 Corresponding author: Ahmad UB; E-mail: Department of Soil Science, Kano University of Science and Technology, Wudil Kano State, Nigeria. Copyright © 2021 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution Liscense 4.0. Response of groundnut (Arachis hypogea) to rhizobia inoculation, mineral nitrogen and inoculation amendment at the two agro ecological zones of northern Nigerian savannah Abdulkadir N. A. 1 , Ewusi-Mensah N. 2 , Opuko, A. 2 , Yusuf, A. A. 3 , Logah, V. 2 , Adamu U. K. 1 , Almu H. 1 , Sani, A. 1 , Muhammad A. A. 1 , Hayatu, B. 1 , Ahmad, U. B 1, , Lamido, A. K. 1 , Aliyu, R. W. 1 and Jibrin, H. J. 4 1 Department of Soil Science, Kano University of Science and Technology, Wudil Kano State, Nigeria. 2 Department of Crop and Soil Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana. 3 Soil Science Department, Faculty of Agriculture/Institute for Agricultural Research, Ahmadu Bello University P.M.B 1044, Zaria, Nigeria. 4 Agronomy Department Faculty of Agriculture/Institute for Agricultural Research, Ahmadu Bello University P.M.B 1044, Zaria, Nigeria. GSC Advanced Research and Reviews, 2021, 08(01), 022–027 Publication history: Received on 01 June 2021; revised on 04 July 2021; accepted on 07 July 2021 Article DOI: https://doi.org/10.30574/gscarr.2021.8.1.0140 Abstract Nitrogen is the most limiting major nutrient required by all living plants. Nitrogen fertilizer is costly and too much application of nitrogen causes detrimental effects to our ecosystem. Alternatively, the use of commercial microbial inoculants will be an alternative to chemical fertilizer for the small holder farmers in northern Nigeria. Groundnut (pea nut) was selected as a test crop for the inoculation. The experiment was conducted at Sudan savannah in Kano State and Guinea savannah in Bauchi state of Nigeria during the 2016 cropping season. The design of the experiment was RCBD with seven treatments and four replications in each site. Two rhizobia inoculants were tested on groundnut in two agroecological zones of northern Nigeria to monitor their performance and their ability to establish symbiotic and nodulate the crops. The treatments combinations were; histic, biofix, nitrogen, cattle manure, histic + cattle manure, biofix + cattle manure and control. In the groundnut field, Biofix produced higher nitrogen fixed than all treatments in the Sudan savanna, while in the Guinea savanna no significant differences (P = 0.67) were observed between the treatments and the control. However, inoculated plots had higher nitrogen fixation than the control. Keywords: Biological nitrogen fixation; Rhizobium; Inoculants; Grain uptake; Groundnut 1. Introduction Groundnut (Arachis hypogaea L.) or peanut is one of the important legume crops of tropical and semi-arid tropical countries of the world, where it supplies edible oil and vegetable protein [18]. The productivity of groundnuts varies from 3500 kg/ha in the United States of America to 2500 kg/ha in South America, 1600 kg/ha in Asia and less than 800 kg/ha in Africa. According to V. Prasad et.al., [18] groundnut yields in Africa are lower compared to the average world yields. In Nigeria average yield are much lower (0.6-0.7 tons/ha.), and this is a serious challenge in the African farming system [18]. Groundnut is an annual crop which grows best in light textured sandy loam soils with neutral pH. Best temperature for their growth and development ranges from 28 to 30 ºC and the crop requires rainfall of about 500-600 mm. The main yield limiting factors in semiarid regions are drought and high temperature stress [2]. There were low literatures on groundnut inoculation as compared to soybean. However, inoculation of groundnut seed with right rhizobia could enhance nitrogen fixation [2].