Vegetative development of soybeans grown on different soil types

Abstract

Nine soybean (Glycine max (L.) Merrill) genotypes, three from each of Maturity Groups V, VI, and VII, were grown on Dubbs silt loam (Typic Hapludalf, fine-silty, mixed, thermic) and Sharkey clay (Vertic Haplaquept, very fine montmorillonitic, thermic) soils to evaluate the effect of soil environment on vegetative development. Leaf enlargement rate (cm2 leaf−1 day−1), final leaf size, internode length, plant height, and number of nodes per plant were all significantly greater on the silt loam for each genotype. The lowered leaf enlargement rate on the clay may have been due to the lower hydraulic conductivity of the clay, and thus fewer hours during the night conducive to leaf enlargement. A highly significant correlation (R2 = 0.96) was found between leaf enlargement rate and final leaf size, indicating that number of days to the different maximum leaf sizes is nearly identical regardless of soil environment. These results indicate that the soil environment and its related physical and textural properties are important factors in determining canopy development of soybeans.