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United States Department of Agriculture

Agricultural Research Service

Research Project: ENVIRONMENTALLY SOUND MANURE MANAGEMENT FOR REDUCTION OF GAS EMISSIONS, NUTRIENTS, AND PATHOGENS

Location: Agroecosystem Management Research

Title: Soil carbon accumulation under switchgrass barriers

Authors
item Blanco-Canqui, Humberto -
item Gilley, John
item Eisenhauer, Dean -
item Jasa, Paul -
item Boldt, Alan -

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 25, 2014
Publication Date: N/A

Interpretive Summary: The benefits of grass barriers or hedges for reducing off-site transport of non-point source water pollutants from croplands are well recognized, but their ancillary benefits on soil properties have received much less attention. We studied 15-yr cumulative effects of narrow and perennial switchgrass barriers on soil organic C (SOC) and total N, particulate organic matter (POM), and associated soil structural properties as compared with the cropped area on an Aksarben silty clay loam with 5.4% slope in eastern NE. Five switchgrass barriers were established in 1998 at about 38 m intervals parallel to the crop rows in a field under a conventional till and no-till grain sorghum, soybean ,and corn rotation . Compared with the cropped area, switchgrass barriers accumulated about 0.85 Mg ha-1 yr-1 of SOC and 80 kg ha-1 yr-1 of total soil N at the 0 to 15 cm soil depth. Switchgrass barriers also increased coarse POM by 60%. Mean weight diameter of water-stable aggregates increased by 70% at the 0 to 15 cm and by 40% in the 15 to 60 cm, indicating that switchgrass barriers improved soil aggregation at deeper depths. Large (4.75-8 mm) macroaggregates under switchgrass barriers contained 30% more SOC than those under the cropped area. Switchgrass-induced changes in SOC concentration were positively associated with aggregate stability and porosity. Overall, switchgrass barriers when integrated with intensively managed agroecosystems can increase the SOC pool and improve soil structural properties.

Technical Abstract: The benefits of grass barriers or hedges for reducing off-site transport of non-point source water pollutants from croplands are well recognized, but their ancillary benefits on soil properties have received much less attention. We studied 15-yr cumulative effects of narrow and perennial switchgrass barriers on soil organic C (SOC) and total N, particulate organic matter (POM), and associated soil structural properties as compared with the cropped area on an Aksarben silty clay loam with 5.4% slope in eastern NE. Five switchgrass barriers were established in 1998 at about 38 m intervals parallel to the crop rows in a field under a conventional till and no-till grain sorghum, soybean ,and corn rotation . Compared with the cropped area, switchgrass barriers accumulated about 0.85 Mg ha-1 yr-1 of SOC and 80 kg ha-1 yr-1 of total soil N at the 0 to 15 cm soil depth. Switchgrass barriers also increased coarse POM by 60%. Mean weight diameter of water-stable aggregates increased by 70% at the 0 to 15 cm and by 40% in the 15 to 60 cm, indicating that switchgrass barriers improved soil aggregation at deeper depths. Large (4.75-8 mm) macroaggregates under switchgrass barriers contained 30% more SOC than those under the cropped area. Switchgrass-induced changes in SOC concentration were positively associated with aggregate stability and porosity. Overall, switchgrass barriers when integrated with intensively managed agroecosystems can increase the SOC pool and improve soil structural properties.

Last Modified: 12/26/2014
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