The effects of a foliar spray containing phosphorus and zinc on the development, composition and yield of forage maize

Forage maize grown in areas where spring temperatures are low and accumulated heat is limited will be restricted in terms of maturity and thus nutritional value. A stagnant growth phase is commonly caused by low temperatures between germination and the five‐leaf stage, which could be caused by reduced mineral availability. The effects on maize plant development and harvest characteristics of supplying phosphorus and zinc to young plants in a foliar spray were investigated. Three different application dates, between the four‐leaf and the seven‐leaf stage, were compared. Applying the phosphorus and zinc foliar spray at the four‐leaf stage resulted in a significant ( P < 0·05) increase in starch content at harvest. Cob index [proportion of plant dry matter (DM) in the cob] was increased ( P < 0·05) by applying the nutrient spray at the four‐, five‐ and seven‐leaf stages. However, there was no effect on DM yield, suggesting some alteration in partitioning within the plant.