Nitrogen effects on maize yield following groundnut in rotation on smallholder farms in sub-humid Zimbabwe

Rotating maize (Zea mays L.) with groundnut (Arachis hypogaea L.) has been proposed as a way to maintain soil fertility and prevent maize productivity declines in the smallholder cropping systems ofsub-humid Zimbabwe. Field experiments with fertilizer-N on maize in rotation with groundnut were conducted at three locations with sandy typic Kandiustalf soils. The specific objectives were to (i) evaluate the response to fertilizer-N of maize in rotation with groundnut compared with continuous maize and, (ii) determine the fertilizer-N replacement value of groundnut. Maize grain yields were increased up to 0.7 tha-1 following groundnut compared with continuous maize when no fertilizer was applied to both cropping systems. Maize yield response to fertilizer-N was higher after groundnut than continuous maize. The small groundnut yields were associated with little yield improvement for a subsequent maize crop. Fertilizer needs on maize were reduced by 0 - 64 kgNha-1 when maize followed groundnut

Integrating Archaeological Theory and Predictive Modeling: a Live Report from the Scene

Archaeological predictive modeling has been used successfully for over20 years as a decision-making tool in cultural resources management. Itsappreciation in academic circles however has been mixed because of its perceivedtheoretical poverty. In this paper, we discuss the issue of integrating currentarchaeological theoretical approaches and predictive modeling. We suggest amethodology for doing so based on cognitive archaeology, middle range theory,and paleoeconomic modeling. We also discuss the problems associated with testingpredictive models