Location: Soil, Water & Air Resources ResearchTitle: Improving soil quality on marginal lands with tree windbreaks
|Sauer, Thomas - Tom|
|BREVIK, ERIC - Dickinson State University|
|WACHA, KENNETH - Orise Fellow|
Submitted to: Eurosoil Congress
Publication Type: Abstract Only
Publication Acceptance Date: 6/4/2021
Publication Date: 8/27/2021
Citation: Sauer, T.J., Brevik, E., Wacha, K.M. 2021. Improving soil quality on marginal lands with tree windbreaks. Eurosoil Congress.
Technical Abstract: Food security can be reduced when agricultural lands are converted from crop to bioenergy feedstock production. Targeting marginal lands for agroforestry practices to produce woody bioenergy feedstock avoids some of the competition for food production and may improve soil health and the local microclimate and provide additional ecosystem services. The objective of this study was to evaluate the effect of eastern red cedar (Juniperus virginiana L.) windbreaks on soil quality in the U.S. Great Plains. Eastern red cedar has great potential for bioenergy production due to its adaptability to a wide range of soil and climate conditions and the physical and chemical characteristics of its biomass. Nine sites were selected from latitudes 41-47° N and longitudes 94-103° W with mean annual precipitation (MAP) from 425 to 970 mm and mean annual temperature (MAT) from 4.9 to 9.9° C. Tree age varied from 22 to 59 years. Ponded infiltration (twin ring technique) and penetration resistance at 2.5 cm increments to 30 cm (digital static cone penetrometer) were measured at 9 locations under the trees and 9 locations at the same orientation in adjacent fields (crop, pasture, or hay) at each site. Soil samples were collected at corresponding locations and analyzed for several key properties including soil organic carbon (SOC), total nitrogen, pH, nutrients, particle size, bulk density, and aggregate stability. Stocks of SOC to 30 cm depth averaged 0.92 kg m-2 (16.8%) greater under trees as compared to adjacent land use. Both SOC stocks and tree growth were strongly correlated (R2 > 0.61) with MAP. Infiltration rates averaged 163 mm h-1 (55%) greater and penetration resistance averaged 228 kPa lower under tree cover. Infiltration rates were found to be proportional to higher aggregate stability, with significantly greater (34%) fractions of stable aggregates found under tree canopies. Additional soil hydraulic properties (saturated hydraulic conductivity and sorptivity) were calculated from the twin ring infiltration data. These results suggest that precipitation was more likely to infiltrate and be available for root uptake under the trees. Increased SOC stocks likely led to improvements in soil physical and chemical quality following tree planting for bioenergy feedstock production and may allow some marginal lands to be converted back to crop or forage production at a higher level of productivity. This research was supported by funding from the North Central Regional Sun Grant Center at South Dakota State University through a grant provided by the US Department of Agriculture under award number 2014-38502-22598.