Vertical Profile of C, N, P, K and Radionuclides in Soil Collected from Highland Tea Plantation Areas

Abstract

Problem statement: Cameron Highlands is a well known agricultural area in Peninsular Malaysia. Long term usage of fertilizer has caused accumulation of major elemental component in the soil. This accumulation will cause enrichment of the nutrient in the catchment located at downstream of the river through runoff. Approach: Two tea plantations on the upstream with hilly condition plantation were selected as the location for monitoring the accumulation of the major nutrient component N, P and K. C was also determined to estimate the total organic content in the soil. Natural radionuclides i.e., ²²⁶Ra, ²²⁸Ra and ⁴⁰K were also determined and anthropogenic radionuclides ¹³⁷Cs were detectable. The samples were measured using Elemental Analyzer, Energy Dispersive X-rays Fluorescence (EDXRF) and gamma spectrometer. The data set were analyzed using Principle Component Analysis (PCA) and Cluster Analysis (CA) to check the distribution and elemental sources. Results: The trend for all depth profile measurement results shown monotonically trend through the depth where it shown no observable trend except for C, N, P and ¹³⁷Cs decreasing through the depth. PCA results indicate that there are two sources for plantation A and three sources for plantation B that led to the accumulation of these elements. Three clusters of group element were found for both tea plantation area and the major sources are from fertilizer, natural occurring and atmospheric natural process. The model for C, N and P was found to be exponentially proportional to the depth with removing mixing layer. Conclusion: The range of concentrations for measured elements shows that the concentrations of elements in tea plantation B are higher than in tea plantation A. All depth profile gives monotonically trend except for C, N, P and ¹³⁷Cs since these elements were added to the soil. C, N and P are decreasing exponentially with depth. The amount of ¹³⁷Cs was found to be detectable for both study locations and it was from the fall out of nuclear explosion. Other radionuclides seem to be from natural existence and atmospheric natural process.