Dr Bendangla Imsong, E.Lireni Kikon and Dr Phool Kumari
KVK Dimapur
Balanced use of fertilizers refers to the scientific and judicious application of all essential plant nutrients in proper proportion and adequate quantity according to the nutrient requirement of the crop and the fertility status of the soil. It aims to supply nutrients in such a way that crops receive sufficient nourishment for optimum growth, higher productivity, and better quality produce without degrading soil health or causing environmental pollution.
In agriculture, plants require a number of nutrients for proper growth and development. Among these, nitrogen (N), phosphorus (P), and potassium (K) are required in larger quantities and are known as primary nutrients. Secondary nutrients like calcium, magnesium, and sulphur, along with micronutrients such as zinc, boron, iron, manganese, copper, and molybdenum, are also essential for healthy crop growth. Balanced fertilization ensures that all these nutrients are supplied in suitable amounts rather than relying excessively on only one or two nutrients.
The concept of balanced fertilizer use is based on the principle of applying nutrients in the right proportion, right quantity, right time, and right method according to crop demand and soil conditions.
For example, excessive use of nitrogen alone may result in lush green growth but weak plants, poor grain formation, increased pest and disease incidence, and lodging. Similarly, deficiency of phosphorus may reduce root development, while inadequate potassium can make plants more susceptible to drought and diseases. Therefore, maintaining a proper balance among nutrients is essential for efficient crop production.
Balanced fertilizer use also involves adopting the 4R Nutrient Stewardship approach:
• Right Source – selecting suitable fertilizer sources such as urea, DAP, SSP, MOP, compost, or biofertilizers.
• Right Rate – applying fertilizers in recommended doses based on soil test and crop requirement.
• Right Time – applying nutrients at critical growth stages for maximum uptake.
• Right Placement – applying fertilizers through proper methods like band placement, broadcasting, fertigation, or foliar spray to minimize nutrient loss.
Another important aspect of balanced fertilization is the integrated use of different nutrient sources. Chemical fertilizers alone cannot sustain soil productivity for long periods. Therefore, balanced nutrient management encourages the combined use of:
i) Chemical Fertilizers
Chemical fertilizers are manufactured nutrient sources that supply essential plant nutrients in concentrated and readily available forms. They mainly provide nitrogen (N), phosphorus (P), and potassium (K), which are required in large quantities by crops. Common examples include urea, DAP, SSP, and MOP. These fertilizers help in rapid plant growth, higher productivity, and correction of nutrient deficiencies. However, excessive or imbalanced use of chemical fertilizers may deteriorate soil health, reduce beneficial microbial activity, and lead to environmental pollution. Therefore, they should be applied judiciously based on soil test recommendations and crop requirements.
ii) Organic Manures
Organic manures are natural nutrient sources derived from plant and animal wastes. They improve soil structure, water-holding capacity, aeration, and microbial activity while supplying nutrients slowly over time.
iii) Farmyard Manure (FYM)
Farmyard manure is prepared from decomposed cattle dung, urine, litter, and farm wastes. It supplies small amounts of nutrients and increases soil organic matter. FYM improves soil texture and enhances microbial activity.
iv) Compost
Compost is prepared by decomposing crop residues, kitchen waste, weeds, and other biodegradable materials. It enriches soil fertility and improves soil physical properties.
v) Vermicompost
Vermicompost is produced through the decomposition of organic wastes by earthworms. It is rich in nutrients, beneficial microorganisms, enzymes, and growth-promoting substances. Vermicompost improves soil fertility, enhances nutrient availability, and promotes healthy plant growth.
vi) Green Manures
Green manuring involves growing fast-growing crops, mainly legumes, and incorporating them into the soil while still green. Common green manure crops include dhaincha, sunnhemp, and cowpea. These crops add organic matter and nitrogen to the soil through biological nitrogen fixation. Green manuring improves soil structure, moisture retention, and microbial activity while reducing soil erosion.
vii) Crop Residues
Crop residues are the remains of crops left in the field after harvest, such as straw, stubbles, leaves, and roots. Instead of burning them, incorporating crop residues into the soil helps recycle nutrients, increase soil organic carbon, and improve soil health. Residue incorporation also enhances moisture conservation, reduces soil erosion, and supports beneficial soil organisms.
viii) Biofertilizers
Biofertilizers are preparations containing beneficial living microorganisms that enhance nutrient availability and uptake by plants.
a) Rhizobium
Rhizobium forms symbiotic associations with leguminous crops such as pulses and fixes atmospheric nitrogen in root nodules, thereby reducing nitrogen fertilizer requirement.
b) Azospirillum
Azospirillum is associated mainly with cereals and grasses. It helps fix atmospheric nitrogen and promotes root development and plant growth.
c) Azotobacter
Azotobacter is a free-living nitrogen-fixing bacterium that improves nitrogen availability and produces growth-promoting substances beneficial for crops.
d) Phosphate Solubilizing Bacteria
Phosphate Solubilizing Bacteria (PSB) convert insoluble forms of phosphorus into soluble forms that can be readily absorbed by plants, thereby improving phosphorus use efficiency.
Biofertilizers are eco-friendly, cost-effective, and help reduce dependence on chemical fertilizers while improving soil biological activity.
ix) Micronutrient Fertilizers
Micronutrient fertilizers supply essential nutrients required in small quantities for normal plant growth and development. Important micronutrients include zinc, boron, iron, manganese, copper, and molybdenum. Deficiency of micronutrients can lead to poor crop growth, chlorosis, reduced flowering, poor grain formation, and lower yield. Micronutrient fertilizers are applied through soil application, foliar spray, or seed treatment depending on crop requirement and deficiency symptoms.
Soil testing plays a crucial role in balanced fertilizer use. Soil analysis helps determine nutrient deficiencies, soil pH, organic carbon status, and fertilizer requirement. Based on soil test recommendations, fertilizers can be applied more efficiently and economically. This prevents both under-application and over-application of nutrients.
Balanced fertilizer use is important not only for higher crop yield but also for environmental sustainability. Excessive and imbalanced use of fertilizers can lead to:
• Soil degradation
• Nutrient imbalance
• Water pollution through nutrient runoff and leaching
• Groundwater contamination
• Increased greenhouse gas emissions
On the other hand, balanced nutrient management improves nutrient use efficiency, reduces production costs, conserves natural resources, and sustains agricultural productivity over time.
Different crops require different nutrient combinations. Cereals generally require higher nitrogen, pulses need more phosphorus and less nitrogen due to biological nitrogen fixation, while oilseeds often require sulphur along with NPK. Vegetables and fruit crops usually require balanced and continuous nutrient supply for better yield and quality. Hence, fertilizer recommendations should always be crop-specific and location-specific.
In conclusion, balanced use of fertilizers is an essential component of sustainable agriculture. It ensures optimum nutrient supply for crops, maintains soil fertility, improves crop productivity and quality, reduces environmental hazards, and supports long-term agricultural sustainability.
