relatively small sample size for the 2005 CEAP-ARMS, farm-size was defined for only two classes
(for both conservation program participants and non-participants). We then formulated and
estimated a cost-function based, crop-specific acreage allocation model of producer adoption of
conservation structural practices. Corn field acreage-supply equations were estimated for four
production technology decision options, including corn-field acres with no structural practices, with
only infield structures, with only perimeter-field structures, and with both structural practices, all
evaluated jointly for both conservation program participants and non-participants. A GEE
procedure, designed to account for the correlation between producer practice adoption decisions,
was used to estimate two models. In the first model, field-level acreage allocations for 2005 corn
were evaluated as a function of normalized per-unit input prices for nitrogen use, agricultural
wages, and diesel use, as well as for three technology choice variables and three practice-
installation time-period variables. For the second model, similar acreage-allocation equations were
estimated, but with additional covariates to control for influences associated with farm structure,
field-crop management, and site-specific environmental attributes.
The 2005 CEAP-ARMS Phase II data show that for farms growing corn (in IN, IL, IA, and
NE), significant differences exist between conservation program participants and non-participants,
and across farm-size types. For example, while higher-sales participating farms operated 1,263
acres (on average) relative to 1,019 acres for similar non-participants, participant farms accounted
for only 14 percent of farms growing corn and for only about 17 percent of corn acres planted in
2005. Most corn farms in the study area (and most corn acres planted) were not participating in
USDA conservation programs in 2005. Participating farms were also less diversified (a larger share
of farm revenue came from corn production) than were non-participant farms. However, the net
farm income for higher-sales non-participant farms exceeded that for similar participant farms by
nearly 84 percent. Higher-sales participant farms also received higher government conservation
21