Vegetables in greenhouse are most prone to calcium deficiency.

Vegetables are calcium-loving crops. When planting, people often attach importance to the application of nitrogen, phosphorus and potassium fertilizer, but despise calcium fertilizer. With the emergence of a large number of protected cultivation, it is more likely to lead to calcium deficiency in greenhouse soil. So, how to supplement calcium to crops reasonably?

Reasonable selection of calcium fertilizer

Different calcium fertilizers have different properties, and the pH value of soil in greenhouse is 6.5-7.5. alkaline or neutral fertilizers, such as hydrated lime and calcium nitrate, should be applied, but acidic or physiological acidic substances should be used less. Common phosphate fertilizers such as calcium superphosphate, calcium magnesium phosphate and heavy superphosphate are important sources of calcium fertilizer. Bone meal and plant ash all contain a certain amount of calcium, which can not be ignored, which can be selected according to the situation.

It is recommended to use water-soluble fertilizers containing medium and micronutrient elements containing calcium (not less than 120 grams / liter, magnesium not less than 20 grams / liter, zinc not less than 50 grams / liter, boron not less than 3 grams / liter), supplement calcium and other trace elements, pay attention to choose fertilizers with low salt concentration, which are safer for crops.

The best fertilization period

After the vegetable growth entered the prosperous period, the soil calcium nutrition began to decrease, at the same time, the calcitonin in vegetable leaves began to decrease, and the application of calcium fertilizer was the best time. In production, basal calcium fertilizer can be used to prevent calcium deficiency in the early stage of vegetable growth. In the shed that has been planted for many years, 2000-3000 kg of mature organic fertilizer is applied per mu, and then 30-45 kg of superphosphate is added.

Suitable fertilization method

For the vegetable greenhouse with heavy acidity of soil, the method of re-applying base fertilizer is adopted, that is, 100 kg of plant ash or 50 kg of hydrated lime per mu, in order to adjust the acidity and alkalinity of the soil. The specific method is to mix organic fertilizer with cooked lime or plant ash, apply it evenly to the ground surface, and plough it into the ground.

For growing vegetables, especially after entering the vigorous growth period, the method of topdressing can be used to supplement calcium nutrition, generally 40 kilograms of hydrated lime per mu, and the amount of lime in sandy soil can be reduced appropriately. This can not only supplement calcium, but also help to neutralize soil acidity, increase pH value and improve soil aggregate structure. Can also be 80 kg of cooked lime or 50 kg of plant ash, open one end of the film, trench depth of 10 cm, fertilizer will be applied to the bottom of the ditch after watering, underwater infiltration after covering the soil film. Or deep ploughing and plastic film mulching cultivation can enhance its ability of water and fertilizer conservation, maintain the relative stability of soil moisture and reduce the loss of calcium. It can also be combined with disease prevention spray to use foliar topdressing to supplement calcium, and the concentration of topdressing is generally 0.3% to 0.5%. Generally, 0.1% 0.2% calcium nitrate or 1% superphosphate can be sprayed every 15 days or so, and the effect is good.