Effect of nitrate addition on efficient use of ammonium sulfate fertilizer on corn under saline conditions. II. Field experiment

Abstract

Two field experiments during two consecutive seasons, were conducted on corn (Zea mays L. var. Ghota-82), grown on a saline soil under flood irrigation system at ACSAD research station located at the Euphrates Valley, Deir-Ez-zor District, east of Syria. The objective was to study the effect of applying different ratios of mixed NO₃-N and NH₄-N fertilizers on the biomass yield of corn. Five rates of nitrogen (N) (0, 50, 100, 150, and 200 kg N/ha) were applied either in a single or in combination of two forms of ¹⁵N labelled nitrogen fertilizers (¹⁵NH4)₂ SO₄ and Ca (¹⁵NO₃)₂ Total N, ¹⁵N, nitrogen use efficiency (N recovery), and dry matter yield were the parameters investigated. The results showed that (1) the high concentrations of NH₄-N reduced dry matter yield; (2) NO₃-N was more effective in increasing total N content of plant tissues than the same concentration of NH₄-N; (3) combination treatments always induced both higher yields and N content of plant tissues than single treatments of NH₄-N; (4) NH₄-N form increased the NO₃-N uptake, and the NO₃-N form had an effect on the absorption of NH₄-N; and (5) and the recovery of NO₃-N form was much higher than NH₄-N form under saline soil conditions.

Acknowledgments

Thanks to Prof. I. Othman, Director General of AECS, for his encouragement, Dr. N. E. Sharabi, Head, Department of Agriculture, for his remarks, Dr. M. Zarkawi for his valuable comments and revision of the manuscript, Prof. F. Al-Rabbat for reviewing the manuscript, and Eng. J. Attar for drawing the figures.