From Seed to Seed:
Plant Science for K-8 Educators
 |
 |
 |
 |
|
From Seed to Seed: |
|
|
Air The air we breathe is almost 80 percent nitrogen-an important plant nutrient. (It's the "N" in the N-P-K rating you have seen on fertilizer labels.) If there is so much nitrogen in the air, why do so many garden plants require supplemental nitrogen in the form of fertilizer? Most plants cannot use nitrogen in the form in which it exists in the air. Some types of plants, however, use nitrogen fixation through a special relationship they 
form with soil bacteria. Fixing nitrogen simply means converting it to a
form that plants can use. Plants with this ability, such as legumes,
generally do not require nitrogen fertilizers.It's easy to imagine that plants get plenty of air-after all, like us they are constantly exposed to the air. However, plant roots also need air. When the soil stays wet too long, plant roots are deprived of oxygen and begin to suffocate and die. So the problem with overwatering isn't that there is too much water, it's that there isn't enough air! Water saturates the soil and fills up all of the air spaces, causing the roots to suffocate. |
||||
Made possible by a grant from Oracle Corp. Copyright 2001, National Gardening
Association, Inc. For questions regarding this web site, contact Webmaster |
