General suitability maps and crop information is presented to assist growers considering new crops.
These data should be combined with other data and given serious consideration
before growing a new crop. Every effort has been made to verify the
validity of the data, but inaccuracies may occur.
Coming to Terms with Terminology
Information supplied in this web site is based on published literature
and the efforts of many researchers who have collected plant requirement
information. Although care has been taken to collect accurate data and to compare
data from different sources inaccuracies may occur. Problems also may occur in
interpreting such data. For example, it was assumed that reported requirements
had similar meanings. But, “absolute maximum temperature” could mean the
temperature at which:
- Cell division
or cell elongation ceases and crop growth stops until conditions improve
- Tissue is
destroyed, characterized by tissue turning yellow and eventually brown
yield is affected; fruit aborts
- Plants die
The impact of the different definitions may be significant. The number of crops included made it
impractical to verify the definition of each requirement for each crop.
Unique requirements associated with crop genetics and/or
specific location effects exist. For example:
Suitability versus Survival
exist for well-studied crops. The Natural Resources Conservation Service
Plants Database states soybean requires from 32 to 50 inches of rainfall
per year. The Food and Agriculture Organization of the United Nations
Ecocrop web site suggests 24 to 60 inches. Although similar, the different
ranges would indicate smaller or larger areas to be suitable for soybean.
Estimates for more exotic and less researched crops would be expected to
be less reliable.
For many crops, environmental requirements differ for
varieties adapted to different geographical regions. Researchers reporting
requirements for varieties adapted to their area may ignore requirements that
describe the entire crop. Our intent was to include the range of requirements
for widely adapted crops.
Farmers are aware of the narrow distinction between
crop success and failure: farming just a few fields away from a timely summer
rain, or a few feet of elevation above the low, cold spots on a cold spring
morning. Users are encouraged to investigate crop information beyond this web site,
especially for crops that are marginally suitable. A crop that can grow in your
area may not be a good crop choice. For example, pecan varieties produce nuts
in the southern portion of the state. While some pecan varieties will grow in
protected areas north of this range, they will not produce nuts
Suitability versus Yield
Our intent was not to
predict yield. The model relies on a relatively few climate and soil
requirements to create overall suitability maps. Requirements were selected
because of their importance and availability. Additional requirements likely
would strengthen the suitability maps but undoubtedly would reduce the number
of overall maps. Traditional crops would remain on the list of mapped crops while
less studied potential alternative crops would not be included.
Data used to compose the overall suitability maps are insufficient to
predict yield. Although under certain circumstances suitability may be related
to yield, computer models for traditional crops, such as corn, require many
detailed inputs to estimate yield (e.g. daily weather information, planting
date, variety, etc.).
Suitability versus Profitability
Suitability does not guarantee profit. A crop suited to an area may not
be profitable due to other factors, such as insects, diseases, weeds, limited
availability of a suitable variety, and market access. For example, although
sorghum is well suited to Illinois, it may not be the best crop for many
farmers because corn typically yields more than sorghum. Because sorghum is
rarely planted, marketing may be a problem because grain elevators may not
reserve bin space for it, resulting in additional transportation costs for