In the three-factor test conducted in the 1950s, potassium was effective. In the late 1950s, rubber trees showed symptoms of potassium deficiency. After entering the mid-1960s, on some soils with low potassium levels in South China, cement kiln ash and potassium fertilizers were applied to rice, showing good results. After the early 1970s, more potent soils were available for potash. Now in the south, potash has been deeply rooted in the hearts of the people and has been welcomed by farmers. At present, potassium fertilizer has also shown good results in some soils and crops in North China, but in general, the amount of potassium applied in China is still very small. . In 1985/1986, China was the country with the most nitrogen fertilizer, accounting for 19% of the world; the application of phosphate fertilizer accounted for the world's third 9% of the world; the application of potassium fertilizer was the fifteenth in the world, accounting for 1.4% of the world. . Fortunately, after 1987, the amount of potassium fertilizer applied in China has increased significantly, and the demand for potash will continue to grow in the future. Therefore, further increasing the source of potassium fertilizer and using potassium fertilizer are an important issue in agricultural production.
The important role of potash fertilizer in agricultural production
First, maintaining a high soil potassium fertility is the basis for high yield and stable production.
The amount of potassium required by crops is often higher than that of nitrogen and phosphorus. The potassium absorbed by the crops comes from the soil and the applied potash. Before the 1970s, there was basically no supply of chemical potassium fertilizer in China. The balance of potassium in farmland soil was maintained by the natural supply of farmyard manure and soil potassium. Because the previous multiple cropping index and yield are not high, the crop absorbs less potassium per year, thus maintaining the balance of potassium. With the rapid development of agriculture, the expenditure of potassium in the soil is increasing, and there is a serious imbalance. For example, a large number of experiments and surveys conducted by the Nanjing Institute of Soil Science of the Chinese Academy of Sciences show that the total nutrient balance of farmland in Taihu Lake is nitrogen. Phosphorus is basically balanced with a slight surplus, and potassium has a large loss. The annual deficit is 52.5 kg/ha (equivalent to 3.5 kg/mu); the potassium in the suburbs of Shanghai, Zhejiang Hangzhou-Jiaxing-Huzhou Plain and Fujian low-yield areas are all deficient. The annual deficit is 30-75 kg/ha (equivalent to 2-4 kg/mu). Because soil potassium has not been replenished for a long time, the contradiction of potassium deficiency is increasingly exposed. In some southern provinces, the area of ​​potassium deficiency accounts for about 60%. Therefore, potassium fertilizer should be added to supplement the loss of soil potassium to establish a higher potassium balance, maintain a higher soil potassium fertility, and provide a material basis for high yield and stable yield of crops.
2. Potassium can enhance the stress resistance of crops. Potassium can make crops grow robust. In 1998, some areas in China continued to have drought, and the effect of potassium fertilizer on winter rapeseed was unprecedented. This shows the role of potassium in enhancing drought resistance of crops. Very big. When the potassium supply is sufficient, the root system develops well, which is beneficial to absorb water from the soil. Potassium can increase the osmotic pressure of cell fluid, maintain the elasticity of the cell wall, and reduce the loss of water. Potassium also plays an important role in the regulation of stomatal opening and closing. When potassium is sufficient, it can reduce water evaporation. When potassium is sufficient, the plant cell wall is thickened, the stem is tough, the mechanical resistance against parasitic penetration is increased, and the low molecular weight compound in the crop is reduced. The pathogen lacks the food source, which prevents the development of the disease, so the potassium is enhanced. The role of crop disease resistance is obvious. In some areas where the application of nitrogen fertilizer in China is serious, the disease is greatly reduced after the application of potassium fertilizer, so there is a saying that “potassium fertilizer is like pesticideâ€. In addition, potassium enhances the crop's ability to resist pests, freeze damage and resist adverse soil conditions.
Third, increase the application of potassium fertilizer can improve the quality of crops
Potassium can promote photosynthesis, improve photosynthetic efficiency, and promote the transportation of photosynthetic products. When potassium is sufficient, monosaccharides are carried out to the synthesis of sucrose and starch, so potassium has a good influence on the yield and quality of starch and sugar crops. Potassium also promotes the absorption and utilization of nitrogen by crops and promotes protein synthesis. Therefore, sufficient potassium supply not only increases production, but also increases protein content in grains and improves quality. The good effect of potassium in improving product quality, in addition to the improvement of basic nutrients (such as protein, carbohydrates, etc.), can also increase mineral content, improve the appearance of the fruit and increase the storage stability of the fruit.
Practice has proved that the adverse effects of single application of nitrogen fertilizer can not be improved to the same extent by the application of potassium fertilizer. Potassium application sometimes does not necessarily increase yield, but it does a good job of improving quality. With the improvement of people's living standards and the rate of agricultural products, the quality of products is paid more attention, especially in order to occupy the international market, and the quality requirements are higher. The role of potash in this aspect should be exerted.
Fourth, with the application of potassium fertilizer, adjust the proportion of nutrients, can fully play the role of other fertilizers, the various nutrients needed by the crop, generally into a certain proportion, such as the ratio of nitrogen, phosphorus and potassium absorbed by rice is 2:1:2.5 (nitrogen: five oxygen Diphosphorus: potassium oxide). When the nutrient supply is out of balance, it will affect the normal growth and development of crops. Therefore, the balanced supply of various nutrients is a necessary condition for high yield of crops. The proportion of nitrogen, phosphorus and potassium fertilizer application is also an indicator to measure the level of agricultural development.
In recent years, the application of nitrogen fertilizer alone in some potassium-deficient soils has been unable to increase production, or the effectiveness of nitrogen fertilizer has decreased. Potassium deficiency in soil, imbalance of nitrogen and potassium nutrients is one of the reasons for the decline in nitrogen fertilizer efficiency. For example, the late rice test showed that when the amount of nitrogen increased from 2.1 kg to 4.2 kg and 6.3 kg, the rice yield decreased from 286 kg to 269. Kilograms and 255 kilograms, after applying potassium fertilizer, rose to 340 kg, 346 kg and 355 kg. In order to give full play to the effectiveness of fertilizers, when soil nutrient supply is insufficient, nitrogen, phosphorus and potassium fertilizers should be balanced.
Potassium supply level and potassium requirement in different regions of China
The effect and extent of potash is mainly determined by the level of potassium supply in the soil. Understanding the status of potassium supply in different regions can provide a basis for the allocation and rational application of potassium fertilizer.
I. Soil potassium content and influencing factors The total potassium (potassium oxide) content in the soil is generally about 0.3% - 2.5%. If all of these potassium are in an effective state, then the crop can be used for one or two hundred years, but unfortunately Most of the soil (more than 98%) of soil potassium is present in soil minerals, and crops are extremely difficult to use. We call it mineral potassium, which is the first form and the main body of soil total potassium. The second form of potassium is slow-acting potassium, which usually accounts for about 2% of total potassium. It can be gradually released and is a reserve of available potassium. When assessing the long-term potassium supply potential of the soil, the potassium content and conversion rate of this form should be considered primarily. The third form of potassium is available potassium, which is mainly exchangeable potassium, and also includes a small amount of water-soluble potassium. It only accounts for 0.1% to 2% of the total potassium, which is mainly used in the crop season.
The content of various forms of potassium in different soils varies greatly, which is mainly due to the difference in soil parent material and weathering conditions. In northern China, the weathering effect is weak. No matter what kind of soil is formed on the parent rock, the clay part of the clay has a large amount of hydromica and a montmorillonite mineral with strong ability to maintain exchangeable potassium, except for coarse texture and clay. In addition to low content, the general potassium supply capacity is high. In the south of the Yangtze River, due to the gradual enhancement of weathering and leaching, the water mica in the clay is gradually reduced, while the kaolin minerals and the trihydrate aluminum mine, which do not contain potassium and have poor potassium retention capacity, gradually increase, so the soil is dehydrated. Gradually obvious. The degree of potassium deficiency in the same climatic conditions is closely related to the parent rock. In addition, soils developed from alluvial deposits and sediments often have different potassium supply capacities due to differences in soil material sources and textures.
2. Overview of potassium supply and potassium demand in different regions
1. Brick red soil and red soil in brick red soil area (except those developed by granite and metamorphic rocks) and the paddy soil formed by it are the most prominent soils in the zonal soil of China, especially from shallow sea sediments and basalts. The soil has a very low potassium content. The large-scale application of potash in China begins with this area. Currently, various tropical economic forests and crops need to be applied with potash. This is also a region where high potency can be achieved by applying potassium fertilizer.
2. From the perspective of the whole country, the potential of potassium supply in this area is also low. For example, the soil developed by limestone in Guangxi, the soil developed by red sandstone in Jiangxi and Hunan is the lowest level of potassium in the region, so the effect of potassium fertilizer Also the most significant. The soil developed by the Quaternary red clay in the hilly area is also very demanding for potash. The soil developed by river alluvials has higher potassium levels than red soil, and lake sediments are generally higher than alluvial deposits.
3. Neutral and calcareous purple soil developed by purple shale in the southwestern part of Central China and parts of Central China. It is a soil with higher potassium supply in the southern part of the area, but the acid purple soil has lower potassium content and has potassium application effect. Report.
4. Middle and Lower Reaches of the Yangtze River In this area, the paddy soil developed by alluvial and lake sediments and yellow-brown soil has a lower potassium potential than the soils of North China and Northwest China, but is higher than the red soil of Central China. At present, the high-yield Taihu paddy soil area has begun to show the effect of potash fertilizer, especially for dry crop wheat and rapeseed.
5. The potassium supply level of calcareous soil in the North China Plain is different due to the texture. The clay soil has high potassium content and does not need potassium fertilizer at present; the potassium soil in sandy soil is medium, and some crops are effective in applying potassium; Brown soil is the soil with lower potassium levels in the region. In general, the potash fertilizer efficiency of some soils in North China has increased.
6. Northwest Loess Area The bauxite and black furnace soil in this area are affected by the loess parent material, and the potential for potassium supply is high. At present, there is little obvious response to the application of potash fertilizer.
7. Black soil in Northeast China Black soil and chernozem are rich in potassium. At the same time, the multiple cropping index in this region is not high. Except for special crops, potassium fertilizer is generally not needed, but grass carbon soil is an exception.
8. Desert area The soil in this area is the soil with the highest potassium supply in China.
Ways to improve the effectiveness of potassium fertilizer
About one-third of China's cultivated land is currently deficient in potassium, which requires a large amount of potash. Now, the source of potash is limited, and how to apply it reasonably to obtain greater benefits is an important issue in current rational fertilization. The existing experience is briefly described below.
1. The same soil is applied in combination with nitrogen and phosphorus fertilizers. When the nitrogen and phosphorus nutrient content is low, or the nitrogen and phosphorus fertilizers are used in a small amount, and the production level is not high, the problem of potassium will not be prominent, and the amount of nitrogen and phosphorus fertilizer will increase greatly. With the increase in production, the need for potash will become increasingly apparent. This has been fully confirmed by the development of agriculture in the past 40 years. A large number of experiments have shown that rice can generally increase yield by about 15% when potassium fertilizer is applied on the basis of nitrogen and phosphorus fertilizers. At present, in some areas, the role of nitrogen fertilizer has declined. One of the reasons is that there is no attention to the application of potassium fertilizer, and the proportion of nitrogen and potassium is imbalanced. Therefore, in production practice, attention must be paid to balanced fertilization.
2. Applying Potassium Fertilizer to Cold-Immersed Fields Potassium fertilizer is applied to cold-soaked fields with poor soil conditions. The improvement of potassium nutrients in rice enhances root activity and enhances the oxidative power of roots, thus reducing the content of reducing substances in the soil and oxidizing. The reduction potential is increased, thus preventing or mitigating the hazards of sulfides, organic acids and ferrous iron, thereby contributing to the growth of rice, so that the application of potassium fertilizer in cold-soaked fields often results in good results.
3. Reasonable distribution of potassium fertilizer in crop rotation In the double-season rice and wheat, single-season rice rotation system, the application of potassium fertilizer has a great effect on the post-season rice and wheat. The effect of potassium fertilizer on late rice is more than that of upland rice. It is mainly related to the growth period of dry and late rice and the supply of soil potassium. For example, a test showed that the soil available potassium content in early rice transplanting was 9.9 mg/100. Gram dry soil, when it matures, it drops to 4.3 mg/100 g dry soil. The soil potassium can not be restored and then planted and planted late rice. In addition, the late application of organic fertilizer is less, so the effect of applying potassium fertilizer in late rice is greater. When potassium fertilizer is limited, it should first be ensured in late rice application.
Fourth, pay attention to the application of potassium in Putian As the saying goes: "Half a good rice," which indicates that the quality of the seedlings will affect the growth and development of rice. After the robust seedlings are transplanted into the field, the greening is quick, the tillers are early, and the leaves are many, which has obvious effect of increasing yield. Potassium fertilizer has a good effect on cultivating Zhuangjing. When the amount of potassium fertilizer is the same, it is applied separately from Putian and Datian. Compared with all of them applied to the field, there is often a significant increase in yield. The trials in Jiangxi showed that the total yield of potassium chloride was 7.5 kg/mu, and the yields of 35 kg and 5 kg, respectively, compared with 7.5 kg for Datian, were 357.3 kg and 318.7 kg, respectively. Increase production by 11%.
V. The effect of applying potash fertilizer on economic crops is obvious. Economic crops are generally sensitive to potash fertilizer, which requires a large amount. For example, the main production of sugar cane absorbs about 40-53 kilograms of potassium oxide per acre and about 95 kilograms of banana, and as a food crop rice, 500 kilograms of rice. The absorbed potassium oxide is only 10 kg. Potassium fertilizer can not only increase the yield, but also improve the quality of the product. The soil for growing cash crops often has a low level of potassium supply. Therefore, the development of cash crops requires the application of a large amount of potash.
6. Apply different varieties of potassium fertilizer according to crop characteristics Potassium chloride and potassium sulfate are commonly used potassium fertilizer varieties. In recent years, new potassium and magnesium fertilizers have been imported. The price of potassium sulphate and sulphur potassium magnesium fertilizer is higher than that of potassium chloride, the amount is small, and it does not contain chlorine. It should be mainly used for avoiding chlorine crops, such as tobacco, and potassium chloride can be widely used for other crops except chlorine. On the crop.
Seven, pay attention to application technology Potassium fertilizer application and application period is also important to improve the role of potassium fertilizer. Each crop has its best suitable potassium fertilizer dosage. If it is applied more, the crop will be absorbed extravagantly. Generally, it is not harmful, but it is not economical. For most crops, potash is better as base fertilizer, and some crops are better combined with base fertilizer and previous top dressing. When the plant has obvious potassium deficiency, the application is also effective, but the yield and quality of the crop have been significantly damaged. Because the clay minerals of the southern soil have weak adsorption capacity for potassium, and the rainwater in the south is more, the applied potassium fertilizer is easily leached, and the sandy soil has a weak fertilizer-retaining property. Therefore, in these soils, the divided application should be emphasized. To reduce the loss of potassium.
Eight, try to use organic fertilizers, especially stalks and grass ash. China's potash resources are lacking, a large number of potash fertilizers are all imported, in addition to the reasonable application of potash fertilizer, but also must be taken locally to increase the source of potash. In areas where conditions permit, grass and ash should be strongly promoted. In addition, in areas where conditions permit, returning stalks to the field is also an important measure to supplement potash.
The important role of potash fertilizer in agricultural production
First, maintaining a high soil potassium fertility is the basis for high yield and stable production.
The amount of potassium required by crops is often higher than that of nitrogen and phosphorus. The potassium absorbed by the crops comes from the soil and the applied potash. Before the 1970s, there was basically no supply of chemical potassium fertilizer in China. The balance of potassium in farmland soil was maintained by the natural supply of farmyard manure and soil potassium. Because the previous multiple cropping index and yield are not high, the crop absorbs less potassium per year, thus maintaining the balance of potassium. With the rapid development of agriculture, the expenditure of potassium in the soil is increasing, and there is a serious imbalance. For example, a large number of experiments and surveys conducted by the Nanjing Institute of Soil Science of the Chinese Academy of Sciences show that the total nutrient balance of farmland in Taihu Lake is nitrogen. Phosphorus is basically balanced with a slight surplus, and potassium has a large loss. The annual deficit is 52.5 kg/ha (equivalent to 3.5 kg/mu); the potassium in the suburbs of Shanghai, Zhejiang Hangzhou-Jiaxing-Huzhou Plain and Fujian low-yield areas are all deficient. The annual deficit is 30-75 kg/ha (equivalent to 2-4 kg/mu). Because soil potassium has not been replenished for a long time, the contradiction of potassium deficiency is increasingly exposed. In some southern provinces, the area of ​​potassium deficiency accounts for about 60%. Therefore, potassium fertilizer should be added to supplement the loss of soil potassium to establish a higher potassium balance, maintain a higher soil potassium fertility, and provide a material basis for high yield and stable yield of crops.
2. Potassium can enhance the stress resistance of crops. Potassium can make crops grow robust. In 1998, some areas in China continued to have drought, and the effect of potassium fertilizer on winter rapeseed was unprecedented. This shows the role of potassium in enhancing drought resistance of crops. Very big. When the potassium supply is sufficient, the root system develops well, which is beneficial to absorb water from the soil. Potassium can increase the osmotic pressure of cell fluid, maintain the elasticity of the cell wall, and reduce the loss of water. Potassium also plays an important role in the regulation of stomatal opening and closing. When potassium is sufficient, it can reduce water evaporation. When potassium is sufficient, the plant cell wall is thickened, the stem is tough, the mechanical resistance against parasitic penetration is increased, and the low molecular weight compound in the crop is reduced. The pathogen lacks the food source, which prevents the development of the disease, so the potassium is enhanced. The role of crop disease resistance is obvious. In some areas where the application of nitrogen fertilizer in China is serious, the disease is greatly reduced after the application of potassium fertilizer, so there is a saying that “potassium fertilizer is like pesticideâ€. In addition, potassium enhances the crop's ability to resist pests, freeze damage and resist adverse soil conditions.
Third, increase the application of potassium fertilizer can improve the quality of crops
Potassium can promote photosynthesis, improve photosynthetic efficiency, and promote the transportation of photosynthetic products. When potassium is sufficient, monosaccharides are carried out to the synthesis of sucrose and starch, so potassium has a good influence on the yield and quality of starch and sugar crops. Potassium also promotes the absorption and utilization of nitrogen by crops and promotes protein synthesis. Therefore, sufficient potassium supply not only increases production, but also increases protein content in grains and improves quality. The good effect of potassium in improving product quality, in addition to the improvement of basic nutrients (such as protein, carbohydrates, etc.), can also increase mineral content, improve the appearance of the fruit and increase the storage stability of the fruit.
Practice has proved that the adverse effects of single application of nitrogen fertilizer can not be improved to the same extent by the application of potassium fertilizer. Potassium application sometimes does not necessarily increase yield, but it does a good job of improving quality. With the improvement of people's living standards and the rate of agricultural products, the quality of products is paid more attention, especially in order to occupy the international market, and the quality requirements are higher. The role of potash in this aspect should be exerted.
Fourth, with the application of potassium fertilizer, adjust the proportion of nutrients, can fully play the role of other fertilizers, the various nutrients needed by the crop, generally into a certain proportion, such as the ratio of nitrogen, phosphorus and potassium absorbed by rice is 2:1:2.5 (nitrogen: five oxygen Diphosphorus: potassium oxide). When the nutrient supply is out of balance, it will affect the normal growth and development of crops. Therefore, the balanced supply of various nutrients is a necessary condition for high yield of crops. The proportion of nitrogen, phosphorus and potassium fertilizer application is also an indicator to measure the level of agricultural development.
In recent years, the application of nitrogen fertilizer alone in some potassium-deficient soils has been unable to increase production, or the effectiveness of nitrogen fertilizer has decreased. Potassium deficiency in soil, imbalance of nitrogen and potassium nutrients is one of the reasons for the decline in nitrogen fertilizer efficiency. For example, the late rice test showed that when the amount of nitrogen increased from 2.1 kg to 4.2 kg and 6.3 kg, the rice yield decreased from 286 kg to 269. Kilograms and 255 kilograms, after applying potassium fertilizer, rose to 340 kg, 346 kg and 355 kg. In order to give full play to the effectiveness of fertilizers, when soil nutrient supply is insufficient, nitrogen, phosphorus and potassium fertilizers should be balanced.
Potassium supply level and potassium requirement in different regions of China
The effect and extent of potash is mainly determined by the level of potassium supply in the soil. Understanding the status of potassium supply in different regions can provide a basis for the allocation and rational application of potassium fertilizer.
I. Soil potassium content and influencing factors The total potassium (potassium oxide) content in the soil is generally about 0.3% - 2.5%. If all of these potassium are in an effective state, then the crop can be used for one or two hundred years, but unfortunately Most of the soil (more than 98%) of soil potassium is present in soil minerals, and crops are extremely difficult to use. We call it mineral potassium, which is the first form and the main body of soil total potassium. The second form of potassium is slow-acting potassium, which usually accounts for about 2% of total potassium. It can be gradually released and is a reserve of available potassium. When assessing the long-term potassium supply potential of the soil, the potassium content and conversion rate of this form should be considered primarily. The third form of potassium is available potassium, which is mainly exchangeable potassium, and also includes a small amount of water-soluble potassium. It only accounts for 0.1% to 2% of the total potassium, which is mainly used in the crop season.
The content of various forms of potassium in different soils varies greatly, which is mainly due to the difference in soil parent material and weathering conditions. In northern China, the weathering effect is weak. No matter what kind of soil is formed on the parent rock, the clay part of the clay has a large amount of hydromica and a montmorillonite mineral with strong ability to maintain exchangeable potassium, except for coarse texture and clay. In addition to low content, the general potassium supply capacity is high. In the south of the Yangtze River, due to the gradual enhancement of weathering and leaching, the water mica in the clay is gradually reduced, while the kaolin minerals and the trihydrate aluminum mine, which do not contain potassium and have poor potassium retention capacity, gradually increase, so the soil is dehydrated. Gradually obvious. The degree of potassium deficiency in the same climatic conditions is closely related to the parent rock. In addition, soils developed from alluvial deposits and sediments often have different potassium supply capacities due to differences in soil material sources and textures.
2. Overview of potassium supply and potassium demand in different regions
1. Brick red soil and red soil in brick red soil area (except those developed by granite and metamorphic rocks) and the paddy soil formed by it are the most prominent soils in the zonal soil of China, especially from shallow sea sediments and basalts. The soil has a very low potassium content. The large-scale application of potash in China begins with this area. Currently, various tropical economic forests and crops need to be applied with potash. This is also a region where high potency can be achieved by applying potassium fertilizer.
2. From the perspective of the whole country, the potential of potassium supply in this area is also low. For example, the soil developed by limestone in Guangxi, the soil developed by red sandstone in Jiangxi and Hunan is the lowest level of potassium in the region, so the effect of potassium fertilizer Also the most significant. The soil developed by the Quaternary red clay in the hilly area is also very demanding for potash. The soil developed by river alluvials has higher potassium levels than red soil, and lake sediments are generally higher than alluvial deposits.
3. Neutral and calcareous purple soil developed by purple shale in the southwestern part of Central China and parts of Central China. It is a soil with higher potassium supply in the southern part of the area, but the acid purple soil has lower potassium content and has potassium application effect. Report.
4. Middle and Lower Reaches of the Yangtze River In this area, the paddy soil developed by alluvial and lake sediments and yellow-brown soil has a lower potassium potential than the soils of North China and Northwest China, but is higher than the red soil of Central China. At present, the high-yield Taihu paddy soil area has begun to show the effect of potash fertilizer, especially for dry crop wheat and rapeseed.
5. The potassium supply level of calcareous soil in the North China Plain is different due to the texture. The clay soil has high potassium content and does not need potassium fertilizer at present; the potassium soil in sandy soil is medium, and some crops are effective in applying potassium; Brown soil is the soil with lower potassium levels in the region. In general, the potash fertilizer efficiency of some soils in North China has increased.
6. Northwest Loess Area The bauxite and black furnace soil in this area are affected by the loess parent material, and the potential for potassium supply is high. At present, there is little obvious response to the application of potash fertilizer.
7. Black soil in Northeast China Black soil and chernozem are rich in potassium. At the same time, the multiple cropping index in this region is not high. Except for special crops, potassium fertilizer is generally not needed, but grass carbon soil is an exception.
8. Desert area The soil in this area is the soil with the highest potassium supply in China.
Ways to improve the effectiveness of potassium fertilizer
About one-third of China's cultivated land is currently deficient in potassium, which requires a large amount of potash. Now, the source of potash is limited, and how to apply it reasonably to obtain greater benefits is an important issue in current rational fertilization. The existing experience is briefly described below.
1. The same soil is applied in combination with nitrogen and phosphorus fertilizers. When the nitrogen and phosphorus nutrient content is low, or the nitrogen and phosphorus fertilizers are used in a small amount, and the production level is not high, the problem of potassium will not be prominent, and the amount of nitrogen and phosphorus fertilizer will increase greatly. With the increase in production, the need for potash will become increasingly apparent. This has been fully confirmed by the development of agriculture in the past 40 years. A large number of experiments have shown that rice can generally increase yield by about 15% when potassium fertilizer is applied on the basis of nitrogen and phosphorus fertilizers. At present, in some areas, the role of nitrogen fertilizer has declined. One of the reasons is that there is no attention to the application of potassium fertilizer, and the proportion of nitrogen and potassium is imbalanced. Therefore, in production practice, attention must be paid to balanced fertilization.
2. Applying Potassium Fertilizer to Cold-Immersed Fields Potassium fertilizer is applied to cold-soaked fields with poor soil conditions. The improvement of potassium nutrients in rice enhances root activity and enhances the oxidative power of roots, thus reducing the content of reducing substances in the soil and oxidizing. The reduction potential is increased, thus preventing or mitigating the hazards of sulfides, organic acids and ferrous iron, thereby contributing to the growth of rice, so that the application of potassium fertilizer in cold-soaked fields often results in good results.
3. Reasonable distribution of potassium fertilizer in crop rotation In the double-season rice and wheat, single-season rice rotation system, the application of potassium fertilizer has a great effect on the post-season rice and wheat. The effect of potassium fertilizer on late rice is more than that of upland rice. It is mainly related to the growth period of dry and late rice and the supply of soil potassium. For example, a test showed that the soil available potassium content in early rice transplanting was 9.9 mg/100. Gram dry soil, when it matures, it drops to 4.3 mg/100 g dry soil. The soil potassium can not be restored and then planted and planted late rice. In addition, the late application of organic fertilizer is less, so the effect of applying potassium fertilizer in late rice is greater. When potassium fertilizer is limited, it should first be ensured in late rice application.
Fourth, pay attention to the application of potassium in Putian As the saying goes: "Half a good rice," which indicates that the quality of the seedlings will affect the growth and development of rice. After the robust seedlings are transplanted into the field, the greening is quick, the tillers are early, and the leaves are many, which has obvious effect of increasing yield. Potassium fertilizer has a good effect on cultivating Zhuangjing. When the amount of potassium fertilizer is the same, it is applied separately from Putian and Datian. Compared with all of them applied to the field, there is often a significant increase in yield. The trials in Jiangxi showed that the total yield of potassium chloride was 7.5 kg/mu, and the yields of 35 kg and 5 kg, respectively, compared with 7.5 kg for Datian, were 357.3 kg and 318.7 kg, respectively. Increase production by 11%.
V. The effect of applying potash fertilizer on economic crops is obvious. Economic crops are generally sensitive to potash fertilizer, which requires a large amount. For example, the main production of sugar cane absorbs about 40-53 kilograms of potassium oxide per acre and about 95 kilograms of banana, and as a food crop rice, 500 kilograms of rice. The absorbed potassium oxide is only 10 kg. Potassium fertilizer can not only increase the yield, but also improve the quality of the product. The soil for growing cash crops often has a low level of potassium supply. Therefore, the development of cash crops requires the application of a large amount of potash.
6. Apply different varieties of potassium fertilizer according to crop characteristics Potassium chloride and potassium sulfate are commonly used potassium fertilizer varieties. In recent years, new potassium and magnesium fertilizers have been imported. The price of potassium sulphate and sulphur potassium magnesium fertilizer is higher than that of potassium chloride, the amount is small, and it does not contain chlorine. It should be mainly used for avoiding chlorine crops, such as tobacco, and potassium chloride can be widely used for other crops except chlorine. On the crop.
Seven, pay attention to application technology Potassium fertilizer application and application period is also important to improve the role of potassium fertilizer. Each crop has its best suitable potassium fertilizer dosage. If it is applied more, the crop will be absorbed extravagantly. Generally, it is not harmful, but it is not economical. For most crops, potash is better as base fertilizer, and some crops are better combined with base fertilizer and previous top dressing. When the plant has obvious potassium deficiency, the application is also effective, but the yield and quality of the crop have been significantly damaged. Because the clay minerals of the southern soil have weak adsorption capacity for potassium, and the rainwater in the south is more, the applied potassium fertilizer is easily leached, and the sandy soil has a weak fertilizer-retaining property. Therefore, in these soils, the divided application should be emphasized. To reduce the loss of potassium.
Eight, try to use organic fertilizers, especially stalks and grass ash. China's potash resources are lacking, a large number of potash fertilizers are all imported, in addition to the reasonable application of potash fertilizer, but also must be taken locally to increase the source of potash. In areas where conditions permit, grass and ash should be strongly promoted. In addition, in areas where conditions permit, returning stalks to the field is also an important measure to supplement potash.
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