Abstract:
Eight soil series from two agro-ecological zones of Ghana were evaluated for their suitability for maize production intensification using three approaches: the Soil Quality Index (SQI), DSSAT yield simulations and the Multi-criteria Analysis (MCA). Four of the series were from the Forest – Savanna Transition namely Wenchi series (Feric Dystric Leptosol), Ejura series (Haplic Lixisol), Damongo series (Dystric Nitosol) and Lima series (Eutric Gleysol). The four soils from the Guinea Savannah were Mimi series (Haplic Lixisol), Verempere series (Ferric Luvisol), Kpelesawgu series (Eutric Plinthosol) and Kupela series (Eutric Gleysol). The SQI rating considered soil properties such as bulk density, pH, organic carbon, total nitrogen, available phosphorus and water holding capacity. For DSSAT, the impacts of weather variability were considered in addition to soil and management factors. The MCA evaluation expanded the criteria to include economic factors such as price, input and labour costs, soil erosion and conservation factors as well as distance to market. All the approaches led to different ranking of the soil series. The SQI results rated the soil series in the order: Damongo > Kupela > Mimi > Varempere > Lima > Ejura > Wenchi > Kpelesawgu. The ranking by DSSAT was: Lima > Kupela > Mimi > Ejura > Damongo > Kpelesawgu > Varempere > Wenchi. Yield stability was lowest for Lima (7%) and highest for Varempere (131%). Using the MCA, the ranking was: Damongo > Mimi > Lima > Ejura > Varempere > Wenchi > Kpelesawgu > Kupela. In spite of the differences in ranking of the soils by the three systems, Damongo was the “best” in two cases (SQI and MCA). It was however not the best for DSSAT mean yield. It showed a yield variability average of 49%. Based on the results, Damongo, Mimi, Lima and Ejura soil series could be considered suitable for maize intensification, whereas the other soils may be considered as marginal. The study showed
that the soils in the forest - savanna transition zone (Brong Ahafo) is more suitable for maize production than those of the guinea savannah (Northern Region) zone.
