Soybean, corn, and wheat yields with variable soil pH on Plinthic Acrisols

Liming costs have escalated since the mid 1970's in the United States. Studies of crop response to lime with irrigation are limited as well as those of crop response to soil acidifying agents. This study was conducted to determine yield response of irrigated soybean [Glycine max (L.) Merrill], corn (Zea mays L.), and wheat (Triticum aestivum L.) to lime and S and the change in soil pH, in response to lime and S. Irrigated soybean, corn, and wheat were grown on Dothan and Tifton loamy fine sand (Plinthic Acrisols) with different levels of calcite, dolomite, and S. Soil samples were collected before applying treatments and during each growing season. Soil pH and Mehlich I extractable P, K, Ca, and Mg in addition to grain yield of each crop were determined. Highest soybean yield (4.2 t ha−1) occurred in 1984 at a soil pH of 4.9 (1:1 v/v soil—water suspension) while the yield was zero at a pH of 3.7 on S treated plots. A soil pH of 4.8 in 1985 reduced soybean yield from 3.4 to 2.7 t ha−1 in comparison to untreated plots (pH = 5.6). In 1986, soybean yield was 0.8 t ha−1 at pH 4.0 in comparison to 2.3 t ha−1 at pH 5.1 and 5.9. Corn did not respond to lime with control pH of 5.3 in 1985 or 5.1 in 1986 but S at pH 4.6 reduced yield from 12.3 to 8.7 t ha−1 in 1985 and S reduced yield from 11.0 to 0.9 t ha−1 at pH 4.0 in 1986. Sulfur reduced wheat yield from 4.3 to 1.7 t ha−1 in 1985 and from 2.2 to 0.9 t ha−1 in 1987. Soil pH after cropping with S addition was 4.4 each year. Wheat did not respond to lime when unlimed soil had a pH of 5.2 or above.