I'm Steve Ember with the VOA Special English Agriculture
Report.
Many different kinds of plants are part of the leguminosae group. They
are called legumes. These plants can produce their own nitrogen. Beans are
legumes. Peanuts are legumes. Alfalfa is a legume. There are also many
different kinds of trees that are legumes.
As a food, beans are high in protein. Most beans also contain a lot of
nutrients such as calcium, iron, phosphorus and niacin. Some beans contain
amino acids and lysine.
The leaves of bean plants and other legumes also are high in nutrients.
They are often fed to farm animals. Some farmers grow legumes especially
for their animals. Cows, goats and other animals are permitted to eat the
leaves on the plants in the fields.
Many farmers around the world know the value of growing legumes along
with their main crops, or between harvests. The legumes replace nitrogen
used by crops. They also provide a cover for the soil to help protect it
from heavy rains and strong winds.
The roots of the legume plants hold the soil in place. This keeps the
soil from being blown away by the wind or washed away by rain. The roots
also loosen the soil. This lets the rain reach deep into the ground.
Legumes produce nitrogen through a process involving bacteria in the
soil and nitrogen in the air. The bacteria form small growths on the plant
roots. These growths are called nodules. They capture the atmospheric
nitrogen that has entered the soil.
The nodules change the nitrogen into ammonia, a form of nitrogen that
plants can use. The process is called nitrogen fixation. The bacteria
needed for the process, rhizobia or frankia, are found in most soils. But
if they are not present in the soil in a field, they can be "painted" on
the legume seeds before the seeds are put in the ground. A local
agriculture agent can show how to do this.
When planted next to fields, legume trees will add nitrogen to the
soil. They provide shade and protect young crop plants from the heat of
the sun. They provide firewood. And their wood can be used as building
material. Some legume trees also provide medicines and chemicals for
coloring cloth.
This VOA Special English Agriculture Report was written by Bob Bowen.
Read and listen to our reports at voaspecialenglish.com. I'm Steve Ember.
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