Legacy phosphorus and no tillage agriculture in tropical oxisols of the Brazilian savanna.

Crop production in the Brazilian Cerrado is limited by soil phosphorus (P) supply without large inputs of inorganic P fertilizer, which may become more costly and scarce in the future. Reducing dependency on fertilizer P requires a greater understanding of soil P supply in the highly weathered soils in this important agricultural region. We investigated the impact of no tillage (NT) and conventional tillage (CT) agriculture on accumulated (legacy) soil P and P forms in four long-term sites.