Major Heat Arrives, All Things Flourish
As the last solar term of summer, Major Heat coincides with the dog days of sweltering heat. Under the combined conditions of high temperature, intense sunlight and high humidity, field crops enter a critical overlapping stage of vigorous growth, yield formation, and high incidence of pests and diseases.
At this time, crops grow rapidly and consume large amounts of nutrients. However, improper fertilization in hot weather can easily lead to root burn, nutrient deficiency, fertilizer loss, excessive vegetative growth and flower drop. An old farming proverb says: "Fertilize smartly in Major Heat, harvest abundantly after autumn." Unlike fertilization in mild spring and autumn, topdressing during Major Heat emphasizes "light application, steady supply, precise timing, and cool conditions". Scientific, localized nutrient supplementation strengthens stalks, stabilizes fruit, enhances drought resistance and secures yields, laying a solid foundation for a bumper harvest throughout the year.
Today’s exclusive fertilization guide for Major Heat covers grain, oil, fruits, vegetables, and cash crops, with highly practical tips. Growers, save this for reference!
I. Core Fertilization Principles for Major Heat: Avoid Missteps, Maximize Nutrient Efficiency
The weather during Major Heat is extreme, with high temperature evaporation and frequent thunderstorms, making fertilizers highly prone to volatilization and runoff. Blind fertilization wastes resources and damages crops. Master these four core principles for twice the results with half the effort:
1. Fertilize According to the Weather, Strictly Control Timing
Avoid midday heat: Fertilizing when temperatures exceed 35°C causes rapid nitrogen volatilization, soil salt accumulation, and root burn.
No fertilization 24 hours before heavy rain: Rainwater washes away over 70% of nutrients, wasting fertilizer.
Optimal window: Evenings or cloudy days, when temperatures are mild and evaporation is low, promoting root absorption.
2. Less Quantity, More Frequency: Light and Frequent Applications
Crop roots are active but vulnerable in summer. Avoid heavy, concentrated fertilization at one time. Follow the principle of "small amounts, frequent applications": reduce single fertilizer rates and increase topdressing frequency. This sustains nutrient supply, prevents fertilizer burn, and avoids soil compaction and salinization.
3. Control Nitrogen, Boost Potassium, Supplement Micronutrients
Limit pure nitrogen: Excess nitrogen causes excessive vegetative growth, dense canopies, increased pests/diseases, and flower/fruit drop.
Prioritize potassium: Enhances drought, heat, and lodging resistance.
Add secondary and micronutrients: Calcium, magnesium, boron, zinc, etc., correct deficiencies causing yellow leaves, fruit cracking, and empty grains.
4. Combine Water and Fertilizer, Balance Wet and Dry
In hot, dry weather, fertilization must be paired with irrigation—apply nutrients with water (fertigation) for rapid dissolution and root penetration.
Paddy fields: Maintain alternating wet and dry conditions.
Upland crops: Keep soil moist; avoid dry fertilizer application to prevent root burn.
