Abstract

The effects of four nitrogen rates (N₁ = 150 kg N ha^-1; N₂ = 100 kg N ha^-1; N₃ = 50 kg N ha^-1 and N₄ = 0 kg N ha^-1) on Total dry matter (TDM), photosynthetically active radiation intercepted (PARabs), Water Consumption (WC), Radiation use efficiency (RUE), Water use efficiency (WUE) and the relation between photosynthetically active radiation intercepted and water consumption for Durum Wheat were investigated during three growing seasons (2005-2006, 2006-2007 and 2007-2008). Results showed that, the cumulative PARabs increase with nitrogen levels. In fact, N₁ treatment recorded the highest cumulative PAR abs (920.2, 1041.5 and 1031.3 MJ m^-2) and the lowest (812.7, 999.4 and 954 MJ m^-2) obtained under N₄ treatment, respectively for three growing seasons. Also, RUE, TDM and WUE have increased with nitrogen rates. The highest RUE observed under the N₁ (from 1.32 to 1.43 g MJ^-1) and the lowest under N₄ (from 1.1 to 1.27 g MJ^-1). N₁ treatment improved the TDM compared to N₃ and N₄ rates, respectively from 11.7 to 12.6% and from 15 to 22.3%. The highest WUE were obtained under the N₁ (from 2.8 to 3.1 kg m^-3) and the lowest were observed under N₄ (from 2.4 to 3 kg m^-3). The relationship between cumulative PAR abs and cumulative water consumption was linearly regression with a high correlation coefficient (R²) which indicates that cumulative PAR abs increases when water consumption increases.

This work is licensed under a Creative Commons Attribution 4.0 License.