OPTIMUM RATIOS OF NITROGEN AND PHOSPHORUS FERTILIZERS FOR CORN DETERMINED BY HOMÈS’ METHOD OF SYSTEMATIC VARIATIONS

Abstract

A greenhouse experiment was carried out to investigate the possibility of an optimum N/P ratio for sweet corn (Zea mays L.), using Homès’ method of systematic variations.Three levels of N and P fertilizers were applied to a soil. Each level was comprised of nine fertilizer treatments differing only in N/P ratio in a replacement series. Accordingly, the three levels represented 8.12, 16.04, and 32.02 meq per 4.4 kg soil of NO3− plus H2PO4−, respectively.There appeared to be a definite N/P ratio of fertilizer which resulted in a maximum yield and which was similar for all three levels of the replacement series of N plus P. However, this effect was most pronounced at the highest level of N plus P. The Homès method for determining the optimum N/P ratio of a fertilizer was successful primarily at the highest level of N plus P.N/P ratios of corn plant tissues from about 9 to 18 coincided with maximum dry matter yields at the highest level of N plus P.