Harun GitariMwende NgieMohamed, Aden2024-02-012024-02-012023https://ir-library.ku.ac.ke/handle/123456789/27400A Research Thesis Submitted in Partial Fulfilment of the Requirements for the Award of Master of Science Degree in Dryland Agriculture and Enterprise Development in the School of Agriculture and Environmental Sciences, Kenyatta University,November 2023.Most arid and semiarid areas are bare and greatly infested with intrusive wild species. Buffel grass (Cenchrus ciliaris L.) and Sudan grass (Sorghum sudanense Piper.) are the supreme drought-tolerant grasses that are commonly grown in dry regions. Besides water, nitrogen (N) is a vital element limiting the growth, yield, and herbage quality of such grasses since it has key roles in physiological and biochemical functions in plants. Hence, this study aimed to assess the performance of Buffel and Sudan grasses under nitrogen fertilization in Mandera County. This study comprised a field trial laid as a split-plot in a randomized complete block design with grasses being assigned to the main plots, whereas N rates (0, 35, 70, 105, and 140 kg N ha-1) occupied the subplots. Data collection was carried out on growth parameters (plant height, leaf length, number of leaves per plant, leaf width, stem girth, and tiller number), yield parameters (shoot weight, root weight, and aboveground biomass yield DBY), and quality attributes (acid detergent fiber ADF, crude protein CP, and neutral detergent fiber NDF). Across the seasons, plant height progressively increased with increasing N rates up to a maximum of 141 and 246 cm for Buffel grass and Sudan grass, respectively, which were associated with a 105 kg N ha−1 rate. Nonetheless, there was no noteworthy enhancement in plant height (142 and 246 cm) with an additional upsurge in N fertilizer rate to 140 kg N ha−1 relative to the one of 105 kg N ha−1. Regarding the leaf length, Sudan grass had longer and wider leaves at all treatment levels than the Buffel grass. Plant height, leaf length, width, and the number of leaves per plant increased with increasing N level up to the rate of 140 kg N ha-1, though this was not statistically different from the rate of 105 kg N ha−1, for both kinds of grasses. The results revealed that Sudan grass contained higher crude protein than Buffel grass at all levels of treatments (10.33 and 8.80% at the rate of 105 kg N ha−1 respectively). More so, crude protein content was found to be higher in plots where N application was made than in the control plots. There were great associations between the dependent variables (DBY, ADF, NDF, and CP) and independent variables (plant height, leaf length, No. of leaves, leaf width, stem girth, and No. of tillers), with the coefficient of regression ranging from 0.56 to 0.96 for Buffel grass and 0.59 to 0.96 for Sudan grass. Findings from this study indicate that for optimal growth, yield, and nutrient content benefits, Buffel and Sudan grasses ought to be grown using nitrogen fertilizer at 105 kg N ha−1 rate. The study recommends the use of nitrogen fertilizer at the right time in the growth cycle of Buffel and Sudan grasses.enBuffel (Cenchrus Ciliaris)Sudan (Sorghum Sudanense)Grasses’ GrowthQuality ResponsesNitrogen ApplicationMandera CountyKenyaThesis