Demonstration of of Zinc solubilising bacteria in Paddy in selected zinc deficient soils of Dharmapuri district

Among the micronutrients iron, manganese, zinc, copper and molybdenum zinc is found to be predominantly deficient throughout the country. Zinc is an imperative micronutrient required for optimum plant growth as it is the precursor for many of the growth hormone production. Zinc solubilizing bacteria (ZSB) are potential alternatives for zinc supplementation and convert applied inorganic zinc to available forms (Zn2+). In addition, the application of zinc-solubilizing bacteria as a potential biosource represents a cost-effective and alternate biofortification strategy. Zinc-solubilizing bacteria act as natural bio-fortifiers that can solubilize the unavailable form of zinc by secreting organic acids, siderophores, and other chelating compounds.It has been found from the analytical reports of soil and plants that 48.5% of the soils and 44% of the plant samples were potentially zinc-deficient. In India, zinc (Zn) is now considered as fourth most important yield limiting nutrient in agricultural crops. Zn deficiency in Indian soils is likely to increase from 49 to 63% by 2025.The deficiency of zinc was found in more than fifty per cent of Tamil Nadu soil. In Paddy, Zn deficiency causes multiple symptoms that usually appear 2 to 3 weeks after transplanting (WAT) rice seedlings; leaves develop brown blotches and streaks that may fuse to cover older leaves entirely, plants remain stunted and in severe cases may die, while those that recover will show substantial delay in maturity and reduction in yield. Zn deficiency has been associated with a wide range of soil conditions: high pH (>7.0), low available Zn content, prolonged submergence and low redox potential and high available P. Availability of both soil and applied zinc is higher in upland soil than in submerged soil. Soil submergence causes decrease in zinc concentration in the soil solution.Rice crop removes 30-40 g Zn per tonne of grain. Zinc deficiency in Paddy can also be overcome by 0.5 per cent of foliar application of Zn (or) as soil application of ZnSO4 @ 25 kg/ha.