Humic Acid A Boon For Sustainable Agriculture 

Humic acid is a naturally occurring compound that is formed by the decomposition of dead plants and animal matter over time.  It is characterized by its dark color and high molecular weight. Humic acid plays a crucial role in enhancing nutrient availability and uptake by plants. In the absence of humic acid, nutrients applied through fertilizers may become locked up in the soil or washed away, leading to nutrient deficiencies in plants. It is safe for the environment and does not harm beneficial microorganisms in the soil.  

In this article, we will discuss how humic acid is a boon for sustainable agriculture and why farmers should consider using it in their farming practices.   

What is Humus? 

Humus is a brown or dark brown complex organic component of soil, formed by decomposition of plant and animal matter. The formation of humus is a slow process that takes years depending on the organic matter, soil conditions and microbial activity. Humus accounts for about 60 – 80% of soil organic content.  

Humic substances are components of humus which includes humic acid, fulvic acid and humin that vary depending upon molecular weight, colour and solubility in water at different pH levels. ` 

• Humic acid is a dark brown humic substance with higher molecular weight than fulvic acid and is soluble in water at higher soil pH values. These complex mixtures of organic compounds act as natural chelating agents.  
• Fulvic acid is a humic substance consisting of low molecular weight molecules that are typically yellow to light brown in color. It is soluble in both acidic and alkaline conditions and helps to transport nutrients into plant cells and promote root development. 
• Humin is a black complex organic complex that is not soluble in both alkali and acid. It has high molecular weight and is highly resistant to decomposition. They function to improve soil structure and improve cation exchange capacity of soil. 

Humic acid and fulvic acids are the humic substances that are commercially used for soil and plant application in various forms like granules or liquid.  

Benefits of Humic acid on Soil Physical, Chemical and Biological Health 

Soil Physical Health: 

• Improve soil structure by increasing soil aggregation, which are groups of soil particles held together by organic matter. This helps to create larger pores in the soil which improves water infiltration, aeration and root growth. 
• Improves the water holding capacity (up to 7 times) of soil and thus helps to reduce the frequency and severity of droughts, particularly in sandy or low-organic matter soils. 
• Reduces soil compaction which can improve soil aeration, water infiltration, and root growth. 
• Reduces the risk of soil erosion by improving soil structure and increasing water-holding capacity. 
• Makes soil more friable and improves soil tilth. 

Soil Chemical Health: 

• Improves nutrient availability by converting the nutrient elements into available forms thus making it accessible for plant uptake. It acts as a chelating agent, which means it can bind to and transport nutrients to plant roots. 
• Reduces nutrient leaching by increasing the Cation Exchange Capacity (CEC) of soil. 
• Enhances soil pH buffering capacity 
• Binds with heavy metals and other toxic substances, reducing their mobility in the soil and preventing them from being taken up by plants. 
• Helps to reduce chlorosis symptoms due to iron deficiency in plants by increasing iron uptake.  
• Increases nitrogen uptake by plants 

Soil Biological Health: 

• Increases the growth and activity of beneficial soil microorganisms by providing them a source of carbon and energy. This can lead to improved nutrient cycling and plant growth. 
• Increases plant growth and productivity. 

Benefits of Humic Acid on Plant Growth 

• Stimulates root growth and branching, allowing plants to better absorb nutrients and water from the soil. This can improve plant growth and overall plant health. 
• Helps in increasing germination capacity of seeds. 
• Stimulate the production of phytohormones and enzymes that can enhance plant growth by increasing resistance to stress, diseases, and pests.  
• Helps in root formation and root respiration. 
• Helps in photosynthesis by promoting the development of chlorophyll, amino acids and sugars. 
• It helps in thickening of cell wall in fruits and thus improving their shelf life. 
• Enhances the physical appearance and nutritional value of the produce. 
• Act as a catalyst in many biological processes like nitrogen fixation and bioremediation. 
• Increases crop yield and improves crop quality by improving plant health, nutrient uptake, and resistance to stress. 

How can we apply humic acid to plants?  

Humic acids are available in both liquid and granular form and hence can be applied using several methods including soil application, foliar application, seed treatment, and fertigation. 

1. Soil Application:

Humic acid can be added to the soil in the form of granules, powders, or liquids. They can be mixed with soil before planting or applied as top dressing after planting. It can be applied to the soil by broadcasting, banding or drenching method. Soil application can improve soil structure, water holding capacity, nutrient availability and microbial activity. It is recommended to mix humic acid with water to ensure even distribution in the soil. 

2. Foliar Application:

Humic acid can also be applied directly to the leaves of plants through foliar spraying.  Since humic acid is directly delivered to plant’s foliage in this method, it can be quickly absorbed and utilized by the plant. This can enhance nutrient uptake, photosynthesis, and plant growth. It is recommended to dilute the humic acid solution with water and apply it during early morning or late afternoon. This method is particularly useful for plants that experience nutrient deficiencies. 

3. Seed treatment:

Seed treatment using humic acid can be done to seeds before sowing. Seed treatment can increase germination rate, seedling vigor, and early plant growth. It is recommended to soak the seeds in a solution containing humic acid and water for a few hours before planting. 

4. Fertigation:

Humic acid can be dissolved in water and applied through irrigation water or drip system provide a continuous supply of nutrients and organic matter to the plants. Fertigation can improve nutrient use efficiency and reduce nutrient leaching. This method helps in even distribution of nutrients throughout the root zone of the plants.  

NOTE:

• Water the soil after soil application of humic acid to help humic acid penetrate deeper into the soil. 
• Avoid foliar application of humic acid during the middle of the day when the sun is at its peak. 
• Humic acid can also be mixed with fertilizers and applied to the soil. But follow the recommended dose for both and mix them thoroughly before application to ensure even distribution. 

Time of Application 

The time of humic acid application may vary depending on several factors such as the crop type, growth stage, soil type, climatic conditions, and based on the need. However, it can be applied to plants at different stages of growth such as; 

• Pre-planting to improve germination of seeds  
• At the time of planting to promote early root development, improve nutrient uptake, and increase plant growth.  
• During vegetative growth to avoid nutrient deficiencies by increasing nutrient intake and enhance plant growth and  
• During flowering and fruiting stage, to improve fruit quality 

NOTE: The frequency of application may also depend on the specific product used. So please check the product’s description and label before use. Use only the recommended dosage. 

Boost your plant’s growth with any of these humic acid products 

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Conclusion 

Humic acid is a mixture of various organic compounds providing numerous benefits for agriculture. It can improve soil quality, increase nutrient availability, enhance plant growth and boost crop yield. Its natural origin and environmentally friendly properties make it a great choice for sustainable agriculture.  The versatile applications of humic acid, combined with its ability to promote higher yields and reduce the need for synthetic fertilizers and pesticides, make it an indispensable asset for agriculture. Farmers and gardeners should consider incorporating humic acid into their farming practices to reap the benefits of this natural compound.