An investigation of soil-plant and plant-animal mineral nutrition landscapes of agricultural areas in the Fairbanks and Delta Junction regions of Interior Alaska

Abstract

I attempted to identify biologically limiting minerals and assess mineral variability by collecting soil and plant samples in June, July, and August from 14 bromegrass fields and adjacent woodlands, in the Fairbanks and Delta Junction regions. Soil extractable P, K, Ca, Mg, Al, B, Cd, Co, Cr, Cu, Fe, Mn, Pb, Zn, NO⁻³ and NH⁴ as well as pH and organic matter content were measured at three depths. Bromus inermis, Calamagrostis canadensis, Epilobium angustifolium and Salix alaxensis were analyzed for N, P, K, S, Ca, Mg, Al, B, Cd, Cu, Fe, Mn, and Zn. Plant sample variability was assessed by species, date, and location. Mineral content of plants and soils among locations was highly variable with proximate sites showing little similarity. Local differences seemed more important than regional variation in determining soil and plant mineral abundances. Plant mineral content was highly affected by species, date, and location. With the exception of magnesium, plant mineral content was generally not correlated with extractable soil minerals. In most cases, organic matter content and pH were generally not correlated with plant mineral content. Plants, in these regions, may be limited by sulfur, magnesium, and boron availability. High levels of manganese and cadmium in some plant species and low levels of copper and possibly zinc in late season forages may negatively affect herbivores.