Humic acid is a natural organic substance widely used in agriculture to improve soil, increase fertilizer utilization, promote crop growth, and enhance stress resistance. Its scientific application methods are as follows:
I. Main Functions of Humic Acid
1. Improves soil structure: Promotes soil aggregate formation and improves compacted and saline-alkali soils.
2. Improves fertilizer efficiency: Reduces nitrogen, phosphorus, and potassium loss, increasing utilization rate by 20%~45%.
3. Stimulates root development: Increases the number and length of lateral roots, enhancing absorption capacity.
4. Enhances stress resistance: Improves crop resistance to drought, cold, and pests and diseases.
5. Improves fruit quality: Increases sweetness, enhances color, and promotes earlier ripening.
II. Common Application Methods of Humic Acid
1. Seed soaking/root dipping
Soak seeds in a 0.01%~0.05% potassium or sodium humate solution for 5~8 hours, then dry before sowing. This can improve germination rate and seedling uniformity.
1. **Root Drip Application:** Before transplanting, dip the roots in a 1000-fold dilution to shorten the seedling establishment period.
2. **Base Fertilizer Application:** Before sowing or transplanting, apply 200-300 kg of humic acid organic fertilizer or 50-80 kg of humic acid compound fertilizer per acre, incorporating it into the soil layer to a depth of 15-20 cm during tilling.
It can be mixed with organic fertilizer at a ratio of 1:5 to 1:10, or compounded with chemical fertilizer at a ratio of 3%-5%.
3. **Topdressing (Fertigation/Drip Irrigation):** During critical periods of crop nutrient demand (such as the jointing stage and fruit expansion stage), apply 5-8 kg of humic acid water-soluble fertilizer per acre in combination with conventional chemical fertilizer through fertigation or drip irrigation.
Fulvic acid water-soluble fertilizers are even more effective due to their small molecular size, high water solubility, and rapid absorption.
4. Foliar Spray
Prepare a 0.1%~0.5% humic acid solution (e.g., 1~5 grams of powder per liter of water) and spray during the seedling, flowering, and fruit expansion stages.
The optimal spraying time is 2-4 PM to avoid high-temperature evaporation.
It can be mixed with potassium dihydrogen phosphate, urea, etc., for significant synergistic effects.
III. Precautions for Using Humic Acid
It cannot replace chemical fertilizers or organic fertilizers; it should be used as a synergist in combination.
Use sodium humate with caution in saline-alkali soils; potassium humate or fulvic acid are preferable.
Avoid application at high temperatures or low temperatures (<18℃), as this will affect the effectiveness.
Prioritize products that meet national standards (e.g., GB/T 35111-2017, NY/T 1106-2010), and pay attention to the labeling of “humic acid content”.
