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ARS Home » Plains Area » Temple, Texas » Grassland Soil and Water Research Laboratory » Research » Publications at this Location » Publication #367401
Research Project: Resilient Management Systems and Decision Support Tools to Optimize Agricultural Production and Watershed Responses from Field to National Scale

Location: Grassland Soil and Water Research Laboratory

Title: Intercropping switchgrass with hybrid poplar increased carbon sequestration on a sand soil

Author
item Collins, Harold
item KIMURA, E - Texas A&M Agrilife
item Polley, Herbert
item Fay, Philip
item FRANSEN, S - Washington State University

Submitted to: Biomass and Bioenergy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/3/2020
Publication Date: 5/1/2020
Publication URL: https://handle.nal.usda.gov/10113/6926346
Citation: Collins, H.P., Kimura, E., Polley, H.W., Fay, P.A., Fransen, S. 2020. Intercropping switchgrass with hybrid poplar increased carbon sequestration on a sand soil. Biomass and Bioenergy. 138:105558. https://doi.org/10.1016/j.biombioe.2020.105558.
DOI: https://doi.org/10.1016/j.biombioe.2020.105558

Interpretive Summary: A concern in the production of biofuels has been the replacement of prime crop lands with production of dedicated biofuel crops that may result in the loss of food production. A potential solution to offset these concerns is to grow biomass crops on marginal lands or maximize land use by intercropping within perennial systems that would promote environmental benefits and increase economic returns. The outcome of this project was the development of soil C inventories from the production of switchgrass produced within an intercropping system with hybrid poplar. Four years of intercropping resulted in a 17% increase in soil organic carbon in the soil surface compared to the monoculture of poplars and an increase in the amount and age of stabilized C. The study further showed the potential for switchgrass to be a viable energy crop with essential information for biofuel producers to adjust energy production goals and possibly develop secondary markets such as C-credit trading.

Technical Abstract: Switchgrass (Panicum virgatum) has been identified as an important source of cellulosic biomass to produce biofuels and improve soil C cycling and storage. The natural 13C abundance of soils was used to calculate the quantity and turnover of C in a hybrid poplar (Populus x generosa and P. x canadensis) plantation intercropped with switchgrass. Levels of intercrop were: grass cultivars inter-planted with poplar trees (IC), monoculture switchgrass cultivars (SM) and monoculture hybrid poplar trees (PM). Four years of intercropping increased soil organic carbon (SOC) 17% in the surface 60 cm for Kanlow and 13% for Blackwell and Trailblazer cultivars. The surface soil was enriched 1.4‰ '13C cropped to Kanlow and Trailblazer, and 1.9‰ '13C for Blackwell above the PM. On average 12% of SOC in the surface horizon of SM was derived from switchgrass and 9% in IC. Monoculture SOC accrual rates were 0.78 for OP367, 0.63 for PC4, 1.25 for Blackwell and Trailblazer, and 1.7 Mg C ha-1yr-1 for Kanlow. Accrual rates for IC averaged 1.0 Mg C ha-1yr-1. The resistant (Cr) C pool was 62%, the slow (Cs) 34% and active (Ca) 4% of total soil C for PM. The Cs increased 31% in the 0-15 cm horizon of SM and IC compared to PM. Field soil MRTs of the Ca and Cs cropped to switchgrass averaged 50d and 15yr for surface soil, respectively, compared to 41d and 9yr for the initial field and PM. Switchgrass production intercropped with hybrid poplar increased SOC in a soil that by nature was low in SOC and provides biofuel producers information to adjust energy production goals and/or develop secondary markets such as C-credit trading.