Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.
What we understand from the question is that this investment is basically depositing money, which is considered as loan in Shariah to the government, and the government guarantees the depositor that it will pay him back the amount with a fixed profit which is not allowed in Shriah. Allah Says (interpretation of meaning) in this matter: {O you who believe! Be afraid of Allâh and give up what remains (due to you) from Ribâ (usury) (from now onward), if you are (really) believers.}[2:278].
As for the reasoning that the government uses the deposited money for the development of farmers does not change the ruling since giving loan against some benefit is forbidden. There are many Halal ways for the development.
However, a Muslim should avoid from any involvement in Riba.
Allah knows best.