Potash developer Sirius Minerals has entered a memorandum of understanding over a joint venture with state-owned Tanzania Fertilizer Company.Sirius said the agreement was aimed at establishing and formalising a joint venture to blend and distribute polyhalite based fertilizer products in Tanzania and the surrounding region.In July, Sirius had reached a deal with the Tanzanian Ministry of Agriculture to implement a series of crop trials utilising the company's polyhalite as a fertilizer base, while the current agreement contains provisions for the negotiation of an offtake agreement to supply up to 500,000 tonnes of polyhalite per year."The Tanzania Fertilizer Company is the oldest fertilizer distribution business in Tanzania and a superb partner for this opportunity," said Chris Fraser, Sirius's chief executive and managing director. "Our partners believe that polyhalite could play a significant role in the future of fertilizer use and we are delighted to be working towards a platform for polyhalite into the important and growth markets of Tanzania and other countries in East and Central Africa."Both firms stated they believe that polyhalite, which provides four of the six essential nutrients required for plant growth at very low chloride levels, is a close fit to the requirements of Tanzanian agriculture.In August, Sirius announced that it had received instruction from planning from local authorities and the North York Moors National Park Authority to amend its application for its York Potash project, with the planning application for the mineral transport system no longer included as part of the planning application for the mine.Sirius shares were up 8.94% to 13.89p at 08:37 on Thursday.