97241
Assessing the Impacts of Land Use Change from Cotton (Gossypium hirsutum L.) to Cellulosic Bioenergy Crops on Watershed Hydrology and Water Quality in the Texas High Plains.

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See more from this Division: Submissions
See more from this Session: Graduate Student Poster Competiton – Crops
Sunday, February 7, 2016
Hyatt Regency Riverwalk San Antonio , Regency Ballroom
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Yong Chen, Texas Agrilife Research-Vernon, Vernon, TX, Srinivasulu Ale, Department of Biological & Agricultural Engineering, Texas A&M AriLife-Vernon, Vernon, TX and Nithya Rajan, P.O.Box 1658, Texas A&M University, College Station, TX
The semi-arid Texas High Plains (THP) region, where cotton is grown in a vast acreage, is one of the most intensive agricultural regions in the world. Rapid declines in groundwater levels, recurring droughts in the recent times, and projected warmer and drier summers in the future in this region are expected to induce potential land use change from cotton to high water use efficient crops such as cellulosic bioenergy crops. The objective of this study is to assess the impacts of this potential land use change from cotton to cellulosic bioenergy crops such as Alamo switchgrass, Miscanthus  giganteus, big bluestem and biomass sorghum on hydrology and water quality in the Double Mountain Fork Brazos watershed in the THP using SWAT, APEX and integrated SWAT-APEX models. Results indicated that the average (1994-2009) annual surface runoff increased by 59% under biomass sorghum scenario, and decreased by 88%, 77% and 93% under the switchgrass, Miscanthus and big bluestem scenarios, respectively, when compared to the baseline cotton scenario. Miscanthus and switchgrass exhibited superior biomass yield, water use efficiency and water conservation under dryland and irrigated conditions, respectively, relative to cotton, big bluestem and biomass sorghum. The average annual total nitrogen (TN) load decreased by 91% and 67% under the switchgrass and Miscanthus scenarios relative to the baseline cotton scenario. The results from climate sensitivity analysis indicated that the simulated water balance parameters, TN load and crop yield were more sensitive to the increase in precipitation than to the increase in atmospheric CO2 concentrations or air temperature. The surface runoff and TN load increased exponentially with the increase in precipitation. It was interesting to find that the global warming could potentially increase cotton yields, but it could reduce Miscanthus and switchgrass biomass production in the THP.
See more from this Division: Submissions
See more from this Session: Graduate Student Poster Competiton – Crops