Soil characteristics associated with agricultural enclosures (Manavai) on Rapa Nui

Abstract

Some scholars argue that human-induced environmental changes on Rapa Nui (Easter Island) led to the collapse of the island’s population and its culture. This project investigates changes to agricultural soils. Sediment samples were taken from several manavai, agricultural enclosures, at Maitaki Te Moa and Anakena. Samples were taken both inside and outside the manavai to test soils associated with agricultural use. Sediment samples were analyzed for several properties: pH, percent nitrogen (%N), percent organic carbon (%OC), and the cations phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg). These data were indicative of changing soil properties and can show human alterations. I tested the null hypotheses to compare soils inside and outside manavai; in the event of a significant difference the hypothesis was rejected, indicating anthropogenic alterations. Overall trends indicate a major difference in soils from the two regions as well as human influences inside the manavai.