Relative Efficiency of Broadcast Versus Banded Potassium for Corn¹

Abstract

Abstract Three experiments were conducted in Illinois to determine the relative efficiency of broadcast versus banded potassium for corn. The pounds of banded K required to obtain a specified corn yield were divided by the pounds of broadcast K required to obtain the same yield. This ratio (banded K/broadcast K) represents the relative efficiency of broadcast K in terms of banded K, with respect to corn yield. Four or 5 rates of broadcast K and 4 rates of banded K, in factorial arrangement, constituted the fertilizer treatments. Multiple regression equations of the quadratic form were calculated to express yield as a function of broadcast and of banded K. The regression equations account for 77, 81, and 62% of the variation in yield for the Cisne, Bluford, and Belknap soils, respectively. The largest yield increases from added K were 83, 33, and 13% for the three soils. Less K was required to obtain a given yield when the K was banded than when broadcast. The relative efficiency of broadcast K, as compared to banded K, ranged from 0.33 to 0.88. In some cases, no rate of broadcast K equaled the yield produced by a given rate of banded K.