Zinc is an essential micronutrient for paddy crops. It plays a crucial role in various physiological and metabolic processes, including the synthesis of chlorophyll, protein, and growth hormones. Zinc also improves the quality of rice grains by increasing their nutrient content and disease resistance. However, zinc deficiency is becoming a widespread problem in paddy cultivation worldwide.
Zinc deficiency in paddy crops usually occurs in soils with low zinc availability, high pH, poor drainage, or excessive use of nitrogen fertilizers. The symptoms of zinc deficiency include stunted growth, low tillering, reduced leaf area, interveinal chlorosis, and necrosis. The affected plants may also show delayed maturity, low yield, and poor grain quality.
The deficiency of zinc sulphate in paddy crops can be corrected by applying zinc fertilizers, such as zinc sulphate, zinc oxide, or zinc chelates. The most effective method is soil application of zinc fertilizers before sowing or at the early growth stage. The recommended rate of zinc application is 25-50 kg/ha of zinc sulphate or equivalent amounts of other zinc fertilizers.
Foliar application of zinc fertilizers can also provide a quick fix for zinc deficiency in paddy crops. However, foliar spray should be done with caution, as excessive zinc concentration can cause toxicity or leaf burn. The recommended rate of foliar application is 0.5-1% zinc sulphate solution or other zinc chelates, and the spray should be done in the early morning or late afternoon to avoid heat stress on the plants.
Apart from zinc fertilization, other agronomic practices can also help in alleviating zinc deficiency in paddy crops. These include maintaining optimal soil pH (6.0-6.5), improving soil drainage and aeration, reducing nitrogen fertilizer use, and applying organic matter and biofertilizers. Crop rotation with leguminous crops can also enhance soil zinc availability by fixing atmospheric nitrogen, improving soil fertility, and inducing soil microbial activity.
In conclusion, zinc deficiency is a critical issue in paddy crop production, which can be corrected by timely and adequate zinc fertilization and other agronomic practices. Farmers should adopt a comprehensive approach to soil management, crop nutrition, and pest management to ensure healthy and profitable paddy crops.