rock above is resting on what used to be the soil surface. This
banana field is acidic and has multiple nutrient deficiencies. As a
result, the plants never grew properly and left the soil exposed to
the rain. Over the years, more than eight inches of topsoil have
been lost. The poor fertility resulted in the loss of topsoil, which
makes the field less fertile, which causes poor growth, which
exposes more soil to erosion; a cycle which ends with the land
becoming totally unproductive. A balanced fertilization program not
only would have prevented the erosion problem, but would have also
produced high yields and increased profits.
is a lot of misinformation on the effect of fertilizer use on the
environment. While there are some problems to be solved, it should
be pointed out that balanced fertilization has had a tremendous
positive effect on our environment.
Probably the most
important contribution that fertilizers have made to the environment
is in preserving wildlife habitat. Fertilizer use has allowed
farmers to continuously achieve high yields on the same land for
many years, eliminating the need for clearing new lands.
In many situations
where fertilizers are not used, farmers have resorted to
slash-and-burn agriculture. They clear a new area of forest and can
only farm for two or three crops as the land quickly becomes
unproductive. They then move on to a new area of forest, leaving the
previous one bare and exposed to erosion. In contrast, plots at
Rothhamsted Experimental Station in England have been receiving
commercial fertilizers since 1843 and are more productive today than
any time in the past. Similar results are being obtained from the
plots established in 1876 by the University of Illinois.
fertilization is also an important tool in fighting erosion.
photograph above shows the benefit of using balanced fertilization.
On the left of the field, the properly fertilized sugarcane is
growing much faster than the improperly treated portion on the
right. As a result, the crop on the left covers the soil faster and
protects it from direct exposure to the rain, thereby reducing
erosion. It also shades out weeds more effectively, reducing the
need for herbicides. The crop on the left also leaves more residue
after harvest, increasing the organic matter content of the soil as
well as effectively reducing runoff of water.