This study evaluated the effects of grazing management practices, topographic position, and land cover types on mineral-associated organic carbon (MAOC) and particulate organic carbon (POC) in a semi-arid rangeland of Kenya. Research was conducted at Mpala Research Centre (controlled grazing) and Ilmotiok Community Group Ranch (continuous grazing) in Laikipia County. A factorial experimental design with a split-plot arrangement was used in this study. Grazing management practices (controlled and continuous grazing) and topographic positions (midslope, foot slope, and bottomland) were assigned to the main plots, while land cover types (bare ground, grass patches, and tree mosaics) were designated as subplots. Soil samples were collected at 10 cm intervals, 0–10 cm, 10–20 cm, and 20–30 cm depth for MAOC and POC analysis. Data analysis was done using R software, where nonparametric tests were done when the assumptions of normality and homogeneity of variance were violated. Controlled grazing resulted in higher MAOC (0.361%) and POC (0.683%) compared to continuous grazing (0.352% and 0.548%, respectively), indicating an increase of 2.56% in MAOC and 24.64% in POC under controlled grazing. This can largely be attributed to improved vegetation recovery, especially in midslope areas. The highest MAOC (0.367%) was found in the bottomland, likely due to reduced erosion and improved water retention. The midslope and foot slope positions had lower MAOC means of 0.358% and 0.344%, respectively. Depth analysis showed peak MAOC at 20 cm (0.390%), with controlled grazing resulting in better carbon retention at 30 cm. Similarly, controlled grazing yielded a mean POC of 0.683% versus 0.548% for continuous grazing, with bottomland having the highest POC of 0.754%. A Kruskal‒Wallis tests showed significant differences in MAOC and POC across land cover types (χ² = 42.701, p < 0.001 for MAOC, and χ² = 83.53, p < 0.001 for POC), with tree mosaics and bare land contributing most to POC and MAOC, respectively. These findings highlight the beneficial role of controlled grazing and diverse land cover in enhancing soil carbon storage. To promote sustainable rangeland management, it is recommended that rangeland managers adopt controlled grazing practices and allow diverse land cover types, such as tree mosaics, to increase carbon sequestration and ecosystem resilience.

The decline in soil organic carbon (SOC) due to continuous cultivation practices threatens soil productivity and compromises climate change mitigation efforts. This study investigates the effect of agro-ecological zones (AZ), management practices (MP), and specific forages on SOC and its related fractions: particulate organic carbon (POC) and mineral-associated organic carbon (MAOC), in Meru County, Eastern Kenya. Thirty-five predetermined perennial forage fields with Brachiaria (B), Panicum (Panicum maximum) (P), Napier grass (P.P. Schumach) (N), paired with maize (Zea mays) (M) growers, and with two MP [farmyard manure (FYM) and inorganic fertilizer application] were selected per agro-ecological zone. A factorial plot design was employed, with zones as the main plots, the MP as split plots, and the forages as split-split plots. Soil samples were collected from 1 m-by-1 m plots across 35 farms at depths of 0–50 cm, and analyzed for pH, bulk density, SOC content, POC, MAOC, and other micronutrients. Soil samples were statistically analyzed using two-way ANOVA. From the survey, 70% of the respondents had perennial forages of more than 3 years except for panicum which majority had planted for <3 years. Most of the farmers interviewed applies organic manure. Bulk density ranged from 1.07 to 1.19 g cm⁻³, with the highest values under inorganic fertilizers and the lowest under FYM, showing significant differences between paired plots (p = 0.0011). Soil pH ranged from 5.13 to 5.36, and MP significantly affected all micronutrients, with FYM combined with Panicum having the highest cation exchange capacity (19.45 cmol/kg) and manganese (96.30 ppm), and FYM combined with maize showing the highest available phosphorus (54.08 cmol/kg). Results showed no significant differences in mean values of POC and MAOC across zones, though the Lower Zone (LZ) had higher POC (6.63 g C kg⁻¹) and MAOC (7.24 g C kg⁻¹) compared to the Mid Zone (MZ) and Upper Zone (UZ). Different forages exhibited varying levels of MAOC, POC, and SOCs, with Brachiaria showing the highest SOC (15.69 g C kg⁻¹) and Panicum the lowest (14.84 g C kg⁻¹). Particulate organic carbon and MAOC content were significantly different across forages and maize (p < 0.05), with Brachiaria having higher MAOC (5.37 g C kg⁻¹) and POC (5.97 g C kg⁻¹). FYM combined with Brachiaria resulted in the highest POC (6.09 g C kg⁻¹) and MAOC (5.44 g C kg⁻¹). POC and MAOC concentrations varied significantly with soil depth, showing higher values in the top 10 cm. The Mid Zone recorded significantly higher SOC, POC, and MAOC than the UZ and LZ. This study concludes that AZ and MP substantially influence SOC sequestration, with FYM and Brachiaria being most effective in LZ.

BackgroundEnhancing soil organic carbon storage in areas under extensive livestock grazing has become a challenge in most arid and semi-arid rangelands in Sub-Saharan Africa. In Kenya for instance, continuous unplanned grazing in community lands has led to overgrazing and degradation of the rangelands. For decades, livestock production has shaped the landscape through various management practices. Grazing can be used to increase soil organic carbon (SOC) content but intensive use of land can lead to its depletion. This study was set out to elucidate the effect of two types of grazing management under varying land cover types on mineral-associated organic carbon (MAOC) and particulate organic carbon (POC) in the soil. The study was carried out in two ranches, Mpala Research Centre (controlled grazing) and Ilmotiok Community Group Ranch (continuous grazing). The experimental design was a completely randomized block design in split-plot arrangement with three replicates. The main plots were the grazing practices; (controlled grazing and continuous grazing); and sub-plots were the land cover types: (bare ground, patches of grasses, and mosaics of trees). These treatments were randomly selected and replicated three times. Three topographical positions (mid-slope, foot slope and bottom land) were used as a blocking factor.ResultsThe interaction had no significant effect on MAOC fraction in any soil depth interval. Controlled grazed zones significantly recorded higher organic carbon content (POC= 0.887% CC SD=0.49) compared to zones under continuous grazing (POC = 0.718% CC SD=0.3). Mosaic of trees (POC =1.15% CC, SD = 0.22) recorded the highest concentration of carbon followed by patches of grass (POC = 0.87% CC, SD= 0.37) and bare ground (POC = 0.38% CC SD = 0.12) had the least.ConclusionThis study shows that grazing practices as well as land cover types have a significant effect on POC but not on MAOC. Mosaic of trees under controlled grazing has higher POC whereas bareground under continuous grazing had the least POC. Destocking should be done under continuous grazed zones to reduce further loss of POC and MAOC and allow vegetation recovery.

Integrated land–soil–crop information systems are increasingly important for supporting climate-smart agricultural planning and implementation, yet their development in Eastern Africa is constrained by fragmented mandates, weak technical capacity, and limited data interoperability. This study assesses how institutional readiness, user demand, and technical and human-capacity conditions shape the integration of such systems into national Agricultural Knowledge and Innovation Systems (AKIS). A mixed-methods, multi-country assessment was conducted in Ethiopia, Kenya, and Rwanda (2022–2024), drawing on 145 semi-structured key-informant interviews, stakeholder mapping, national workshops, and a regional synthesis consultation. The analysis addressed three objectives: (i) diagnose institutional readiness and user demand; (ii) assess technical, infrastructural, and human-capacity requirements; and (iii) identify governance and design principles for embedding integrated information systems within AKIS and Climate-Smart Agriculture (CSA) strategies. The results show consistently high demand for spatially explicit soil and crop data but persistent fragmentation of mandates, uneven coordination, and substantial subnational capacity gaps. Despite these constraints, emerging digital-agriculture strategies, open-data policies, and regional soil-health initiatives provide potential entry points for integration. The study offers a comparative evidence base and design principles—covering governance, interoperability standards, co-production processes, and capacity strengthening—needed to transition from project-driven fragmentation toward interoperable and sustainable information systems. These findings provide diagnostic and design-oriented insights for national and regional efforts to strengthen agricultural information systems that support CSA implementation in Eastern Africa.