Effects of rubber plantations on the nutrient status of soils established under different land-uses

Thumbnail Image
Journal Title
Journal ISSN
Volume Title
Natural rubber (NR) cultivation has been on the increase in the Ahanta West, Nzema East, Jomora and Wassa West Districts of the Western Region, since the inception of the Rubber Outgrower Plantation Project (ROPP) in 1995. As a result, many land-uses especially secondary forests have been converted to NR plantations, raising several environmental issues including nutrient removal from the soil, change in soil surface chemistry, and fear of disruption in soil fertility. The purpose of this study was to assess the effects of rubber plantations on the nutrient status of soils established from different land-uses. Forty-five soil samples were collected from NR plantations at Ghana Rubber Estates Limited (GREL) for laboratory analysis. Samples covered depths 0-20 cm, 20-40 cm, and 40-60 cm, and represented three land-use types (secondary forest, old rubber plantation and abandoned farmland). Total nitrogen, Total phosphorus, available potassium, calcium, magnesium and pH analyses were determined using the atomic absorption spectrophotometer (AAS). The results generally indicated no significant differences (P > 0.05) in the soil properties among the three land-use types. Similarly, soil depth did not have any strong effect on the soil nutrient status. However, total nitrogen (35.3 – 69 %), total phosphorus (65.5 – 137 %) and available potassium (44.3 - 76.5 %) increased with age of the NR stand whilst calcium (10.2 - 51.1 %) and magnesium (5.1 - 11.3 %) decreased with increasing age of the NR stand. These results suggest that NR establishment had no deleterious effects on soil quality parameters, consistent with the notion that most soil nutrients are returned into soils through accumulation and subsequent turnover of leaf litter.
A thesis submitted to the Department of Theoretical and Applied Biology Kwame Nkrumah University of Science and Technology in partial fulfillment of the requirements Master of Science degree in Environmental Science, 2015