Description: This is
a VOA Special English Agriculture Report.
See text below
Text:
Some trees can survive a long time without water.
Think of trees that grow in the desert. But other
trees may need more moisture than they can get from
rainfall or from the air -- from, say, coastal or
mountain fog. The soil stores moisture during cooler
weather. But most of that moisture is gone by the
middle or end of the hottest months of the year.
Trees and other plants can look thirsty. Leaves can
become droopy and hang downward. They can also turn
yellow. Yellowing can be a sign of too much water.
But it can also be a warning sign of too little
water. The Vacaville Tree Foundation is a volunteer
community group in California. It has advice for
watering newly planted trees and established trees.
With a newly planted tree, the roots have not yet
spread out from the root ball. The root ball can
become dry faster than the dirt around it. So put
water on the area of the root ball and the
surrounding soil until the roots become established.
Once a tree is well established, water deeply
instead of often. The amount of water needed depends
on the tree and the soil. Clay soils hold water for
longer periods while sandy soils hold less water.
During the hottest season, a deep watering may
satisfy a tree for anywhere from ten days to four
weeks. Part of skilled watering is knowing to stop
when the soil needs a little time to absorb the
water. Otherwise the water runs off the surface and
gets wasted. Ted Swiecki is a plant scientist in
California with the Phytosphere Research company and
the Vacaville Tree Foundation. He says people should
not water established trees at the base of the
trunk. This can harm the tree. Too much water in the
soil at the base of a tree can lead to the growth of
fungi. If the area is too wet, harmful organisms
have a better chance to invade the tree and cause
disease. Mr. Swiecki says this is true especially in
Mediterranean and semi-dry climates. Many trees in
these climates have adapted to having a dry area
near their base during the hottest season. Mr.
Swiecki notes that water displaces air in the soil.
But roots are aerobic; they require oxygen for the
soil. He says the roots could be starving for oxygen
if you keep the soil too wet, blocking the entry of
much-needed air. For VOA Special English, I'm , I'm
Alex Villarreal. You can learn English and stay
informed every day from your computer or mobile
device at voaspecialenglish.com. You can also find
us on Facebook, Twitter and iTunes at VOA learning
English.
Hi. I
personally reviewed this video and found it appropriate for
the news section of English Global Group. This
is a Voice of America video which covers an interesting
topic in Special English. I would appreciate some feedback from both
students and teachers about this video. You can comment in
the window below using any of a number of different services
including Facebook, Yahoo, AOL, and Hotmail.
To post a comment:
• Click "Comment using..." in
the window below
• Click your favorite service: Facebook, Yahoo, AOL, Hotmail
• Login to the service
• Click "Add a comment..."
• Post your comment in the window
Students: Please post a
comment stating what you found interesting about this video. You are
welcome to include links to your English study blogs and any
other materials you think might be useful for learning
English.
Teachers: Please post your
thoughts about this video. You are welcome to include links to
your sites, blogs, and any other materials you think might
be useful for learning English.
Hi. I
personally reviewed this video and found it appropriate for
the news section of English Global Group. This
is a Voice of America video which covers an interesting
topic in Special English. I would appreciate some feedback from both
students and teachers about this video. You can comment in
the window below using any of a number of different services
including Facebook, Yahoo, AOL, and Hotmail.
