What fertilizer is good for secondary fertilization of corn

It is recommended to use fertilizers such as urea, diammonium phosphate, and potassium chloride for secondary fertilization of corn. The selection of nitrogen fertilizer, phosphorus fertilizer, potassium fertilizer or compound fertilizer for secondary topdressing should be based on the growth stage of corn and soil conditions, mainly considering factors such as soil fertility, corn growth, climatic conditions, fertilizer solubility, nutrient balance, etc.

1. Urea

Urea has a high nitrogen content and is suitable for topdressing during the corn jointing to large horn stage. Nitrogen can promote stem and leaf growth and improve photosynthetic efficiency. When applying, avoid high temperature periods and deeply cover the soil to reduce ammonia volatilization. Sandy soil should be applied in stages to avoid nutrient loss. Be careful to avoid direct contact with seeds or roots to prevent seedling burning.

2. Diammonium phosphate

Diammonium phosphate contains both nitrogen and phosphorus nutrients and is suitable for plots with insufficient soil available phosphorus. Phosphorus can promote root development and spike differentiation, and enhance lodging resistance. When topdressing, it can be applied in strips next to the plants, mixed with soil, and then watered. Alkaline soil should be used in conjunction with organic fertilizers to prevent phosphorus from being fixed. Phosphorus deficient fields can increase their usage, but the total phosphorus content needs to be controlled to prevent eutrophication.

3. Potassium Chloride

Potassium chloride is suitable for topdressing during the corn booting stage, especially in potassium deficient soils. Potassium can enhance disease and drought resistance, promote grain plumpness. Sandy loam soil should be applied in batches, while clay soil can be deeply applied in one go. Salt alkali land needs to be replaced with potassium sulfate to avoid chloride ions exacerbating salt damage. Timely irrigation after application to promote the diffusion of potassium ions into the root system.

4. Compound fertilizer

High nitrogen compound fertilizer is suitable for corn fields with weak growth, and can simultaneously supplement medium and trace elements. Choose ratios such as 15-15-15 or 28-6-6, and adjust the nitrogen, phosphorus, and potassium ratios based on leaf color diagnosis. Slow release compound fertilizer can prolong fertilizer efficiency and reduce the frequency of topdressing. When applying, it should be evenly spread to avoid excessive local concentration. The use of humic acid fertilizers can improve nutrient utilization efficiency.

5. Organic fertilizer

Fermented farm manure or commercial organic fertilizer can improve soil structure, and the effect is better when applied in combination with chemical fertilizers. Cow manure, compost, and other materials are rich in organic matter and can slowly release nutrients. When applying, it is necessary to ensure complete decomposition to prevent root burning and the spread of pests and diseases. Sticky soil can increase usage, and continuous cropping fields should be used in conjunction with microbial agents. Pay attention to controlling the dosage and avoid late ripening due to excessive consumption.

Secondary fertilization of corn needs to be flexibly adjusted based on field diagnosis. During the jointing stage, nitrogen fertilizer is mainly used, while phosphorus and potassium fertilizers are increased during the trumpet stage. In arid areas, water fertilizer integration is recommended. Suggest developing a formula after soil sampling and testing to avoid blind fertilization. Timely plow and cultivate soil after fertilization to improve fertilizer utilization efficiency. Pay attention to the growth of corn and spray potassium dihydrogen phosphate isokinetic fertilizer on the leaves when there are symptoms of fertilizer loss. Avoid applying large amounts of nitrogen fertilizer before the rainy season to prevent nutrient loss and environmental pollution. Reasonable crop rotation and straw returning can gradually reduce the amount of fertilizer used.