Impacts of altered agricultural land cover patterns on carbon and water cycling in the central plains of the U.S

The grasslands in the central plains of the U.S. are the main agricultural regions of the world. The goal of this project was to ascertain the carbon and water cycle impacts due to changing landcover and changing climate in response to differential cropping strategies in conjunction with landcover change and future climate projections. We utilized one hundred and twelve years (1900- 2011) of daily precipitation and temperature records across the state of Kansas to quantify the temporal dynamics associated with different landcover. We used the Agro-BGC model to estimate carbon fluxes from each of the meteorological stations for each of the different landcover classes. In addition, we investigated the role of landcover change by forcing landcover transitions and assessing the responses in the carbon and water fluxes and storage pools. Budyko curves were utilized to explain annual water-energy balance for different landcover types. The sensitivity to the timing of meteorological events were assessed using a critical climate period analysis, which indicated precipitation and temperature around summer (121st day - 180th day, window size=60 for both net primary production (NPP) and evapotranspiration (ET)) had contributed most for annual NPP and ET, but the critical time period was later in the western regions of the domain. Finally, the impacts of climate change over next 100 years were assessed using a stochastic weather generator to produce synthetic sequences of daily weather consistent with future climate projections. Taken together, these results illustrate the importance of considering landcover, disturbance, and future climate change in conjunction in order to assess future viability of agricultural production in the central U.S.