Phosphorus conservation in cropping systems

Abstract

This project is proposed as a continuance of the research on phosphorus use efficiency in cropping systems that has been developed by our group. Two sub-projects are proposed: one exploring the possibility of improving phosphorus uptake by maize due to localized fertilization with ammonium N, which has been demonstrated in alkaline soils, but it is not known if this could also occur in acid soils, as intended in the present study. This sub-project is already under way. The other sub-project is to try to elucidate the fact that Urochloa ruzisiensis, while apearing to enhance available P in soil when extracted with resin, hinders soybean growth and yelds grown afterwards. In general, with no P application, soybean yields are lower when cropped after U. ruzisiensis (Janegitz, 2012; Adams, 2014). The field experiment of this subproject has been conducted for 14 years. (AU)