Spatial Analysis of U.S. Agricultural Distributions
GUIDED SPATIAL ANALYSIS
A few key location factors from both physical and human systems are
mapped for the U.S. so that they can be used for visual analysis
of their spatial association with various crops and livestock.
U. S. Agricultural Location Factors
The 100th meridian (the north-south boundary between the Texas panhandle
and Oklahoma) is often used as a general dividing line between the humid
eastern United States and the arid western United States. Of course,
this is a very broad generalization.
The 37th parallel (the northern border of Oklahoma) is generally the boundary
for the 200-day growing season (to the south of this line). Crops
needing long growing seasons are generally found south of this parallel.
Growing season is the length of time between the last killing frost in
the spring and the first killing frost in the fall.
Generally, the best soil for agriculture in terms of fertility and terrain
can be found in the interior plains (composed of the Great Plains and the
interior lowlands of the midwest. Other large areas of excellent
land for agriculture would include the lower Mississippi River valley and
the central valley of California.
An interesting way to think of the location of the market for agricultural
products in the United States is to visualize the population distribution
using this composite satellite image of North America at night. Where
there are more lights there are more people.
Guided Analysis of U. S. Agricultural Distributions
Visual comparison of this map of the market value of all agricultural
products shows the importance of the interior plains in influencing the
location of agriculture.
This dot map of the value of crops (no animal products) once again shows
the association or correlation between agricultural crop production and
the best agricultural land (interior plains, lower Mississippi River valley,and
the central valley of California).
Note that the distribution of animal products is more widely distributed
around the U.S. than are crops and tends to be in clusters. Animals,
on average, do not require as much land as crops and can exist in drier
climates (animals can go to water sources or water can be brought to the
animal more easily that distributing water over large dry fields for crops).
Note, also, U.S. farmers and ranchers earn over $12 billion dollars more
for animals than for crops. This indicates the dominance of a livestock
economy which is made possible by the high incomes of Americans and the
lack of dietary restrictions regarding the eating of meat in our culture.
Table
of Contents | Location
Factors | Student-Conducted
Analysis
Created 6/20/97 by Charles T. Ziehr. Last updated April 24,
2000.
The URL for this page is http://arapaho.nsuok.edu/~ziehr/virtual/human_wg/agric/ag_lf.html