Assessing the Role of Agroforestry in Soil Fertility Improvement in Mbelenka-Lebialem, Southwest Cameroon

Abstract

Soils are the universal reservoirs through which living organisms get the resources for their livelihoods either directly like plants and indirectly like other organisms and animals. The ability of soils to serve as a universal reservoir depends on its fertility. Agroforestry practices have been seen to improve and conserve soil fertility. This research work carried out from the 10^th of May 2015 to the 10^th of November 2015 was aimed at assessing the role of agroforestry practices in the improvement of soil fertility in the study area. Information was collected using questionnaires, field surveys and the analysis of soil samples in the laboratory. The results obtained were subjected to regression and correlation analysis using the Statistical Package for Social Sciences (SPSS). These results showed that the main agroforestry practices in this area include live fences and scattered trees on farmlands. It was also observed that farmers use indicators such as yields, softening of soil, wilting of the crops, rotten tubers, erosion and rains to determine soil fertility. There was no significant difference between various soil parameters (pH, acidity, CEC, ECEC, C/N, and exchangeable Al) in the two major agroforestry practices identified. There was equally no significant difference between the various soil elements and yields in the two major systems identified. The only element that showed a significant difference (P<5%) in the two systems and also for yields was phosphorous. Since only phosphorous significantly influenced yields in this area, a model was established to show that crop yields are dependent on phosphorous as indicated by the equation Yields = 1.77+ 0.03 P. Scattered trees on farm lands were recommended to farmers, the practice of improved fallow using a local fertilizing species identified as well as the use of Guatemala grass (Tripsacum laxum) and Vetiver grass (Vetiveria zizanoides) should be introduced on slopes to control erosion.