General status of nutrients (N,P,K) in soils of China
1989
Lu Rukun (Academia Sinica, Nanjing (China). Inst. of Soil Science)
1. The content range of total soil nutrients of China are as follows: N: 0.04-0.38%; P: 0.02-0.11%; K: 0.05-2.5%. 2.Generally, the NPK content of soils under natural vegetative cover is higher than that under cultivation conditions, and the nutrients content of paddy soils is greater than that of dryland soils of the same origin. 3. Total and available nutrient levels of soils are mainly influenced by parent material, weathering and history of cultivation. 4. Almost all the soils of arable lands of China need nitrogen application, while about 1/3-1/2 of arable land area is deficient in phosphorus, and 1/4-1/3 deficient in potassium. 5. The phosphorus level of soils deficient now in phosphorus is increasing gradually because of phosphorus fertilizer application, while that of soils not deficient now in phosphorus is getting decreased because of phosphorus unbalance. 6. The area of soils deficient in potassium has a tendency to increase. 7. Based on the results now available, the sketch maps of soil nitrogen, phosphorus and potassium status of China were compiled
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