Quicklime is often used in agricultural production, mainly because it has the following functions:
● It can supply calcium nutrients to crops; when the concentration of hydrogen ions, active iron and aluminum in acidic soil is high, it will have toxic effects on crops. The application of lime can neutralize soil acidity, precipitate high concentrations of active iron and aluminum, and eliminate poisons;
● It can adjust soil acidity, promote the activities of beneficial microorganisms, accelerate the decomposition of organic nitrogen, phosphorus and sulfur compounds in the soil, and increase the content of available nitrogen, phosphorus and sulfur in the soil;
● After lime is applied, it is beneficial to the formation of soil aggregate structure, thereby enhancing the soil’s ability to retain water and fertilizer;
● It can prevent and control diseases and insect pests. Quicklime is an alkaline substance that has the ability to kill diseases, insect eggs and weeds in the soil. For example, clubroot disease of cruciferous vegetable crops and bacterial wilt disease of nightshade vegetables rarely occur in neutral to alkaline soils.
The rational use of lime has many functions, but in the actual production process, if the operation is improper, it will affect the normal growth of vegetables. The different uses of quicklime have the following considerations:
Use with fertilizers
When the base fertilizer is applied in the production, quicklime can be applied together. However, it should be noted that quicklime has strong neutralizing ability, and the amount of lime should be reduced when applying alkaline fertilizers; and the amount of lime can be appropriately increased when applying acid fertilizers.
★ Application points:
Evenly spread to prevent local soil from being too alkaline or not applied. Drill crops can be applied in small quantities. Tomato, cabbage, etc. can be applied in a small amount when planting. When planting calcium-loving vegetables such as soybeans and tubers on calcium-deficient soil, use 15-25 kg of lime per acre for furrow or hole application.
In acid paddy fields, lime is applied as base fertilizer in combination with other fertilizers during soil preparation. In paddy fields planted with green manure, 25 to 50 kg of lime can be applied per mu when turning the ground and pressing green to promote the decomposition of green manure, accelerate the release of nutrients, and at the same time eliminate some toxic substances produced by the decomposition of green manure. If the soil is highly acidic, 50 to 100 kilograms of lime should be applied per mu, or even as high as 150 kilograms to be effective.
When dryland crops are combined with ploughing, or when crops are sown and planted, a small amount of lime can be mixed with an appropriate amount of soil and miscellaneous fertilizers and applied to the seeding hole or seeding ditch.
Some vegetable farmers are used to putting quicklime and fermented manure (organic fertilizer) into the soil, and then turning the ground to disinfect the soil. This practice is actually inappropriate. Because quicklime easily reacts with the fermented organic fertilizer, which affects the fertilizer efficiency of organic fertilizer and the sterilization and disinfection effect of quicklime.
Therefore, the quicklime should be deeply digged into the soil, and then the organic fertilizer should be applied a week later. It cannot be mixed with ammonium nitrogen fertilizer, decomposed organic fertilizer and water-soluble phosphate fertilizer, so as not to cause nitrogen loss and phosphorus degradation, resulting in reduced fertilizer efficiency.
For sterilization and insecticide
When quicklime is used for sterilization and insecticide in vegetable production, it is mainly used for spreading, acupoint application, smearing and spraying.
1. Sasha
Spreading 100-150 kg of quicklime per acre can adjust the pH of the soil, and can prevent and treat the white silkworm disease of cucumber, pumpkin (black-seed pumpkin), sweet (spicy) pepper, potato, kidney bean, lentil, etc., tomato, eggplant, sweet (spicy) Bacterial wilt of peppers and strawberries, clubroot of cabbage, radish, cabbage, etc., bacterial soft rot of carrots, ginger blast, melon wilt, pea seedlings stem base rot (blight), potato powder scab disease, etc.
Spreading 50-100 kg of quicklime per acre can prevent and cure pepper scab. After ploughing the vegetable field, sprinkle 25-30 kg of quicklime per mu, and dry the soil for 7 days, which can prevent vegetable springtails. On sunny days, use 5 to 7.5 kg of quicklime per acre, and sprinkle it in a line between the rows to prevent slugs.
2. Acupuncture
Spreading 250 grams of raw (dissolved) lime per hole can prevent bacterial wilt, canker, eggplant bacterial wilt, potato soft rot, zucchini soft rot, melon blight, celery and caraway soft rot, cabbage Such as soft rot and clubroot, leek white silk disease, ginger bacterial wilt, carrot bacterial soft rot, konjac anthracnose, strawberry fusarium wilt, etc.Mix 1 part of lime and 2 parts of sulfur to make mixed powder, and apply 10 kg per acre of holes to prevent and cure smut of green onions and onions. Pour 300-500 ml of 20% lime water into each hole, which can prevent tomato bacterial wilt, canker and zucchini soft rot.
When applying quicklime in furrows or holes, avoid contact with seeds or vegetable roots.
3. Smear
Apply 2% lime slurry to the incision before the yam enters the cellar to prevent rot disease; after the sweet pepper is planted, when the stalk is thick with chopsticks, add quicklime to water to make a paste, and brush directly on the stem base to reduce Occurrence of disease at the base of bell pepper stems.
4. Spray
Using 500-900 grams of lime powder per mu, diluted with 50-90 kg of water, and spraying with clear liquid, it can control amber snails and elliptical turnip snails.
For soil disinfection
When treating vegetable field soil with quicklime, pay attention to:
1. Keep it properly
Quicklime can form calcium hydroxide when it meets water. Many vegetable farmers are used to pulling quicklime by car in advance, and then putting it on the roadside and leaving it alone. When it is used, most of the quicklime absorbs water and turns into calcium hydroxide, which is already ineffective. Therefore, it is best to use the quicklime and pull it now, or cover it with a film after pulling it, and then open it when it is used.
2. Do not use too much
Is it that the more quicklime is used, the better the sterilization effect?
In fact, the amount of quicklime per mu should not exceed 500 kg, otherwise it will cause the rapid decomposition of soil organic matter and damage the soil structure. At the same time, phosphate and trace elements such as iron, manganese, boron, zinc, copper and other trace elements in the soil will also form insoluble sediments , reducing soil fertility.