Vol. 51—1997 - NorthEastern Weed Science Society

Waggoner
December 24, 1994
145
E
Fig 12. When
herbicide and
environmental
eastward from
from 0 to 250
he exchange rates per hectare and per kg of
fertilizer are 100, 200 and I, the contours of
expense. On the map, herbicide increases
o to 2 kgfha and fertilizer increases northward
k fha.
Earlier I sho
with America.
harvested in
the land for
per capita ha
would have be
step and feed
area, 17 time
Yellowstone.
wheat farmers spared land. I conclude
The lower area on Fig 13 shows cropland
he U.S. since 1932, and the narrow areas show
allow, failed and Federal programs. If cropland
continued as it was in 1932, the top area
n cropped, too. Improving production factors in
ng people better, farmers spared the upper
the size of Indiana and 177 times the size of