Ammonium N (NH4+–N) and nitrate N (NO3−–N) are the maininorganic forms of N in soils; both forms can be taken up byplants. The preferred N form varies in different plant species, and Nuptake by plants is dependent on the applied N and soil conditions.For many species, including maize, the mixture of NH4+–N andNO3−–N supports better plant growth than either form suppliedseparately (Marschner, 2012). Furthermore, P supply combined