Effect of Soil Tillage Systems on Soil Hydrological Processes in Common Bean (Phaseolus Vulgaris L.) Farms in Mukono District, Uganda
| dc.contributor.advisor | Tilahun, Seifu A. (PhD) | |
| dc.contributor.author | Fatumah, Nakiguli | |
| dc.date.accessioned | 2021-09-16T08:57:28Z | |
| dc.date.accessioned | 2023-11-18T09:52:22Z | |
| dc.date.available | 2021-09-16T08:57:28Z | |
| dc.date.available | 2023-11-18T09:52:22Z | |
| dc.date.issued | 2021-07-13 | |
| dc.description.abstract | Goal 15 of the United Nations 2030 Agenda for Sustainable Development addresses the protection, restoration, and promotion of sustainable use of terrestrial ecosystems by halting and reversing land degradation. Soil tillage is one of the main factors causing land degradation in sub Saharan Africa. In this study, the effect of soil tillage systems on infiltration rate, soil moisture content, soil water storage, surface runoff volume, suspended sediment concentration, and sediment yield in common bean (Phaseolus Vulgaris L.) farms, at Goma and Kimenyedde experimental sites in Mukono District, Uganda was evaluated. The study also assessed the effect of soil tillage systems on grain yields, water use efficiency, and economic returns of the common beans. The study further evaluated the performance of the Agricultural Policy/Environmental eXtender model in the simulation of surface runoff volume and sediment yield. The soil tillage systems were: no-tillage, stubble-mulching, deep tillage, and conventional tillage. Field experiments were arranged in Complete Block Design under four soil tillage systems, consisting of two tillage directions: tillage down the slope and tillage perpendicular to the direction of slope during three wet seasons. The results showed the highest and lowest infiltration rate and soil moisture content under no-tillage and conventional tillage, respectively. No-tillage and stubblemulching improved soil water storage by 46 and 45%, respectively, compared with conventional tillage in the 0-100 cm soil depth over the 16 months. The highest surface runoff volume was observed during the third season at Goma site under conventional tillage with tillage down the slope (1082 mm), while the lowest surface runoff volume was observed during the second season in Kimenyedde site under no-tillage (165 mm). Tillage perpendicular to the direction of slope reduced surface runoff volume by the range of 5-15%, relative to tillage down the slope. The highest and lowest suspended sediment concentration were observed under conventional tillage (2.65 ± 0.5 g L-1) at Goma site during the third season and no-tillage (0.43 ± 0.1 g L-1) at Kimenyedde site in the second season, respectively. Sediment yield was highest under conventional tillage at Goma (183.01 kg ha-1) during the third season and lowest under no-tillage (9.19 kg ha-1) at Kimenyedde site, during the second season. Soil tillage systems significantly (p < 0.05) affected water use efficiency, with water use efficiency values generally greater under no-tillage and stubble-mulching than under deep tillage and conventional tillage. Grain yield was highest under no-tillage and stubble-mulching than deep tillage and conventional tillage, with over 5, 38, and 43% higher grain yield under no-tillage than under stubble-mulching, deep tillage, and conventional tillage, respectively. Seasonal precipitation distribution considerably influenced crop yield, soil water storage, and water use efficiency. The net profit was three and five times higher under no-tillage than under conventional tillage and deep tillage, respectively. No-tillage and stubble-mulching were the optimum soil tillage systems for increasing infiltration rate, soil water storage, enhancing water use efficiency, improving grain yield and economic returns in central Uganda. Evaluation of Agricultural Policy/Environmental eXtender model performance for surface runoff volume and sediment yield simulation provided good results. For both calibration and validation periods, Nash-Sutcliffe efficiency values were > 0.5, coefficient of determination > 0.6, and percent bias values were within ±20% for surface runoff volume and sediment yield. The Agricultural Policy/Environmental eXtender model can be a useful tool for evaluating surface runoff volume and sediment yield for different management practices in Mukono District. Adopting no-tillage and stubble-mulching would be efficient strategies for controlling excessive surface runoff and sediment in the region. | en_US |
| dc.identifier.uri | http://etd.aau.edu.et/handle/12345678/27916 | |
| dc.language.iso | en | en_US |
| dc.publisher | Addis Ababa University | en_US |
| dc.subject | Effect of Soil | en_US |
| dc.subject | Tillage Systems | en_US |
| dc.subject | Soil Hydrological Processes | en_US |
| dc.subject | Common Bean (Phaseolus Vulgaris L.) | en_US |
| dc.subject | Farms in Mukono District | en_US |
| dc.subject | Uganda | en_US |
| dc.title | Effect of Soil Tillage Systems on Soil Hydrological Processes in Common Bean (Phaseolus Vulgaris L.) Farms in Mukono District, Uganda | en_US |
| dc.type | Thesis | en_US |