(I) Principles of application of compound fertilizers Compound fertilizers have the advantages of high nutrient content, less auxiliary components, storage and transportation, and improved physical and chemical properties of fertilizers. However, there are also disadvantages such as fixed nutrient ratio and difficulty in meeting the requirements of fertilization techniques. . Therefore, the application of compound fertilizer requires grasping the pertinence, and if it is not used properly, it will not play its due role. Scientific application of compound fertilizers should consider the following aspects.
1. Choose the right variety.
The application of compound fertilizer should be based on the physical and chemical properties of the soil and the nutritional characteristics of the crop. If the compound fertilizer is applied, and the characteristics of the variety are not compatible with the soil conditions and the nutritional habits of the crop, the lighter may cause a certain amount of nutrient waste, and in the case may result in a reduction in production. Factors that should be considered in the scientific selection of compound fertilizers include:
(1) Soil characteristics and nutrient formation of compound fertilizers.
The nitrogen in the compound fertilizer includes ammonium nitrogen and nitrate nitrogen. Their properties are obviously different: ammonium nitrogen is easily adsorbed by soil and has less loss, and is suitable for both dry land and paddy fields; and nitrate nitrogen is in paddy field. Easy to leaching, or lost due to denitrification, suitable for use in drylands.
The available phosphorus in the compound fertilizer has two kinds of water solubility and hydrazine solubility. Water-soluble phosphorus has a fast fertilizer effect and is suitable for application on various soils, while strontium-soluble phosphorus is suitable for application on neutral and acidic soils, and is less effective in phosphorus-deficient calcareous soil.
The potassium in the compound fertilizer has two kinds of potassium sulfate and potassium chloride. Although the two fertilizers have the same effect, for some chlorine-repellent crops such as tobacco, the application of the compound fertilizer containing potassium chloride has the adverse effect of lowering the quality.
According to the test results of various places, the fertilizers of ammonium phosphate and ammonium biphosphate, urea heavy calcium, urea and calcium are more stable, suitable for all kinds of soils and various crops in our province; nitrophosphate and nitrophosphate Compound fertilizers should not be applied on paddy fields and rainy slopes, but can be applied on dry soil. For calcareous soils with severe phosphorus deficiency, the water solubility rate of phosphorus pentoxide in nitrophosphate should be greater than 50%; complexes containing calcium and magnesium phosphates Mixed fertilizers such as urea, calcium, magnesium and phosphorus should be applied to acidic or neutral soils in the south. Chlorine-containing compound fertilizers should not be applied to chlorine-sensitive crops such as tobacco and potato; double-chlorine fertilizers, such as NPK ternary compound fertilizer, have the same or slightly higher fertilizer efficiency than many urea-phosphorus systems. Mixed fertilizers are not suitable for irrigated land and saline-alkali soil areas because they contain more chlorine. They should also be used in limited quantities for irrigated land in arid and semi-arid areas.
(2) Fertilization characteristics of crops The nutritional characteristics of different crops are different. It is necessary to select suitable compound fertilizer varieties according to the type of crops, which is of great significance for improving crop yield and improving quality. In general, the application of grain crops should focus on increasing production. For legume crops, phosphorus-potassium compound fertilizer is the main choice. The application of potash can not only increase the yield of cash crops, but more importantly improve the quality of the products. For example, potassium application of tobacco can increase the thickness of leaves and improve the flammability and aroma of tobacco; potassium application by fruit trees and watermelon can increase sweetness and reduce acidity; potassium application of sugar cane and sugar beet can increase sugar content and increase sugar yield. Therefore, NPK ternary compound fertilizer should be used for cash crops. For oil crops in cash crops, due to the large amount of phosphorus required, low-nitrogen and high-phosphorus binary or low-nitrogen, high-phosphorus and low-potassium ternary compound fertilizers can be selected.
(3) Rotation mode Due to the different rotation system, the varieties of compound fertilizers applied to the crops in the crop rotation cycle are also different. For example, in the wheat-maize rotation system, the wheat seedling stage is in the low-temperature growth stage and is particularly sensitive to phosphorus deficiency. High-phosphorus compound fertilizer varieties should be used. In the summer maize production period, the phosphorus released from the soil is relatively high. More, and can also take advantage of the application of phosphate fertilizer in the wheat, so the choice of low-phosphorus compound fertilizer. In the rice-rice rotation system, the fertilizer effect of phosphate fertilizer on the same phosphorus-deficient soil is better than that of late rice, while the fertilizer efficiency of potassium fertilizer is better than that of early rice in late rice. Therefore, early rice should be applied with high-phosphorus compound fertilizer, and late rice can be used. Use high potassium compound fertilizer varieties.
2. Compound fertilizer is used together with elemental fertilizer.
The composition of the compound fertilizer is fixed, so it is not only difficult to meet the nutrient requirements of different soils, different crops or even the same crop at different growth stages, and it is difficult to meet the different requirements of different nutrients in fertilization techniques. At the same time of applying the compound fertilizer, the elemental fertilizer should be applied according to the nutrient content of the compound fertilizer and the nutrient conditions of the local soil and the nutrient habits of the crop to ensure the supply of nutrients.
The determination of the amount of fertilizer applied can be calculated according to the composition of the compound fertilizer, the nutrient content and the nutrient requirements of the crop. For example, 14 kg of pure nitrogen, 7 kg of phosphorus pentoxide and 10 kg of potassium oxide should be applied per mu, and the application ratio is 1:0.5:0.7. If the compound fertilizer is selected, it contains 14% nitrogen and phosphorus pentoxide. %, potassium oxide 20% ternary compound fertilizer, 50 kg fertilizer can meet the needs of potassium fertilizer, and nitrogen and phosphate fertilizers are not satisfied. Therefore, it is necessary to apply 7 kg of pure nitrogen and 2.5 kg of phosphorus pentoxide to achieve the fertilization standard, which is solved by applying elemental fertilizer.
3. Different application methods are adopted according to the variety characteristics of the compound fertilizer.
The compound fertilizers produced at home and abroad are generally divided into two categories: binary compound fertilizer and ternary compound fertilizer. Each type of fertilizer can be divided into many compound fertilizer varieties according to its production method, composition and nutrient content.
(1) Binary compound fertilizer.
The binary compound fertilizer includes ammonium phosphate, phosphorus nitrate fertilizer, ammonium thiophosphate, ammonium nitrate phosphate, ammonium urea phosphate, potassium nitrate, potassium dihydrogen phosphate and the like. A brief description of the following.
a, ammonium phosphate.
Ammonium phosphate, abbreviated as ammonium phosphate, is formed by neutralizing concentrated phosphoric acid with ammonia and is a mixture of monoammonium phosphate and diammonium phosphate. The amount of the two products differs depending on the degree of nitriding during the manufacturing process. Monoammonium phosphate is relatively stable and has an acidic reaction with a pH of 4.4. The stability of diammonium phosphate is slightly poor, and it has an alkaline reaction. The pH value is 8.0. Under high temperature and high humidity conditions, ammonia is often volatilized.
Pure ammonium phosphate is grayish white, and because of the impurities often contained in the manufacturing process, the ammonium phosphate fertilizer is mostly dark gray. Ammonium phosphate has a certain hygroscopicity, so it is usually added into a moisture-proofing agent to form a granule. Ammonium phosphate contains 18% nitrogen and 46% phosphorus pentoxide. The nitrogen and phosphorus nutrients are quick-acting and easy to be absorbed by crops. Granular ammonium phosphate is most suitable as a seed fertilizer and base fertilizer. If it is used as a seed fertilizer, it should not be in direct contact with the seed, so as to avoid adverse effects of high concentration of fertilizer on seed germination. The amount of fertilizer applied should be calculated according to the amount of phosphorus pentoxide in the fertilizer. The insufficient amount of nitrogen can be supplemented with elemental nitrogen fertilizer.
b, potassium nitrate.
Potassium nitrate is formed by dissolving sodium nitrate together with potassium chloride and recrystallizing it. China's potassium nitrate is white crystal, containing 12%-15% nitrogen, 45%-46% potassium oxide, soluble in water, low hygroscopicity, good physical properties, suitable for the topdressing and base fertilizer of the potassium-tolerant chlorine crop. Potatoes, tobacco, and beets all have good fertilizer effects. In addition, potassium nitrate can also be effectively used as a top dressing. The suitable concentration is 0.6%-1%. The nitrogen in potassium sulfate is nitrate, so it is generally not suitable for rice fields.
c. Potassium dihydrogen phosphate potassium dihydrogen phosphate is formed by adding potassium hydroxide to potassium chloride or potassium chloride to form potassium hydroxide, and then acidifying with phosphoric acid. The pure potassium dihydrogen phosphate is white crystal, and the potassium dihydrogen phosphate used as a fertilizer contains 50% phosphorus pentoxide and 30% potassium oxide. Because the price of potassium dihydrogen phosphate is relatively expensive, it is most suitable for topdressing or soaking. The suitable concentration for soaking seeds is 0.2%; the suitable concentration for root-seeking is 0.1-0.3%.
(2) ternary compound fertilizer.
Most of the ternary compound fertilizer is a mixed compound fertilizer. In our province, the soil and climatic conditions vary widely, and there are many varieties of crops. The requirements for the ratio of NPK to ternary compound fertilizer are also different. Therefore, all regions should produce various proportions of ternary complex according to different needs. Mixed fertilizer.
(II) Application method of compound fertilizer The compound fertilizer has phosphorus or phosphorus and potassium components, and most of them are granular, which is slower than the powder unit fertilizer. Therefore, it is generally used as base fertilizer, and can also be used as seed fertilizer and top dressing.
1, base fertilizer.
Also known as the base fertilizer, it is the fertilizer applied during land preparation and tillage. The application of compound fertilizer can meet the demand of various nutrients in the seedling stage and is beneficial to strong seedlings, so sufficient base fertilizer is the basis for obtaining high yield of crops. The amount of base fertilizer is closely related to crop types and soil properties.
(1) The base fertilizer of food crops.
Wheat, mid-season and other crops have a longer growth period, about 150 days, and the base fertilizer accounts for more than half of the total fertilizer use. Double-season rice, late rice and early-maturing crops in arid areas have short growth periods, and early growth of strong seedlings is the key to increasing yield. These crops should pay attention to base fertilizer. The determination of the amount of base fertilizer should take into account the nutritional characteristics of the crop at different growth stages. Taking phosphorus as an example, phosphorus is easy to fix in the soil, and the mobility is small. The growth of the crop should avoid the phosphorus deficiency in the later stage, and keep the “wanting and not decayingâ€, and must meet the demand of phosphorus. Some crops are also very sensitive to the reaction of phosphorus in the late growth stage. For example, when soybeans are in the flowering and pod-forming stage, sweet potato needs more phosphorus supply during the period of root enlargement. If the early phosphorus is sufficient, it can promote the storage of more phosphorus in the plant to transfer to the part of phosphorus deficiency in the later stage. Therefore, most of the phosphorus should be applied as a base fertilizer. In the annual crop with medium phosphorus content, all phosphorus is applied by the base fertilizer; in the northwest single season crop where the soil phosphorus deficiency is severe or cold, 70% of phosphorus is used as a base fertilizer. The compound fertilizer is used as the base fertilizer, and the dosage can be calculated according to the composition of the compound fertilizer, the nutrient content and the requirement of fertilizing the crop, wherein the insufficient nutrients can be obtained by supplementing the unit fertilizer.
The amount of base fertilizer should also take into account the soil conditions. The principle of “slim or sticky soil, less soil or less soil†should be mastered. Because the lean seedling stage is prone to lack of fertilizer, and the sandy soil retains poor fertilizer, it is easy to leak in paddy fields or rainy seasons. Therefore, the method of “small number of times†should be adopted in the application of compound fertilizer.
(2) The base fertilizer of cash crops.
There are many types of cash crops, complex nutritional characteristics, and different requirements for base fertilizers. The types of compound fertilizers and the amount of fertilizer applied are determined by crop types. For example, the yield of Chinese cabbage, Brassica napus, sugar cane, cotton, etc. is high, the amount of fertilizer is large, and the amount of base fertilizer is large. However, the nitrogen requirement of these crops is applied multiple times, and the nitrogen in the fertilizer only accounts for 30%-40% of the total growth period. Therefore, the compound fertilizer with low nitrogen, high phosphorus and potassium should be used in the fertilizer variety. Peanut, soybean, legume green manure and other crops have no shape or a small number of nodules at the seedling stage, and the nitrogen fixation ability is weak. Therefore, when using compound fertilizer as the base fertilizer, the nitrogen content should be more than 60% of the nitrogen requirement during the growth period. .
(3) The base fertilizer of perennial fruit trees and tea trees.
The base fertilizer of perennial crops is different from the base fertilizer. The base fertilizer is the fertilizer applied in combination with deep tillage and soil change when planting or replanting. The base fertilizer often has multiple application methods, taking tea trees as an example, one is cutting planting or seed. The other is applied to the tea garden every autumn and winter, both of which are called the base fertilizer of tea trees.
The base fertilizer is mainly composed of delayed organic nutrients such as organic fertilizer. Its main function is to increase soil organic matter, promote the improvement of soil physical and chemical properties, and lay a good soil foundation for later crop growth. However, the base fertilizer is mainly applied with organic fertilizer and phosphorus-potassium compound fertilizer.
2, seed fertilizer.
Refers to the fertilizer applied during sowing or transplanting. The fertilizer is mainly composed of phosphorus-potassium compound fertilizer. Some compound fertilizers with high nutrient content and high price are suitable for use as seed fertilizers, such as potassium dihydrogen phosphate. The roots of the seedlings have weaker root absorption capacity, but they are the critical period of phosphorus nutrition. For the soils with severe phosphorus deficiency or small grain and low phosphorus storage, such as rapeseed, tomato, alfalfa, etc. Fertilizer is beneficial to Miao Qi Miao Zhuang. In the cold regions of the north, most of the base fertilizer has been applied before tilling. For example, when planted in spring, a small amount of seed fertilizer is applied in layers, which not only has good fertilizer effect, but also avoids the influence of spring sowing on the performance of preservation. Taking phosphorus as an example, the seed fertilizer accounts for about 30% of the total phosphorus in the whole growth period. If the base fertilizer is not applied or applied insufficiently, the amount of phosphorus-potassium compound fertilizer used as seed fertilizer should be increased appropriately. When using compound fertilizer as seed fertilizer, it is generally not advisable to follow the fertilizer, and the direct contact between fertilizer and seedling should also be avoided. The soil should be kept at a certain distance from the seed or seedling.
3, foliar fertilizer.
Foliar fertilizer is applied for topdressing and sprayed on the leaves of the crop. The method of spraying fertilizer on the foliage is called foliar fertilization or root dressing.
The epidermis and stomata of crop leaves can absorb water-soluble mineral fertilizers and some simple organic compounds such as urea, amino acids and sugars, and the nutrients absorbed by the leaves are the same as the nutrients absorbed by the roots. The operation and assimilation of crops. At the same time, because its nutrient operation speed is fast, such as urea 1-2 days, it has obvious effect, and it takes 4-6 days to apply it to the soil. Foliar fertilization can often be used as a supplement to root topdressing, which has certain significance in strengthening crop nutrition, especially in the case of root nutrients.
Foliar fertilizer has a short residual time and generally requires multiple spraying. Compound fertilizers commonly used as foliar fertilizers include binary compound fertilizers such as potassium dihydrogen phosphate and potassium nitrate, and liquid compound fertilizers such as ammonium polyphosphate. Currently, foliar fertilizers are often used in combination with pesticides and crop growth regulators to provide multiple functions. The application of foliar fertilizer should be based on the type of crop and the nutrient composition and proportion of the fertilizer, and the appropriate spray concentration and application method should be selected.
(3) Application technology of compound fertilizer 1. Application technology of solid compound fertilizer.
(1) Calculation of the amount of compound fertilizer applied.
There are many varieties and specifications of compound fertilizers. Blind application will inevitably lead to excessive or insufficient nutrient, which will affect the yield increase effect of fertilizers, increase the input of fertilizers, and ultimately lead to a decrease in benefits. Therefore, when using compound fertilizer, the appropriate amount of fertilizer should be determined first. The following two examples illustrate how to determine the amount of fertilizer based on the composition of the compound fertilizer, the nutrient content, and the requirements for crop fertilization.
Example 1: The required fertilizer amount per mu is n10 kg, p2o5 5 kg, and the ratio of nitrogen to phosphorus application is 1:0.5. Phosphorus is used as the base fertilizer, and half of the nitrogen is topdressed, that is, the base fertilizer should contain 5 kg of n and 5 kg of p2o5. The compound fertilizer used was diammonium phosphate, which contained n18% and contained p2o546%. The calculation steps are as follows:
Calculate the amount of diammonium phosphate required to apply 5 kg of p2o5 per mu. Divide 5 kg of p2o5 by the percentage of p2o5 (46%) in diammonium phosphate, and obtain 5÷46%=10.87 kg, ie, apply 5 kg of p2o5 to phosphate. Ammonium 10.87 kg.
Calculate the nitrogen content in 10.87 kg of diammonium phosphate. Multiply the percentage of nitrogen in the diammonium phosphate (18%) by 10.87 kg, and obtain 10.87×18%= 1.935 kg. It is necessary to add 3.065 kg of elemental nitrogen fertilizer to reach 5 kg. Nitrogen requirements.
If it is supplemented with ammonium bicarbonate, the nitrogen content of ammonium bicarbonate is known to be 17%, and the amount to be added is 3.065÷17%=18 kg.
The above calculations indicate that the amount of fertilizer applied as base fertilizer should be 10.87 kg of diammonium phosphate and 18 kg of ammonium bicarbonate.
Example 2: The required fertilizer amount per mu is n10 kg, p2o5 5 kg, k2o 5 kg, and the application ratio is 1:0.5:0.5. Phosphorus and potassium are used as base fertilizers, and half of the nitrogen is used as top dressing. That is, the base fertilizer should include 5 kg n, 5 kg p2o5, 5 kg k2o, and the compound fertilizer type is n14%, p2o59%, k2o20%. Yuan compound fertilizer. The calculation method is the same as in Example 1. The steps are as follows:
Calculate the amount of ternary compound fertilizer needed to apply 5 kg of k2o per mu, ie 5÷20%=20 kg.
Calculate the nitrogen content and phosphorus content of 25 kg ternary compound fertilizer: the nitrogen content is 25×14%=3.5 kg, and the p2o5 is 25×9%=2.25 kg. It is necessary to add 1.5 kg n and 2.75 kg p2o5 to reach the base fertilizer requirement.
The amount of nitrogen supplemented with n17% ammonium bicarbonate is 1.5÷17%=8.8 kg; the phosphorus is supplemented with p2o516% calcium, and the required amount is 2.75÷16%=17.2 kg. According to the calculation, the amount of ternary compound fertilizer used as base fertilizer is 25 kg, and it is still required to apply 8.8 kg of ammonium bicarbonate and 17.2 kg of calcium.
Table 6-6
Compound fertilizer base ratio test results Soil crops Test number Comparison Compound fertilizer base application Compound fertilizer base application 75% topdressing 25%
Compound fertilizer
Fat half lsd
0.05
Compound fertilizer dosage
Fluvo-agriculture, wheat, 5
213
312
307
285.8
29.7
5+5+0
Earthy corn 2
200
305
290
279
7.5
5+5+0
Brown soil wheat 6
399
397
400.5
14.1
5+5+5
Brown soil corn 6
394
521.3
496.8
463.6
49.9
5+5+5
Brown soil sweet potato 3
2420
2766
2712
2731
250.5
2+2+2
Brown soil peanut 2
308
345
333.8
324.5
3.3
2+2+2
Brown soil millet 1
257
346
329.5
330
6.0
5+5+2
When the base fertilizer is insufficient or the base fertilizer is not applied, the use of compound fertilizer for topdressing also has an effect of increasing yield. The experiments conducted by the Soil and Fertilizer Institute of Sichuan Province and Gansu Academy of Agricultural Sciences on crops such as wheat, rice and corn have proved this. Although the compound fertilizer can supply the nitrogen demand in the late growth stage of the crop, the phosphorus and potassium in the compound fertilizer are not as good as the fertilizer effect in the early application. Therefore, for high-yield crops with long growth period, compound fertilizer is used as base fertilizer, and then elemental nitrogen fertilizer is used as top dressing, and the economic benefit is better. For intercropping crops that do not use base fertilizer or insufficient base fertilizer, when it is necessary to apply phosphorus and potassium compound fertilizer, the compound fertilizer can be applied early. Using compound fertilizer to apply rice and wheat tiller fertilizer, late corn chasing and applying stalk fertilizer, cotton chasing bud fertilizer, and beans to apply seedling fertilizer before flowering have good effects. Tea trees should be applied in the early stage of production.
(3) Location and method of application of compound fertilizer.
1 base fertilizer. When the compound fertilizer was used as the base fertilizer of rice, there was no significant difference between the surface application effect and the deep application effect. The method of applying the surface is: after plowing the field or ploughing the field, immediately filling the shallow water, spreading the compound fertilizer, and then licking it for 1-2 times, so that the fertilizer can be evenly distributed in the 7 cm deep soil layer, that is, the surface fertilizer The role. The method of deep application is to first spread the fertilizer on the wet soil before the ploughing, and then turn the fertilizer into the soil layer, and then fill it with water and cultivate it so that most of the fertilizer has a depth of 10 cm in the soil. about.
The base fertilizer of the dry land adopts the method of deep application of the whole plough layer. The compound fertilizer is evenly applied to the field before the arable land, and then the ploughing is carried out into the soil, so that it can be turned over with the shovel. It can also be sprinkled into the furrow when cultivating land, and covered by the next plow plough, also called "furrow slippery".
2 kinds of fertilizer. The application of the seed fertilizer includes application methods such as seed dressing, strip application, point application, acupoint application and field fertilizer.
Seed dressing: Mix the compound fertilizer with 1-2 times of fine dry decomposed organic fertilizer or fine soil, and then mix with the seeds after soaking the seeds, and mix with the seeds.
Article application, point application, and point application: wheat and millet in strips are applied with strips; corn, sorghum, and cotton are ordered on the spot; potato and sweet potato are planted in the hole. The specific method is: uniformly apply the compound fertilizer along the dug ditches and holes, and then sow and cover the soil. It is advisable to apply fertilizer to 2-8 cm below the seed to avoid direct contact between the fertilizer and the seed, which will affect the germination rate of the seed, otherwise the emergence rate of the crop will decrease and the yield will decrease.
(4) Application techniques of different forms of compound fertilizer.
1 ammonium type and nitrate type compound fertilizer. Ammonium-type compound fertilizers and nitrate-type compound fertilizers are equally effective on most dry crops. Nitrogen is easily lost in rice fields by nitrate-type compound fertilizer. In the hilly tea area, more annual rainfall can also lead to the loss of nitrate nitrogen. In such cases, the ammonium compound type compound fertilizer can obtain better fertilizer efficiency than the nitrate type compound fertilizer, and the yield is increased by 5%-24%. For the seedlings and young trees of fruit trees, the effect of ammonium compound fertilizer is better; after the age and the result period, the nitrate compound fertilizer is more conducive to the absorption and operation of fruit trees.
2 Compound fertilizer containing potassium chloride and potassium sulfate. The potassium component in the compound fertilizer is mostly potassium chloride or potassium sulfate or both. According to foreign research reports, most crops, especially cereal crops, are neutral to chloride ions in compound fertilizer. When the price of potassium sulfate is higher than that of potassium chloride, it is worth considering the use of compound fertilizer containing chloride ions. In rice fields, the application of potassium chloride-containing compound fertilizer has a higher yield-increasing trend than the application of potassium sulfate-containing compound fertilizer, which may not be related to the accumulation of sulfate roots. Therefore, rice paddy should use potassium chloride compound fertilizer to obtain greater economic benefits. However, some crops are sensitive to chlorine reactions, such as tobacco, grapes, potatoes and other chlorine-free crops, should use low- or no chlorine-containing compound fertilizer. According to the previous concept, the application of chlorine-containing fertilizers in tea gardens is prone to "chlorine damage", and tea trees are also included in the chlorine-free crops. The results of the Tea Research Experiment of the Chinese Academy of Agricultural Sciences (1981) showed that there were no symptoms of chlorine damage in the adult tea gardens of 10 kg of potassium chloride per year and 5 kg of tea in the young tea gardens, but more than 20 kg per mu, 8 days or so The chlorosis of individual plants occurs, and the degree is aggravated with the prolongation of time and the increase of dosage.
3 compound fertilizers of different particle sizes. Studies have shown that the effect of increasing the yield of compound fertilizers with different particle sizes is very different. The excessive particle size causes crop yield reduction, which is related to the dissolution and release of nutrients. Granular or spherical compound fertilizer dissolves slowly in rice fields, has less nutrient loss, high fertilizer utilization rate, and stable fertilizer efficiency. However, due to the slower fertilizer efficiency in the early stage, it sometimes affects the greening and tillering of rice, and it is necessary to cooperate with the application of quick-acting elemental nitrogen fertilizer.
(2) The application period of the compound fertilizer.
Granular compound fertilizer is slower than single fertilizer, so it is generally used as base fertilizer and seed fertilizer. According to the experiments of the Institute of Soil and Fertilizer of the Chinese Academy of Agricultural Sciences on wheat, corn, sweet potato, millet and other crops, under the conditions of additional fertilizer in the early or middle stage of crop growth, compound fertilizer, whether binary or ternary, It is better to use base fertilizer.
1. Choose the right variety.
The application of compound fertilizer should be based on the physical and chemical properties of the soil and the nutritional characteristics of the crop. If the compound fertilizer is applied, and the characteristics of the variety are not compatible with the soil conditions and the nutritional habits of the crop, the lighter may cause a certain amount of nutrient waste, and in the case may result in a reduction in production. Factors that should be considered in the scientific selection of compound fertilizers include:
(1) Soil characteristics and nutrient formation of compound fertilizers.
The nitrogen in the compound fertilizer includes ammonium nitrogen and nitrate nitrogen. Their properties are obviously different: ammonium nitrogen is easily adsorbed by soil and has less loss, and is suitable for both dry land and paddy fields; and nitrate nitrogen is in paddy field. Easy to leaching, or lost due to denitrification, suitable for use in drylands.
The available phosphorus in the compound fertilizer has two kinds of water solubility and hydrazine solubility. Water-soluble phosphorus has a fast fertilizer effect and is suitable for application on various soils, while strontium-soluble phosphorus is suitable for application on neutral and acidic soils, and is less effective in phosphorus-deficient calcareous soil.
The potassium in the compound fertilizer has two kinds of potassium sulfate and potassium chloride. Although the two fertilizers have the same effect, for some chlorine-repellent crops such as tobacco, the application of the compound fertilizer containing potassium chloride has the adverse effect of lowering the quality.
According to the test results of various places, the fertilizers of ammonium phosphate and ammonium biphosphate, urea heavy calcium, urea and calcium are more stable, suitable for all kinds of soils and various crops in our province; nitrophosphate and nitrophosphate Compound fertilizers should not be applied on paddy fields and rainy slopes, but can be applied on dry soil. For calcareous soils with severe phosphorus deficiency, the water solubility rate of phosphorus pentoxide in nitrophosphate should be greater than 50%; complexes containing calcium and magnesium phosphates Mixed fertilizers such as urea, calcium, magnesium and phosphorus should be applied to acidic or neutral soils in the south. Chlorine-containing compound fertilizers should not be applied to chlorine-sensitive crops such as tobacco and potato; double-chlorine fertilizers, such as NPK ternary compound fertilizer, have the same or slightly higher fertilizer efficiency than many urea-phosphorus systems. Mixed fertilizers are not suitable for irrigated land and saline-alkali soil areas because they contain more chlorine. They should also be used in limited quantities for irrigated land in arid and semi-arid areas.
(2) Fertilization characteristics of crops The nutritional characteristics of different crops are different. It is necessary to select suitable compound fertilizer varieties according to the type of crops, which is of great significance for improving crop yield and improving quality. In general, the application of grain crops should focus on increasing production. For legume crops, phosphorus-potassium compound fertilizer is the main choice. The application of potash can not only increase the yield of cash crops, but more importantly improve the quality of the products. For example, potassium application of tobacco can increase the thickness of leaves and improve the flammability and aroma of tobacco; potassium application by fruit trees and watermelon can increase sweetness and reduce acidity; potassium application of sugar cane and sugar beet can increase sugar content and increase sugar yield. Therefore, NPK ternary compound fertilizer should be used for cash crops. For oil crops in cash crops, due to the large amount of phosphorus required, low-nitrogen and high-phosphorus binary or low-nitrogen, high-phosphorus and low-potassium ternary compound fertilizers can be selected.
(3) Rotation mode Due to the different rotation system, the varieties of compound fertilizers applied to the crops in the crop rotation cycle are also different. For example, in the wheat-maize rotation system, the wheat seedling stage is in the low-temperature growth stage and is particularly sensitive to phosphorus deficiency. High-phosphorus compound fertilizer varieties should be used. In the summer maize production period, the phosphorus released from the soil is relatively high. More, and can also take advantage of the application of phosphate fertilizer in the wheat, so the choice of low-phosphorus compound fertilizer. In the rice-rice rotation system, the fertilizer effect of phosphate fertilizer on the same phosphorus-deficient soil is better than that of late rice, while the fertilizer efficiency of potassium fertilizer is better than that of early rice in late rice. Therefore, early rice should be applied with high-phosphorus compound fertilizer, and late rice can be used. Use high potassium compound fertilizer varieties.
2. Compound fertilizer is used together with elemental fertilizer.
The composition of the compound fertilizer is fixed, so it is not only difficult to meet the nutrient requirements of different soils, different crops or even the same crop at different growth stages, and it is difficult to meet the different requirements of different nutrients in fertilization techniques. At the same time of applying the compound fertilizer, the elemental fertilizer should be applied according to the nutrient content of the compound fertilizer and the nutrient conditions of the local soil and the nutrient habits of the crop to ensure the supply of nutrients.
The determination of the amount of fertilizer applied can be calculated according to the composition of the compound fertilizer, the nutrient content and the nutrient requirements of the crop. For example, 14 kg of pure nitrogen, 7 kg of phosphorus pentoxide and 10 kg of potassium oxide should be applied per mu, and the application ratio is 1:0.5:0.7. If the compound fertilizer is selected, it contains 14% nitrogen and phosphorus pentoxide. %, potassium oxide 20% ternary compound fertilizer, 50 kg fertilizer can meet the needs of potassium fertilizer, and nitrogen and phosphate fertilizers are not satisfied. Therefore, it is necessary to apply 7 kg of pure nitrogen and 2.5 kg of phosphorus pentoxide to achieve the fertilization standard, which is solved by applying elemental fertilizer.
3. Different application methods are adopted according to the variety characteristics of the compound fertilizer.
The compound fertilizers produced at home and abroad are generally divided into two categories: binary compound fertilizer and ternary compound fertilizer. Each type of fertilizer can be divided into many compound fertilizer varieties according to its production method, composition and nutrient content.
(1) Binary compound fertilizer.
The binary compound fertilizer includes ammonium phosphate, phosphorus nitrate fertilizer, ammonium thiophosphate, ammonium nitrate phosphate, ammonium urea phosphate, potassium nitrate, potassium dihydrogen phosphate and the like. A brief description of the following.
a, ammonium phosphate.
Ammonium phosphate, abbreviated as ammonium phosphate, is formed by neutralizing concentrated phosphoric acid with ammonia and is a mixture of monoammonium phosphate and diammonium phosphate. The amount of the two products differs depending on the degree of nitriding during the manufacturing process. Monoammonium phosphate is relatively stable and has an acidic reaction with a pH of 4.4. The stability of diammonium phosphate is slightly poor, and it has an alkaline reaction. The pH value is 8.0. Under high temperature and high humidity conditions, ammonia is often volatilized.
Pure ammonium phosphate is grayish white, and because of the impurities often contained in the manufacturing process, the ammonium phosphate fertilizer is mostly dark gray. Ammonium phosphate has a certain hygroscopicity, so it is usually added into a moisture-proofing agent to form a granule. Ammonium phosphate contains 18% nitrogen and 46% phosphorus pentoxide. The nitrogen and phosphorus nutrients are quick-acting and easy to be absorbed by crops. Granular ammonium phosphate is most suitable as a seed fertilizer and base fertilizer. If it is used as a seed fertilizer, it should not be in direct contact with the seed, so as to avoid adverse effects of high concentration of fertilizer on seed germination. The amount of fertilizer applied should be calculated according to the amount of phosphorus pentoxide in the fertilizer. The insufficient amount of nitrogen can be supplemented with elemental nitrogen fertilizer.
b, potassium nitrate.
Potassium nitrate is formed by dissolving sodium nitrate together with potassium chloride and recrystallizing it. China's potassium nitrate is white crystal, containing 12%-15% nitrogen, 45%-46% potassium oxide, soluble in water, low hygroscopicity, good physical properties, suitable for the topdressing and base fertilizer of the potassium-tolerant chlorine crop. Potatoes, tobacco, and beets all have good fertilizer effects. In addition, potassium nitrate can also be effectively used as a top dressing. The suitable concentration is 0.6%-1%. The nitrogen in potassium sulfate is nitrate, so it is generally not suitable for rice fields.
c. Potassium dihydrogen phosphate potassium dihydrogen phosphate is formed by adding potassium hydroxide to potassium chloride or potassium chloride to form potassium hydroxide, and then acidifying with phosphoric acid. The pure potassium dihydrogen phosphate is white crystal, and the potassium dihydrogen phosphate used as a fertilizer contains 50% phosphorus pentoxide and 30% potassium oxide. Because the price of potassium dihydrogen phosphate is relatively expensive, it is most suitable for topdressing or soaking. The suitable concentration for soaking seeds is 0.2%; the suitable concentration for root-seeking is 0.1-0.3%.
(2) ternary compound fertilizer.
Most of the ternary compound fertilizer is a mixed compound fertilizer. In our province, the soil and climatic conditions vary widely, and there are many varieties of crops. The requirements for the ratio of NPK to ternary compound fertilizer are also different. Therefore, all regions should produce various proportions of ternary complex according to different needs. Mixed fertilizer.
(II) Application method of compound fertilizer The compound fertilizer has phosphorus or phosphorus and potassium components, and most of them are granular, which is slower than the powder unit fertilizer. Therefore, it is generally used as base fertilizer, and can also be used as seed fertilizer and top dressing.
1, base fertilizer.
Also known as the base fertilizer, it is the fertilizer applied during land preparation and tillage. The application of compound fertilizer can meet the demand of various nutrients in the seedling stage and is beneficial to strong seedlings, so sufficient base fertilizer is the basis for obtaining high yield of crops. The amount of base fertilizer is closely related to crop types and soil properties.
(1) The base fertilizer of food crops.
Wheat, mid-season and other crops have a longer growth period, about 150 days, and the base fertilizer accounts for more than half of the total fertilizer use. Double-season rice, late rice and early-maturing crops in arid areas have short growth periods, and early growth of strong seedlings is the key to increasing yield. These crops should pay attention to base fertilizer. The determination of the amount of base fertilizer should take into account the nutritional characteristics of the crop at different growth stages. Taking phosphorus as an example, phosphorus is easy to fix in the soil, and the mobility is small. The growth of the crop should avoid the phosphorus deficiency in the later stage, and keep the “wanting and not decayingâ€, and must meet the demand of phosphorus. Some crops are also very sensitive to the reaction of phosphorus in the late growth stage. For example, when soybeans are in the flowering and pod-forming stage, sweet potato needs more phosphorus supply during the period of root enlargement. If the early phosphorus is sufficient, it can promote the storage of more phosphorus in the plant to transfer to the part of phosphorus deficiency in the later stage. Therefore, most of the phosphorus should be applied as a base fertilizer. In the annual crop with medium phosphorus content, all phosphorus is applied by the base fertilizer; in the northwest single season crop where the soil phosphorus deficiency is severe or cold, 70% of phosphorus is used as a base fertilizer. The compound fertilizer is used as the base fertilizer, and the dosage can be calculated according to the composition of the compound fertilizer, the nutrient content and the requirement of fertilizing the crop, wherein the insufficient nutrients can be obtained by supplementing the unit fertilizer.
The amount of base fertilizer should also take into account the soil conditions. The principle of “slim or sticky soil, less soil or less soil†should be mastered. Because the lean seedling stage is prone to lack of fertilizer, and the sandy soil retains poor fertilizer, it is easy to leak in paddy fields or rainy seasons. Therefore, the method of “small number of times†should be adopted in the application of compound fertilizer.
(2) The base fertilizer of cash crops.
There are many types of cash crops, complex nutritional characteristics, and different requirements for base fertilizers. The types of compound fertilizers and the amount of fertilizer applied are determined by crop types. For example, the yield of Chinese cabbage, Brassica napus, sugar cane, cotton, etc. is high, the amount of fertilizer is large, and the amount of base fertilizer is large. However, the nitrogen requirement of these crops is applied multiple times, and the nitrogen in the fertilizer only accounts for 30%-40% of the total growth period. Therefore, the compound fertilizer with low nitrogen, high phosphorus and potassium should be used in the fertilizer variety. Peanut, soybean, legume green manure and other crops have no shape or a small number of nodules at the seedling stage, and the nitrogen fixation ability is weak. Therefore, when using compound fertilizer as the base fertilizer, the nitrogen content should be more than 60% of the nitrogen requirement during the growth period. .
(3) The base fertilizer of perennial fruit trees and tea trees.
The base fertilizer of perennial crops is different from the base fertilizer. The base fertilizer is the fertilizer applied in combination with deep tillage and soil change when planting or replanting. The base fertilizer often has multiple application methods, taking tea trees as an example, one is cutting planting or seed. The other is applied to the tea garden every autumn and winter, both of which are called the base fertilizer of tea trees.
The base fertilizer is mainly composed of delayed organic nutrients such as organic fertilizer. Its main function is to increase soil organic matter, promote the improvement of soil physical and chemical properties, and lay a good soil foundation for later crop growth. However, the base fertilizer is mainly applied with organic fertilizer and phosphorus-potassium compound fertilizer.
2, seed fertilizer.
Refers to the fertilizer applied during sowing or transplanting. The fertilizer is mainly composed of phosphorus-potassium compound fertilizer. Some compound fertilizers with high nutrient content and high price are suitable for use as seed fertilizers, such as potassium dihydrogen phosphate. The roots of the seedlings have weaker root absorption capacity, but they are the critical period of phosphorus nutrition. For the soils with severe phosphorus deficiency or small grain and low phosphorus storage, such as rapeseed, tomato, alfalfa, etc. Fertilizer is beneficial to Miao Qi Miao Zhuang. In the cold regions of the north, most of the base fertilizer has been applied before tilling. For example, when planted in spring, a small amount of seed fertilizer is applied in layers, which not only has good fertilizer effect, but also avoids the influence of spring sowing on the performance of preservation. Taking phosphorus as an example, the seed fertilizer accounts for about 30% of the total phosphorus in the whole growth period. If the base fertilizer is not applied or applied insufficiently, the amount of phosphorus-potassium compound fertilizer used as seed fertilizer should be increased appropriately. When using compound fertilizer as seed fertilizer, it is generally not advisable to follow the fertilizer, and the direct contact between fertilizer and seedling should also be avoided. The soil should be kept at a certain distance from the seed or seedling.
3, foliar fertilizer.
Foliar fertilizer is applied for topdressing and sprayed on the leaves of the crop. The method of spraying fertilizer on the foliage is called foliar fertilization or root dressing.
The epidermis and stomata of crop leaves can absorb water-soluble mineral fertilizers and some simple organic compounds such as urea, amino acids and sugars, and the nutrients absorbed by the leaves are the same as the nutrients absorbed by the roots. The operation and assimilation of crops. At the same time, because its nutrient operation speed is fast, such as urea 1-2 days, it has obvious effect, and it takes 4-6 days to apply it to the soil. Foliar fertilization can often be used as a supplement to root topdressing, which has certain significance in strengthening crop nutrition, especially in the case of root nutrients.
Foliar fertilizer has a short residual time and generally requires multiple spraying. Compound fertilizers commonly used as foliar fertilizers include binary compound fertilizers such as potassium dihydrogen phosphate and potassium nitrate, and liquid compound fertilizers such as ammonium polyphosphate. Currently, foliar fertilizers are often used in combination with pesticides and crop growth regulators to provide multiple functions. The application of foliar fertilizer should be based on the type of crop and the nutrient composition and proportion of the fertilizer, and the appropriate spray concentration and application method should be selected.
(3) Application technology of compound fertilizer 1. Application technology of solid compound fertilizer.
(1) Calculation of the amount of compound fertilizer applied.
There are many varieties and specifications of compound fertilizers. Blind application will inevitably lead to excessive or insufficient nutrient, which will affect the yield increase effect of fertilizers, increase the input of fertilizers, and ultimately lead to a decrease in benefits. Therefore, when using compound fertilizer, the appropriate amount of fertilizer should be determined first. The following two examples illustrate how to determine the amount of fertilizer based on the composition of the compound fertilizer, the nutrient content, and the requirements for crop fertilization.
Example 1: The required fertilizer amount per mu is n10 kg, p2o5 5 kg, and the ratio of nitrogen to phosphorus application is 1:0.5. Phosphorus is used as the base fertilizer, and half of the nitrogen is topdressed, that is, the base fertilizer should contain 5 kg of n and 5 kg of p2o5. The compound fertilizer used was diammonium phosphate, which contained n18% and contained p2o546%. The calculation steps are as follows:
Calculate the amount of diammonium phosphate required to apply 5 kg of p2o5 per mu. Divide 5 kg of p2o5 by the percentage of p2o5 (46%) in diammonium phosphate, and obtain 5÷46%=10.87 kg, ie, apply 5 kg of p2o5 to phosphate. Ammonium 10.87 kg.
Calculate the nitrogen content in 10.87 kg of diammonium phosphate. Multiply the percentage of nitrogen in the diammonium phosphate (18%) by 10.87 kg, and obtain 10.87×18%= 1.935 kg. It is necessary to add 3.065 kg of elemental nitrogen fertilizer to reach 5 kg. Nitrogen requirements.
If it is supplemented with ammonium bicarbonate, the nitrogen content of ammonium bicarbonate is known to be 17%, and the amount to be added is 3.065÷17%=18 kg.
The above calculations indicate that the amount of fertilizer applied as base fertilizer should be 10.87 kg of diammonium phosphate and 18 kg of ammonium bicarbonate.
Example 2: The required fertilizer amount per mu is n10 kg, p2o5 5 kg, k2o 5 kg, and the application ratio is 1:0.5:0.5. Phosphorus and potassium are used as base fertilizers, and half of the nitrogen is used as top dressing. That is, the base fertilizer should include 5 kg n, 5 kg p2o5, 5 kg k2o, and the compound fertilizer type is n14%, p2o59%, k2o20%. Yuan compound fertilizer. The calculation method is the same as in Example 1. The steps are as follows:
Calculate the amount of ternary compound fertilizer needed to apply 5 kg of k2o per mu, ie 5÷20%=20 kg.
Calculate the nitrogen content and phosphorus content of 25 kg ternary compound fertilizer: the nitrogen content is 25×14%=3.5 kg, and the p2o5 is 25×9%=2.25 kg. It is necessary to add 1.5 kg n and 2.75 kg p2o5 to reach the base fertilizer requirement.
The amount of nitrogen supplemented with n17% ammonium bicarbonate is 1.5÷17%=8.8 kg; the phosphorus is supplemented with p2o516% calcium, and the required amount is 2.75÷16%=17.2 kg. According to the calculation, the amount of ternary compound fertilizer used as base fertilizer is 25 kg, and it is still required to apply 8.8 kg of ammonium bicarbonate and 17.2 kg of calcium.
Table 6-6
Compound fertilizer base ratio test results Soil crops Test number Comparison Compound fertilizer base application Compound fertilizer base application 75% topdressing 25%
Compound fertilizer
Fat half lsd
0.05
Compound fertilizer dosage
Fluvo-agriculture, wheat, 5
213
312
307
285.8
29.7
5+5+0
Earthy corn 2
200
305
290
279
7.5
5+5+0
Brown soil wheat 6
399
397
400.5
14.1
5+5+5
Brown soil corn 6
394
521.3
496.8
463.6
49.9
5+5+5
Brown soil sweet potato 3
2420
2766
2712
2731
250.5
2+2+2
Brown soil peanut 2
308
345
333.8
324.5
3.3
2+2+2
Brown soil millet 1
257
346
329.5
330
6.0
5+5+2
When the base fertilizer is insufficient or the base fertilizer is not applied, the use of compound fertilizer for topdressing also has an effect of increasing yield. The experiments conducted by the Soil and Fertilizer Institute of Sichuan Province and Gansu Academy of Agricultural Sciences on crops such as wheat, rice and corn have proved this. Although the compound fertilizer can supply the nitrogen demand in the late growth stage of the crop, the phosphorus and potassium in the compound fertilizer are not as good as the fertilizer effect in the early application. Therefore, for high-yield crops with long growth period, compound fertilizer is used as base fertilizer, and then elemental nitrogen fertilizer is used as top dressing, and the economic benefit is better. For intercropping crops that do not use base fertilizer or insufficient base fertilizer, when it is necessary to apply phosphorus and potassium compound fertilizer, the compound fertilizer can be applied early. Using compound fertilizer to apply rice and wheat tiller fertilizer, late corn chasing and applying stalk fertilizer, cotton chasing bud fertilizer, and beans to apply seedling fertilizer before flowering have good effects. Tea trees should be applied in the early stage of production.
(3) Location and method of application of compound fertilizer.
1 base fertilizer. When the compound fertilizer was used as the base fertilizer of rice, there was no significant difference between the surface application effect and the deep application effect. The method of applying the surface is: after plowing the field or ploughing the field, immediately filling the shallow water, spreading the compound fertilizer, and then licking it for 1-2 times, so that the fertilizer can be evenly distributed in the 7 cm deep soil layer, that is, the surface fertilizer The role. The method of deep application is to first spread the fertilizer on the wet soil before the ploughing, and then turn the fertilizer into the soil layer, and then fill it with water and cultivate it so that most of the fertilizer has a depth of 10 cm in the soil. about.
The base fertilizer of the dry land adopts the method of deep application of the whole plough layer. The compound fertilizer is evenly applied to the field before the arable land, and then the ploughing is carried out into the soil, so that it can be turned over with the shovel. It can also be sprinkled into the furrow when cultivating land, and covered by the next plow plough, also called "furrow slippery".
2 kinds of fertilizer. The application of the seed fertilizer includes application methods such as seed dressing, strip application, point application, acupoint application and field fertilizer.
Seed dressing: Mix the compound fertilizer with 1-2 times of fine dry decomposed organic fertilizer or fine soil, and then mix with the seeds after soaking the seeds, and mix with the seeds.
Article application, point application, and point application: wheat and millet in strips are applied with strips; corn, sorghum, and cotton are ordered on the spot; potato and sweet potato are planted in the hole. The specific method is: uniformly apply the compound fertilizer along the dug ditches and holes, and then sow and cover the soil. It is advisable to apply fertilizer to 2-8 cm below the seed to avoid direct contact between the fertilizer and the seed, which will affect the germination rate of the seed, otherwise the emergence rate of the crop will decrease and the yield will decrease.
(4) Application techniques of different forms of compound fertilizer.
1 ammonium type and nitrate type compound fertilizer. Ammonium-type compound fertilizers and nitrate-type compound fertilizers are equally effective on most dry crops. Nitrogen is easily lost in rice fields by nitrate-type compound fertilizer. In the hilly tea area, more annual rainfall can also lead to the loss of nitrate nitrogen. In such cases, the ammonium compound type compound fertilizer can obtain better fertilizer efficiency than the nitrate type compound fertilizer, and the yield is increased by 5%-24%. For the seedlings and young trees of fruit trees, the effect of ammonium compound fertilizer is better; after the age and the result period, the nitrate compound fertilizer is more conducive to the absorption and operation of fruit trees.
2 Compound fertilizer containing potassium chloride and potassium sulfate. The potassium component in the compound fertilizer is mostly potassium chloride or potassium sulfate or both. According to foreign research reports, most crops, especially cereal crops, are neutral to chloride ions in compound fertilizer. When the price of potassium sulfate is higher than that of potassium chloride, it is worth considering the use of compound fertilizer containing chloride ions. In rice fields, the application of potassium chloride-containing compound fertilizer has a higher yield-increasing trend than the application of potassium sulfate-containing compound fertilizer, which may not be related to the accumulation of sulfate roots. Therefore, rice paddy should use potassium chloride compound fertilizer to obtain greater economic benefits. However, some crops are sensitive to chlorine reactions, such as tobacco, grapes, potatoes and other chlorine-free crops, should use low- or no chlorine-containing compound fertilizer. According to the previous concept, the application of chlorine-containing fertilizers in tea gardens is prone to "chlorine damage", and tea trees are also included in the chlorine-free crops. The results of the Tea Research Experiment of the Chinese Academy of Agricultural Sciences (1981) showed that there were no symptoms of chlorine damage in the adult tea gardens of 10 kg of potassium chloride per year and 5 kg of tea in the young tea gardens, but more than 20 kg per mu, 8 days or so The chlorosis of individual plants occurs, and the degree is aggravated with the prolongation of time and the increase of dosage.
3 compound fertilizers of different particle sizes. Studies have shown that the effect of increasing the yield of compound fertilizers with different particle sizes is very different. The excessive particle size causes crop yield reduction, which is related to the dissolution and release of nutrients. Granular or spherical compound fertilizer dissolves slowly in rice fields, has less nutrient loss, high fertilizer utilization rate, and stable fertilizer efficiency. However, due to the slower fertilizer efficiency in the early stage, it sometimes affects the greening and tillering of rice, and it is necessary to cooperate with the application of quick-acting elemental nitrogen fertilizer.
(2) The application period of the compound fertilizer.
Granular compound fertilizer is slower than single fertilizer, so it is generally used as base fertilizer and seed fertilizer. According to the experiments of the Institute of Soil and Fertilizer of the Chinese Academy of Agricultural Sciences on wheat, corn, sweet potato, millet and other crops, under the conditions of additional fertilizer in the early or middle stage of crop growth, compound fertilizer, whether binary or ternary, It is better to use base fertilizer.
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