Farmers could also help save the earth's precious supplies of water and petroleum. To save water, they could plant more water-efficient plants instead of the standard types of wheat or corn. They could also use watering systems that are much less wasteful. To save petroleum, farmers could make use of bio-gas generators which could be fueled by the vegetable and animal wastes of the farms. In less-developed countries, bio-gas generators could reduce the need for firewood and so help save forests, as well. In less-developed countries, the small farmers need help. They need to learn more about crops that are better suited to local conditions. They need to learn how to limit erosion and make the best use of their resources. These farmers will never be successful without land and economic reform. This should be the aim of governments and international agencies. The current industrial and cash crop policies are only making the situation worse.