Productivity of Emory and Dewey soils for soybeans

In 1974 a soybean (Glycine max) productivity study was conducted on Emory and Dewey soils in Blount County, Tennessee. The yield data were obtained from soybeans grown alone and soybeans following wheat. These yields were related to pH, available phosphorus, exchangeable potassium, rainfall, percent sand, silt, and clay. When soybeans were grown alone there was a significant difference at the 0.05 level of probability in yields, percent silt, and percent clay between Dewey C3 and the Emory A1 and Dewey B1 soils. When soybeans followed wheat there was also a significant difference in soybean yield and percent clay between Dewey C3 and the Emory A1 and Dewey B1 soils; however, there was a significant difference for silt among all soil mapping units. Available phosphorus, pH, and exchangeable potassium accounted for little of the yield variation as measured by the linear regression analysis. The three independent variables that gave the best stepwise regression model were percent clay, rainfall, and available phosphorus. These three variables account for 63.3 percent of the total variation in yield.