Effects of Mineral and Biological Nitrogen on Yields and Nodulation of Two Groundnut (Arachis hypogaea L.) Varieties in the Semiarid Region of Sudan

Abstract Legumes are widely recognized for improving soil fertility through atmospheric nitrogen fixation. The present study investigates the cultivation of groundnut ( Arachis hypogaea L.) in the semiarid urban marginal lands of Khartoum, Sudan. A field study was conducted over two seasons to examine the effects of rhizobium inoculation (RI), mineral nitrogen (MN, 43 kg N ha −1 ) fertilizer and a control (C, no addition) on nodulation, yield and its components. Two varieties, Sodari and Kiriz , were tested in a randomized complete block design (RCBD) with three replicates. The data collected include the number of nodules and the dry weights of nodules, shoots, and roots at 45, 75, and 105 days after sowing (DAS). Data on yield and yield components of seeds and pods were obtained at harvest. The nitrogen (N), phosphorus (P), and potassium (K) contents of the plant samples were analysed in the second season. The dry weights of nodule, shoot, and root of inoculated plants is comparable to that of N–fertilized plants. In the second season, MN increased the number of nodules by 58.6%, 28.4%, and 40.8% compared to RI at 45, 75, and 105 DAS, respectively. In the second season, Kiriz significantly outperformed Sodari in most parameters. Kiriz variety outperformed Sodari in pod, seed, and 100–seed weights by 128%, 88%, and 80%, respectively, over the two seasons. Application of RI significantly increased plant phosphorus uptake by 29% compared to C and by 109.5% compared to MN treatments.