Wildlife Values of Sustainable Agricultural Practices in the Northern Great Plains

Wildlife Values of Sustainable Agricultural Practices in the Northern Great Plains

Summary

Objectives:
1) To estimate and compare species richness and density of breeding, migrating, and wintering
birds using sustainable agricultural copping systems and conventional systems.
2) To determine if three farming systems (organic, no-till, and conventional) differ in soil
characteristics that might be critical to the overall functioning of the agroecosystem, especially as
it relates to wildlife populations.
3) To inform private and governmental farmland operators of management practices that both
benefit land use and enhance wildlife populations.

Methods:
Bird use and soil quality were compared among three cropping systems (organic, no-till, and
conventional). Data ware collected for three major cropland types including wheat for small
grain, sunflower for row crop, and fallow for unseeded. Biologists from the Northern Prairie
Wildlife Research Center determined population density and diversity of breeding, wintering,
and migrating birds using the three cropping systems. All study fields were searched to locate
nests and to determine breeding effort and success. Scientists from the Carrington Research
Extension Center characterized soil quality by measuring physical, chemical, and biological
properties. The Northern Plains Sustainable Agriculture Society and the Manitoba-North Dakota
Zero Tillage Farmer's Association collaborated in developing study plans, selecting study
cooperators, and specifying data priorities. Cooperating landowners provided study sites and
information on chemical and physical inputs, crop yields, type of equipment used, and data for
calculating soil erosion losses.

Results:
Minimum-tillage and organic fields had a greater variety and density of birds than did
conventional crop fields. Fallow fields, surprisingly, had the highest density and variety of bird
species compared to the two other types. Minimum-tillage fields, organic fields, and fallow fields
appeared to be more attractive to birds because they contain more vegetation, particularly plant
residue. Although bird populations were higher in minimum-tillage and organic fields, success of
eggs and young was low due to predation and mechanical activities. Nest success might be
increased by use of true no-tillage techniques, which would reduce mechanical activities in the
field. However, the increased amount of herbicide required for a no-till system might be a
concern, because some synthetic chemicals are suspected to have toxic effects on wildlife.

Soil quality factors were helpful in distinguishing farming practices for their impact on the
environment, including wildlife. Among the soil characteristics observed, those associated with
the physical properties seemed to best reflect the previous decade of farming practices and be the
least sensitive to the time of observation. Conventional farming practices generally had the
highest bulk densities and the smallest proportion of large soil aggregates. Both alternative
strategies, either reducing tillage or increasing organic matter return, seemed capable of
improving the physical condition of the soil. Both no-till and organic farms also generally
resulted in greater quantities of organic matter in the surface soils compared to conventional
practices. These are also properties which might be most easily observed through regular visual
inspection.

Chemical factors, such as soil nitrogen content, were sensitive to the time of observation, but
provided important information on recent management events. Organic farming practices usually
resulted in the lowest leachable form of soil nutrients. Biological indicators might prove
intermediate in temporal variability between the rapid changes in chemical parameters and the
long-term changes in physical parameters. Short, intermediate, and long-term soil quality
indicators could be useful tools for improving management and reducing the overall
environmental impact of agriculture.

Operational Recommendations:
Farmers interested in enhancing populations of ground-nesting birds should be encouraged to
minimize farming operations during the peak of the nesting period. The development of
later-maturing varieties of sweet clover or alternate legumes should be aggressively pursued, and
incentives given to farmers for adopting more environmentally friendly practices that conserve
native wildlife.