How to apply calcium fertilizer-lime and gypsum in soil?

Answer: Lime and gypsum are used to supplement soil calcium, adjust soil physical and chemical properties and improve soil.

(1) lime. It can be divided into quicklime, hydrated lime and limestone powder, which is strongly alkaline. Applying lime in soil can not only supplement crop calcium, but also adjust soil acidity and alkalinity, improve soil structure, promote the activity of beneficial microorganisms in soil, and accelerate the decomposition of organic matter and nutrient release. It can reduce the fixation of iron and aluminum ions on phosphorus in soil and improve the availability of phosphorus; Lime can kill bacteria, eggs and weeds in the soil.

① Application method of lime: it is mainly used in acidic soil, and can be used as base fertilizer or topdressing. Lime is applied together with farmyard manure, combined with base fertilizer and soil preparation, or combined with green manure stubble pressing and straw returning to the field. Topdressing can be carried out in the growing period of crops, and the amount of basal application is greater than topdressing. Generally, 15 ~ 25 kg is applied to rice seedling field, 50 ~ 100 kg is applied to Honda, and about 25 kg is applied to tillers after young panicle differentiation. 25 ~ 50 kg of base fertilizer should be applied to dry land, 65,438+050 ~ 250 kg of soil improvement and 65,438+05 kg of topdressing should be applied to strip or hole.

② Attention should be paid to the following points when applying lime: firstly, excessive lime should not be used, otherwise it will accelerate the decomposition of organic matter, reduce soil fertility and easily cause soil hardening and structural damage; Secondly, lime is alkaline and should be applied evenly to prevent local soil from being too alkaline and affecting crop growth, and avoid contact with seeds or roots; Three, wheat, barley and other crops that are not acid-resistant can be appropriately applied more, beans, beets, rice and other moderately acid-resistant crops can be applied less, potatoes, tobacco, tea trees and other crops with strong acid resistance can not be applied. The residual period of lime is 2 ~ 3 years. When a large amount of lime is applied at one time, it should not be applied every year.

(2) gypsum. There are three kinds of agricultural gypsum: raw gypsum, plaster of Paris and phosphogypsum, which are acidic. Mainly used for alkaline soil, eliminating soil alkalinity, improving soil and supplying crops with calcium and sulfur nutrition.

① Used for alkali improvement: Gypsum should generally be applied to alkaline soil with pH above 9 and containing sodium carbonate, and the application amount per mu is 65,438+000 ~ 200 kg, which is suitable as base fertilizer and has a long after-effect period, so it is unnecessary to apply it every year. At the same time, it should be used in combination with planting green manure or with farm manure and phosphate fertilizer.

② Application as calcium and sulfur nutrition: the amount of root soaking per mu in paddy field is about 3 kg, and the amount of base fertilizer or topdressing is 5 ~ 10 kg. Dry land is spread on the soil surface, and then combined with tillage base fertilizer, it can also be used as seed fertilizer for strip application or hole application. Base application rate 15 ~ 25 kg, seed fertilizer amount 4 ~ 5 kg.