This week, we take a suggestion from a listener in Brazil. Agricultural specialist Luiz Augusto Verona in Chapeco would like to hear about agroecology（農業(yè)生態(tài)學）. He says it is a subject that these days "everybody talks about."

The word agroecology is generally used to describe farming methods that can be carried out in a way that does not damage the environment. Sustainable development（可持續(xù)發(fā)展）is another term often used in connection with agroecology. Sustainable development methods are designed to save resources.

Interest in agroecology has increased in recent years. Now, many universities offer studies in this area. The University of California at Santa Cruz and Pennsylvania State University are just two of the schools that offer agroecology programs. Many agricultural programs are also linking studies in animal biology, soil science and other studies.

In many ways agroecology is an answer to the technological movement to increase production in some crops. This movement which developed in the 1960s and 70s became known as the Green Revolution（綠色革命）. Scientists developed ways to make highly productive forms of wheat, corn and rice.

Norman Borlaug helped bring about the Green Revolution. Mister Borlaug was an agricultural researcher for the DuPont Company. Later, he went to Mexico where he worked at the International Maize and Wheat Improvement Center（國際玉米小麥改良中心）. He became the director. He also helped create new kinds of highly productive wheat. Mister Borlaug won the Nobel Peace Prize in 1970 for his efforts to develop more productive crops and to train scientists. He remains active in this work today.

The Green Revolution produced huge increases in crop size in India, Mexico, Pakistan and the Philippines. It has also placed importance on the use of chemical fertilizers and insect poisons, and on the need for new crops. Today's genetically changed crops are the next step.

Agroecology seeks to use scientific knowledge of the environment to make good choices about growing crops. Many experts say it is not competing with the goals of the Green Revolution. They say both have a single goal: to feed the world's people.

Listen next week as we tell more about agroecology.

This VOA Special English Agriculture Report was written by Mario Ritter. This is Steve Ember.