Liquid Fertilizers: Enhancing Crop Productivity and Sustainability (By: Prachi S. Mahajan)

 Liquid Fertilizers: Enhancing Crop Productivity and Sustainability

Author: Prachi S. Mahajan (M.Sc.  Agriculture)

Introduction: Agriculture-allied sectors serve as the backbone of countries' economies, providing livelihood to millions of people and meeting the food demands of a large population. To achieve higher crop yields with sustainable agricultural practices, nowadays farmers are turning to liquid fertilizers (LF). Liquid fertilizers play a significant role in modern agriculture by improving crop yield and quality. These LF are having the ability to provide nutrients directly to the plant roots or aerial parts which ensures efficient nutrient uptake, reducing nutrient losses due to leaching or volatilization. Additionally, applications of liquid fertilizers make possible the use of various agricultural practices, such as no-till farming, reduced-tillage systems, and precision farming. This review is about the exploration of various types of liquid fertilizers commonly used in agriculture, and gardening, with their role in improving biomass, productivity, and health.

·         Types of liquid fertilizers

1. Nitrogen-Based Liquid Fertilizers: These fertilizers provide essential nitrogen, promoting leafy growth and overall plant vigor. Recently developed “Nano-urea” is a cutting-edge innovation. These nanoparticles deliver nitrogen to plants more efficiently by minimizing nitrogen losses and environmental impacts (one can visit for more information https://www.iffco.in/en/nano-urea-liquid-fertilizer). Examples:

i. Urea-Ammonium Nitrate (UAN) Solution It combines urea and ammonium nitrate, providing a readily available source of nitrogen to crops. UAN is widely used for orchards, home gardens, and majorly in cereal crops like wheat, rice, and maize, promoting vigorous vegetative growth and higher yields.

ii. Ammonium Sulfate Solution: It contains ammonium and sulfate ions, supplying both nitrogen and sulfur to plants.

2. Phosphorus-Based Liquid Fertilizers: In agriculture and gardening, phosphorus plays a vital role in promoting strong root development, healthy flowering, and fruit production. It aids in energy transfer within plants, facilitating essential processes like photosynthesis and DNA synthesis. Ensuring an adequate supply of phosphorus can result in robust and bountiful yields.

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i. Diammonium Phosphate (DAP) Solution: For crops requiring higher phosphorus levels, the DAP solution comes to the rescue. This liquid fertilizer contains both phosphorus and nitrogen, making it suitable for oilseeds, legumes, and other phosphorus-demanding plants. DAP helps improve root development, flower formation, and seed setting.

ii. Phosphoric Acid: This liquid fertilizer contains concentrated phosphorus and is commonly used to provide a quick supply of phosphorus to plants.

3. Potassium-Based Liquid Fertilizers: These are nutrient solutions containing a significant amount of potassium, one of the essential macronutrients required for plant growth. These are commonly used in agriculture and gardening to enhance overall plant health, promote disease resistance, drought resistance and support various physiological functions such as water uptake and enzyme activation. Potassium-based liquid fertilizers are easily absorbed by plants through their roots, providing a quick and effective way to correct potassium deficiencies and optimize crop yields. Examples:

i. Potassium Nitrate Solution (PNS): Potassium is a crucial nutrient for overall plant health, stress tolerance, and fruiting. PNS offers a combined supply of potassium and nitrogen, making it ideal for fruiting and flowering crops like tomatoes, grapes, and citrus fruits.

ii. Potassium Chloride Solution: It provides a readily available source of potassium, an essential nutrient for plant growth and stress tolerance.

iii. Potassium Sulfate Solution: This liquid fertilizer contains potassium and sulfur, both important for plant health.

4. Micronutrient Liquid Fertilizers: These contain essential trace elements such as iron, zinc, manganese, copper, and boron, which are required in small quantities but are crucial for healthy plant growth and development. Liquid formulations of essential micronutrients like zinc sulfate, ferrous sulfate, manganese sulfate, copper sulfate, and boron provide a quick remedy to these deficiencies, ensuring optimal plant growth and development. In the last few decades, it has been largely adapted to drip irrigation systems. Examples:

i. Iron Chelates: These contain chelated iron, ensuring better availability of iron to plants, especially in alkaline soils.

ii. Zinc Sulfate Solution: This liquid fertilizer supplies essential zinc to crops.

iii. Manganese Sulfate Solution: It contains manganese, crucial for photosynthesis and enzyme activation.

iv. Copper Sulfate Solution: Provides copper, which is vital for various plant metabolic processes.

v. Boron Solutions: Liquid fertilizers with boron support proper flower and fruit development.

5. Organic Liquid Fertilizers: Organic liquid fertilizers are nutrient-rich solutions made from natural sources such as plant and animal materials. They are used to supply essential nutrients to plants and improve soil fertility in organic gardening and farming practices. Unlike synthetic fertilizers, organic liquid fertilizers are derived from organic matter and are often preferred by environmentally conscious gardeners and farmers due to their sustainable nature. Examples:

i. Jeevamrut: it is a popular organic liquid fertilizer widely used in sustainable farming and gardening practices. Originating from traditional Indian farming methods, Jeevamrut is created by fermenting a mixture of cow dung, cow urine, jaggery, pulse flour, and water for several days. Beneficial microorganisms, nutrient-enriched solutions, and essential growth promoters are applied to the soil or sprayed on plants which enhance plant health and growth.

ii. Compost Tea: This is made by submerging tea compost in water, providing a range of nutrients and beneficial microorganisms. Can be considered as an organic alternative and enrich plant nutrition by promoting soil health.

iii. Fish Emulsion: this is derived from fish byproducts; fish emulsion is rich in nitrogen, phosphorus, and trace elements hence providing nutrition to the soil and ultimately plants in the farm or gardens.

vi. Seaweed Extract: an unexplored potential of seaweed is tapped by using them in plant growth promotion. As a sustainable and eco-friendly option, seaweed-based liquid fertilizers are gaining popularity. These seaweed extracts contain compounds like cytokinins, auxins, and gibberellins, supporting plant growth, stress resistance, and overall crop health.

v. Liquid Bone Meal: This is one of the derived products of concentrated manures, it is made from ground-up bones suspended in water and is a good source of phosphorus, which promotes root development and flowering in plants.

vi. Composted Vegetable Matter: Liquids obtained from composting vegetable scraps can be used as liquid fertilizers, providing a balanced mix of nutrients.

vii. Molasses: Though not a traditional fertilizer, molasses is used as a microbial stimulant. It feeds beneficial microorganisms in the soil, aiding nutrient cycling and soil structure.

6. Biofertilizers: Liquid biofertilizers have emerged as a viable option to enhance soil fertility and plant nutrition in a sustainable manner. Beneficial microorganisms like nitrogen-fixing bacteria (e.g., Rhizobium, Azotobacter) and phosphate-solubilizing bacteria contribute to improved nutrient availability and nutrient cycling. Multiple beneficial microbes-derived biofertilizers consortia is a powerful tool in sustainable agriculture. The consortia consist of diverse and friendly microorganisms like nitrogen-fixing bacteria, phosphate-solubilizing bacteria, and plant growth-promoting rhizobacteria. They work synergistically to enhance nutrient availability, improve soil structure, and stimulate plant growth, reducing the need for chemical fertilizers and supporting eco-friendly farming practices.

7. Fertigation Solutions: in gardens and orchards, precise and efficient nutrient delivery is required. Fertigation solutions of liquid fertilizers are specifically designed for application through irrigation systems, allowing farmers to adjust nutrient application rates based on crop requirements and soil conditions.

·         Role of Liquid Fertilizers:

1. Faster Nutrient Absorption: Liquid fertilizers are easily absorbed by plants, leading to quicker nutrient uptake and quicker response. This rapid nutrient availability allows crops to access vital elements when they need them the most during their growth stages.

2. Uniform Application: Liquid fertilizers are friendly with electrostatic sprayers and can be uniformly applied to the entire crop field. This ensures better coverage, adhesion, and consistent distribution of nutrients. This uniformity helps prevent nutrient deficiencies in various areas of the field, promoting balanced plant growth.

3. Precision Farming: to avoid the loss of farmers or gardeners, it is necessary to use inputs precisely. Modern fustigation systems and foliar sprayings, liquid fertilizers enable precision farming. Users can adjust application rates of each nutrient based on crop requirements, soil conditions, and considering weather parameters, this facilitates optimized resource utilization.

4. Easy Mixing: Liquid fertilizers allow their easy mixing with other agricultural inputs like other fertilizers, stickers, pesticides, and growth regulators. This mixing capability allows users to apply multiple products in a single application which allows for saving time and labor expenses.

·         Guidelines on how to use liquid fertilizers:

1. Instructions on the packet are important: Always read carefully and follow the manufacturer's instructions provided on the packet of liquid fertilizer. These instructions provide important information on care during handling, remedies during accidental cases, application rates, dilution ratios, timing, and suitability of fertilizer.

2. Soil Testing: generally before applying bulk fertilizers soil testing is recommended. However, in the case of liquid fertilizers, it will increase preciseness and efficiency. Soil tests help to identify any nutritional deficiencies or excess conditions, enabling users to modify the amount of fertilizer as per the needs of crops.

3. Dilution and Mixing: Most liquid fertilizers are friendly to be diluted with water before their application. Recommended dilution ratio given on the product packet must be understood and followed. Use clean and non-reactive containers for mixing the liquid fertilizers thoroughly with water and prepare a uniform solution.

4. Application Methods: Liquid fertilizers are suitable to be applied through various methods:

a. Soil Application: one can apply the diluted liquid fertilizer directly to the rhizosphere (soil around the roots or base of the plants). This method is suitable for large plants with extensive root systems.

b. Drip Fertigation: different drip irrigation with fertigation can be used to apply liquid fertilizers through irrigation systems. This method also allows automation for precise nutrient delivery to the root zone, minimizing nutrient losses.

c. Foliar Spray: some liquid fertilizers and growth promoters can be applied directly to the leaves of the plants using foliar spraying. This method provides a quick nutrient boost and is beneficial for correcting nutrient deficiencies rapidly.

5. Timing of the Application: since precision is the key, the timing of liquid fertilizer application is essential. Application of fertilizers during the active growth stages of plants when they have higher nutrient demands is important. For example, apply nitrogen-rich fertilizers during the vegetative growth phase and phosphorus-rich fertilizers during flowering and fruiting stages.

6. Avoiding Over-application: using excessive amounts of liquid fertilizer (knowingly or unknowingly by skipping instructions on the packet) can lead to nutrient imbalances and damage to plants. This also creates environmental pollution therefore always follow the recommended application rates to avoid over-fertilization.

7. Monitoring Plant Response: Regularly monitor plants for any signs and symptoms of nutrient deficiencies or excesses. Adjust the fertilizer application based on plant response and changing soil conditions.

8. Proper Storage: liquid fertilizers must be stored in a cool, dry place, away from direct sunlight and extreme temperatures (as per the instructions on the packet).

9. Safety Precautions: When handling liquid fertilizers, wearing appropriate gloves and goggles protects the user’s skin and eyes. Inhaling of droplets, fumes, or mist must be avoided using appropriate masks.

10. Environmental Considerations: Prevent runoff and leaching by applying liquid fertilizers when the weather is calm and not expected to rain. Be aware of potential environmental impacts and avoid applying fertilizers close to water bodies to prevent water pollution.

It's important to note that the availability of specific liquid fertilizers may vary depending on the region and local agricultural practices. Farmers and gardeners are encouraged to consult with local agricultural extension experts, services, and suppliers to choose the most suitable liquid fertilizers for their specific crops, gardens, and soil conditions. Additionally, it is crucial to follow recommended application rates and best practices to ensure efficient and sustainable fertilizer use.

Conclusion: Liquid fertilizers have revolutionized modern agriculture, offering several advantages over traditional solid fertilizers. Their ability to deliver essential nutrients quickly and efficiently has made them an indispensable tool for farmers seeking higher crop yields and sustainable agricultural practices. When used judiciously and in combination with other best farming practices, liquid fertilizers contribute significantly to the overall productivity and profitability of agricultural systems.