Impact of nitrogen nutrition and moisture deficits on growth, yield and radiation use efficiency of wheat (Triticum aestivum L.)

Abstract

Crop production in arid and semi arid areas is restricted by soil deficiencies in moisture and plant nutrients, especially nitrogen. In order to evaluate the impact of nitrogen nutrition and moisture deficits on growth, yield and radiation use efficiency of wheat (Triticum aestivum L.), a field experiment was conducted at Agronomic Research Area, University of Agriculture Faisalabad, during 2008 to 2009. The study comprised of four nitrogen levels, that is, N₀ = control, N₁ = 60, N₂ = 120 and N₃ = 180 kg N ha^-1 and three water deficit levels, that is, I₁ = irrigation at 25 mm potential soil moisture deficit (PSMD), I₂ = irrigation at 50 mm potential soil moisture deficit (PSMD), I₃ = irrigation at 75 mm potential soil moisture deficit (PSMD). Results of the study revealed that maximum grain yield (6.72 t ha^-1) was obtained in the case of N₃ (180 kg N ha^-1) when I₂ = irrigation at 50 mm potential soil moisture deficit (I₂ × N₃) was applied in contrast to lowest grain yield (2.00 t ha^-1) in response to I₃= irrigation at 75 mm potential soil moisture deficit × no nitrogen (control) (I₃ × N₀). Highest plant height (86.27 cm), number of spike bearing tillers m^-2 (320), grains per spike (49.73), 1000-grain weight (50.55 g), biological yield (15.48 t ha^-1), straw yield (8.76 t ha^-1) and harvest index (43.42%) increased with increasing levels of nitrogen. The maximum value of these parameters was also observed in I₂ where irrigation was applied at 50 mm potential soil moisture deficit. The maximum value of RUE for TDM (6.45 g MJ^-1) was observed in I₂ × N₃ irrigation at 50 mm potential soil moisture deficit and nitrogen (180 kg ha^-1) treatment combination. Similarly, maximum RUE for grain yield (2.80 g MJ^-1) was observed for nitrogen (50 mm potential soil moisture deficit and 180 kg N ha^-1).

Keywords: Wheat, nitrogen nutrition, moisture deficits, radiation use efficiency, yield, Triticum aestivum L.