When there is a scarcity of grain, the government should follow the methods prescribed in the sastra and approved by the acaryas; thus there will be a sufficient production of grains, and food scarcity and famine can be checked. Bhagavad-gita recommends that we perform yajna, sacrifices. By the performance of yajna, sufficient clouds gather in the sky, and when there are sufficient clouds, there is also sufficient rainfall. In this way agricultural matters are taken care of. When there is sufficient grain production, the general populace eats the grains, and animals like cows, goats and other domestic animals eat the grasses and grains also. According to this arrangement, human beings should perform the sacrifices recommended in the sastras, and if they do so there will no longer be food scarcity. In Kali-yuga, the only sacrifice recommended is sankirtana-yajna. In this verse there are two significant words: yogena, “by the approved method,” and drstena, “as exemplified by the former acaryas.” One is mistaken if he thinks that by applying modern machines such as tractors, grains can be produced. If one goes to a desert and uses a tractor, there is still no possibility of producing grains. We may adopt various means, but it is essential to know that the planet earth will stop producing grains if sacrifices are not performed. The earth has already explained that because nondevotees are enjoying the production of food, she has reserved food seeds for the performance of sacrifice. Now, of course, atheists will not believe in this spiritual method of producing grains, but whether they believe or not, the fact remains that we are not independent to produce grain by mechanical means.

Srila Prabhupada, SB 4.18.8, ppt