This is Doug Johnson with the VOA Special English AgricultureReport.
Today we finish a two-part series. A listener in Brazil askedabout agroecology. This is a field of ideas about how to farmproductively but also protect natural resources.
Last week, we discussed how agroecology is seen in many ways asan answer to the Green Revolution. That movement has given us modernfarming methods.
Agroecology and the Green Revolution both want to increaseproductivity. But they work toward this common goal in differentways. Many agroecologists question how long modern farming methodscan continue.
Modern farming uses land intensively. Often the same crop isgrown on the same land year after year. Soil breaks down and washesaway. Also, fewer kinds of the same plant are grown. This can limitthe number of kinds that may have useful genetic qualities.
Another issue is fertilizer. Agroecologists say they would useorganic materials and compost in place of chemicals. The GreenRevolution has shown that chemical fertilizer can greatly increasecrop productivity. But it can also pollute water supplies.
To water crops, agroecologists say they would use methods thatreduce the need for irrigation. Irrigation is an ancient idea. Wateris pulled from the ground or brought from another place. Irrigatedcrops are highly productive. Sixteen percent of all farmland in theworld is irrigated. But this sixteen percent of the farmlandproduces forty-percent of all food.
Yet irrigation systems can use up groundwater faster than naturecan replace it. And there are costs to taking water from otherareas.
To control pests, agroecologists say they would use helpfulinsects to kill harmful ones. In the last fifty years, however,farmers have increased the use of insecticides. These chemicalpoisons do destroy harmful insects. But they also kill helpful ones,and can cause pollution and health problems. Also, pests can developthe ability to resist chemicals.
One place to learn more about agroecology is at the Web siteagroecology dot o-r-g. This site is operated by the University ofCalifornia at Santa Cruz. Steven Gliessman is a professor in theCenter for Agroecology there. He has written several books on thesubject.
This VOA Special English Agriculture Report was written by MarioRitter. If you have a question for us, write to special@voanews.com.This is Doug Johnson.