Effective application of humic acid fertilizers leads to a more substantial increase in crop yields.

　　Since ancient times, agricultural cultivation has been an integral part of our lives. With the advancement of biotechnology, a wide variety of plant seeds have been discovered, and numerous agricultural fertilizers have been developed in succession. Among these, humic acid fertilizer is widely regarded as highly effective. Today, the use of humic acid fertilizer makes a significant contribution to modern agriculture. In this article, we will provide a brief overview of relevant knowledge about humic acid fertilizer.

　　I. Definition of Humic Acid Fertilizer

　　Humic acid fertilizers are products derived from peat, lignite, and weathered coal, manufactured through various processes to yield formulations rich in humic acids, nitrogen, phosphorus, potassium, and certain micronutrients. Common types include ammonium humate, ammonium nitro‑humate, humic acid–phosphorus compounds, ammonium‑humate‑phosphorus blends, sodium humate, and potassium humate. In agricultural production, humic acid fertilizers primarily promote crop growth, improve soil quality, enhance nutrient availability, and stimulate soil microbial activity.

　　II. Application Methods and Dosage of Humic Acid Fertilizer

　　1. Seed soaking can increase the germination rate, promote earlier emergence, and enhance the root‑forming capacity of seedlings. The typical soaking concentration ranges from 0.005% to 0.05%, with a soaking duration of 5 to 10 hours; for hard‑shelled seeds such as rice and cotton, the soaking time is 24 hours.

　　2. Root soaking and root dipping: Before transplanting, rice, sweet potatoes, and other crops can have their seedlings soaked in a solution of sodium humate or potassium humate at a concentration of 0.01%–0.05%. This treatment promotes rapid root development and enhances survival rates.

　　3. Foliar spraying is typically carried out using a solution at a concentration of 0.01%–0.05%. During the flowering stage, apply 2–3 times, with each application using 50 liters of solution per 667 square meters. The optimal time for spraying is between 2:00 PM and 4:00 PM.

　　4. As a base fertilizer, solid humic acid fertilizer is typically applied at a rate of 100–150 kg per 667 m². When applying humic acid solution as a base fertilizer, use a concentration of 0.05%–0.1%, with 250–400 liters of aqueous solution per 667 m². It can be mixed with farmyard manure and applied either by furrow application or hole application.

　　5. As a topdressing, during the seedling stage and prior to heading, apply approximately 250 liters of a 0.01%–0.1% aqueous solution per 667 square meters, irrigating close to the crop roots. In paddy fields, it can be applied either with irrigation water or by surface spreading, helping to promote seedling emergence, strengthen seedlings, and enhance growth and development.

　　The foregoing constitutes the relevant knowledge about humic acid fertilizers, and we trust that, after reviewing it, you now have a solid understanding of this topic. The introduction of humic acid fertilizers has significantly enhanced agricultural practices, leading to a substantial increase in crop yields.