A field experiment was carried out at Ismailia Agriculture Station to study efficiency of the applied rates and methods of cobalt on growth, yield and elemental composition of peanut plants grown on a sandy soil under sprinkler irrigation system.
Results showed that the growth and yield components of peanut increased progressively and significant with increasing the applied Co level to the high rates of (4 kg fed-1, 250 L of 1 g L-1 fed-1 and 0.02 g kg-1 seed for surface, foliar and coating application, respectively) as well as with an inversely affected the growth parameter, which their values remained significantly higher than the corresponding ones for the control treatment. It is evident that soil application of Co generally, showed a superiority as compared to the other two methods, foliar and coating applications. For the most of investigated plant parameters. Also, it is quite to mention that Co at either any applied rate or method could achieved significantly increases in peanut uptake of N, P, K, Fe, Mn, Zn, Cu and Co. In general, Co at the minimum rate was of more pronounced effect on peanut uptake for most the studied element, except of N and K, where the opposite was true.