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Biomass Production and Soil Carbon Analysis of Switchgrass under Rainfed or Minimal Irrigation in a Semiarid Environment
Author(s) -
Wang Limei,
Qian Y.L.,
Brummer Joe,
Wilhelm S.J.,
Leach Jan E.
Publication year - 2019
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj2018.09.0568
Subject(s) - panicum virgatum , agronomy , irrigation , cultivar , biomass (ecology) , environmental science , soil carbon , soil water , biology , bioenergy , biofuel , soil science , ecology
Core Ideas In this study, switchgrass grew well on marginally saline soil with limited irrigation. The southern‐origin cultivars had greater biomass yield than the northern cultivars. Irrigation increased above and below ground biomass, but not soil C and N content. Switchgrass had the potential to sequester C into the soil.Limited information is available on switchgrass (Panicum virgatum L.) productivity in semiarid environments. A field experiment was conducted in semiarid Colorado, with the objectives were to determine: 1) aboveground biomass production of six upland switchgrass cultivars, and 2) soil organic carbon content of two switchgrass cultivars grown on a marginally saline soil under rainfed and minimal irrigation conditions. The experiment was a split plot design with rainfed vs. minimal irrigation treatment as the main plot and six cultivars [three southern cultivars (Blackwell, Pathfinder, and Trailblazer) and three northern cultivars (Sunburst, Forestburg, and Dacotah)] as subplot with three replications. Aboveground biomass for the six cultivars ranged from 1.1 to 7.8 Mg ha −1 yr −1 in the establishment year, and 3.2–9.3 and 3.3–11.7 Mg ha −1 yr −1 under rainfed and minimally irrigated conditions, respectively, during the following three stand years. Minimal irrigation (mean annual irrigation water of 21 cm) increased biomass yield compared to the rainfed control. Southern‐origin cultivars produced more biomass than the northern lines under both rainfed and minimal irrigation. Four years after establishment, within the top 0.6 m of soil, irrigation increased root biomass, with averages of 9.9 and 5.2 Mg ha −1 yr −1 for irrigation and rainfed treatments, respectively. Soil organic carbon accumulated rapidly at 0–20 cm soil depth in Blackwell and Pathfinder plots, at the rates of 1.07–1.36 Mg C ha −1 yr −1 . Switchgrass growth in the semiarid environment was improved with limited supplemental irrigation and had the potential to sequester C into soil.