Date of this Version
Ohnesorg, W.J. 2016. Export of Insect Ecosystem Services from Hayed Native Prairie. Ph.D. Dissertation, University of Nebraska-Lincoln, Lincoln, Nebraska, USA.
Natural areas, such as prairie, have the potential to provide the benefits of pest suppression and pollination for agricultural production. In Nebraska, prairie is often used for hay production. The impact of prairie hay production management practices on beneficial arthropods is not well understood. Four prairie hay meadows adjacent to row crop fields were selected in northeast Nebraska. The goal was to assess the impact of haying them on beneficial arthropods and the movement of natural enemies into adjacent crop fields. Three management practices were evaluated for hay harvested from prairie meadows one cut per growing season, two cuts per growing season, and an uncut control. During the course of this study, prairie hay yield and quality were compared between the one and two cutting treatments. The study was conducted from 2012 to 2014. Due to the extreme conditions of drought and heat in 2012, the meadow scheduled to be cut twice received only one cutting, and consequently, 2013 and 2014 data are the only years used in analyzing the results. Natural enemies in the row crop field were sampled using yellow sticky cards (YSC) and pitfall traps. Traps were placed 0, 5, 10, 25, and 50m from the interface of corn or soybean fields with the prairie hay meadow. Two additional sampling methods were used in the prairie hay meadow: sweep netting and blue cross vane traps. Natural enemies and beneficial arthropods were analyzed for abundance/activity density and community composition differences. Prairie hay meadow vegetation was sampled using 10 1m2 quadrats per plot and the importance value for each plant taxa was calculated. Crop field YSC natural enemy differences in abundance were at 25 and 50m. Pitfall differences in abundance were at 0, 5, and 10m. The uncut control had a greater abundance or activity density measured by pitfall traps. Community composition differences occurred at 10m or less into the crop field. Little discernable pattern was observed in the abundance/activity density of arthropod natural enemies or pollinators within the prairie hay plots. The same was observed for arthropod natural enemies or pollinators community composition. Vegetation community composition was significantly different between the uncut treatment and the one and two cutting treatments. This may be a result of buildup of plant litter that is typically annually removed. There was a significant difference in annual yield of prairie hay with the two cutting higher than the one cutting in 2014 and both years combined. The difference may be due to management at one site allowing an additional three weeks of growth in 2014. The two cutting treatment had significantly higher crude protein. There was no difference in hay acid detergent fiber or total digestible nutrients. Abundance and activity density results from the crop field suggest that undisturbed natural areas, such as prairie, could be a potential source of insect natural enemies.
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