Effects of different ratios of nitrate to ammonium on Fe, Mn and Zn uptake, and wheat (Triticum. aestivum) growth under glasshouse condition

Nitrate and ammonium forms of nitrogen are being applied to improve plant growth and uptake of other nutrients. Given that the effect of application of different nitrate to ammonium ratios accompanied by other fertilizers (i.e. Fe, Mn and Zn) has not been studied on wheat growth as well as uptake of Fe, Mn and Zn, three glasshouse pot studies were conducted with factorial arrangement of treatments in a completely randomized design (CRD) with three replications in the calcareous soil. In each experiment, the interaction of different nitrate to ammonium ratios and the fertilizer (Fe, Mn and Zn) rates were studied separately. The treatments were five nitrate to ammonium ratios (00/100, 25/75, 50/50, 75/25 and 100/00), three levels of Fe (0, 5 and 10 mg/kg soil), three levels of Mn (0, 3 and 6 mg/kg soil), and three levels of Zn (0, 1 and 2 mg/kg soil). The results indicated that all nitrate to ammonium ratios, except 00/100, significantly increased wheat shoot and root weights. Similarly, in the presence of nitrate, the uptake of Fe, Mn and Zn were increased significantly. The uptake of nutrients was increased by increasing of Zn, Mn and Fe fertilizer application at different ratio of nitrate to ammonium. In addition, application of both nitrate and ammonium compared to their single application could promote Zn, Mn and Fe uptake at different rates of  these elements. At single application of ammonium, increasing of Zn, Mn and Fe application promoted root growth and Zn, Mn and Fe uptake. It can be concluded that the presence of nitrate could increase growth of wheat and Fe, Mn and Zn uptake; but single use of ammonium may decrease growth and uptake of other nutrients.