RADIATION AND NITROGEN USE EFFICIENCIES OF C3 WINTER CEREALS TO NITROGEN SPLIT APPLICATION

Abstract

Three field experiments were conducted at the Experimental Farm, Bahauddin Zakariya University, Multan, Pakistan during the winter season 2010-11 to study the response of 3 winter cereal crops viz., wheat (Triticum aestivum L.), oat (Avena sativa L.) and barley (Hordeum vulgare L.) to nitrogen split application in terms of growth, final yield, radiation and nitrogen use efficiencies (R&NUEs). There were 2 variables; 3 cultivars each of wheat (Sahar-2006, Lasani-2008 and AARI-2010), oat (CK-1, F-411 and Ravi) and barley (Jao-87, Haider-93 and BO-7022) crops and 4 nitrogen split applications i.e., NS1 = whole N at sowing, NS2 = ½ N at sowing + ½ N at 1st irrigation, NS3 = 1/3 N at sowing + 1/3 N at 1st irrigation + 1/3 N at 2nd irrigation and NS4 = ¼ N at sowing + ¼ N at 1st irrigation + ¼ N at 2nd irrigation + ¼ N at 3rd irrigation). The wheat cv. Sahar-2006, oat cv. CK-1 and barley cv. BO-7022 out yielded other cultivars by producing total dry matter 574 to 722 g m-2, 429 to 533 g m-2 and 455 to 555 g m-2, respectively. Similarly, the respective grain yield values for these cultivars were 265 to 350 g m-2, 205 to 265 g m-2 and 202 to 263 g m-2, respectively. For wheat, oat and barley crops radiation use efficiency (RUE) ranged from 1.14 g MJ-1 to 1.47 g MJ-1, 0.85 g MJ-1 to 1.08 g MJ-1 and 0.91 g MJ-1 to 1.13 g MJ-1, respectively. In general, wheat, oat and barley had higher RUE values at 3rd N split application and the lowest were found in case of 4th N split application regime. Over all agronomic nitrogen use efficiency (ANUE) for wheat, oat and barley ranged from 10.96 to 19.20 kg kg-1, 7.04 to 13.30 kg kg-1 and 17.00 to 30.60 kg kg-1, respectively. Among N split applications, 3rd N application produced the higher ANUE of 16.96 to 19.20 kg kg-1, 11.74 to 13.30 kg kg-1 and 29 to 30.60 kg kg-1 in case of wheat, oat and barley crops, respectively. Over all, economic nitrogen use efficiency (ENUE) for wheat, oat and barley ranged from 3.03 to 5.30 $ kg-1, 2.73 to 5.16 $ kg-1 and 2.27 to 4.09 $ kg-1, respectively.