Akinson Tumbure

Doctor of Philosophy, (Soil Science)
Study Completed: 2021
College of Sciences


Thesis Title
The development and assessment of alternative techniques to improve the agronomic value of Dorowa phosphate rock (Zimbabwe)

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Soil phosphorus deficiency is widespread in Zimbabwean smallholder farming areas. However, due to the high cost of imported fertilisers, farmers have limited options to ameliorate their soils which leads to recurring food insecurity problems. Mr Tumbure investigated the potential to produce effective phosphorus fertilisers locally from the nearby un-reactive Dorowa phosphate rock. He tried three ways to improve the solubility of the rock: (i) thermal treatment with recycled glass, (ii) co-pyrolysis with an agricultural waste (maize stover), and (iii) acidulation of the phosphate rock with pyrolysis condensate. He tested the products in glasshouse studies and found that the partial phosphate glass and co-pyrolysis biochar products improved the phosphorus supply capacity to growing crops. These results confirm that the newly developed products would provide a good fertiliser option for farmers around the Dorowa phosphate rock mine. Use of these novel phosphorus products could also be more economical than the current acidulated fertilisers.

Professor Michael Hedley
Dr Peter Bishop
Dr Mike Bretherton