Nitrogen mineralization in soils from Michigan's Saginaw valley and thumb region

Abstract

An accurate estimate of nitrogen (N) mineralized during the growing season is needed for agronomically and environmentally sound N fertilizer recommendations. The objective of this study was to evaluate mineralization potential (N_o) of the predominate soil series in the Saginaw Valley and Thumb region of Michigan with the goal of utilizing this information to formulate N fertilizer recommendations. Air‐dried samples representing 17 sites were incubated and NO₃ and NH₄ produced were measured periodically. These data were used to determine N‐mineralization potential (N_o) utilizing exponential and hyperbolic models. The initial hypothesis for this study was the existence of a unique N_o value for each soil series. If this were the case, then this measurement could be used to formulate soil series specific N recommendations. Results show there is as much variability in N_o values within soil series as between soil series. Consequently, utilizing a single N_ovalue for a soil series in formulating N recommendations is not practical.