Compound chemical fertilizers are chemical fertilizers that contain two or more of the nutrients such as nitrogen, phosphorus and potassium.
A. Binary compound fertilizer
(1) nitrogen and phosphorus compound fertilizer ammonium phosphate: non-hygroscopic caking, easily soluble in thousands of water, aqueous solution pH 7.0 to 7.2. It is a chemically neutral fertilizer. Among them, nitrogen and phosphorus are fast-acting easy to be absorbed and used by plants.
(2) Application method: It is especially suitable for phosphorus-deficient soil and plants requiring more phosphorus. The amount of base fertilizer is generally about 7.5 kg per mu, and the amount of seed fertilizer is generally 2.5 to 3 kg per mu. Do not make direct contact with seeds when making seed fertilizer, so as not to inhibit seed germination.
(3) nitrogen and potassium compound fertilizer nitrogen and potassium fertilizer: its main component is K2SO4, (NH4)2SO4, containing 14% N, K20 in 11% to 16%. It is white crystalline, easily soluble in water and has low hygroscopicity.
(4) Application method: NPK compound fertilizer is especially suitable for potassium-loving plants. In the lack of nitrogen and potassium soil fertilization effect is more significant, in the lack of phosphorus soil application should be used with a single phosphorus fertilizer.
(5) phosphorus and potassium compound fertilizer potassium phosphate is a kind of high concentration phosphorus and potassium compound fertilizer that can be directly absorbed and used by crops, suitable for any soil and crops.
(6) Application method: Potassium dihydrogen phosphate can be used as base fertilizer, fertilizer and seed fertilizer. But at present, it is only used for seed dipping, seed dressing and extra-root fertilization.
① Use 0.5 kg of potassium dihydrogen phosphate to 200 to 300 kg of water to soak the seeds for about 15 hours, take out and dry then sow the seeds.
②Apply 125 to 300 g of potassium dihydrogen phosphate with 1.5 kg of water. Dissolve and mix with the seeds, then smother the seeds for 2 to 3 hours, dry and sow the seeds.
③Appropriate concentration of 0.1%-0.3% for extra-root fertilization. It is appropriate to spray 50-75 kg per mu, and the spraying period is before and after the flowering period.
④Sugae, southern fir, five-needle pine, cedar, etc. Spray 1-2 times at 5-7 days interval during the growing period.
B. Ternary compound fertilizer nitrogen, phosphorus, potassium compound fertilizer, is a chemical fertilizer containing three nutrients: nitrogen, phosphorus and potassium.
Generally used as base fertilizer and chasing fertilizer. For base fertilizer, apply 5-7.5 kg per mu, and it is better for fruit trees and other crops as chasing fertilizer.
C. How to apply compound fertilizer
1, is less application diligent application
The nitrate and ammonium nitrogen in compound fertilizers absorb some heat during the dissolution process. It may affect the ground temperature and be detrimental to the growth of crop roots.
2, with pure biological fertilizer (without nitrogen, phosphorus, potassium) application
Pure biological fertilizer contains many kinds of beneficial bacteria,.which can activate and improve the soil. These biological bacteria can promote the absorption and utilization of nitrogen. phosphorus and potassium in compound fertilizer.
3, is to be applied in a targeted manner
Like leafy vegetables, because of its fast growth. Need high nitrogen, phosphorus needs less, we should use a compound fertilizer containing high nitrogen, phosphorus less to use. Can choose a compound fertilizer with high potassium and low phosphorus.