Soil testing and Formula fertilization Technology for Spring Maize

1. The characteristics of fertilizer requirement: during the whole growth period, maize absorbed the most nitrogen, followed by potassium, and less phosphorus. The absorption of nitrogen has absorbed 85% of the total nitrogen before heading and fertilization. 70% of the absorption of phosphorus was absorbed before heading. More than 70% of potassium is absorbed before heading, and the remaining 30% is absorbed during heading and fertilization. therefore, potash fertilizer is generally applied in the early growth stage. It has a good effect to use straw directly as corn base fertilizer. In the soil with low soil fertility, straw should be applied with a small amount of nitrogen fertilizer to adjust the ratio of carbon to nitrogen and accelerate the decomposition of straw. 2. Fertilization technology: under the medium fertility level, the amount of fertilizer applied per mu in the whole growth cycle of spring corn is 1500mu 2000 kg of farm manure (or 250Mel 300kg of commercial organic fertilizer), 17kg of nitrogen fertilizer, 5kg of phosphate fertilizer and 9kg of potash fertilizer. Nitrogen fertilizer and potash fertilizer are divided into base fertilizer and double topdressing, phosphate fertilizer is all used as base fertilizer, chemical fertilizer and farm manure (or commercial organic fertilizer) are mixed. Base fertilizer: 1500 Mu farm manure or 250 MUE 300 kg commercial organic fertilizer, 6 kg urea, 11 kg diammonium phosphate, 5 kg potassium chloride, and 1 mu 2 kg zinc sulfate in zinc deficient soil. It is recommended to apply long-acting fertilizer, and straw is recommended to return to the field to improve soil fertility. Topdressing: small trumpet mouth period topdressing: 15 kg urea per mu, 7 Mel 8 kg potassium chloride. Big trumpet mouth period topdressing: 9kg urea 8m / mu, 4kg potassium chloride 5kg / mu. Extra-root topdressing: if there is no zinc application in the base fertilizer, the seeds can be soaked in zinc fertilizer and treated with 0.05% zinc sulfate solution for 24 hours. Seed dressing is diluted with 3 grams of zinc sulfate and a small amount of water for every 1 kg of seeds, and then mixed well with seeds. Foliar spraying can be sprayed with 0.05% zinc sulfate solution at seedling stage or jointing stage. The seeds were soaked with boron-deficient boron fertilizer and soaked in 0.01murl 0.05% boric acid solution for 24 hours.