Is it permissible to enter into a partnership with a farmer, providing my capital and his expertise, while the land and labor are his, and he receives one-third of the profit?

The Islamic way is to rent the land from its owner and lease it to someone for cultivation. The produce would then belong to the tenant, and the landowner would receive a known rent for his land and effort. It is not permissible to stipulate that the rent be a portion of what the land produces, as this involves an element of gharar (excessive uncertainty). It is also permissible to buy half of the land from him and then share in the land, its value, the effort, and the produce.