Ten things to avoid when fertilizing greenhouse vegetables in winter, growers must keep in mind

In winter greenhouse vegetable cultivation, calcium deficiency causing scorched edges on tender leaves, zinc deficiency causing small leaves, iron deficiency causing yellowing, boron deficiency causing necrosis of terminal buds and poor root growth, and various other deficiency symptoms are becoming more and more common, and they are difficult to distinguish and even harder to prevent and control. As we all know, vegetable nutrient deficiency occurs because the roots fail to absorb enough of a certain nutrient in time, which then causes abnormal symptoms, but the cause of the root absorption disorder is not necessarily a lack of that element in the soil. In most cases, it is improper management measures such as fertilizing and watering that lead to deterioration of soil properties. Either the effective activity of nutrient elements in the soil declines, like half-cooked food that is hard to swallow, or the roots grow poorly, so even though the food is tasty, they cannot eat it. Therefore, when fertilizing greenhouse vegetables in winter, ten things should be noted.

1. Do not apply large amounts of undecomposed cake fertilizer

Because cake fertilizer contains a lot of nitrogen, has a small carbon-to-nitrogen ratio and decomposes quickly, it easily produces high temperatures and high concentrations of ammonia and organic acids locally, and easily burns the roots. The cake fertilizer should be crushed and mixed with crushed straw, then soaked in human feces and urine for about 3 to 5 weeks, and used only after high-temperature fermentation.

2. Do not apply ammonium sulfate, and it is forbidden to apply ammonium bicarbonate

Ammonium sulfate is a physiologically acidic fertilizer. After application, it increases soil acidity and destroys soil structure. After ammonium bicarbonate is applied, it releases a large amount of ammonia gas, which is unfavorable to vegetable growth in a strongly enclosed greenhouse.

3. Do not apply chlorine-containing chemical fertilizers

Chloride ions can reduce the starch and sugar content of vegetables, making vegetable quality worse and reducing yield. Moreover, chloride ions remaining in the soil can cause soil acidification and easily lead to soil calcium loss.

4. Do not fertilize under drought conditions

Vegetables are water-loving crops. Fertilizing when the soil is dry not only prevents the fertilizer effect from being fully exerted, but also suddenly increases the concentration of the soil solution, which easily burns vegetable roots. Therefore, vegetable fertilization should be combined with irrigation, or furrows should be opened for fertilization, the fertilizer should be buried firmly and then irrigated, or fertilizer should be applied with the water.

5. Do not apply too much diammonium phosphate

Most vegetables need relatively little phosphorus, and too much phosphate fertilizer instead inhibits the absorption of medium and trace elements. Diammonium phosphate should also not be mixed with alkaline fertilizers such as plant ash, so as to avoid causing ammonia volatilization and ammonia damage.

6. Do not apply potassium fertilizer as a topdressing in the late growth stage of vegetables

Vegetables generally need more potassium fertilizer before and after flowering, and then the need gradually decreases.

7. Do not apply phosphate fertilizer in a scattered way

Phosphorus is easily absorbed and fixed by the soil and loses its fertilizer effect. Therefore, when phosphate fertilizer is used as a base fertilizer, it is best to apply it in furrows, or apply it in a concentrated way in the soil layer where roots are dense during the early stage of vegetables.

8. Do not apply large amounts of zinc and iron fertilizer to the soil

Zinc and iron are trace elements, and they are difficult for roots to absorb from the soil, and their conduction is also slow. Therefore, an appropriate amount of zinc and iron fertilizer can be added to the base fertilizer. When vegetables are deficient in zinc, a micro-fertilizer containing zinc (such as Zhongbao Yuyi) can be sprayed on the leaves, and the effect is faster.

9. Do not spray potassium fertilizer and calcium fertilizer at the same time

When potassium and calcium meet, they are even less easily absorbed by vegetable leaves, so spraying them together should be avoided. However, spraying boron and calcium together, and zinc and iron together, has better effects.

10. Do not apply a large amount of water-soluble fertilizer in one flush application

In winter, soil temperature is relatively low and root absorption capacity is somewhat poor. If a large amount of fertilizer is applied in one flush, the amount that roots can absorb is often very little, and the fertilizer gradually accumulating in the soil will in turn worsen soil properties and reduce root absorption capacity. Therefore, winter flush fertilization should be small and frequent.