Wheat Leaves Yellow

India, wheat is primarily grown during the winter season. However, the problem of yellowing of the lower leaves of wheat due to extreme cold (below 5°C) is quite common. This issue negatively affects the plants' photosynthesis process and growth. It is particularly seen around December 25th in Northern India.

The problem is more prevalent in fields where the practice of burning crop residue is followed. Burning crop residue significantly reduces the number of microorganisms in the soil, which play a crucial role in nourishing plants. If your wheat crop is also affected by this problem, let’s understand the reasons and effective management solutions.

Reasons for Yellowing of Wheat's Lower Leaves:

1. Effect of Extreme Cold
   When the temperature drops below 5°C, the microorganisms in the soil become inactive. These microorganisms are essential for making nutrients in the soil soluble and available to plants, helping them stay healthy and nourished.
2. Effect of Crop Residue Burning
   Burning crop residue results in a significant reduction in the number of microorganisms in the soil, disrupting the process of nutrient supply to the plants. This also impacts the soil's fertility.
3. Nutrient Imbalance in Plants
   When plants do not receive sufficient nutrients, their growth is affected, and the leaves start turning yellow. This problem is more serious during the winter.

Management Solutions for Yellowing of Wheat’s Lower Leaves:

1. Irrigation Management
   • Ensure there is no waterlogging in the field.
   • Perform the first irrigation 20 to 25 days after sowing and continue irrigation as needed to ensure proper water usage and plant health.
   • Irrigating on cold nights can help reduce frost damage.
2. Proper Nutrient Management
   • Use one-third of nitrogen (urea) and full doses of phosphorus and potassium at sowing.
   • Apply the second and third doses during the first and second irrigations.
   • Apply zinc sulfate (25 kg/hectare) and sulfur (20-25 kg/hectare).
   • Foliar sprays of nitrogen and micronutrients can be beneficial.
3. Organic Fertilizers and Practices
   • Use organic fertilizers like cow dung manure, vermicompost, and neem cake.
   • Apply Trichoderma and PSB for disease management.
   • Instead of burning crop residues, use decomposers and mix them into the soil.
4. Prevention of Cold and Frost Damage
   • Use smoke in the field to prevent cold damage.
   • Irrigating on cold nights helps maintain a balanced temperature.
5. Pest and Disease Management
   • Choose disease-resistant wheat varieties like PBW-343, HD-2967, and WH-1105, which protect the plants from various diseases and improve yield and quality.
   • Treat seeds with Trichoderma or carbendazim before sowing.
   • Use fungicides, such as Propiconazole (0.1%) for yellow rust and Carbendazim (0.2%) for root rot.
6. Nutrient Spray
   • If the problem is severe, spray 1-2% urea (10-20 grams per liter of water).
   • Spraying 5% magnesium sulfate helps keep the plants fresh and green.

Conclusion: Effective management is essential to control the yellowing of wheat's lower leaves. By adopting proper irrigation, nutrient balancing, organic fertilizers, and measures to protect against cold, this problem can be prevented. Additionally, avoiding the burning of crop residues and managing them correctly enhances soil fertility and productivity.