Effects of Nitrogen (From Two Sources: Urea and Ammonium bicarbonate) and Phosphorus on Dry Matter and Macronutrients Uptake by Corn Plant in an Alkaline Sandy Loam Soil under Greenhouse Conditions

Background and Objectives

Nitrogen application has been reported to improve P uptake by plants. It has recently been reported that bicarbonate can increase the available P for some sandy soils. On the other hand, P fertilizers that have acidic reaction in soil may reduce the negative effects of N fertilizers, especially ammonia (NH3) volatilization, which facilitated in alkaline conditions. So far, no study has been reported on the interaction of N from ammonium bicarbonate and P fertilizer in Iranian alkaline soils and their effects on dry matter and macronutrients uptake by corn plant. Therefore, the aim of this research was to study the interaction of urea and ammonium bicarbonate with P on dry matter of corn plant and macronutrients uptake through simulation of band application in pots and the comparison was with urea, the common N fertilizer in Iran.



Methodology

This research were conducted under greenhouse conditions in an alkaline sandy loam soil and factorial experiment in a completely randomized design. The first factor was P in two levels (zero and 25 mg P kg-1 soil) from pure monocalcium phosphate source [Ca(H2PO4)2.H2O] and the second factor was N in seven levels (0, 75, 150, and 300 mg kg-1 soil) from two sources of urea [CO(NH2)2] and ammonium bicarbonate (NH4HCO3) which carried out by planting corn (Zea mays Single Cross,704 variety). The P fertilizer was placed 8 cm below the intended place for seed as a solid, before planting. After planting immediately, a third of applied N was injected as a solution 6 cm below the seed and about 2 cm above P fertilizer. The rest of the N fertilizer was injected 20 and 40 days after planting. After 80 days from the planting date the corn plants were harvested and dry weight of the shoot and root, as well as the concentration and amount of nutrient uptake (content) including N, potassium (K), P, Calcium (Ca), and magnesium (Mg) were measured.

Results

The results showed that increasing applied N levels increased N concentration and content of corn plant shoot and root and P, K, Ca, and Mg shoot concentrations. However, dry weights of the shoot and root, apparent recovery of N, P content, as well as root K concentration and content decreased. At 150 and 300 mg N kg-1 level, ammonium bicarbonate treatment had greater shoot dry weight and at 75 and 150 mg N kg-1 levels had more root dry weight than that of urea. At 150 mg N kg-1 level, ammonium bicarbonate treatment had more P content in the shoot and root. Phosphorous application increased dry weight of shoot and root, concentration and amount of P uptake, and root K concentration while shoot K concentration and concentrations of P and Mg in the root decreased. The interaction effects of N  P on dry weight of shoot and root, root P concentration and K and Mg concentration in the shoot were significant (p<0.01).