How to calculate the amount of fertilizer application? A formula helps you calculate quickly

In the past, farmers often relied on experience to fertilize or controlled the amount of fertilizer input per acre within their acceptable cost limits. From the perspective of reducing fertilizer input and improving fertilizer utilization efficiency, scientifically calculating the amount of fertilizer applied can truly save planting costs for farmers. The determination of fertilizer application can be divided into nutrient balance method and field experiment method. Here, we first introduce the basic calculation principle of nutrient balance method.

Nutrient balance method

The basic concept of nutrient balance method is that the nutrient absorption of crops is equal to the sum of the nutrient supply of soil and fertilizer. Fertilizer provides some nutrients for crops through fertilization. However, the amount of fertilizer applied to crops is not exactly the same as the supply of fertilizer nutrients, as only a portion of the nutrients invested in farmland are absorbed and utilized by current season crops.

Considering the factor of fertilizer utilization rate, the amount of fertilizer can be calculated by the following formula:

Planned crop fertilization amount (kg)=(total nutrient required for planned yield - soil nutrient supply)/[fertilizer nutrient content x fertilizer utilization rate (%)]

(The amount of fertilizer applied to crops here refers to the amount of a certain nutrient element applied.)

Regarding the specific types of fertilizers, the actual amount of fertilizer used should be calculated using the following formula:

Planned crop fertilizer application amount (kg)=actual fertilizer application amount (kg) x effective ingredient content (%)

In the above two formulas:

1. The total amount of nutrients required for planned yield (kg)=(planned yield/100) x the amount of nutrients required to form a yield of 100kg (refer to the approximate amount of nutrients required for different crops to form an economic yield of 100kg).

The planned output is an additional 10% -15% increase in the average product yield of local crops over three years.

2. Soil nutrient supply (kg)=(yield in fertilizer free area/100) x the amount of nutrients required to form a yield of 100kg

The amount of soil fertilizer supply is generally estimated through soil sampling and testing. In the absence of laboratory conditions, estimation can also be made based on the yield without fertilization (blank yield).

In general, the seasonal utilization rate of fertilizers is 30% -35% for nitrogen fertilizers, 20% -25% for phosphorus fertilizers, and 25% -35% for potassium fertilizers.