Response on light interception and radiation use efficiency of selected winter cereals at optimum N fertilizers
¹University of Gonbad Kavous, Faculty of Agriculture, Department of Plant Production, Fallahi street, postal code 163, Iran
²Montana State University, Western Triangle Agricultural Research Center, USA
Nitrogen is an important element for leaf development and light interception. In order to study light interception and radiation use efficiency of winter cereals under optimum N fertilizer application the experiment was conducted during 2013–2014 and repeated in 2014–2015 in the research field of Gonbad Kavous University, Iran. Treatments included winter cereals [i.e. bread wheat (Triticum aestivum L.), durum wheat (Triticum turgidum L.), six rowed barley, two rowed barley, hull less barley (Hordeum vulgare L.), oat (Avena sativa L.), and triticale (Triticosecale wittmack L.)] and N rates (0 and optimum level (The optimum nitrogen level was determined as 150 kg ha–1 for bread wheat and hull less barley, 120 kg ha-1 for durum wheat and two rowed barley, 210 kg ha–1 for six rowed barley, 240 kg ha–1 for triticale and 90 kg ha–1 for oat, based on the average of recent 10-years grain yield according to Gonbad Kavous Agriculture Research Centre data’s for each cereal)). Measurements were recorded on leaf area index (LAI), dry matter accumulation (DMA), extinction coefficient (k) and radiation use efficiency (RUE). Results showed that LAI varied from 6.08 in triticale to 3.28 in hull less barley in first year and varied from 4.51 in triticale and 3.38 in oat in the second year. In both years, the accumulation total dry matter was related to triticale (2,054.9 g m–2, 2,557.05 g m–2). The maximum (0.86 ± 0.03) and minimum (0.67 ± 0.03) extinction coefficient were observed in bread wheat and triticale in 2013–2014 and the maximum (0.86 ± 0.043) and minimum (0.56 ± 0.036) k in two rowed barley and hull less barley in 2014–2015, respectively. In first year RUE varied from 2.02 ± 0.07 g mj−1 for durum wheat to 2.78 ± 0.14 g mj−1 in triticale. In the second year, the maximum (3.44 ± 0.25) RUE related to hull less barley and the minimum (2.80 ± 0.12) in six rowed barley. Light extension coefficient (k) and RUE variation associated to LAI and intercepted light by the canopy.