Release of non-exchangeable % MathType!Translator!2!1!AMS LaTeX.tdl!TeX -- AMS-LaTeX! % MathType!MTEF!2!1!+- % feaaeaart1ev0aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbbjxAHX % garmWu51MyVXgatuuDJXwAK1uy0HwmaeHbfv3ySLgzG0uy0Hgip5wz % aebbnrfifHhDYfgasaacH8qrps0lbbf9q8WrFfeuY-Hhbbf9v8qqaq % Fr0xc9pk0xbba9q8WqFfea0-yr0RYxir-Jbba9q8aq0-yq-He9q8qq % Q8frFve9Fve9Ff0dmeaabaqaciGacaGaaeqabaWaaeWaeaaakeaada % ahbaWcbeqaaiaabgdacaqG1aaaaOGaaeOtaiaabIeadaqhaaWcbaGa % aeinaaqaaiaabUcaaaaaaa!3C62! $$ {}^{{{\text{15}}}}{\text{NH}}^{{\text{ + }}}_{{\text{4}}} $$ from subgrade, decomposed granite substrates and uptake by non-mycorrhizal and mycorrhizal California native annual grass, Vulpia microstachys