Native prairie filter strips reduce runoff from hillslopes under annual row-crop systems in Iowa, USA

Abstract

Intensively managed annual cropping systems have produced high crop yields but have often produced significant ecosystem services alteration, in particular hydrologic regulation loss. Reconversion of annual agricultural systems to perennial vegetation can lead to hydrologic function restoration, but its effect is still not well understood. Therefore, our objective was to assess the effects of strategic introduction of different amounts and location of native prairie vegetation (NPV) within agricultural landscapes on hydrological regulation. The study was conducted in Iowa (USA), and consisted of a fully balanced, replicated, incomplete block design whereby 12 zero-order ephemeral flow watersheds received four treatments consisting of varying proportions (0%, 10%, and 20%) of prairie vegetation located in different watershed positions (footslope vs. contour strips). Runoff volume and rate were measured from 2008 to 2010 (April-October) with an H-Flume installed in each catchment, and automated ISCO samplers.Over the entire study period, we observed a total of 129 runoff events with an average runoff volume reduction of 37% based on the three treatments with NPV compared to watersheds with row crops. We observed a progressively greater reduction across the 3 years of the study as the perennial strips became established with the greatest differences among treatments occurring in 2010. The differences among the watersheds were attributed mainly to NPV amount and position, with the 10% NPV at footslope treatment having the greatest runoff reduction probably because the portion of NPV filter strip that actually contacted watershed runoff was greater with the 10% NPV at footslope. We observed greater reductions in runoff in spring and fall likely because perennial prairie plants were active and crops were absent or not fully established. High antecedent soil moisture sometimes led to little benefit of the NPV treatments but in general the NPV treatments were effective during both small and large events. We conclude that, small amounts of NPV strategically incorporated into corn-soybean watersheds in the Midwest US can be used to effectively reduce runoff. RightsWorks produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted. Intensively managed annual cropping systems have produced high crop yields but have often produced significant ecosystem services alteration, in particular hydrologic regulation loss. Reconversion of annual agricultural systems to perennial vegetation can lead to hydrologic function restoration, but its effect is still not well understood. Therefore, our objective was to assess the effects of strategic introduction of different amounts and location of native prairie vegetation (NPV) within agricultural landscapes on hydrological regulation. The study was conducted in Iowa (USA), and consisted of a fully balanced, replicated, incomplete block design whereby 12 zero-order ephemeral flow wa...

Prairie strips improve biodiversity and the delivery of multiple ecosystem services from corn–soybean croplands

“…with the baseline treatment of 100% annual crops: dominance by plants with perennial life histories that are actively growing for a greater portion of the year, the production of long-lived, deep and/ or dense root systems (35), and the availability of floral resources throughout the growing season (36). The first two characteristics are associated with more consistent evapotranspiration rates (37), improved soil quality (38) and nutrient retention (25), increased water-holding capacity (39), and reduced runoff during heavy rainfall events (27). In addition to well-developed root systems, many prairie plant species have stiff stems that stand up in heavy rains and impede the flow of runoff.…”

“…In previous disciplinary papers we established that prairie strips in row cropland provided habitat for native biodiversity (22)(23)(24), improved soil quality (25), fostered desirable patterns of biogeochemical functioning and hydrological regulation (26)(27)(28)(29), and offered a low-cost agricultural conservation option for farmers and farmland owners relative to alternative best-management practices (30). Here, we sought to use a holistic, integrative approach to assess the effects of prairie strips relative to the proportion of the catchments they occupied.…”

Nutrient removal by prairie filter strips in agricultural landscapes

“…The average annual runoff during the growing season was 82, 150, and 145 mm (3.2, 5.9, and 5.7 in) for the 10% PFS, 10% PFS with strips, and 20% PFS with strips, respectively, approximately a 60%, 27%, 29% reduction as compared with that for the No-PFS treatment. The greater PFS area at the footslope position for the 10% PFS treatment could lead to the greater runoff reduction than other PFS treatments (Hernandez-Santana et al 2013). The runoff from the No-PFS treatment was significantly higher than that from most of PFS treatments since the second year of PFS establishment.…”

Nitrogen and carbon dynamics in prairie vegetation strips across topographical gradients in mixed Central Iowa agroecosystems

“…Both riparian buffers and PVS function as physical barriers that reduce N losses by minimizing soil erosion (Dosskey, 2001;Dosskey et al, 2002;Helmers and Eisenhauer, 2006;Hernández-Santana et al, 2013;Zhou et al, 2010Zhou et al, , 2014. Additionally, riparian buffers and PVS retain NO 3 -N through biogeochemical transformations resulting from plant uptake and microbial processes.…”