In recent years, due to the continuous increase of land multiple cropping index and crop yield, the sulphur nutrients absorbed by crops have increased. In some places, due to the change of chemical fertilizer varieties, a large amount of high-concentration non-sulfur fertilizers such as phosphamine and urea have been applied. Calcium, ammonium sulfate and other sulfuric acid-containing fertilizers are reduced; some soils with low organic matter content and coarse texture have low sulfur content. In areas with heavy rain, more sulfur is lost from rainwater and seepage water; environmental pollution treatment is increasingly strengthened, and the atmosphere The concentration of sulfur in water and water is reduced, and the sulfur obtained from crops and irrigation water is reduced. At the same time, the amount of organic fertilizer and farmyard manure is reduced, and the amount of sulfur supplied to soil by organic sulfur is decreasing. Therefore, it is easy to cause soil sulfur deficiency in some areas. Mastering the symptoms of sulfur deficiency in common crops and taking effective measures in a timely manner play an important role in guiding agricultural production.
First, the main crops are deficient in sulfur.
When the crop is deficient in sulfur, the growth is hindered, the leaves are chlorotic or yellow, the leaf area is small, and the stem is small and short, similar to the symptoms of nitrogen deficiency. The difference is: when the sulfur is deficient, the leaves are chlorotic yellow, first appear in the young leaves; and the nitrogen deficiency is first expressed from the lower old leaves.
1. Wheat: The plant color is light green, and the young leaves are more green than the old leaves. When the sulfur is severely deficient, the leaves appear brown spots.
2. Rapeseed: The initial performance is light green, the color of young leaves is lighter than that of old leaves. Later, the leaves gradually appear purple-red plaques, the leaves are curled upwards, the flowering pods are late, the flower pods are light and pale, and the roots are short and thin.
3, rice: late green, less or no tillering, the plant is thin and short, the leaves are thin and the number of tablets is small, the young leaves are light green or yellow-green, the tip of the leaves has water-stained round brown spots, the tip of the leaves is scorched. The roots are dark brown, with less white roots and delayed growth.
4, cotton: the plant is short, the whole plant becomes light green or yellow-green, and the growth period is postponed.
5. Soybeans: The new leaves are light green to yellow, and the veins of the veins are chlorotic, but the old leaves are still light green. The old leaves are also green and yellow, and brown spots appear. The plants are thin, the roots are slender, and the nodules are poorly developed.
6. Tobacco: The whole plant is light green, the lower part of the old leaf is easy to be scorched, the tip of the leaf is often curled, and some prominent bubble points appear on the leaf surface.
7. Potato: The leaves and veins are usually yellow, and the symptoms are similar to those of nitrogen deficiency, but the leaves do not dry out in advance. When the sulfur is extremely deficient, brown spots appear on the leaves.
Second, the application technology of sulfur fertilizer 1, the application period: the crop is near the reproductive growth, the peak period of demand for sulfur. As the crop ages, the ability to absorb sulfur decreases. Therefore, the sulfur fertilizer should be applied before the reproductive growth, and the base fertilizer is better applied. It can be mixed with fertilizers such as NPK and combined with the cultivated land. For example, in the process of crop growth, sulfur deficiency can be used as a top dressing or foliar spray with quick-acting sulfur fertilizer such as ammonium sulfate, calcium persulfate or potassium sulfate.
2. Application rate: The application rate of sulfur fertilizer should be determined according to the type of crop and the degree of sulfur deficiency in the soil. To plant more sulfur-rich crops on soils with more sulfur deficiency, more sulfur fertilizer should be applied. According to the results of field trials for many years, the suitable sulphur content of several crops in Anhui Province is: 2 kg per mu of rice and wheat; 4 kg per acre of soybean; 4-6 kg per mu of rapeseed. Generally speaking, 1.5-3 kg of sulfur per acre of sulfur-deficient soil can meet the needs of seasonal crops, such as 20 kg of calcium phosphate per acre, or 10 kg of ammonium sulfate, or 10 kg of gypsum or 2 kg of sulfur powder. . In order to improve the fertilizer efficiency, the amount of sulfur should be adapted to the amount of nitrogen and phosphorus applied, and the amount of nitrogen and phosphorus should be increased. The amount of sulfur should be increased accordingly. It is recommended that in the production of wheat, 10 kg of nitrogen should be applied per mu, and 2 kg of sulfur should be applied. In the production of soybeans, 3 kg of phosphorus should be applied per mu, and 3 kg of sulfur should be applied.
3. Application method: The sulfur fertilizer can be applied alone or in combination with NPK, and combined with the cultivated land to turn into the soil. Sulfur-based fertilizers should be applied early, mixed with fine soil or chemical fertilizers, cultivated into soil as base fertilizer, mixed with seeds and applied to seed ditch (points) for seed fertilizer, and mixed with soil for fertilizer application. .
First, the main crops are deficient in sulfur.
When the crop is deficient in sulfur, the growth is hindered, the leaves are chlorotic or yellow, the leaf area is small, and the stem is small and short, similar to the symptoms of nitrogen deficiency. The difference is: when the sulfur is deficient, the leaves are chlorotic yellow, first appear in the young leaves; and the nitrogen deficiency is first expressed from the lower old leaves.
1. Wheat: The plant color is light green, and the young leaves are more green than the old leaves. When the sulfur is severely deficient, the leaves appear brown spots.
2. Rapeseed: The initial performance is light green, the color of young leaves is lighter than that of old leaves. Later, the leaves gradually appear purple-red plaques, the leaves are curled upwards, the flowering pods are late, the flower pods are light and pale, and the roots are short and thin.
3, rice: late green, less or no tillering, the plant is thin and short, the leaves are thin and the number of tablets is small, the young leaves are light green or yellow-green, the tip of the leaves has water-stained round brown spots, the tip of the leaves is scorched. The roots are dark brown, with less white roots and delayed growth.
4, cotton: the plant is short, the whole plant becomes light green or yellow-green, and the growth period is postponed.
5. Soybeans: The new leaves are light green to yellow, and the veins of the veins are chlorotic, but the old leaves are still light green. The old leaves are also green and yellow, and brown spots appear. The plants are thin, the roots are slender, and the nodules are poorly developed.
6. Tobacco: The whole plant is light green, the lower part of the old leaf is easy to be scorched, the tip of the leaf is often curled, and some prominent bubble points appear on the leaf surface.
7. Potato: The leaves and veins are usually yellow, and the symptoms are similar to those of nitrogen deficiency, but the leaves do not dry out in advance. When the sulfur is extremely deficient, brown spots appear on the leaves.
Second, the application technology of sulfur fertilizer 1, the application period: the crop is near the reproductive growth, the peak period of demand for sulfur. As the crop ages, the ability to absorb sulfur decreases. Therefore, the sulfur fertilizer should be applied before the reproductive growth, and the base fertilizer is better applied. It can be mixed with fertilizers such as NPK and combined with the cultivated land. For example, in the process of crop growth, sulfur deficiency can be used as a top dressing or foliar spray with quick-acting sulfur fertilizer such as ammonium sulfate, calcium persulfate or potassium sulfate.
2. Application rate: The application rate of sulfur fertilizer should be determined according to the type of crop and the degree of sulfur deficiency in the soil. To plant more sulfur-rich crops on soils with more sulfur deficiency, more sulfur fertilizer should be applied. According to the results of field trials for many years, the suitable sulphur content of several crops in Anhui Province is: 2 kg per mu of rice and wheat; 4 kg per acre of soybean; 4-6 kg per mu of rapeseed. Generally speaking, 1.5-3 kg of sulfur per acre of sulfur-deficient soil can meet the needs of seasonal crops, such as 20 kg of calcium phosphate per acre, or 10 kg of ammonium sulfate, or 10 kg of gypsum or 2 kg of sulfur powder. . In order to improve the fertilizer efficiency, the amount of sulfur should be adapted to the amount of nitrogen and phosphorus applied, and the amount of nitrogen and phosphorus should be increased. The amount of sulfur should be increased accordingly. It is recommended that in the production of wheat, 10 kg of nitrogen should be applied per mu, and 2 kg of sulfur should be applied. In the production of soybeans, 3 kg of phosphorus should be applied per mu, and 3 kg of sulfur should be applied.
3. Application method: The sulfur fertilizer can be applied alone or in combination with NPK, and combined with the cultivated land to turn into the soil. Sulfur-based fertilizers should be applied early, mixed with fine soil or chemical fertilizers, cultivated into soil as base fertilizer, mixed with seeds and applied to seed ditch (points) for seed fertilizer, and mixed with soil for fertilizer application. .
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