First, the characteristics of corn fertilizer
1. The demand characteristics of corn for nutrients in different growth stages
Corn needs a different nutrient ratio for each growth period. From emergence to jointing, maize absorbs 2.5% nitrogen, 1.12% effective phosphorus, and 3% effective potassium. From jointing to flowering, it absorbs 51.15% of nitrogen, 63.81% of available phosphorus, and 97% of effective potassium. From flowering to maturity, it absorbs nitrogen 46.35. %, effective phosphorus 35.07%, effective potassium 0%.
The critical period of corn nutrition: the critical period of corn phosphorus nutrition is in the three-leaf stage, generally the seed nutrition turns to the soil nutrition period; the corn nitrogen critical period is later than phosphorus, usually in the period of vegetative growth to reproductive growth. The critical period has little demand for nutrients, but the nutrients should be comprehensive and the proportion should be appropriate. During this period, too many nutrients are too little or unbalanced, which will have obvious adverse effects on the growth and development of corn, and no matter how to supplement the lack of nutrients in the future, it will not help.
Maximum efficiency of corn nutrition: The maximum efficiency of corn is in the big bell stage. This is the fastest and fastest period of corn nutrient absorption. During this period, the absolute and relative amount of nutrients needed by corn were the largest, and the absorption rate was the fastest. The effect of fertilizer was the biggest. At this time, the fertilizer application rate was appropriate, and the corn yield increase effect was the most obvious.
2. The demand for nutrients throughout the growing period of corn
Corn growth needs to absorb a variety of mineral nutrients from the soil, of which nitrogen is the most, followed by potassium, and phosphorus ranks third. Generally, for every 100 kg of grain 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 NPK is 1:0.48:0.8.
Second, the amount of corn fertilizer
1. Determine the target output The target output is the amount of corn to be planted in the current year. It is determined by the soil fertility of the cultivated land. In addition, it is also possible to increase the average yield of corn in the first three years of the plot by 10%-15% as the target yield of corn. For example, a plot of land is a higher fertility soil. The planned corn yield reached 600 kg in that year. The nitrogen, phosphorus and potassium nutrients required for the whole growth period of maize were 15 kg, 7.2 kg and 12 kg, respectively.
2. Calculate the amount of nutrient supply in the soil Determine how much quick-acting nutrients are contained in the soil, and then calculate how much nutrients are contained in the 1 mu of land. 1 mu of topsoil is calculated as 20 cm, with a total of 150,000 kg of soil. If the measured value of soil alkaline nitrogen is 120 mg/kg, the effective phosphorus content is 40 mg/kg, and the available potassium content is 90 mg/kg. The total amount of available alkaline nitrogen in the soil of 1 mu of land is: 150,000 kg × 120 mg / kg × 10 minus 6 power = 18 kg, the total available phosphorus is 6 kg, and the total amount of available potassium is 13.5 kg. Because soil various factors affect the effectiveness of soil nutrients, all available nutrients in the soil cannot be fully absorbed by corn, and a soil nutrient correction factor needs to be multiplied. The research on formula fertilization parameters in different provinces in China shows that the correction coefficient of alkali nitrogen is between 0.3 and 0.7, the effective phosphorus correction coefficient (Olsen method) is between 0.4 and 0.5, and the correction coefficient of available potassium is between 0.5 and 0.85. The utilization rate of NPK fertilizer is: 30%-35% nitrogen, 10%-20% phosphorus, 40%-50% potassium.
3. Determine the amount of corn fertilization With the nutrient content and soil nutrient supply and fertilizer utilization rate required for the whole growth period of corn, the amount of corn fertilization can be directly calculated. Converting the pure nutrient component into the amount of fertilizer can be used to guide fertilization. According to the data in 1, 2, the yield of 600 kg of corn per mu is (15-18×0.6) ÷0.30=14 kg. The amount of phosphate fertilizer is (7.2-6×0.5)÷0.2=21 kg. Considering the obvious effect of phosphate fertilizer, the phosphate fertilizer can be halved, that is, 10 kg. The amount of potassium fertilizer is (12-13.5×0.6)÷0.50=8 kg. If diammonium phosphate, urea and potassium chloride are applied, 20 kg to 22 kg of diammonium phosphate, 22 kg to 25 kg of urea and 14 kg of potassium chloride should be applied per mu.
4. Application of micro-fertilizer Corn is very sensitive to zinc. If the effective zinc in the soil is less than 0.5 mg/kg-1.0 mg/kg, zinc fertilizer is needed. The availability of zinc in soil is higher than alkaline conditions under acidic conditions, so alkaline and calcareous soils are now prone to zinc deficiency. In areas where long-term application of phosphate fertilizer, due to the antagonistic effect of phosphorus and zinc, it is easy to induce zinc deficiency, which should be supplemented. The commonly used zinc fertilizers are zinc sulfate and zinc chloride. The amount of base applied is 0.5 kg to 2.5 kg, and the seed dressing is 4 g/kg to 5 g/kg. The soaking concentration is 0.02%-0.05%. If the compound fertilizer contains a certain amount of zinc, it is not necessary to apply zinc fertilizer alone.
Third, corn fertilization method
1. Base fertilizer 2000 kg - 3000 kg of organic fertilizer, all phosphate fertilizer, one-third of nitrogen fertilizer, all potassium fertilizer as base fertilizer or seed fertilizer. It can be applied to the seeding ditch once in combination with the plough and the fertilizer is applied to the 10 cm - 15 cm plough layer. All fertilizers can be used as base fertilizer.
2. Fertilizers Fertilizers are the most cost-effective method of fertilization. There are many methods for applying fertilizers, such as seed dressing, soaking seeds, strips, and acupoints. Seed dressing can be humic acid, biological fertilizer and micro-fertilizer. Dissolve the fertilizer, spray it on the corn seed, and mix it while spraying, so that the fertilizer solution is evenly applied to the surface of the seed, and dried after sowing. Soaking seeds: Dissolve the fertilizer into a certain concentration, soak the seeds in the solution for 12 hours, and then sown immediately after drying. Strip application, acupoint application: Fertilizer is suitable for strip application, point application, and the amount of fertilizer used for fertilizer is 2 kg - 5 kg. However, the fertilizer must be separated from the seed; deep fertilization is better, and the depth is preferably 10 cm - 15 cm. Urea, ammonium bicarbonate, ammonium chloride, potassium chloride should not be used as seed fertilizer.
3. Topdressing The remaining two-thirds of the nitrogen fertilizer is used for topdressing. Topdressing, seedling fertilizer, stalk fertilizer, panicle fertilizer and grain fertilizer are the four topdressing periods, and the following two periods are the focus:
Stalk fertilizer: Topdressing within 10 days after jointing, it promotes stem growth and promotes differentiation of young ears. One-third of the nitrogen fertilizer in topdressing is used as jointing fertilizer, combined with shovel, the distance between fertilizer and seedling is 5 cm - 7 cm.
Spike fertilizer: The remaining nitrogen fertilizer is applied in the big bell mouth period 10 days to 15 days before the corn is sucked, which can promote the large grains of the ear and also have good effects on grain filling in the later stage.
From: Peasant Digest (Jin Yan Li Jinfeng)
1. The demand characteristics of corn for nutrients in different growth stages
Corn needs a different nutrient ratio for each growth period. From emergence to jointing, maize absorbs 2.5% nitrogen, 1.12% effective phosphorus, and 3% effective potassium. From jointing to flowering, it absorbs 51.15% of nitrogen, 63.81% of available phosphorus, and 97% of effective potassium. From flowering to maturity, it absorbs nitrogen 46.35. %, effective phosphorus 35.07%, effective potassium 0%.
The critical period of corn nutrition: the critical period of corn phosphorus nutrition is in the three-leaf stage, generally the seed nutrition turns to the soil nutrition period; the corn nitrogen critical period is later than phosphorus, usually in the period of vegetative growth to reproductive growth. The critical period has little demand for nutrients, but the nutrients should be comprehensive and the proportion should be appropriate. During this period, too many nutrients are too little or unbalanced, which will have obvious adverse effects on the growth and development of corn, and no matter how to supplement the lack of nutrients in the future, it will not help.
Maximum efficiency of corn nutrition: The maximum efficiency of corn is in the big bell stage. This is the fastest and fastest period of corn nutrient absorption. During this period, the absolute and relative amount of nutrients needed by corn were the largest, and the absorption rate was the fastest. The effect of fertilizer was the biggest. At this time, the fertilizer application rate was appropriate, and the corn yield increase effect was the most obvious.
2. The demand for nutrients throughout the growing period of corn
Corn growth needs to absorb a variety of mineral nutrients from the soil, of which nitrogen is the most, followed by potassium, and phosphorus ranks third. Generally, for every 100 kg of grain 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 NPK is 1:0.48:0.8.
Second, the amount of corn fertilizer
1. Determine the target output The target output is the amount of corn to be planted in the current year. It is determined by the soil fertility of the cultivated land. In addition, it is also possible to increase the average yield of corn in the first three years of the plot by 10%-15% as the target yield of corn. For example, a plot of land is a higher fertility soil. The planned corn yield reached 600 kg in that year. The nitrogen, phosphorus and potassium nutrients required for the whole growth period of maize were 15 kg, 7.2 kg and 12 kg, respectively.
2. Calculate the amount of nutrient supply in the soil Determine how much quick-acting nutrients are contained in the soil, and then calculate how much nutrients are contained in the 1 mu of land. 1 mu of topsoil is calculated as 20 cm, with a total of 150,000 kg of soil. If the measured value of soil alkaline nitrogen is 120 mg/kg, the effective phosphorus content is 40 mg/kg, and the available potassium content is 90 mg/kg. The total amount of available alkaline nitrogen in the soil of 1 mu of land is: 150,000 kg × 120 mg / kg × 10 minus 6 power = 18 kg, the total available phosphorus is 6 kg, and the total amount of available potassium is 13.5 kg. Because soil various factors affect the effectiveness of soil nutrients, all available nutrients in the soil cannot be fully absorbed by corn, and a soil nutrient correction factor needs to be multiplied. The research on formula fertilization parameters in different provinces in China shows that the correction coefficient of alkali nitrogen is between 0.3 and 0.7, the effective phosphorus correction coefficient (Olsen method) is between 0.4 and 0.5, and the correction coefficient of available potassium is between 0.5 and 0.85. The utilization rate of NPK fertilizer is: 30%-35% nitrogen, 10%-20% phosphorus, 40%-50% potassium.
3. Determine the amount of corn fertilization With the nutrient content and soil nutrient supply and fertilizer utilization rate required for the whole growth period of corn, the amount of corn fertilization can be directly calculated. Converting the pure nutrient component into the amount of fertilizer can be used to guide fertilization. According to the data in 1, 2, the yield of 600 kg of corn per mu is (15-18×0.6) ÷0.30=14 kg. The amount of phosphate fertilizer is (7.2-6×0.5)÷0.2=21 kg. Considering the obvious effect of phosphate fertilizer, the phosphate fertilizer can be halved, that is, 10 kg. The amount of potassium fertilizer is (12-13.5×0.6)÷0.50=8 kg. If diammonium phosphate, urea and potassium chloride are applied, 20 kg to 22 kg of diammonium phosphate, 22 kg to 25 kg of urea and 14 kg of potassium chloride should be applied per mu.
4. Application of micro-fertilizer Corn is very sensitive to zinc. If the effective zinc in the soil is less than 0.5 mg/kg-1.0 mg/kg, zinc fertilizer is needed. The availability of zinc in soil is higher than alkaline conditions under acidic conditions, so alkaline and calcareous soils are now prone to zinc deficiency. In areas where long-term application of phosphate fertilizer, due to the antagonistic effect of phosphorus and zinc, it is easy to induce zinc deficiency, which should be supplemented. The commonly used zinc fertilizers are zinc sulfate and zinc chloride. The amount of base applied is 0.5 kg to 2.5 kg, and the seed dressing is 4 g/kg to 5 g/kg. The soaking concentration is 0.02%-0.05%. If the compound fertilizer contains a certain amount of zinc, it is not necessary to apply zinc fertilizer alone.
Third, corn fertilization method
1. Base fertilizer 2000 kg - 3000 kg of organic fertilizer, all phosphate fertilizer, one-third of nitrogen fertilizer, all potassium fertilizer as base fertilizer or seed fertilizer. It can be applied to the seeding ditch once in combination with the plough and the fertilizer is applied to the 10 cm - 15 cm plough layer. All fertilizers can be used as base fertilizer.
2. Fertilizers Fertilizers are the most cost-effective method of fertilization. There are many methods for applying fertilizers, such as seed dressing, soaking seeds, strips, and acupoints. Seed dressing can be humic acid, biological fertilizer and micro-fertilizer. Dissolve the fertilizer, spray it on the corn seed, and mix it while spraying, so that the fertilizer solution is evenly applied to the surface of the seed, and dried after sowing. Soaking seeds: Dissolve the fertilizer into a certain concentration, soak the seeds in the solution for 12 hours, and then sown immediately after drying. Strip application, acupoint application: Fertilizer is suitable for strip application, point application, and the amount of fertilizer used for fertilizer is 2 kg - 5 kg. However, the fertilizer must be separated from the seed; deep fertilization is better, and the depth is preferably 10 cm - 15 cm. Urea, ammonium bicarbonate, ammonium chloride, potassium chloride should not be used as seed fertilizer.
3. Topdressing The remaining two-thirds of the nitrogen fertilizer is used for topdressing. Topdressing, seedling fertilizer, stalk fertilizer, panicle fertilizer and grain fertilizer are the four topdressing periods, and the following two periods are the focus:
Stalk fertilizer: Topdressing within 10 days after jointing, it promotes stem growth and promotes differentiation of young ears. One-third of the nitrogen fertilizer in topdressing is used as jointing fertilizer, combined with shovel, the distance between fertilizer and seedling is 5 cm - 7 cm.
Spike fertilizer: The remaining nitrogen fertilizer is applied in the big bell mouth period 10 days to 15 days before the corn is sucked, which can promote the large grains of the ear and also have good effects on grain filling in the later stage.
From: Peasant Digest (Jin Yan Li Jinfeng)
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