What is the amount on which zakat is due after it has been deposited in land and gold investments, and is the deposited amount subject to zakat, given that profits will not appear until two years for land and eight months for gold?

If the two amounts reach the nisab (definition) (threshold) and a hawl (full lunar year) passes over them, then zakat (definition) is obligatory on both, unless the contribution is in fixed assets not intended for trade. In that case, zakat is due on the revenue if it reaches the nisab and a hawl passes over it. It is not permissible to delay the payment of obligatory zakat when one is able to do so.