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ARS Home » Plains Area » Lincoln, Nebraska » Agroecosystem Management Research » Research » Publications at this Location » Publication #308729
Title: Soil carbon accumulation under switchgrass barriers

Author
item BLANCO-CANQUI, HUMBERTO - University Of Nebraska
item Gilley, John
item EISENHAUER, DEAN - University Of Nebraska
item JASA, PAUL - University Of Nebraska
item BOLDT, ALAN - University Of Nebraska

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/25/2014
Publication Date: 10/29/2014
Publication URL: http://handle.nal.usda.gov/10113/61131
Citation: Blanco-Canqui, H., Gilley, J.E., Eisenhauer, D.E., Jasa, P.J., Boldt, A. 2014. Soil carbon accumulation under switchgrass barriers. Agronomy Journal. 106(6):2185-2192. DOI: 10.2134/AGRNJ14.0227.

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 offsite transport of non-point-source water pollutants from croplands are well recognized, but their ancillary benefits on soil properties have received less attention. We studied the 15-yr cumulative effects of narrow and perennial switchgrass (Panicum virgatum L.) barriers on soil organic C (SOC), total N, particulate organic matter (POM), and associated soil structural properties as compared with the cropped area on an Aksarben silty clay loam (fine, smectitic, mesic Typic Argiudoll) with 5.4% slope in eastern Nebraska. Five switchgrass barriers were established in 1998 at ~38-m intervals parallel to the crop rows in a field under a conventional tillage and no-till grain sorghum [Sorghum bicolor (L.) Moench]–soybean [Glycine max (L.) Merr.]–corn (Zea mays L.) 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 0 to 15 cm and by 40% at 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 (r = 0.89***) and porosity (r = 0.47*). Overall, switchgrass barriers integrated with intensively managed agroecosystems can increase the SOC pool and improve soil structural properties.