Whole-Farm Nutrient and Agchemical Input Budgeting for Sustainable Farming: Analysis and Demonstration
With participating farm families, demonstrate and evaluate a whole- farm systems approach to
managing crop nutrients and pest problems on representative dairy farms.
Three dairy farms representing the range of size of conventional dairy operations in Wisconsin
were selected for the study. All three farms had "typical" dairy crop rotations with the majority of
their fields in corn and alfalfa. Pre-change baseline data was collected before and after harvest on
these farms in the 1992 growing season. The data collected included soil testing each field on the
farms in the fall of 1991, crop production inputs (both purchased and farm-derived); equipment
use (for harvest, seedbed preparation, planting, cultivation and agrichemical application; labor
logs for farm operations (Montgomery farm); yields (first, second, and third harvest forage yields
and quality; grain yields).
During the winter of 1992-93, the cooperating farmers, crop consultant, and project researchers
for each farm developed a plan to maximize the use of on-farm nutrients, reduce losses through
leaching or run-off, and reduce purchased inputs as much as practical. The plans took into
account the results of preplant residual soil nitrate tests. Along with indicating fertilizer and
manure application rates field-by-field, they guided the farmer in choice of cultivars, timing of
field operations, and herbicide choices and application timing.
During the 1993 growing season, the farmers attempted to follow these plans. They documented
all manure, fertilizer, and pesticide applications along with all field operations. Field-by-field
yields were again taken in 1993. New nutrient management and pest control plans were prepared
for the 1994 crop season. Field-by-field data collection continued. Following harvest in 1994, all
fields were soil sampled again.
Field-by-field, potassium and phosphorus levels vary widely from very low to very high across
the farms. On all three farms, more phosphate is entering the farm as feed and fertilizer than is
leaving in milk and animals sold. At least four times more potash was imported than was
exported from the farms. When field-by-field nutrient management plans were prepared for the
farms in 1993 and 1994, however, deficits on alfalfa called for the importation of additional
phosphate and potash. The substantial amount of nutrients available from animal manures on the
farms was suitable for fertilizing corn, but could not be applied to alfalfa fields at rates sufficient
to meet its total phosphate and potash requirements without detrimental effects to the stand.
On-farm nitrogen resources (manure applications, legume residues, and residual nitrate left in the
soil profile) were able to supply almost all of the corn nitrogen needs on the farms. As manure
supplied most of corn potash and phosphate needs, starter rates for corn were decreased.
Overall yields on both the Montgomery and Thull Farms were much better in 1994 than they
were in the beginning of the project. However the effect of the new management strategies in
these gains can not be distinguished from the weather. In 1992, weather conditions led to poor
yields statewide. The next year, 1993, was somewhat better, and 1994 was a very much better
year for most of the state.
Farmer Adoption and Impact:
Obviously, this project was successful in getting the farmers we worked with directly to make
some major changes. This has been the experience of Nutrient and Pest Management (NPM)
Program with on-farm work since 1990 intensive one-on-one assistance and demonstrations is
likely to lead to adoption of recommended practices. In a 1995 survey of NPM cooperating
farmers (45 out of 60 responded), we found that NPM cooperators are much less likely to apply
excessive amount of nitrogen fertilizer than the general farm population questioned in similar
surveys and 81 percent are within 40 pounds per acre of the nitrogen application guidelines
Even with substantial willingness on their part to make management changes and ready
assistance on the part of the researchers, the farmers were not able to follow their nutrient
management plans completely. Constraints to following the plans included labor shortages,
financial deficits that inhibited fertilizer purchases, problems caused by the weather or
unforeseen emergencies, as well as the time it takes to get used to new management strategies.