The purpose of this work was to obtain economic products with high levels of available P to be used as alternatives to soluble fertilisers. To eval-uate the effect of sulphur inoculated with Acidithiobacillus on the available P in rock phos-phate and addition of various forms of organic matter, a greenhouse experiment using a Brazilian tableland soil was conducted. Mimosa caesalpiniifolia inoculated with rhizobia was used as the test plant. The experiment was a fac-torial (4 × 6) arranged in a randomised block design, with 3 replicates. P treatments were: triple superphosphate (TSP) 100 kg/ha P; rock phosphate at rates of 500 and 1000 kg/ha, pelleted with sulphur at 50 and 100 kg/ha S, respectively, inoculated with Acidithiobacillus (+ Ac.) and without Acidithiobacillus (− Ac.); and a control without phosphorus (P 0). Organic matter treatments were: coconut powder at levels of 5 t/ha (CP 5) and 10 t/ha (CP 10); Fibrasil 5 t/ha (FB 5); and no added organic matter (OM 0). Nitrogenase activity, nodulation, shoot dry matter, total N and total P in shoot dry matter and soil pH were determined. P treatments had no effect on plant height, nodulation and nitrogenase activity. Rock phosphate pelleted with S inocu-lated with Acidithiobacillus plus Fibrasil pro-duced the biggest plants and the highest N and P uptake. Rock phosphate with S and Acidithio-bacillus increased available P and reduced soil pH, especially combined with Fibrasil residue, with no inhibitory effect on plant growth. The P biofertilisers and the organic by-products showed potential to benefit smallholder farmers.