The Midwestern US is dominated by corn (Zea mays L.) and soybean (Glycine max L. Merr.) production, and the carbon dynamics of this region are dominated by these production systems. An accurate ...regional estimate of gross primary production (GPP) is imperative and requires upscaling approaches. The aim of this study was to upscale corn and soybean GPP (referred to as GPPcalc) in four counties in Central Iowa in the 2016 growing season (DOY 145–269). Eight eddy-covariance (EC) stations recorded carbon dioxide fluxes of corn (n = 4) and soybean (n = 4), and net ecosystem production (NEP) was partitioned into GPP and ecosystem respiration (RE). Additional field-measured NDVI was used to calculate radiation use efficiency (RUEmax). GPPcalc was calculated using 16 MODIS satellite images, ground-based RUEmax and meteorological data, and improved land use maps. Seasonal NEP, GPP, and RE ( x ¯ ± SE) were 678 ± 63, 1483 ± 100, and −805 ± 40 g C m−2 for corn, and 263 ± 40, 811 ± 53, and −548 ± 14 g C m−2 for soybean, respectively. Field-measured NDVI aligned well with MODIS fPAR (R2 = 0.99), and the calculated RUEmax was 3.24 and 1.90 g C MJ−1 for corn and soybean, respectively. The GPPcalc vs. EC-derived GPP had a RMSE of 2.24 and 2.81 g C m−2 d−1, for corn and soybean, respectively, which is an improvement to the GPPMODIS product (2.44 and 3.30 g C m−2 d−1, respectively). Corn yield, calculated from GPPcalc (12.82 ± 0.65 Mg ha−1), corresponded well to official yield data (13.09 ± 0.09 Mg ha−1), while soybean yield was overestimated (6.73 ± 0.27 vs. 4.03 ± 0.04 Mg ha−1). The approach presented has the potential to increase the accuracy of regional corn and soybean GPP and grain yield estimates by integrating field-based flux estimates with remote sensing reflectance observations and high-resolution land use maps.
Eastern red cedar (ERC, Juniperus virginiana L.) is a common tree species in agroforestry plantings and has great potential for bioenergy production due to physical and chemical characteristics of ...its biomass. The objective of this study was to assess the effects of ERC plantings on carbon (C) sequestration and selected soil quality parameters in existing plantings across the northern U.S. Great Plains. Nine locations were selected in five states with mean annual precipitation (MAP) from 446 to 999 mm and mean annual temperature (MAT) from 4.4 to 10.0°C. Infiltration was measured using the twin ring technique at nine sites in each tree planting and adjacent field (crop, pasture, or hay) at each location. Following infiltration measurements, a 4.8 cm‐diameter soil core to 30 cm depth was collected from inside one infiltration ring of each pair for bulk density, pH, aggregate stability, soil organic carbon (SOC), and total nitrogen (TN) analyses. Penetration resistance in 2.5 cm increments to 30 cm depth was measured in the other infiltration ring. SOC stocks under ERC were significantly higher than in the adjacent field soil at five of the locations and, for all locations, averaged 16.8% greater than in the adjacent field. The estimated SOC accumulation rate for the eight locations with uniform tree stand age averaged 0.30 Mg C ha−1 year−1. Most locations had higher TN and C/N and lower bulk density beneath ERC. Fewer differences for infiltration and penetration resistance and smaller and less consistent differences for pH and aggregate stability were observed. Tree aboveground C stocks were estimated to increase an average of 2.05 Mg C ha−1 year−1. Estimated tree aboveground biomass C and SOC stocks under ERC and in adjacent fields were strongly correlated with MAP. Potential ERC planting for C sequestration or bioenergy feedstock production is not likely to significantly degrade soil quality and may improve soil physical or chemical quality for locations in the US Great Plains.
Core ideas
Eastern red cedar (ERC) is a common tree species with biomass that is well suited for biofuel production.
ERC effects on soil quality should be evaluated if considered for bioenergy feedstock production.
Soils beneath ERC had higher SOC, TN, C/N, and lower bulk density than adjacent fields at most locations.
ERC C accumulation and SOC were highly correlated with MAP.
ERC plantings had generally positive impacts on soil quality.
To test the hypothesis that radiation dose to key sites in the upper aerodigestive tract is associated with long-term functional outcome after (chemo)radiotherapy for head-and-neck cancers.
This ...study examined the outcome for 27 patients treated with intensity-modulated radiotherapy for definitive management of their head-and-neck cancer who were disease free for at least 1 year after treatment. Head-and-neck cancer-specific quality of life (QoL) was assessed before treatment and at 1 year after treatment. Type of diet tolerated, presence of a feeding tube, and degree of weight loss 1 year after treatment were also used as outcome measures. Radiation doses delivered to various points along the upper aerodigestive tract, including base of tongue, lateral pharyngeal walls, and laryngeal structures, were determined from each treatment plan. Radiation doses for each of these points were tested for correlation with outcome measures.
Higher doses delivered to the aryepiglottic folds, false vocal cords, and lateral pharyngeal walls near the false cords correlated with a more restrictive diet, and higher doses to the aryepiglottic folds correlated with greater weight loss (p < 0.05) 1 year after therapy. Better posttreatment speech QoL scores were associated with lower doses delivered to structures within and surrounding the larynx.
Our data show an inverse relationship between radiation dose delivered to laryngeal structures and speech and diet and QoL outcomes after definitive (chemo)radiation treatment. These findings suggest that efforts to deliver lower doses to laryngeal structures may improve outcomes after definitive (chemo)radiation therapy.
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