number of times needed to fertilize corn from planting

Maize growth requires the absorption of a variety of mineral nutrients from the soil, with nitrogen being the most abundant, followed by potassium and phosphorus in third place. Generally, for every 100 kg of kernels produced, 2.5 kg of pure nitrogen, 1.2 kg of phosphorus pentoxide and 2.0 kg of potassium oxide are absorbed from the soil. The ratio of nitrogen, phosphorus and potassium is: 1:0.48:0.8. Fertiliser application = (planned production of a factor needs - soil supply of a factor) / (fertiliser content of a factor (%) × fertiliser seasonal utilisation rate (%)) The utilisation rate of fertiliser varies greatly, according to the test, the general organic farm fertiliser seasonal utilisation rate is about 30%, nitrogen fertiliser seasonal utilisation rate is about 40% to 50% (to 40% (in terms of 40%), phosphorus, potassium fertilizer is about 30% to 40% (in terms of 30%).

For example, how much fertiliser is needed to produce 1000kg of maize seeds per acre?

Assume that the soil contains 17 kg of nitrogen, 6 kg of phosphorus pentoxide and 14.4 kg of potassium oxide per acre at the time of the soil survey. The nutrient utilisation rate in the soil is 50% for nitrogen, 70% for phosphorus pentoxide and 30% for potassium oxide. When the national fertiliser trials averaged 1000 kg per mu, the amount of urea, calcium superphosphate and potassium chloride applied was calculated for each 100 kg of seed produced at 2.9 kg of nitrogen, 1.2 kg of phosphorus and 2.4 kg of potassium required (urea contains 46% effective nitrogen, calcium superphosphate 16% effective phosphorus and potassium chloride 50% effective potassium).

According to the above formula.

Nitrogen fertilizer (urea) required (kg/mu) = (500/100 × 2.9 - 17 × 50%) / (46% × 40%) = 32.16 (kg/mu) formula in 500/100 × 2.9 for the production of 1,000 pounds of corn seed nitrogen requirements, 17 × 50% for the amount of nitrogen supplied to the soil per acre, 46% for the amount of nitrogen contained in urea, 40% for the utilization rate of urea in the season.

If the base fertilizer mu applied 2000 kg of stable fertilizer, stable fertilizer containing 0.45% nitrogen, the seasonal utilization rate of 30%, it is equivalent to 2.7 kg of nitrogen (2000 × 0.45% × 30%), equivalent to 5.87 kg of urea. The actual amount of urea used per mu is 32.16-5.87 = 26.29 (kg). The amount of phosphate and potash fertilizer can also be calculated according to the above method.

Production practice proves that, in general, the amount of fertiliser applied with this method can reach the planned yield target and also continuously improve soil fertility, which is a relatively simple method.