CHANGES IN NITROGEN, CARBON, AND OTHER SURFACE SOIL PROPERTIES DURING SECONDARY SUCCESSION

Soils were analyzed from 10 river terrace plant communities ranging in age from 5 yr to more than 150 yr. Soil C and N concentrations increased significantly with plant community development up to 25 yr. When quadratic transformations were used, soil N accretion was correlated with huisache (Acacia smallii Isely) stem basal area. Texas sugarberry (Celtis laevigata Willd. ) basal area was correlated with the soil N concentration and soil C accretion was correlated with total community basal area. Plant community development (measured as basal area) was examined using stepwise multiple linear regression analysis. Seventy-six percent of the variance of huisache basal area could be explained by community age, soil N, K, Mg, and silt content. Seventy-seven percent of the variance of Texas sugarberry basal area could be explained by community age, soil N, Mg, and clay content. Ninety-one percent of the variance in total community basal area could be explained by community age, soil pH, N, and clay content. Changes in other soil chemical and physical properties occurred during succession and may be important in determining community species composition and structure.