The problem comes down to one thing , land being used for food crops or cash crops , the more crops you grow for fuel the less food crops can be grown. The demand for both isn't going to lessen it's just going to keep growing as is the population , suitable land for farming and homes will become more desirable.
Then you face another problem in that the demand for land will push up the price for farmers and land developers , land will be taken for the building of homes leaving less for crops.

The only realistic answer is LESS PEOPLE !