The other three who are not required should take up different jobs that would increase the total family income. For example, they can be employed in projects like building of dams, canals or roads in the village.
Government can invest some money in transportation and storage of crops, or make better rural roads so that mini-trucks reach everywhere.
Promotion of industries like setting up a dal mill, opening a cold storage could give an opportunity for farmers to store their products like potatoes and onions and sell them when the price is good.
In villages near forest areas, they can start honey collection centres where farmers can come and sell wild honey. It is also possible to set up industries that process vegetables and agricultural produce like potato, sweet potato, rice, wheat, tomato, fruits, which can be sold in outside markets and thus generate employment.
Government can plan to give loans at lower rates of interest to people in rural areas to start something new thereby solving problems of underemployment.