Agriculture Reference
In-Depth Information
9
SOILS AND WATER
9.1
SOIL ON THE THREE FARMS
Soil profiles at the three farms, shown in Figures 9.1 to 9.3, are very different in both
looks and composition. The Philippines (soil profile in Fig. 9.1) has high temperatures
and rainfall leading to rapid decomposition of organic matter. This, coupled with the
constant monocropping
of maize and the constant removal of organic matter, means
that this soil cannot develop an obvious A horizon (Fig. 9.1; see discussion later
in chapter).
In Ecuador (Fig. 9.2) there are moderate temperatures and rainfall leading to
the buildup of organic matter in the soil. This soil is dark is color, has a very strong
structure, and, although it is hard to see in pictures, a very definite A horizon. The
field is rotated and organic matter left on it so that there is a constant input of
organic matter. In spite of the field having a steep slope, it shows no sign of water
erosion, although there has been movement of soil under the pull of gravity, that
is, colluvial movement.
Monocropping is when only one crop is grown in a field.
