Effects of Soil pH on Forage Yield, and Chemical Composition of Sorghum and Millet1

Abstract

AbstractMillet [Pennisetum typhoides (Burm.) Stapf and Hubbard] yields more forage than sorghum [Sorghum bicolor (L.) Moench] does in certain areas of the Southern Coastal Plain. Yield differences are associated with low soil pH in some instances. Experiments were conducted to elucidate the relation between soil pH, forage yield, and selected chemical composition of sorghum and millet.Management practices and plant nutrient applications were applied in a manner and at a level shown by other experiments to be adequate. The forage from both crops was analyzed for N, P, K, Ca, Mg, Al, and Mn. Upon completion of the experiment, soil samples were analyzed for P, K, Ca, Mg, Al, and Mn and soil pH was measured. Millet forage yield was unrelated to the soil pH in the pH range used. Sorghum forage yield increased 2,000 kg/ha when soil pH increased from 5.2 to 5.6. The concentration of Mg in sorghum forage was found to be greater at soil pH of 5.8 and above, while the concentration of Al and Mn decreased at a soil pH ≥ 5.2. The concentration of Ca increased more at soil pH ≥ 5.8; while the concentration of Al and Mn decreased at a soil pH ≥ 5.2. The concentration of Ca increased in millet forage at a soil pH ≥ 5.2; while P and Mg content increased at a soil pH ≥ 5.8.Based on this study, it is recommended that liming acid soils in the Southern Coastal Plain to increase soil pH increases sorghum forage yields and improves the mineral nutritional quality of both sorghum and millet forage.