Introduction to soil testing and formula fertilization technology
2024-10-07 14:03:16
Soil testing and formula fertilization is an important technology for rational fertilization of crops. It can not only improve crop yield and improve quality, but also reduce environmental pollution and waste of resources caused by unreasonable use of chemical fertilizers. The soil testing formula fertilization technology mainly includes: targeted testing of relevant nutrients in the soil (ie soil testing), according to the abundance of nutrient elements, planned yield, etc., the type and quantity of fertilization (both formula), and finally based on crops Fertilizer characteristics are used to formulate the amount of base fertilizer, seed fertilizer, top dressing, use method and time of top dressing (both fertilization). Now take the soil testing formula of wheat as an example and give a brief introduction.
First, soil testing
Before planting wheat, select representative plots with consistent soil types, uniform fertilization, and soil fertility. Before the harvest of the former crops (usually about 15 days), use the diagonal method or S method to take multiple layers. The soil is mixed with one sample and sent to the laboratory for testing related nutrients. The most commonly tested nutrients are available nitrogen, available phosphorus, and available potassium. The comprehensive analysis of soil fertility can also increase the analysis of organic matter, cation exchange, PH, trace elements and other projects.
Second, the formula
The method of determining the amount of fertilization and fertilization formula mainly adopts the nutrient balance method.
The basic principle of the nutrient balance method is that the nutrient uptake of wheat is equal to the sum of the nutrient supply of soil and fertilizer. Its mathematical expression is:
Wheat nutrient uptake = soil nutrient supply + fertilizer nutrient supply
1. Estimation of nutrient uptake of wheat The nutrient uptake of wheat is mainly determined by the yield level, and the amount of fertilization must be determined before the birth. Therefore, a production must be set before the birth, that is, the target output (also called planned output). Therefore, the nutrient balance method is also called the target yield method. The target yield should be determined based on factors such as local soil fertility, climatic characteristics and cultivation conditions. At present, there are two methods for determining the target yield, namely the yield average method and the regression equation method in previous years.
The average yield per capita method in the past few years: target output = average yield per a few years + average yield per a few years X average yield of previous years in the previous years (average yields in previous years usually used 3 or 5 years).
Regression equation method: Through experiment or investigation, in the formula fertilization area, the highest yield of crops obtained by multiple points and the group of blank yields of the current year correspond to yield, and then statistical analysis is carried out to establish the equation and obtain the target yield.
The nutrient uptake of wheat can be calculated by the following formula:
Wheat nutrient uptake (kg) = target yield (tonnes) × nutrient uptake per ton of economic output (kg) (1)
2. Calculation of soil fertility The soil fertility is calculated by soil sampling test.
The calculation formula is: soil fertilizer supply (kg) = soil nutrient test value (mg / kg soil) × soil nutrient utilization coefficient × 0.15 (2)
3, the calculation of organic fertilizer supply amount of organic fertilizer fertilizer (kg) = organic fertilizer dosage X organic fertilizer a nutrient content X organic fertilizer utilization rate of the season. The content of organic fertilizer varies widely, and the utilization rate of various organic fertilizers is also different in the current season, which brings great inconvenience to the calculation. For the convenience of calculation, the supply of organic fertilizer is generally 1 kg per ton of decomposed farmyard manure, 0.5 kg of phosphorus pentoxide, and 1 kg of potassium oxide.
4. Calculation of wheat fertilization amount Part of the nutrients provided by fertilizer for wheat should be fertilized. However, the amount of wheat fertilized and the supply of fertilizer nutrients are not exactly the same. Since only a part of the nutrients input into the farmland are absorbed and utilized by the season wheat, the fertilizer application amount can be calculated by the following formula in consideration of the fertilizer utilization factor:
A nutrient uptake - soil nutrient supply - organic fertilizer supply a nutrient application (kg) = ———————————————————————(3)
Seasonal utilization rate of a nutrient (%)
In the above formula, the amount of wheat applied refers to the amount of a certain nutrient element applied. Specific to the variety of fertilizers, the amount of chemical fertilizers to be used is calculated by the following formula:
A nutrient application rate of wheat (kg)
The amount of physical fertilizer (kg) =———————————— (4)
Active ingredient content (%)
The nutrient uptake per ton of economic output, the soil nutrient utilization factor, the fertilizer utilization rate, and the active ingredient content of the fertilizer are collectively referred to as fertilization parameters in the above formulas (1)-(4). 0.15 is the soil weight conversion factor. The above parameters are best used in the experimental data of the region, but it is often difficult to do. If not, you can also check the relevant fertilizer manual, but the accuracy is not strong.
For example, a small wheat field is a fluvo-aquic soil, and the soil has an alkaline nitrogen content of 80 mg/kg, an effective phosphorus of 15 mg/kg, and a quick-acting potassium of 90 mg/kg. Planting wheat, the planned output is 500 kg. How many kilograms of nitrogen, phosphorus and potassium fertilizer should be applied under the condition of applying 2 tons of common farmyard manure per mu?
According to the fertilizer manual, it is necessary to absorb 3 kg of nitrogen, 1.25 kg of phosphorus pentoxide and 2.5 kg of potassium oxide per 100 kg of wheat produced. Under normal circumstances, the utilization rate of chemical fertilizers in the current season is: 30% to 35% of nitrogen fertilizer, 20% to 25% of phosphate fertilizer, and 25% to 35% of potassium fertilizer. The soil nutrient utilization factor for the season is 70% for available nitrogen, 70% for available phosphorus, and 35% for available potassium.
The nutrient components produced by the production of 500 kg are:
Nitrogen (N); 5 × 3 = 15 kg
P2O5: 5 × 1.25 = 6.25 kg
Potassium oxide (K2O): 5 × 2.5 = 12.5 kg
The nutrient content of soil supply is: nitrogen (N): 80 × 0.15 × 0.7 = 8.4 kg
P2O5: 15×2.27×0.15×0.7=3.57 kg
Potassium Oxide (K2O): 90 × 1.19 × 0.15 × 0.35 = 5.6 kg
The supply of organic fertilizer is:
Nitrogen (N): 2 × 1 = 2 kg
Phosphorus pentoxide (P2O5): 2 × 0.5 = 1 kg
Potassium Oxide (K2O): 2 × 1 = 2 kg
In the above formula, 2.27 is the coefficient of P converted to P2O5, and 1.19 is the coefficient of K converted to K2O.
The amount of nitrogen, phosphorus and potassium fertilizer is:
15-8.4-2
Nitrogen (N) = —————————— = 13.00 kg 0.35
6.25-3.57-1
Phosphorus pentoxide (P2O5) = ———————— = 6.72 kg 0.25
12.5-5.6-2
Potassium Oxide (K2O) = ———————— = 14.00 kg 0.35
If urea, superphosphate or potassium chloride is used, it requires:
13
Urea = —————— = 28.3 kg 0.46
6.72
Superphosphate = ————— =42 kg 0.16
14
Potassium chloride = ————— = 23.3 kg 0.6
The wheat field requires 28.3 kg of urea, 42 kg of superphosphate, and 23.3 kg of potassium chloride. Or use three-element compound fertilizer 45 kg, urea 14 kg, potassium chloride 12 kg.
Third, fertilization
After determining the amount of fertilizer applied, the fertilizer is fertilized according to the ratio of base fertilizer, seed fertilizer and top dressing. According to the fertilizer characteristics and fertilizer characteristics of wheat, 40%-50% of total nitrogen fertilizer and all phosphorus and potassium fertilizers can be used as base fertilizer, and the remaining nitrogen fertilizer can be applied in the period of wheat jointing. For soil fertility or late glutinous wheat, 10%-15% of the total amount of nitrogen fertilizer (or compound fertilizer) can be used as seed fertilizer.
Author: Gong Qingping Source: Shandong Agricultural Technology Extension Station
First, soil testing
Before planting wheat, select representative plots with consistent soil types, uniform fertilization, and soil fertility. Before the harvest of the former crops (usually about 15 days), use the diagonal method or S method to take multiple layers. The soil is mixed with one sample and sent to the laboratory for testing related nutrients. The most commonly tested nutrients are available nitrogen, available phosphorus, and available potassium. The comprehensive analysis of soil fertility can also increase the analysis of organic matter, cation exchange, PH, trace elements and other projects.
Second, the formula
The method of determining the amount of fertilization and fertilization formula mainly adopts the nutrient balance method.
The basic principle of the nutrient balance method is that the nutrient uptake of wheat is equal to the sum of the nutrient supply of soil and fertilizer. Its mathematical expression is:
Wheat nutrient uptake = soil nutrient supply + fertilizer nutrient supply
1. Estimation of nutrient uptake of wheat The nutrient uptake of wheat is mainly determined by the yield level, and the amount of fertilization must be determined before the birth. Therefore, a production must be set before the birth, that is, the target output (also called planned output). Therefore, the nutrient balance method is also called the target yield method. The target yield should be determined based on factors such as local soil fertility, climatic characteristics and cultivation conditions. At present, there are two methods for determining the target yield, namely the yield average method and the regression equation method in previous years.
The average yield per capita method in the past few years: target output = average yield per a few years + average yield per a few years X average yield of previous years in the previous years (average yields in previous years usually used 3 or 5 years).
Regression equation method: Through experiment or investigation, in the formula fertilization area, the highest yield of crops obtained by multiple points and the group of blank yields of the current year correspond to yield, and then statistical analysis is carried out to establish the equation and obtain the target yield.
The nutrient uptake of wheat can be calculated by the following formula:
Wheat nutrient uptake (kg) = target yield (tonnes) × nutrient uptake per ton of economic output (kg) (1)
2. Calculation of soil fertility The soil fertility is calculated by soil sampling test.
The calculation formula is: soil fertilizer supply (kg) = soil nutrient test value (mg / kg soil) × soil nutrient utilization coefficient × 0.15 (2)
3, the calculation of organic fertilizer supply amount of organic fertilizer fertilizer (kg) = organic fertilizer dosage X organic fertilizer a nutrient content X organic fertilizer utilization rate of the season. The content of organic fertilizer varies widely, and the utilization rate of various organic fertilizers is also different in the current season, which brings great inconvenience to the calculation. For the convenience of calculation, the supply of organic fertilizer is generally 1 kg per ton of decomposed farmyard manure, 0.5 kg of phosphorus pentoxide, and 1 kg of potassium oxide.
4. Calculation of wheat fertilization amount Part of the nutrients provided by fertilizer for wheat should be fertilized. However, the amount of wheat fertilized and the supply of fertilizer nutrients are not exactly the same. Since only a part of the nutrients input into the farmland are absorbed and utilized by the season wheat, the fertilizer application amount can be calculated by the following formula in consideration of the fertilizer utilization factor:
A nutrient uptake - soil nutrient supply - organic fertilizer supply a nutrient application (kg) = ———————————————————————(3)
Seasonal utilization rate of a nutrient (%)
In the above formula, the amount of wheat applied refers to the amount of a certain nutrient element applied. Specific to the variety of fertilizers, the amount of chemical fertilizers to be used is calculated by the following formula:
A nutrient application rate of wheat (kg)
The amount of physical fertilizer (kg) =———————————— (4)
Active ingredient content (%)
The nutrient uptake per ton of economic output, the soil nutrient utilization factor, the fertilizer utilization rate, and the active ingredient content of the fertilizer are collectively referred to as fertilization parameters in the above formulas (1)-(4). 0.15 is the soil weight conversion factor. The above parameters are best used in the experimental data of the region, but it is often difficult to do. If not, you can also check the relevant fertilizer manual, but the accuracy is not strong.
For example, a small wheat field is a fluvo-aquic soil, and the soil has an alkaline nitrogen content of 80 mg/kg, an effective phosphorus of 15 mg/kg, and a quick-acting potassium of 90 mg/kg. Planting wheat, the planned output is 500 kg. How many kilograms of nitrogen, phosphorus and potassium fertilizer should be applied under the condition of applying 2 tons of common farmyard manure per mu?
According to the fertilizer manual, it is necessary to absorb 3 kg of nitrogen, 1.25 kg of phosphorus pentoxide and 2.5 kg of potassium oxide per 100 kg of wheat produced. Under normal circumstances, the utilization rate of chemical fertilizers in the current season is: 30% to 35% of nitrogen fertilizer, 20% to 25% of phosphate fertilizer, and 25% to 35% of potassium fertilizer. The soil nutrient utilization factor for the season is 70% for available nitrogen, 70% for available phosphorus, and 35% for available potassium.
The nutrient components produced by the production of 500 kg are:
Nitrogen (N); 5 × 3 = 15 kg
P2O5: 5 × 1.25 = 6.25 kg
Potassium oxide (K2O): 5 × 2.5 = 12.5 kg
The nutrient content of soil supply is: nitrogen (N): 80 × 0.15 × 0.7 = 8.4 kg
P2O5: 15×2.27×0.15×0.7=3.57 kg
Potassium Oxide (K2O): 90 × 1.19 × 0.15 × 0.35 = 5.6 kg
The supply of organic fertilizer is:
Nitrogen (N): 2 × 1 = 2 kg
Phosphorus pentoxide (P2O5): 2 × 0.5 = 1 kg
Potassium Oxide (K2O): 2 × 1 = 2 kg
In the above formula, 2.27 is the coefficient of P converted to P2O5, and 1.19 is the coefficient of K converted to K2O.
The amount of nitrogen, phosphorus and potassium fertilizer is:
15-8.4-2
Nitrogen (N) = —————————— = 13.00 kg 0.35
6.25-3.57-1
Phosphorus pentoxide (P2O5) = ———————— = 6.72 kg 0.25
12.5-5.6-2
Potassium Oxide (K2O) = ———————— = 14.00 kg 0.35
If urea, superphosphate or potassium chloride is used, it requires:
13
Urea = —————— = 28.3 kg 0.46
6.72
Superphosphate = ————— =42 kg 0.16
14
Potassium chloride = ————— = 23.3 kg 0.6
The wheat field requires 28.3 kg of urea, 42 kg of superphosphate, and 23.3 kg of potassium chloride. Or use three-element compound fertilizer 45 kg, urea 14 kg, potassium chloride 12 kg.
Third, fertilization
After determining the amount of fertilizer applied, the fertilizer is fertilized according to the ratio of base fertilizer, seed fertilizer and top dressing. According to the fertilizer characteristics and fertilizer characteristics of wheat, 40%-50% of total nitrogen fertilizer and all phosphorus and potassium fertilizers can be used as base fertilizer, and the remaining nitrogen fertilizer can be applied in the period of wheat jointing. For soil fertility or late glutinous wheat, 10%-15% of the total amount of nitrogen fertilizer (or compound fertilizer) can be used as seed fertilizer.
Author: Gong Qingping Source: Shandong Agricultural Technology Extension Station
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