EFFECT OF PHOSPHORUS AND POTASSIUM FERTILIZERS ON THE AGRONOMIC CHARACTERISTICS OF SPRING WHEAT AND THEIR INTERACTION ON GRAIN YIELD

Abstract

The influence on grain yields and agronomic characteristics of spring wheat was determined when P and K fertilizers were applied singly up to 448 kg/ha and to 996 kg/ha when combined.The combined PK fertilizers resulted in a highly positive interaction and increased grain yields from 2,461 to 4,036 kg/ha when applied at rates up to 224 kg/ha of each nutrient. A slight reduction in yield occurred at the highest combined levels of both elements. Small significant increases in grain yield were obtained from the single applications of K, but P alone did not alter yield.Increased plant height, straw, grain and kernel weights were obtained. Days to mature were reduced from 95 to 91 or 92, and a slight reduction in strength of straw occurred. Plant height and yield were correlated because height and straw weight were strongly associated. Kernel weight was highly correlated with grain weight, which in turn had a marked positive effect on yield.