Nitrogen is active and it is not easy to accumulate in the soil, so regular application is required for nitrogen fertilizer. After P and K are applied to the soil and absorbed by crops, they mainly accumulate in the soil. Long-term large-scale application will gradually increase the soil nutrient content, thereby reducing demand, and the proportion of P and K needed to decline. Therefore, for N, P and K nutrient elements to be treated differently, for N, it is necessary to constantly regulate its content in the soil. For P and K, consider its fertilizer aftereffect, pay attention to its accumulation in the soil, to prevent excessive.
We---Qingdao Haijingling Group is established in 2002, located in Qingdao CITY, SHANDONG; Specialized in manufacturing of Organic Fertilizer ,seaweed extract fertilizer ,N. P. K. Compound fertilizers(in granular, soluble powder ). Ammonium sulphate 21% , TSP46%., Urea 46%, DAP 18-46-0, KCL 60%, SOP 52%. Now we have three advanced production lines of NPK fertilizers, productions capacity: 300, 000 tons per year of N. P. K. Fertilizers, 100, 000 tons per year of Ammonium sulphate 21% , 100, 000 tons per year of TSP46%, and 100, 000 tons per year of Urea 46%.