Response of Upland Rice Cultivars to Nitrogen Fertilizer in the Savannas of Nigeria

Abstract

In the dry savannas of West Africa, cultivation of upland rice (Oryza spp.) under rain‐fed conditions is expanding due to the introduction of the New Rice for Africa (NERICA; WARDA, Bouake, Cote d'Ivoire) but appropriate N recommendations for these new cultivars are lacking. The present study evaluated the response of four NERICA rice cultivars, their parents (WAB 56‐104 (O. sativa, tropical japonica type), CG 14 [O. glaberrima]) to four rates of N (0, 30, 60, and 90 kg ha−1) at Sabon‐Gari (Sudan savanna, SS) and Tilla (northern Guinea savanna, NGS) in 2007 and 2008. There was no interaction between N rates and rice cultivars for grain yield, suggesting that the rice cultivars responded similarly to N application. Grain yield of NERICA rice cultivars responded significantly to N application in the Nigerian dry savannas following a linear response, even at 90 kg N ha−1, thus optimum rate might be above this N level. NERICA 1, NERICA 3, and NERICA 4 had comparable yields and produced 1.4 to 1.7 times more grains than the other cultivars in Sabon‐Gari; while in Tilla, NERICA 4 and WAB56‐104 produced the highest yield. NERICA 1, NERICA 3, and NERICA 4 may be more suitable for cultivation in Sabon‐Gari (SS) while NERICA 4 and WAB56‐104 can be recommended for Tilla (NGS).