Residual effect of iron-nickel interactions on the availability of nutrients

Summary Residual value of micronutrients pair (Fe × Ni) has been investigated in a Cu-deficient and P-responsive red soil by growing a second crop of maize in which maize had already been grown with factorial combination of 4 levels of Fe and Ni. Dry matter yield (shoots) has been found to be lower (50%) in comparison to first year. Due to combined Fe and Ni treatments the concentration and uptake of Fe by shoots increased significantly while reverse was the case in roots, showing synergistic effect of Ni on Fe absorption and its significant translocation to shoots. Concentration and uptake of Mn by shoots and roots decreased at higher levels of Fe and Ni. Concentration of P in shoots decreased whereas concentration and uptake of Zn by shoots remained unchanged. Under the combined effect of Fe × Ni, maize roots contained more of nutrients as compared to shoots. Thus roots appear to be responsible for the recycling of micro and macronutrients in soils.