Agriculture Reference
In-Depth Information
Figure
3.21.
Wheat storage: Traditional and improved.
Storage is a critical problem for wheat and barley. Grain that is too moist can
develop mold, destroying its usefulness. Some fungi produce toxins, such as aflatoxins,
especially dangerous to humans. Insects also damage grains when the larvae eat the
starchy interior and contaminate the rest with webs and fecal material. Rodents are
also a constant threat. What they do not eat is contaminated and unfit for human use.
Large commercial producers often deliver their grain directly to a local grain ele-
vator. The elevator has large concrete towers for storage of grains and to load grain
directly into railcars for shipment. Some farmers will have large metal bins for tempor-
ary storage. This is to hold the harvest in the hope of better prices later in the year. Small
farmers in the developing world save much of their wheat and barley harvest for family
use. Traditional storage methods include large baked clay pots, metal barrels, and
simple adobe clay bins. Storage made of hardened clay by a small farmer is seen in
Figure 3.21. The containers attempt to block entry of insects and rodents into the
stored grain. By making an airtight seal, extensive damage by insects can be
avoided. An improved model made of metal suitable for small farmers in India is
shown on the right in Figure 3.21.
3.3.10 Marketing
Wheat is the grain most widely traded in the world. Over 600 million tons were traded
between countries in 2005.
15
The United States dominates the international wheat
market, contributing about 25.4 million tons in 2005, with Australia, Canada, and
Argentina being close competitors.
16
International marketing of wheat and barley is
made possible by a strictly controlled system of classification. The most widely used
is that of the U.S. Department of Agriculture (USDA). The eight USDA classes of
wheat are shown in Table 3.1. Within each class, there are five grades of quality
from 1 (best) to 5 (worst). Wheat for human consumption is normally limited to U.S.
No. 1 grade. Lower grades are used for nonfood products or livestock feed. Each
class represents a type of wheat useful for specific products. Barley is only classed
