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ARS Home » Plains Area » El Reno, Oklahoma » Oklahoma and Central Plains Agricultural Research Center » Livestock, Forage and Pasture Management Research Unit » Research » Publications at this Location » Publication #401508
Research Project: Integrated Agroecosystem Research to Enhance Forage and Food Production in the Southern Great Plains

Location: Livestock, Forage and Pasture Management Research Unit

Title: Climate and management practices jointly control vegetation phenology in native and introduced prairie pastures

Author
item ZHOU, YUTING - Oklahoma State University
item MA, SHENGFANG - Oklahoma State University
item Wagle, Pradeep
item Gowda, Prasanna

Submitted to: Remote Sensing
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/6/2023
Publication Date: 5/11/2023
Citation: Zhou, Y., Ma, S., Wagle, P., Gowda, P.H. 2023. Climate and management practices jointly control vegetation phenology in native and introduced prairie pastures. Remote Sensing. 15(10):2529. https://doi.org/10.3390/rs15102529.
DOI: https://doi.org/10.3390/rs15102529

Interpretive Summary: Assessing the impacts of climate and management interactions on vegetation phenology is essential. However, it is challenging to quantify due to their confounding effects. By combining Moderate Resolution Imaging Spectroradiometer (MODIS) and Landsat imageries, this study examined the impacts of climate and management interactions on vegetation phenology and gross primary production (GPP) in native and introduced prairie pastures. Climate factors, namely air temperature (Ta) and total rainfall (RF), played important role in controlling the start and length of the season (SOS/LOS), and sums of vegetation indices (VIs), respectively. The GPP was controlled by RF more than by Ta. However, the explanatory power was usually low (mostly R2 < 0.5). In general, drought shortened the LOS and decreased GPP, grazing reduced VIs, and burning caused early greening up and enhanced vegetation growth. The interactions between climate and management practices were evident in specific years only. The interactions of drought and management (baling or grazing) greatly affected vegetation phenology and suppressed production. Burning plus baling might be a good management strategy in a good RF year to increase production. The impacts of climate and management interactions suggested that ranchers need to accommodate both climate and management strategies (dynamic instead of static management plans) to maintain productive and sustainable grasslands.

Technical Abstract: Climate, human disturbances, and management practices jointly control the spatial and temporal patterns of land surface phenology. However, most studies solely focus on analyzing the climatic controls on the inter-annual variability and trends in vegetation phenology. Investigating the main and interacting effects of management practices and climate might be crucial in determining vegetation phenology and productivity. This study examined the impacts of climate and management practices on vegetation phenology and productivity in adjacent native and introduced prairie pastures, which have detailed long-term management records, by combining climate, management, and satellite remote sensing data (e.g., Moderate Resolution Imaging Spectroradiometer and Landsat). Modeled gross primary production (GPP) using the vegetation photosynthesis model (VPM) was also included to investigate the dynamics of productivity. Results showed that air temperature (Ta) was an important factor in determining the start of the season (SOS) and the length of the season (LOS). Total rainfall (RF) during the annual growing season (AGS, derived from vegetation indices (VIs)) had the largest explanatory power (R2 = 0.53) in explaining the variations in the seasonal sums of VIs. The variations in GPP were better explained by RF (R2 = 0.43) than by Ta (R2 = 0.14). Using the thermal growing season (March-October) or AGS climate factors did not show large differences in determining the relationships between phenology, GPP, and climate factors. Drought shortened the LOS and decreased GPP. In terms of management practices, grazing generally reduced VIs, and burning induced early greening up and enhanced vegetation growth. Drought plus other management practices (e.g., grazing or baling) greatly affected vegetation phenology and suppressed GPP. The negative impacts (i.e., removal of biomass) of grazing on vegetation were compensated by enhanced vegetation growth after good RF. This study demonstrated that the interactions of climate and management practices could be positive (burning plus baling in a good RF year) or negative (grazing/baling plus drought), and can significantly affect vegetation phenology and production.