Arid lands cover more than 40% of the terrestrial land surface and host more than two billion people. To produce more food and support a growing population, intensive irrigation is being utilized worldwide to convert arid lands to agricultural fields. However, intensive irrigation of arid lands causes several problems including high water loss through evaporation, salt accumulation, and the formation of calcite mineral deposits, which can clog soil pores and change water-infiltration patterns. Moreover, formation of these calcite minerals is coupled with the release of carbon dioxide (CO2) that could alter regional and global carbon balances. The overarching goal of this project is to advance our fundamental understanding of the release of calcite-derived CO2 from arid agricultural soils using an irrigated pecan orchard in the El Paso region along the Rio Grande valley as a test site. To achieve this goal, the investigators propose to quantify the emission of calcite-derived CO2 from their pecan orchard test site using a suite of measurement tools including portable CO2 isotope analyzers, eddy covariance towers and remote sensing systems mounted on an unmanned aerial vehicle. The successful completion of this project will benefit society through the collection of new data and the development of new fundamental knowledge on how much abiotic CO2 is released to the atmosphere when arid lands are converted to irrigated agricultural fields. Further benefits to society will be achieved through student education and training, and public outreach including the mentoring four graduate students (2 PhD and 2 MS), and 3 undergraduate students at UTEP and a postdoctoral scholar at TAMU.
There is growing evidence that the formation of pedogenic carbonate minerals in irrigated arid agricultural lands is coupled with the release of abiotic CO2 to the atmosphere. Recent studies by the investigators of this proposal have identified such abiotic CO2 signals in soil gases from pecan, alfalfa and cotton fields in El Paso. However, the release of abiotic CO2 from irrigated arid agricultural soils needs further investigation to evaluate its potential impact on regional/global carbon balances and soil physicochemical properties. The goal of this project is to address this knowledge gap through detailed measurements of the flux of abiotic CO2 emitted to the atmosphere by an irrigated pecan orchard test field located in the El Paso region of the Rio Grande valley. To advance this goal, the investigators propose to monitor the ecosystem-atmosphere CO2 exchange in the pecan orchard test field with high spatial and temporal resolution using CO2 isotope analyzers, remote sensing with tunable diode laser absorption spectroscopy, hyperspectral imaging, and coupled eddy covariance flux measurements. Through this integrated measurement program, the PIs hope that they will be able to capture the spatiotemporal variations of the abiotic CO2 fluxes, and identify key parameters/variables (e.g. irrigation intensity, water chemistry and soil physicochemical properties) that control the release of abiotic CO2 from their pecan orchard test site. Thus, the successful completion of this project has potential for transformative impact by providing the first detailed assessment of the potential of irrigated arid lands to modify the land-atmosphere CO2 exchange at regional, national and even global scales.
Signals in the Soil (SitS) solicitation, a collaborative partnership between the National Science Foundation and the United States Department of Agriculture National Institute of Food and Agriculture (USDA NIFA).
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
