinc (Zn) and boron (B) are still deficient in most soils and molybdenum (Mo) in acid soils in particular. Soil acidification is getting worsening in vegetable soils causing many problems both in nutrient disorders and diseases. Total fertilizer consumption in 2012 was 965,000 t (of nutrients), among which there were 500,000 t of N, 180,000 t of P₂O₅, 560,000 t of K₂O and 214,000 t of compound fertilizers. This yields a N: P₂O₅: K₂O: compound fertilizer ratio of 1:0.36:0.11:0.43. The fertilizer application rate on unit sowing area was 280 kg/ha in 2012. This indicates that rate of K fertilizers has been very low and use of compound fertilizers has been sluggish in the region.

Crop lands and crops
At end of 2009, Chongqing had 243.8 million hectare of farmlands, among which sloping lands accounted for 140.5 million ha (45,000 ha with slope>5⁰ and 362,000 ha >25 ⁰). The sowing area was 2.24 million ha for grain crops with an average yield of 5105 kg/ha, 300,000 ha for oil crops, 708,000 ha for vegetables, 343,000 ha for fruits and 114,000 ha for herbs.
Paddy rice, corn, tuber crops (sweet potato, potato), and wheat are the main grain crops, and cash crops are rape, tea, mulberry for silk worms and citrus. The dominant cropping systems are rice-rape/wheat rotation in paddy fields, wheat-corn-sweet potato rotation in the hilly uplands and corn-potato in the mountainous region. Citrus grown in Fengjie county is well-known nationwide in China for its sweetness and high quality. Kidney bean, berberine, southernwood and other local special produces from Wuling and Qingbai mountainous regions are used to make good fortunes for local farmers through export.