Between 1961 and 1963, Cowgill and Hutchinson made studies of soil in the Petén Basin, Guatemala, with the aim of learning about the effects of agricultural practices of the pre-Columbian Maya civilization.[4] Their findings reported that Maya cultivation methods had gradually robbed the soil of vital elements, meaning that it eventually became unable to sustain crops. Some scholars have linked this exhaustion of the soil to the 10th-century decline of the Maya urban settlements in the Petén region.