How to apply sulfur fertilizer to crops
When the crop is deficient in sulfur, its appearance symptoms are similar to those of nitrogen deficiency. The leaves are light green or yellow. The deficiency occurs first on the leaves of young leaves. Generally, the young shoots turn yellow first, the leaves are green and yellow, and the plants are yellowed. The stem is weak, the root is slender and not branched, the flowering is delayed, and the fruit is reduced. Sulphur-sensitive crops are cruciferous such as canola, followed by legumes, tobacco, and cotton, and gramineous crops with less sulfur.
Symptoms of sulfur deficiency in main crops: rapeseed: the initial symptoms of sulfur deficiency are pale green, the color of young leaves is lighter than that of old leaves, and then the leaves gradually appear purple-red plaques, the leaves are curled upwards, flowering pods are delayed, flowers, pods light.
Soybean: The new leaves are light green to yellow, and the green color is uniform. The old leaves of the late growth stage are also yellowish and chlorotic, the leaves are brown spots, the plants are thin, the roots are elongated, and the nodules are poorly developed.
Cotton: The plants are small and the whole plant turns pale green or yellowish green, and the growth period is delayed.
Rice: slow green, no tillering or less tillering, plants are thin and short, the leaves are thin, the young leaves are pale green or yellow-green, the tip of the leaves is water-soaked round brown spots, and the tip of the leaves is scorched. The roots are dark brown, with less white roots and delayed growth.
Reasonable application of sulfur fertilizer
Depending on the type of crop, the type of soil, and the purpose of fertilization, the amount of sulphur fertilizer applied, the method of application, and the period of fertilization vary. The amount of application is generally more than the application, the application of the hole, and the like. Water-soluble fertilizers (such as sulphate sulphur fertilizer) can be used as base fertilizer, top dressing and seed fertilizer, and water-insoluble fertilizers (such as sulphur-based sulphur fertilizer) are generally used as base fertilizers, and should be applied early as base fertilizer. Sulfate fertilizers are generally recommended, including ammonium sulfate, calcium superphosphate, gypsum, potassium sulfate, and the like. Sulfur-based fertilizer with highly dispersible granular sulfur fertilizer. The recommended amount of sulphur fertilizer for different crops is different. The recommended amount of sulphur fertilizer: grain: 1.3-2.7 kg/mu, beans, oil, vegetables: 2.0-4.0 kg/mu; sugar material: 2.7-5.3 kg/mu. At the same time, the application of sulfur fertilizer should be combined with nitrogen, phosphorus and potassium to achieve nutrient balance. Studies have shown that in order to achieve optimal growth of plants, the N/S ratio in plants is 15:1-20:1, and the P/S ratio is 1:1. When crops are fertilized, the N/S ratio is generally 7:1 and the P2O5/S ratio is 3:1.
As an alkaline earth improver (application of gypsum, etc.), the amount used is more than nutrient fertilization, and the amount of application is generally more than that of application, acupoint application, and the like.
Sulphur increase production and income increase effect
Crop yield increase effect. In the past 10 years, more than 600 field trials of China's major crops have shown that more than 85% of field trials have significant yield-increasing effects, with yields ranging from 7% to 15%, with an average of 10%. Citrus, soybean, sugar cane, sweet potato, peanuts and tea leaves have the best effect on sulfur production, generally more than 10%.
Improve quality results. Rational application of sulphur fertilizer can increase the crude protein content of rice and wheat by 10%-27%, peanut and rapeseed oil content by 6.5%, sugar cane and banana sugar content by 10%-23%, tea amino acid content of 6.6%, citrus Vc The content is 4.4%.
The effect of increasing farmers' income. Rational application of sulphur fertilizer increased crop yield and quality, and increased farmers' income. The ratio of sulfur production to grain crops was 9:1, and that of fruit crops was 40:1.
The main function and role of sulfur
Sulfur is one of the 16 nutrients necessary for crops. It is the basic element that constitutes sulfur-containing amino acids and proteins, and is also an important component in the synthesis of other biologically active substances, directly involved in crop metabolism. Rational use of sulphur fertilizer plays an important role in improving crop yield and improving product quality.
Increase crop yields. Sulfur can be directly absorbed and utilized by crops, and is a main component of organic substances such as amino acids and proteins in crops. Like nutrients such as nitrogen, phosphorus and potassium, the rational use of sulphur fertilizer can effectively increase crop yield.
Improve crop quality. Sulfur is an important component of bioactive substances such as synthase and mustard oil, and promotes the synthesis of proteins, oils and vitamins in plants. Rational use of sulphur fertilizer can effectively increase the protein content of flour, the content of volatile compounds in onions, garlic and mustard, the nutritional value of vegetables and fruits, and the commodity rate.
Improve the utilization of other nutrients.
Reasonable use of sulfur fertilizer can increase the nutrient utilization rate of nitrogen, phosphorus and trace elements such as zinc, iron, copper, manganese and boron.
In general, the nutrient function of sulfur is similar to that of nitrogen. The sulfur requirement of crops is basically the same as that of phosphorus. Most crops take 1-2 kg of sulfur (pure nutrients) per mu from the soil, oil crops, legumes. Crops, pastures and some vegetables require more sulfur.
Why are some areas of China lacking sulfur in the soil?
In recent years, the phenomenon of soil sulfur deficiency in China is becoming more and more common, and the effect of applying sulfur fertilizer is becoming more and more obvious. The soil sulfur deficiency in China is mainly distributed in areas with warm and rainy, high degree of weathering and strong leaching crops; sandy soil areas with less organic matter, lighter texture and low substitution; far away from cities and industrial and mining areas, and low sulfur content in precipitation Mountainous areas; hilly areas in the south, cold-soaked fields with strong reducing conditions, long-term no application of areas containing sulfur fertilizer and organic fertilizer.
Source: Farmers Daily Author: Gao Xiang photos, Ma Chang Po