Sulfur, like nitrogen, phosphorus and potassium, is a nutrient element that can be lacking in crop growth. Sulfur is indispensable for proteins, various enzymes and physiologically active substances in crops. Sulfur has unique effects in improving crop yield and improving crop quality. Application of sulfur fertilizer can promote protein synthesis, increase oil content of oil crops, enhance nitrogen fixation capacity of soybean crops, and increase the spicy smell of onion and garlic vegetables. Sulfur fertilizer has significant yield-increasing benefits on a variety of crops. According to the results of the International Sulfur Research Institute in 1997 and 1998, the average yield increase of major crops is above 6%-20%. Sulfur fertilizer not only increases crop yield, but also improves crop quality with significant economic benefits. The input-output ratio of sulfur fertilizer is above 1:3. If sulfur fertilizer is applied in sulfur-deficient soil, the input-output ratio can reach 1:9-10.
The sulfur demand of crops is similar to that of phosphorus demand. Some crops also need more sulfur than phosphorus, such as rapeseed, soybeans, peanuts, tobacco, sugar cane and vegetables. In general, for every ton of grain crops produced, such as rice and wheat crops require 3-4 kg of sulfur, legumes require 6-8 kg of sulfur, and oil crops require 10-12 kg of sulfur. If the crop is deficient in sulfur, the growth will be hindered, the leaves will be chlorotic or yellow, the leaf area will be small, and the stems will be thin and short, similar to the symptoms of nitrogen deficiency. The difference is that the leaf chlorosis will first appear in the young leaves when sulfur is deficient. Nitrogen deficiency is first manifested from the lower old leaves.
Where does sulfur come from? The sulfur needed for crop growth comes from soil, fertilizer, algae water and the atmosphere. The total sulfur content of cultivated soil is 0.01%-0.05%, most of which exists in soil organic matter, and the effective sulfur that can be directly absorbed and utilized by crops accounts for less than 10% of total sulfur. Sulfur-containing fertilizers are an important source of supplemental soil sulfur. Sulphur is also present in rainfall and irrigation water. The amount of sulfur that is reduced from rainwater into the soil each year is about 0.2-0.3 kg/mu. Sulfur dioxide in the atmosphere can be directly absorbed by plants, and sometimes half of the sulfur required by crops comes from the atmosphere. The normal concentration of sulfur dioxide in the atmosphere is 0.05 g/m3, and if the content exceeds 1 g/m3, the plant will be poisoned. Since the soil available sulfur is lost with water, the amount of sulphur is about the amount of sulphur brought in by the rainwater. Therefore, the supply of sulphur in the arable land depends mainly on fertilization.
How to judge soil and crop sulfur deficiency If the crop has the above symptoms of sulfur deficiency, it can be initially judged that the crop is deficient in sulfur. However, sometimes the crop is sulphur-deficient but has no obvious symptoms; sometimes the sulphur deficiency of the crop is accompanied by the lack of other nutrients, or there is a certain disease, and it is difficult to identify whether it is sulphur-deficient. In order to accurately diagnose, it is necessary to carry out a quantitative test of soil available sulfur and plant sulfur, and to carry out a sulfur fertilizer test. Generally, the effective sulfur content of soil is 16 mg/kg of soil as the indicator of sulfur deficiency. Below this value, the soil is often insufficiently supplied with sulfur. Plants use the total sulfur content of dry matter as a nutritional indicator. Generally, the critical index of grass crops is 0.1%, and cotton is 0.2%.
The ratio of sulfur to nitrogen in crops can also be used as an indicator of nutrient status. Generally, the leaf sulfur to nitrogen ratio of field crops is 1:15-20. If the sulfur content is lower than this ratio, it indicates that the crop may be deficient in sulfur.
Why is the sulphur deficiency in farmland gradually serious? In recent years, a large amount of high-concentration non-sulfur fertilizers such as ammonium phosphate and urea have been applied, while the amount of sulphate-containing fertilizers such as superphosphate and ammonium sulphate has decreased, and the amount of organic fertilizers and sulphur-containing pesticides has gradually decreased, resulting in annual The amount of sulfur applied to the soil is decreasing year by year.
Second, the land multiple cropping index and crop yield increase, the amount of sulfur required for crop growth and the amount of sulfur taken along with the harvest increased, so that the soil sulfur content decreased year by year.
Third, with the increase of environmental pollution control, the concentration of sulfur in the atmosphere and water is reduced, and the amount of sulfur obtained from crops and irrigation water is reduced.
4. Some soils with low organic matter content and coarse texture have low sulfur content; in areas with heavy rain, more sulfur is lost from the leakage water of the drainage, which causes the soil sulfur content to decrease.
Among the many causes of crop sulfur deficiency, the first three are the main reasons. According to the analysis results of more than 10,000 soil samples in 18 provinces and cities in China, one third of the soil has a low effective sulfur water content, and the sulfur deficiency in the southern provinces and northeastern regions is more common. Since the supply of sulfuric acid fertilizer is less than one year, and the demand for sulfur increases with the increase of grain output year after year, the sulfur fertilizer gap is getting bigger and bigger. In 1997, the sulfur deficiency was 900,000 tons. It has reached 1.5 million tons and is expected to reach 2.1 million tons in 2007. The situation is very serious.
How to properly apply sulphur fertilizer The sulfuric acid fertilizer currently applied in China is mainly superphosphate, ammonium sulphate and the like. Many compound fertilizers also contain different proportions of sulfur. Gypsum is an important sulphur fertilizer, slightly soluble in water, and should be ground before use to facilitate plant absorption and utilization. Sulfur has a high sulfur content, but it is hardly soluble in water. It is absorbed into the soil after being microbialized by the microorganisms and absorbed by the crop. The fertilizer effect is slow but long lasting.
When the crop is close to the reproductive growth period, it is the peak of sulfur demand. As the crop ages, the ability to absorb sulfur decreases. Therefore, the sulfur fertilizer should be applied before the reproductive growth period. As a base fertilizer, it can be mixed with fertilizers such as nitrogen, phosphorus and potassium, combined with cultivated land. Into the soil. If sulfur deficiency is found during crop growth, quick-acting sulfur fertilizer such as ammonium sulfate can be used for top dressing or spraying.
Sulfur-iodine fertilizer should be applied early, can be mixed with crushed soil and applied, and can be used for seed dressing or planting seedlings (holes) for seed fertilizer, and can also be used for mixing soil and fertilizer. For the root fertilizer.
The amount of fertilizer applied should be determined according to the amount of sulfur required by the crop and the degree of sulfur deficiency in the soil. In general, 1.5-3 kg of sulfur per acre of sulfur-deficient soil can meet the demand of sulfur in the current season. For example, if 20 kg of calcium phosphate or 10 kg of ammonium sulfate is applied per acre, it is also possible to apply 10 kg of gypsum powder or 2 kg of sulfur powder per acre.
The sulfur demand of crops is similar to that of phosphorus demand. Some crops also need more sulfur than phosphorus, such as rapeseed, soybeans, peanuts, tobacco, sugar cane and vegetables. In general, for every ton of grain crops produced, such as rice and wheat crops require 3-4 kg of sulfur, legumes require 6-8 kg of sulfur, and oil crops require 10-12 kg of sulfur. If the crop is deficient in sulfur, the growth will be hindered, the leaves will be chlorotic or yellow, the leaf area will be small, and the stems will be thin and short, similar to the symptoms of nitrogen deficiency. The difference is that the leaf chlorosis will first appear in the young leaves when sulfur is deficient. Nitrogen deficiency is first manifested from the lower old leaves.
Where does sulfur come from? The sulfur needed for crop growth comes from soil, fertilizer, algae water and the atmosphere. The total sulfur content of cultivated soil is 0.01%-0.05%, most of which exists in soil organic matter, and the effective sulfur that can be directly absorbed and utilized by crops accounts for less than 10% of total sulfur. Sulfur-containing fertilizers are an important source of supplemental soil sulfur. Sulphur is also present in rainfall and irrigation water. The amount of sulfur that is reduced from rainwater into the soil each year is about 0.2-0.3 kg/mu. Sulfur dioxide in the atmosphere can be directly absorbed by plants, and sometimes half of the sulfur required by crops comes from the atmosphere. The normal concentration of sulfur dioxide in the atmosphere is 0.05 g/m3, and if the content exceeds 1 g/m3, the plant will be poisoned. Since the soil available sulfur is lost with water, the amount of sulphur is about the amount of sulphur brought in by the rainwater. Therefore, the supply of sulphur in the arable land depends mainly on fertilization.
How to judge soil and crop sulfur deficiency If the crop has the above symptoms of sulfur deficiency, it can be initially judged that the crop is deficient in sulfur. However, sometimes the crop is sulphur-deficient but has no obvious symptoms; sometimes the sulphur deficiency of the crop is accompanied by the lack of other nutrients, or there is a certain disease, and it is difficult to identify whether it is sulphur-deficient. In order to accurately diagnose, it is necessary to carry out a quantitative test of soil available sulfur and plant sulfur, and to carry out a sulfur fertilizer test. Generally, the effective sulfur content of soil is 16 mg/kg of soil as the indicator of sulfur deficiency. Below this value, the soil is often insufficiently supplied with sulfur. Plants use the total sulfur content of dry matter as a nutritional indicator. Generally, the critical index of grass crops is 0.1%, and cotton is 0.2%.
The ratio of sulfur to nitrogen in crops can also be used as an indicator of nutrient status. Generally, the leaf sulfur to nitrogen ratio of field crops is 1:15-20. If the sulfur content is lower than this ratio, it indicates that the crop may be deficient in sulfur.
Why is the sulphur deficiency in farmland gradually serious? In recent years, a large amount of high-concentration non-sulfur fertilizers such as ammonium phosphate and urea have been applied, while the amount of sulphate-containing fertilizers such as superphosphate and ammonium sulphate has decreased, and the amount of organic fertilizers and sulphur-containing pesticides has gradually decreased, resulting in annual The amount of sulfur applied to the soil is decreasing year by year.
Second, the land multiple cropping index and crop yield increase, the amount of sulfur required for crop growth and the amount of sulfur taken along with the harvest increased, so that the soil sulfur content decreased year by year.
Third, with the increase of environmental pollution control, the concentration of sulfur in the atmosphere and water is reduced, and the amount of sulfur obtained from crops and irrigation water is reduced.
4. Some soils with low organic matter content and coarse texture have low sulfur content; in areas with heavy rain, more sulfur is lost from the leakage water of the drainage, which causes the soil sulfur content to decrease.
Among the many causes of crop sulfur deficiency, the first three are the main reasons. According to the analysis results of more than 10,000 soil samples in 18 provinces and cities in China, one third of the soil has a low effective sulfur water content, and the sulfur deficiency in the southern provinces and northeastern regions is more common. Since the supply of sulfuric acid fertilizer is less than one year, and the demand for sulfur increases with the increase of grain output year after year, the sulfur fertilizer gap is getting bigger and bigger. In 1997, the sulfur deficiency was 900,000 tons. It has reached 1.5 million tons and is expected to reach 2.1 million tons in 2007. The situation is very serious.
How to properly apply sulphur fertilizer The sulfuric acid fertilizer currently applied in China is mainly superphosphate, ammonium sulphate and the like. Many compound fertilizers also contain different proportions of sulfur. Gypsum is an important sulphur fertilizer, slightly soluble in water, and should be ground before use to facilitate plant absorption and utilization. Sulfur has a high sulfur content, but it is hardly soluble in water. It is absorbed into the soil after being microbialized by the microorganisms and absorbed by the crop. The fertilizer effect is slow but long lasting.
When the crop is close to the reproductive growth period, it is the peak of sulfur demand. As the crop ages, the ability to absorb sulfur decreases. Therefore, the sulfur fertilizer should be applied before the reproductive growth period. As a base fertilizer, it can be mixed with fertilizers such as nitrogen, phosphorus and potassium, combined with cultivated land. Into the soil. If sulfur deficiency is found during crop growth, quick-acting sulfur fertilizer such as ammonium sulfate can be used for top dressing or spraying.
Sulfur-iodine fertilizer should be applied early, can be mixed with crushed soil and applied, and can be used for seed dressing or planting seedlings (holes) for seed fertilizer, and can also be used for mixing soil and fertilizer. For the root fertilizer.
The amount of fertilizer applied should be determined according to the amount of sulfur required by the crop and the degree of sulfur deficiency in the soil. In general, 1.5-3 kg of sulfur per acre of sulfur-deficient soil can meet the demand of sulfur in the current season. For example, if 20 kg of calcium phosphate or 10 kg of ammonium sulfate is applied per acre, it is also possible to apply 10 kg of gypsum powder or 2 kg of sulfur powder per acre.
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