The influence of drought and heat stress on long‐term carbon fluxes of bioenergy crops grown in the Midwestern USA

Abstract

Perennial grasses are promising feedstocks for bioenergy production in the Midwestern USA. Few experiments have addressed how drought influences their carbon fluxes and storage. This study provides a direct comparison of ecosystem-scale measurements of carbon fluxes associated with miscanthus (Miscanthus × giganteus), switchgrass (Panicum virgatum), restored native prairie and maize (Zea mays)/soybean (Glycine max) ecosystems. The main objective of this study was to assess the influence of a naturally occurring drought during 2012 on key components of the carbon cycle and plant development relative to non-extreme years. The perennials reached full maturity 3-5 years after establishment. Miscanthus had the highest gross primary production (GPP) and lowest net ecosystem exchange (NEE) in 2012 followed by similar values for switchgrass and prairie, and the row crops had the lowest GPP and highest NEE. A post-drought effect was observed for miscanthus. Over the duration of the experiment, perennial ecosystems were carbon sinks, as indicated by negative net ecosystem carbon balance (NECB), while maize/soybean was a net carbon source. Our observations suggest that perennial ecosystems, and in particular miscanthus, can provide a high yield and a large potential for CO2 fixation even during drought, although drought may negatively influence carbon uptake in the following year, questioning the long-term consequence of its maintained productivity.

Gut microbiomes of mobile predators vary with landscape context and species identity

“…In H. axyridis , aphid–symbionts were detected up to 96 hr after aphid consumption (Paula et al., ). Prairie plant communities were more resilient to the drought than row crops (Joo et al., ) and likely allowed the aphidophagous lady beetles in our study to be more selective in their prey choice.…”

Importance of biophysical effects on climate warming mitigation potential of biofuel crops over the conterminous United States

“…Other essential meteorological variables to drive the gap‐filling and partitioning model, including solar radiation (shortwave and longwave, both incoming and outgoing components; CNR1, Kipp & Zonen, the Netherlands), precipitation, air temperature, pressure, and relative humidity (HMP‐45C; Campbell Scientific, Logan, UT, USA), were also collected at the center of each plot. A full site description with details about data analysis and quality control has been published previously (Zeri et al ., , ; Joo et al ., ). The data collected in 2011 were used for model parameterization and evaluation.…”

Sun‐Induced Chlorophyll Fluorescence, Photosynthesis, and Light Use Efficiency of a Soybean Field from Seasonally Continuous Measurements

“…Ecosystem fluxes were calculated following procedures and configurations from previous studies conducted at the same site (Joo et al, 2016;Zeri et al, 2011). The 10 Hz raw data were first processed using EddyPro software (version 6.1.0, LI-COR, Lincoln, NE, USA) for coordinate alignment (double rotation method), compensation of density fluctuations (Webb et al, 1980), low-and high-frequency spectral corrections (Moncrieff et al, 1997(Moncrieff et al, , 2004, and calculating turbulent flux and CO 2 storage flux.…”