Fonseca, TelmoArrobas, MargaridaParada, Maria JoãoRodrigues, M.A.2011-01-062011-01-062010Fonseca, Telmo; Arrobas, Margarida; Parada, Maria; Rodrigues, Manuel (2010). Effect of sampling date on chemical indices of the mineralizable nitrogen in soil. In AGRO2010 the XIth ESA Congress, Montpellierhttp://hdl.handle.net/10198/3016In the 1960s and 1970s there was great emphasis on selecting simple laboratory methods to estimate the potentially available soil N that could be routinely used as a method for the N recommendations systems (Keeney and Breniner, 1966; Stanford and Smith, 1976). Many chemical extractants were investigated (acids alkali, salts, water…) as possible tools for assessing how much N may be mineralized, varying the concentration of the extractant, temperature and time of extractions.engconference object