Abstract:
Homegarden agroforestry system is well recognized as an inclusive and ecologically sound system. However, the recently observed change from enset-based homegardens to cash crop khat is expected to cause a decline in soil fertility. Thus, this study was initiated on one hand to assess the effect of the traditional homegarden system change to a khat-based system on soil physicochemical properties at Wondo Genet and on the other hand to understand nutrient conservation potential of stable homegarden system in Dale districts, Sidama Region. Four kebeles were selected of which thirty-six households were considered for soil sampling. Following the identification of the enset, khat, and coffee land uses types, soil samples were taken from each farm household of each land use type at five different points from two different depths (0 – 20 and 20 – 40 cm). A total of 144 soil samples were collected. The selected soil physical properties were soil texture, moisture content, and bulk density whereas selected soil chemical properties were soil pH, soil organic carbon, total nitrogen, available phosphorus, exchangeable potassium, and nutrient stocks. Two-way analysis of variance (ANOVA) was used to test the significant differences among different land uses on soil physicochemical parameters. The results showed significant (p<0.01) differences between the land uses in soil physical and chemical properties. The enset land use had significantly (p<0.01) higher pH, moisture content, soil organic carbon, total nitrogen, exchangeable potassium, and nutrient stocks than the khat land use in Wondo Genet. However, at Wondo Genet, available phosphorus was significantly higher under the khat land use than in the enset land use. Similarly, the enset land use had significantly (p<0.01) higher pH, moisture content, soil organic carbon, total nitrogen, exchangeable potassium, and nutrient stocks than the coffee land use in Dale. Regarding soil depths, except bulk density, other physical and chemical soil properties were significantly (p<0.01) higher at the upper soil depth than at the lower soil depth. Generally, land use systems like enset-based homegarden improve the soil physical and chemical properties. Therefore, future soil management strategies should be focused on mitigating the continuous loss of soil nutrients in khat and coffee land use through the retention of crop residues, application of organic fertilizer, and scaling-up agroforestry practices.
