Crop fields have been cultivated for a long time, and acidification, salinization, and pathogenic bacteria are serious problems. How to improve the soil?

Due to long-term continuous cropping in vegetable greenhouses, pathogens and insect eggs accumulate; excessive application of physiologically acidic fertilizers and excessive application of nitrogen fertilizers cause a large accumulation of nitrate ammonia, and at the same time, the application of organic fertilizers

If it is too little, the soil buffering will be poor, thus causing soil acidification. In severe cases, crops will have dead seedlings and growing point necrosis. Single and excessive fertilization will cause soil salinity to rise and salt damage will be aggravated. Therefore, it is particularly important to improve various aspects of soil acidification and salinization in greenhouse vegetable plots.

What is soil acidification

Acidification is an important aspect of the soil weathering and soil formation process, which causes the pH value to decrease, forming acidic soil, affecting the activity of organisms in the soil, and changing the composition of nutrients in the soil. form, reducing the availability of nutrients, causing free manganese and aluminum ions to dissolve into the soil solution, causing toxic effects on crops. Generally speaking, the severity of soil acidification is expressed through the pH value. For example, pH value = 4.5 is extremely acidic; pH value = 4.5-5.5 is strongly acidic; pH value = 5.5-6.5 is acidic.

Causes of soil acidification in greenhouses

1. The high yield of greenhouse vegetables has removed too many basic elements from the soil, such as calcium, magnesium, potassium, etc., resulting in excessive consumption of potassium and medium and trace elements in the soil, causing the soil to develop in the direction of acidification.

2． The application of a large amount of physiologically acidic fertilizers results in high temperature and humidity in the greenhouse and little rainwater leaching. As the cultivation years increase, acid roots accumulate seriously in the soil in the cultivated layer, leading to soil acidification.

3. Due to the high multiple cropping index of greenhouses and the large amount of fertilizers used, the organic matter content of the soil decreases, the buffering capacity decreases, and the soil acidification problem aggravates.

4. The input proportion of high-concentration nitrogen, phosphorus and potassium ternary compound fertilizer is too large, while the input of medium and trace elements such as calcium and magnesium is relatively insufficient. Causes soil nutrient imbalance, making calcium, magnesium and other basic elements in soil colloidal particles easily replaced by hydrogen ions.

Dangers of soil acidification in greenhouses

1. Acidic soil breeds fungi, increases root diseases, and makes control difficult. In particular, clubroot of cruciferous vegetables and bacterial wilt and verticillium wilt of solanaceous vegetables are increasing.

2． The soil structure is destroyed, the soil is compacted, the physical properties are deteriorated, the stress resistance is reduced, and the ability of vegetables to withstand natural disasters such as drought and floods is weakened.

3. Under acidic conditions, the solubility and effectiveness of aluminum and manganese increase, causing toxic effects on vegetables.

4. Under acidic conditions, the number of hydrogen ions in the soil increases, which antagonizes the absorption of other cations by vegetables.

How to improve soil acidification

1. Apply more organic fertilizer to cultivate soil fertility

The application of organic fertilizer can increase the organic matter and humic acid in the soil and improve the soil acidification. The soil aggregate structure and permeability promote the activity of rhizosphere microorganisms and promote the conversion of insoluble mineral elements in the soil into soluble nutrients to achieve the effect of fertilizing the soil.

2. Add alkaline fertilizers

such as ammonium bicarbonate, ammonia, lime nitrogen, calcium magnesium phosphate fertilizer, phosphate rock powder, plant ash, etc. to neutralize acidity.

3. Applying quicklime

Application of lime is an important measure to neutralize soil acidity, control soil acidification and increase soil pH.