Fifteen years of the Forchtenberg experiment—results and implications for the understanding of Neolithic land use

Abstract

Experimental research into Neolithic agriculture has been underway in Forchtenberg, southwest Germany, since 1998. The experimental area is a medium age mixed-deciduous forest featuring different soils, mainly haplic and stagnic luvisols. In this experimental setting, research has focussed on comparisons of soil nutrients and crop yields resulting from slash and burn cultivation and from cultivation with hoeing. We show that slash and burn produces significantly higher yields, although always depending on soil quality. Hoe tilling is only profitable on the best soils in the first year after clearance. Continuous cultivation with hoeing produces too low yields, but repeated annual cultivation on slash and burn sites also resulted in progressively lower yields due to decreasing levels of nitrogen in the soil. Nitrogen originates not from burned wood but from the burning and mineralisation of organic matter in the topsoil. After burning and cultivation, a break of about 10–15 years is necessary, not only for forest re-growth, but also for the regeneration of the top soil and its nitrogen content. Slash and burn agriculture is therefore an easy and reliable tool for food production by a small population living in a large forested area.