Alkaline soils that can cultivate fruit trees are generally calcareous soils such as cinnamon soil, yellow soil and shajiang black soil. In this soil, fruit trees are prone to trace elements such as iron, manganese and zinc. Applying the appropriate inorganic salt fertilizer directly to the soil, such as ferrous sulfate, manganese sulfate and zinc sulfate, is also basically ineffective. Alkaline soil top dressing, pay attention to the following points:
(1) Increase the use of organic fertilizers, intercropping green manure and orchard grass cover, increase soil organic matter to activate soil nutrients.
(2) For trace element deficiency, the corresponding inorganic fertilizer can be decomposed with organic fertilizer to increase the effectiveness of trace fertilizer. The deficiency of the disease during the growing season can be supplemented by the spraying of organic chelates.
(3) Phosphate fertilizer is changed to diammonium phosphate or superphosphate. Alkaline soil calcium magnesium phosphate fertilizer or phosphate rock powder is basically ineffective, while the use of diammonium phosphate and superphosphate is very effective. Diammonium phosphate is in the form of granules, which can increase the available phosphorus content in the soil. Calcium superphosphate is best applied to soils with high phosphorus content. Sulfur contains a certain amount of sulfuric acid, which is favorable for the activation of active components in the soil.
(4) Try to use physiological acidic fertilizers such as ammonium sulfate, ammonium chloride, and potassium chloride. These fertilizers can effectively acidify the soil and are generally not susceptible to chlorine poisoning in well-watered areas.