Geoscience Reference
In-Depth Information
work out the mineralization of organic N, its movement down the soil profile, and
its uptake by crops. “Soon”, he said, “farmers may be able to adopt such a model,
and, with their own computers, introduce parameters descriptive of their own local
situation and target yields to predict the optimum spring-N applications for individual
fields”. On present form, we are, in fact, unlikely to be able to predict the total inor-
ganic N pool in the soil within reasonable limits from year to year so this vision still
eludes us. In the radically altered agricultural scene today, such an objective may, in-
deed, seem less pressing.
F
IELD DRAINAGE
Badly drained fields create several kinds of problems for farming. The most obvious
one is the danger of damaging the soil structure, by trampling in grassland (known as
poaching), or by the passage of vehicles in arable fields. If the ground is too soft, it
can delay drilling in the spring, and seriously limit the ability to spray against weeds
and diseases at critical times. A wet soil also needs more nitrogen fertilizer than a well
drained one to produce the same effect on crop growth. And finally, the roots of most
arable crops and fruit can suffer badly if there is an excess of water for any length of
time, especially during the growing season.
