In subsistence farming situations food producers are often more interested in the
reliability of a crop than in producing high yields. They prefer to produce at least some
food every year than to produce a high yield one year and very little or nothing the next
year.
In dry regions the sorghums and millets are often more useful in the long term than
maize. Although maize may sometimes yield more than these types of cereal, especially
in good years, it may often yield very little or it may even fail completely. Thus, even
though the average yields of sorghum and millets are generally lower than maize, it is
often better to plant them because they are more dependable than maize in many
marginal conditions.
Yields of Human and Animal Food
Many crops are dual-purpose; they produce both grain for human consumption and also
and for construction material.
For this reason it is useful to have an understanding of all the uses for the various
crops. For example, very tall varieties of sorghum with strong stems may have low
yields of grain but are more useful than higher yielding short varieties in areas where
stems are prized for building or for fuel.
Haulm (sometimes spelled halm) is pronounced “horm” and is the name given to the
stems and leaves of crops, especially after harvesting. Haulm also often includes the hull
orhusk, the outer coverings of the grains, especially of cereals, and also the empty pods
of crops such as peas and beans. Haulm is most commonly used as animal fodder, either
ensilaged, made into hay, or grazed by animals in the field after harvest.
The haulm of Irish potatoes is often burned off with chemicals in modern farming
systems, to allow the tubers to harden off in the ground, to facilitate mechanical
harvesting, and, most importantly, to limit the spread of Blight disease. Pulses, rape and
linseed are also sometimes burned off to help harvesting, especially if they are very
weedy.
The Spread of Pests, Diseases and Weed Seeds in Haulm
Haulm can often be a source of diseases or insect pests that have been allowed to live
from one season to the next on diseased or infested plant stems, leaves etc. Partial
control of these pests and diseases can be obtained therefore by removing the haulm
from the field immediately after harvest and either burning it or feeding it to animals.
Examples include Stem Borer of maize and sorghum, and the Wilt and Rust diseases
of lentils. Weed seed is also often spread in haulm, such as wild oats and blackgrass in
temperate cereal growing areas.
77
Reliability versus High Yield
leaves and stems for animal food (fodder). Stems (or stalks) are also often used for fuel