How fertilizer is distributed in the soil

After the fertilizer is applied to the soil, only a small part of its nutrients are absorbed and utilized by crops, about 1% of the amount of fertilizer applied, and most of the other nutrients are lost in different forms. Take the nitrogen, phosphorus and potassium fertilizers we usually apply as an example, after they are applied to the soil, the fate of the nutrients can be divided into the following four types: ① is used by crops; ② is leached by water; ③ is gaseous volatilized; ④ remains in the soil. The numbers of the above four destinations vary greatly in different soils. Take ammonium sulfate as an example, spread on the surface of cultivated land, on calcareous soil (alkaline) and non-calcareous (acidic) soil, the nitrogen nutrients absorbed and utilized by crops were 22.5% and 50% of the amount used, respectively; the residues in the soil were 26.3% and 21.4%, respectively. It can be seen that the loss of nitrogen in alkaline soil is greater than that in acidic soil. Among the nitrogen fertilizers, ammonium sulfate has the best stability. If it is replaced with urea and ammonium bicarbonate, the loss will be more, and their utilization rate is less than 30% of the application amount. Most of the nitrogen loss is gaseous volatilization and part of it is leached. When phosphorus fertilizer is applied into the soil, most of the phosphorus nutrients remain in the soil, accounting for 80% of the total application amount. The phosphorus remaining in the soil can be used by the next crop, and phosphorus nutrients are rarely lost by water and gaseous volatilization. When potassium fertilizer is applied to the soil, the crop utilization rate of potassium nutrients is relatively high among the three nutrients, generally about 50%.