Effects of multipurpose tree species (MPTS) in the soil properties in WMSU-EFA [Western Mindanao State University-Experimental Forest Area]

MPTS are trees that have the capacity to provide multifarious products and perform a variety of functions and/or services. These are also known as nitrogen-fixing trees (NFTS), which are usually deep-rooted and have access to nutrients in the subsoil layers. Barre and San Juan (WMSU) sought to learn the effects of MPTS on soil properties at the Western Mindanao State University-Experimental Forest Area (WMSU-EFA) in upper La Paz, Zamboanga City. They also assessed the trees' growth and performance. Specifically, the research determined soil chemical properties such as soil pH, NPK, OM, soil MC%. It also assessed the growth of selected MPTS, in terms of height and basal area, once every quarter for 3 years. Demonstration farm lots consisting of MPTS planted along strips and contours were constructed for the study. Findings of the study revealed the following: Soil chemical properties did not reveal much change as seen from observations. However, there were significant changes in the growth of MPTS planted in the area. Among soil chemical properties, only the soil's organic matter, specifically, nitrogen content showed some degrees of change. It reflected a significant difference when analyzed statistically. Graphical presentations revealed changes in soil properties occurring in a more or less regular pattern. Palo Verde outperformed the other MPTS in terms of lateral and apical growth. Changes can already be seen even through ocular inspection in the field. Giant ipil-ipil was a very slow grower and still remained small after 3 years of study. Its growth might have been affected by the elevation of the area. Researchers recommended Palo Verde instead of Madre de Cacao or giant ipil-ipil for soil rehabilitation purposes in the WMSU-EFA and other adjacent areas. The pattern of change in soil properties should also be verified, so that appropriate vegetables could be prescribed to farmers for planting in a particular time of the year.