Chemical fertilizers must be applied with care: ten major taboos to avoid
Fertilizer is the "food" of vegetables. Apart from carbon, hydrogen and oxygen, the 13 nutrient elements are all supplied by the soil, and applying base fertilizer is an important measure for replenishing soil nutrients. At present, the types of fertilizers used on vegetables are broadly divided into three categories: organic fertilizers (farmyard manure), inorganic fertilizers (chemical fertilizers) and microbial fertilizers (biological bacterial fertilizers)...
1. Do not water immediately after applying urea. Urea is a readily soluble fertilizer with strong mobility and is extremely prone to loss. After broadcasting urea on dry land, never water immediately, and it should not be applied before heavy rain. 2. Ammonium bicarbonate should not be applied on the soil surface. Ammonium bicarbonate is highly volatile and can easily burn seedlings. Therefore, ammonium bicarbonate should not be surface-applied; it is best to dig holes and apply it deeply, then cover with soil.
3. Ammonium bicarbonate should not be applied inside greenhouses and plastic tunnels. Ammonium bicarbonate is known as a "gas fertilizer"; when applied inside greenhouses and plastic tunnels, it easily decomposes rapidly into ammonia gas
4. Ammonium nitrogen fertilizers must not be mixed with alkaline fertilizers. Ammonium nitrogen fertilizers such as ammonium bicarbonate, ammonium sulfate, ammonium nitrate and ammonium phosphate will lose nitrogen when they encounter alkaline substances. Never mix and apply them with alkaline fertilizers such as plant ash and kiln ash potash fertilizer, which cause volatilization, or with calcium cyanamide.
5. Nitrate nitrogen fertilizers should not be applied in paddy fields. The nitrate ions dissociated from nitrate nitrogen fertilizers such as ammonium carbonate are easily leached by water into deep soil layers in paddy fields, causing denitrification and resulting in nitrogen loss.
6. Ammonium sulfate should not be applied over the long term. Ammonium sulfate is a physiologically acidic fertilizer that damages the physical structure of the soil. Long-term application in alkaline soil will also cause the sulfate ions remaining in the soil to react with calcium, making the soil compacted and hard.
7. Phosphate fertilizer should not be applied in a scattered manner. Phosphorus has low mobility and is easily absorbed and fixed by the soil, reducing fertilizer efficiency. When applying phosphate fertilizer, the contact area between the phosphate fertilizer and the soil should be reduced; it is best to use furrow application or hole application, concentrating it near the crop roots.
8. Potassium fertilizer should not be applied in the late stage of crop growth. Potassium has the characteristic of being able to move from the basal stems and leaves of the crop to the tender upper parts for reuse, so potassium deficiency symptoms appear later than those of nitrogen and phosphorus. Therefore, potassium fertilizer should be applied earlier in the early stage of crop production, or applied all at once as a base fertilizer.
9. Chloride-containing fertilizers should not be applied alone over the long term, and application to chlorine-sensitive crops should be avoided. Long-term application of potassium chloride alone will increase the accumulation of chloride ions in the soil, leading to destruction of the soil nutrient structure and soil acidification. Applying it to chlorine-sensitive crops such as sugarcane, sugar beet, watermelon and tobacco will reduce their quality and grade.
10. Nitrogen-containing compound fertilizers should not be applied in large amounts to leguminous crops. Crops such as soybean, peanut, mung bean, broad bean, pea and alfalfa have nitrogen-fixing rhizobia near their roots. If nitrogen-containing compound fertilizers are applied in large amounts, it will not only waste fertilizer but also inhibit the activity of rhizobia and reduce their nitrogen-fixing capacity