Simulation of effects of soil bulk density and p addition on k uptake by soybeans

Abstract

Abstract Increasing soil bulk density has been shown to reduce root growth and decrease K uptake by soybeans (Glycine max L. Merrill). Changing soil bulk density also affects soil buffer power, b, and effective diffusion coefficient, De, which affect K influx. The relative decrease in K uptake due to reduced root growth as compared to reduced K influx is not known. Addition of P may affect root growth and P influx properties of plant roots. The objectives of this paper were (1) to use the Cushman mechanistic model to simulate the effect of changing soil bulk density and soil P on K uptake by soybeans, and (2) to determine the parameters that are changed by changes in bulk density and added P and their effect on K uptake. Plant and soil data of an experiment where Williams soybeans were grown for 21 days in pots of Raub (Aquic Argiudoll) silt loam with factorial treatments of two rates of K (0 and 100 mg K kg‐1 soil), two rates of P (0 and 100 mg P kg‐1 soil), and two bulk densities (1.25 and 1.45 g cm‐3 )...