Absalom Kahumba

This chapter evaluates the integration of ecological principles as a foundation for the design and management of sustainable agroecosystems. It explores how interactions among biotic and abiotic components, such as plants, animals, soil, water, and climate, influence productivity, resilience, and ecosystem functioning in agricultural systems. Core ecological concepts, including energy flow, nutrient cycling, biodiversity, and system integration, are discussed as key drivers of resource efficiency, stability, and long-term sustainability. The chapter emphasises practical agroecological approaches such as crop diversification, conservation tillage, integrated pest management, and agroforestry, with illustrative examples from semi-arid regions of southern and eastern Africa. By linking ecological theory with traditional knowledge and modern farming practices, the chapter demonstrates how agroecological systems can enhance food and feed security, conserve biodiversity, strengthen climate resilience, and support socioeconomic viability in both smallholder and commercial farming systems. Overall, the chapter emphasises agroecology as a viable pathway for balancing agricultural productivity with environmental integrity under increasing climatic and resource constraints.

Woody plant biomass in savanna landscapes exhibits considerable variability; however, biomass variation in African multi-use savannas remains poorly understood. Thus, the study evaluated how areas dominated by encroaching bush species, Senegalia mellifera, Dichrostachys cinerea, and Terminalia sericea, varied in terms of wood quantity, tree equivalence and tree-based evapotranspiration equivalence. The study used a factorial design with two factors (field site and farm), with each farm comprising three field sites, and each field site was dominated by a different encroacher bush species. The Bush Biomass Quantification Tool was used to derive quantitative parameters for the field sites. The study results showed no difference (P > 0.05) in the tree equivalence of sites dominated by different encroacher bush species. However, the Evapotranspiration Tree Equivalence (ETTE) was higher (P < 0.05) in sites dominated by S. mellifera (59,000 ETTE ha–1) compared to those dominated by D. cinerea (17,965 ETTE ha–1) and T. sericea (14,894 ETTE ha–1). Wood quantity was greater (P < 0.05) in sites dominated by S. mellifera (10,095 kg DM ha–1) compared to sites dominated by D. cinerea (6487 kg DM ha–1) and T. sericea (2440 kg DM ha–1). The study concluded that different quantities of wood and bush-feed suitable biomass can be harvested from sites dominated by different encroacher bush species.

Bush encroachment is a form of rangeland degradation that reduces the grazing capacity, livestock and wildlife productivity. This study evaluated how sites dominated by encroaching bush species Sen...

Rangelands serve an important economic and ecological function globally, because they are comprised of different woody vegetation that may have beneficial and detrimental effects on the environment...

This study determined the impact of Tebuthiuron application on plant biodiversity over a three-year period at Neudamm farm. A total of 40 (1m²) quadrats were randomly nested in three 250 m² belt transects per each treatment to record the herbaceous plant density, species composition, dry matter and ground cover. Woody plant density, heights and canopy diameters were measured in each 250 m² belt transects. A General Linear Model (GLM) procedure of SAS (2007) was used for analyses. The herbaceous biomass production was significantly higher (P < 0.05) in chemically treated site of 2015 (975 Kg DM ha^-1) and least in the other two sites. The chemically treated site of 2016 had greater (P < 0.05) ground cover percentage than the other treatment sites. The canopy cover and woody plant densities in all woody height categories were higher (P < 0.05) in the control and chemically treated site of 2017, than the other two sites. The study concluded that the Tebuthiuron had impacted on the plant biodiversity of treated rangelands by improving the herbaceous plant species, biomass yields and reduced bush density. The study recommends that aftercare practices and application of arboricides be carried out routinely to allow herbaceous plants recovery. Keywords: Bush encroachment, arboricides, plant density, biomass production, canopy