Growt of Millettia ferruginea and its impact on soil properties of three coffee plantations of southern Ethiopia.
2008
Zebene Asfaw(Researcher)
Shade trees in the coffee production systems play an important role in providing quality coffee, timber and environmental services. The objective of the study was to investigate the growth of Millettia ferruginea Hochst (Millettia) grown in coffee plantations at Korate Kumate and Morocho sites and assess the impact of Millettia on top-soil properties, mainly soil texture, pH, total nitrogen, organic carbon, CEC, available phosphorus and exchangeable base, The result showed that at 15 years of age significant differences were observed across the sites in total height, diameter at breast height (DBH) and crown width of Millettia trees. At Kumate site, trees were higher by 25 and 48% in height, 18 and 17% in DBH and 28 and 9% in crown diameter than trees grown at Korate and Morocho, respectively. The estimated annual wood production increment at Korate, Kumate and Morocho sites was 2.32, 4.48 and 2.08 m3 ha-1, respectively. Soil textural fractions, mainly sands generally decreased slightly under tree canopies compared to open fields. Organic carbon (OC), total nitrogen contents (TN) and available P of soils were significantly higher (P0.05) under tree canopies compared to the contents in open gaps. Top soil under canopy of Millettia trees, compared with open fields, had higher (P0.04 at Korate, P0.03 at Morocho) K but had no significant effect on some exchangeable bases.
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