The most efficient way to use the plot IS TO GROW CORN AND FEED IT TO SEVERAL COWS TO FEED THE FAMILY.
By growing corns and feeding it to several cows the farmer will be able to feed the cows adequately and they in turn will provide him and his family with enough milk and meat. Apart from this, the farmer will be able to sell the excess milk and meat for money and use the money to buy other things that his family need.
In addition, the wastes from the cow can be used as compost to maintain the fertility of his farm land, thus, he will not have to spend money on fertilizers and the land will serve him for a long period of time.