Soil Nutrition Management – Need & Challenges – Explained Pointwise

A detailed study conducted by ICAR has found that the unscientific use of fertilisers & climate change are contributing to degradation of organic carbon in arable areas of the country. The study has found that if the organic carbon is low, then the deficiency of micronutrients in the soil is high, and if the organic carbon is high, the deficiency is low. In this regard, we need to understand the significance & challenges of soil nutrition management.

Soil Nutrition Management

What is Soil Nutrition & Soil Nutrition Management?

• Soil nutrition refers to the availability and balance of essential nutrients within the soil that are necessary for healthy plant growth and development. It’s a critical aspect of soil health and fertility, directly impacting the productivity of ecosystems and agriculture.
• Soil nutrients can broadly be categorized into:
  

  Macro-Nutrients	Primary Macronutrients (NPK): 1. Nitrogen (N): Crucial for leafy growth, chlorophyll production (photosynthesis), & protein synthesis. 2. Phosphorus (P): Essential for energy transfer, root and flower development, and hastening maturity. 3. Potassium (K): Improves plant vigor, disease resistance, and helps in the formation and movement of sugars, starches, and oils, enhancing fruit quality.Secondary Macronutrients: 1. Calcium (Ca): Important for cell wall structure, root health, and nutrient absorption. 2. Magnesium (Mg): A key component of chlorophyll, vital for photosynthesis. 3. Sulfur (S): Involved in protein synthesis and enzyme activity, contributing to flavor and odor in many plants.
  Micro-Nutrients	Needed in smaller quantities, but equally vital for plant health and various metabolic processes. These include Iron (Fe), Manganese (Mn), Zinc (Zn), Copper (Cu), Boron (B), Molybdenum (Mo), Chlorine (Cl), and Nickel (Ni).
  Non-Mineral Nutrients	Soil Organic Carbon (SOC), Hydrogen (H), and Oxygen (O) are obtained by plants from the atmosphere and water, not directly from the soil minerals.

• Soil nutrition management is the strategic and sustainable approach to managing the availability and balance of nutrients in the soil to optimize plant growth, enhance crop productivity, and maintain soil health, all while minimizing environmental impacts and ensuring economic viability.
• It’s a dynamic process that goes beyond simply adding fertilizers; it involves understanding the complex interactions within the soil ecosystem and making informed decisions to meet the specific nutrient needs of crops throughout their life cycle.
• It works on key principles like:
  1. Right Source i.e. selecting the appropriate type of nutrient.
  2. Right Rate i.e. applying the correct amount of nutrients.
  3. Right Time i.e. timing of nutrient applications to match crop growth stages.
  4. Right Place i.e. placing nutrients where crops can absorb them effectively.

Status of Indian Soils:

• Out of the 8.8 million soil samples tested under Soil Health Card Scheme in 2024, <5% have high or sufficient N, only 40% have sufficient P, 32% have sufficient K & only 20% are sufficient in SOC (Soil Organic Carbon).
• Soils in India also suffer from a deficiency of sulphur, as well as micronutrients like iron, zinc & boron.
• Imbalanced use of N, P & K:
  • In Punjab – Nitrogen is overused (in excess of recommendations by 61%), while potassium & phosphorus are under-used by 89% & 8% respectively.
  • In Telangana – Nitrogen is overused (in excess of recommendations by 54%), while potassium & phosphorus are under-used by 82% & 13% respectively.
• Nationwide, the fertiliser-to-grain ratio has declined significantly from 1:10 in 1970s to 1:2.7 in 2015. That means, more & more fertilisers are being used to produce same quantity of grains.
• Soils in several parts of India are severely deficient in nutrition & need to be immediately taken to ICU to restore them to normal health so that they can produce nutritious food on a sustainable basis.

Why do we need Soil Nutrition Management?

1. To Optimize Crop Yield and Quality: Plants need a balanced supply of 17 essential nutrients (macronutrients and micronutrients) to grow optimally. If even one nutrient is deficient, it can limit growth and yield, regardless of how abundant other nutrients are. Soil nutrition management ensures crops receive the right nutrients in the right amounts at the right time.
2. To Maintain and Enhance Soil Health and Fertility: Intensive farming practices, especially without proper replenishment, can “mine” nutrients from the soil, leading to widespread deficiencies over time. Management practices aim to replenish these nutrients and build up soil fertility.
3. Reducing Nutrient Pollution: Improper nutrient management (e.g., over-application, incorrect timing/placement) can lead to nutrient losses through leaching, runoff etc which can cause environmental problems like eutrophication, contamination of surface water as well as groundwater resources.
4. Mitigating Climate Change: Healthy soils, rich in organic matter, act as significant carbon sinks, sequestering carbon dioxide from the atmosphere. Sustainable soil nutrition management practices contribute to reducing greenhouse gas emissions.
5. Optimizing Input Costs: By applying the right amount of nutrients at the right time and place, farmers can avoid wasteful over-application of fertilizers, leading to significant cost savings.

What are the challenges to Soil Nutrition Management?

1. Nutrient Deficiencies and Imbalances in Soil: Soils in India suffer from deficiencies in multiple macro and micronutrients (e.g., nitrogen, phosphorus, potassium, zinc, boron, sulfur). Compounding this is the imbalanced use of fertilizers, often favoring nitrogen due to subsidies, leading to an skewed NPK ratio and further nutrient imbalances.
2. Low Soil Organic Carbon (SOC): Depleting SOC levels are a major concern. Low SOC reduces the soil’s ability to retain nutrients and water, impairs soil structure, and diminishes microbial activity, making nutrient management more difficult.
3. High Cost of Inputs: Lack of proper soil nutrition management practices leads to more use of fertilisers. Fertilizers, especially those containing micronutrients or organic amendments, can be expensive for small and marginal farmers, who constitute a large portion of the agricultural sector. 
4. Subsidy Distortions: Government subsidies, particularly on nitrogenous fertilizers (like urea), can create perverse incentives, encouraging overuse of certain nutrients while discouraging the balanced application of others. This leads to nutrient imbalances and inefficient resource allocation.
5. Nutritional Deficiency in Crops: Soil nutrient deficiency not only impair agriculture productivity but also degrade the nutritional quality of crops. Crops grown on nutrient deficient soils often mirror those deficiencies, leading to a silent but pervasive form of malnutrition in humans for e.g. Zinc deficiency in Indian soils translates into low Zn content in cereals like wheat & rice, which in turn is linked to childhood stunting.

What have been various government initiatives for SNM?

1. Soil Health Card (SHC) Scheme: Launched in 2015. The scheme aims to inform the farmers about the nutrient status of their soil and provides recommendations on the appropriate dosage of fertilizers and soil amendments needed to maintain soil health and fertility. The SHC includes information on 12 parameters: Macronutrients (Nitrogen, Phosphorus, Potassium), Secondary nutrient (Sulphur), Micronutrients (Zinc, Iron, Copper, Manganese, Boron), and Physical parameters (pH, Electrical Conductivity, Organic Carbon).
2. Paramparagat Krishi Vikas Yojana (PKVY): Also launched in 2015. The scheme aims to promote organic farming in India, aiming to improve soil health and organic matter content, and increase farmers’ net income by realizing premium prices for organic produce.
3. Neem Coated Urea (NCU): Urea is coated with neem oil, which slows down the nitrification process (conversion of urea into forms that can be lost through leaching or volatilization). This ensures a slower, more sustained release of nitrogen, making it more available to the crop over a longer period.
4. PM Programme for Restoration, Awareness Generation, Nourishment, and Amelioration of Mother-Earth (PM-PRANAM): Launched in 2023. The scheme aims to incentivize States and Union Territories to promote the sustainable and balanced use of fertilizers, adopt alternative fertilizers, and encourage organic farming.
5. Integrated Watershed Management Programme (IWMP) and National Policy for Management of Crop Residues (NPMCR): Focus on soil moisture conservation, prevention of nutrient loss, and promotion of in-situ conservation practices to protect and enrich soil.

What can be the way forward?

1. Integrated Nutrient Management (INM): INM is a holistic and sustainable approach to managing soil fertility and plant nutrient supply. It involves the judicious combination of various sources of plant nutrients, including organic, inorganic, and biological components, to achieve optimal crop productivity while enhancing soil health and minimizing environmental degradation.
2. Reform Fertilizer Subsidies: Gradually reorient subsidies from product-based (especially urea) to nutrient-based (NBS) for all fertilizers, including urea, to encourage balanced fertilization (the ideal NPK ratio of 4:2:1). This could involve linking subsidies more directly to Soil Health Card recommendations.
3. Promoting Sustainable Agricultural Practices:
   1. Crop Residue Management: Strictly discourage crop residue burning and promote in-situ management (e.g., using Pusa Decomposer, happy seeder technology) and ex-situ utilization (e.g., for biochar production).
   2. Conservation Agriculture (CA): Actively promote reduced tillage, no-tillage, and direct seeding practices to minimize soil disturbance, improve soil structure, and conserve moisture and organic matter.
   3. Diversify Cropping Systems: Encourage crop rotation and intercropping to break pest cycles, improve nutrient cycling, and reduce the depletion of specific nutrients. Promote millets and other nutri-cereals for dietary diversity and climate resilience.
4. Nano-Fertilizers and Smart Delivery Systems: Accelerate research and development of nano-fertilizers and other precision agriculture technologies (e.g., sensor-based nutrient application, variable rate technology) for efficient nutrient delivery and reduced environmental impact.
5. National Soil Policy: Implement a comprehensive National Soil Policy to integrate efforts across sectors, streamline incentives, and set clear targets for soil conservation, restoration, and sustainable management. This would address erosion, nutrient loss, and carbon sequestration, and align actions with land degradation neutrality goals by 2030.

Conclusion:
Soil nutrition management is no longer only an agriculture issue, it has become a public health imperative because only when the soils receive the nutrients do they produce food that nourishes rather than merely fills the stomach. Thus, a science-based soil nutrition management is the urgent need of the hour for India.