The redistribution of N, P, K, Ca, and Mg by corn from its vegetative parts to the developing ear was measured. This was accomplished by comparing a set of plants grown outdoors and harvested approximately 12 days after silking with a similar set of plants whose nutrient supply was cut off at the same time but which were allowed to grow to maturity. The increase in dry weight of ears between the first and second harvest was 174 g. The mean ear weight of the plants comprising the second harvest was 219 g.
Chemical analysis of the various plant parts permitted a measure of the losses and gains of mineral elements from the first to second harvests. Of the total present in all vegetative plant parts at harvest 1, the following percentages of the various plant nutrients had moved out of the vegetative parts by harvest 2: N, 65%; P, 76%; K, 23%; Ca, 0%; Mg, 45%: If all the plant nutrients redistributed from the vegetative parts between harvest 1 and 2 moved to the developing ear, the following percentages of the nutrients in the mature ear were supplied by the redistribution process: N, 97%; P, 116%; K, 180%; Ca, 0%; and Mg 133%.