What is the
time of application?
Time of application will be governed by micro-nutrient content of seed tubers, the growth stage at which particular micro-nutrient is required and the severity of deficiency in the soil. Generally, the micro-nutrient content of seed tubers is low and most of them are absorbed during the early growth thus, it favours early fertilization with micro-nutrients. At Shimla spray application of Zn was found superior to soil application and also to seed treatment in a soil that had marginal available zinc. But in the highly deficient soil, seed treatment with zinc salts proved to be the best. Therefore, in case the deficiency is severe delayed fertilization with zinc will be less effective.