Page 1. i Cost Analysis of Alternative Harvest and Storage Methods for Switchgrass in the Southea... more Page 1. i Cost Analysis of Alternative Harvest and Storage Methods for Switchgrass in the Southeastern US James A. Larson, Associate Professor Department of Agricultural and Resource Economics The University of Tennessee ...
Full carbon accounting for terrestrial ecosystems is intended to quantify changes in net carbon e... more Full carbon accounting for terrestrial ecosystems is intended to quantify changes in net carbon emissions caused by changes in land management. On agricultural lands, changes in land management can cause changes in CO2 emissions from fossil fuel use, agricultural lime, and decomposition of soil carbon. Changes in off-site emissions can occur from the manufacturing of fertilizers, pesticides, and agricultural lime. We are developing a full carbon accounting framework that can be used for estimates of on-site net carbon flux or for full greenhouse gas accounting at a high spatial resolution. Estimates are based on the assimilation of national inventory data, soil carbon dynamics based on empirical analyses of field data, and Landsat-derived remote sensing products with 30x30m resolution. We applied this framework to a mid-western region of the US that consists of 679 counties approximately centered around Iowa. We estimate the 1990 baseline soil carbon for this region to be 4,099 Tg C...
ABSTRACT The objective of this study was to estimate the storage dry matter (DM) losses for switc... more ABSTRACT The objective of this study was to estimate the storage dry matter (DM) losses for switchgrass bales that were preprocessed using an industrial baler technology prior to storage with three particles sizes of feedstock and two types of bale wraps. Mixed models were used to test difference in DM losses across the particle sizes, wrap materials, and storage days. Response functions were also estimated to determine DM losses for each particle size and wrap material at storage over time. DM losses were found to be different across particle size, wrap material, and storage period. Specifically, the DM losses were lower when the particle size of switchgrass baled decreased from full length to less than two centimeters. The results show switchgrass bales stored at the smallest particle size had lower DM losses than bales stored at the full length of feedstock. Also, applying additional film wrap that completely covers the net wrapped bale reduced DM losses relative to bales wrapped only in net. Furthermore, storage DM losses of preprocessed switchgrass bales increased linearly with days in storage. Our findings suggest that applying both net and film wrap to switchgrass bales composed by a particle size less than two centimeters can reduce DM losses during storage. Economic analysis indicates the price of switchgrass was also important in the choice of storage method for switchgrass. The results provide valuable insight into improving feedstock logistics and the feasibility of the advanced biofuels industry.
To manage lands locally for C sequestration and for emissions reductions, it is useful to have a ... more To manage lands locally for C sequestration and for emissions reductions, it is useful to have a system that can monitor and predict changes in soil C and greenhouse gas emissions with high spatial resolution. We are developing a C accounting framework that can estimate C ...
Page 1. i Cost Analysis of Alternative Harvest and Storage Methods for Switchgrass in the Southea... more Page 1. i Cost Analysis of Alternative Harvest and Storage Methods for Switchgrass in the Southeastern US James A. Larson, Associate Professor Department of Agricultural and Resource Economics The University of Tennessee ...
There is a dearth of research regarding the influence of family members on adolescent dating. Thi... more There is a dearth of research regarding the influence of family members on adolescent dating. This study explored messages that African American adolescents received from family members regarding dating attitudes, norms and behaviors. Qualitative interviews were conducted with sexually experienced urban African American heterosexual adolescents (N = 51) between the ages of 15-17. Analyses revealed that participants received a diversity of messages from a range of both nuclear and extended family members, and that these messages were organized around three temporal phases of dating: initiation, maintenance, and termination. Types and sources of messages are discussed, as well as implications for intervention development.
ABSTRACT Previous work has found yield-maximizing nitrogen (N) rates in switchgrass production an... more ABSTRACT Previous work has found yield-maximizing nitrogen (N) rates in switchgrass production and results have varied widely. Little attention, however, has been given to estimating profit-maximizing N rates. The objectives of this research were to determine the (1) yield- and (2) profit-maximizing N rates for producing switchgrass on four soil types/landscapes in Tennessee. Mixed models were used to perform an analysis of variance on the effects of four N rates on average yield and average net returns for switchgrass grown on the four soil types/landscapes. Data were analyzed from a switchgrass experiment conducted at Milan, Tennessee over a six-year period on: (1) a moderately- to well-drained level upland (WDLU), (2) a moderately- to well-drained flood plain (WDFP), (3) a moderate-to somewhat poorly-drained eroded sloping upland (MDSU), and (4) a poorly-drained flood plain (PDFP). The N rates that maximized average yield were 67, 134, 134, and 200 kg N ha−1 for the WDFP, WDLU, MDSU, and PDFP soil types/landscapes, respectively. The profit-maximizing N rate was estimated by soil type/landscape using three prices of switchgrass and three prices of N. Results demonstrated that yield- and profit-maximizing N rates can be different, and the yield- and profit-maximizing N rates across different across the soil types/landscapes. The profit-maximizing N rate was sensitive to the price of N and the price of switchgrass across all soil types/landscapes, but sensitivity to price changes were not equal for all soil types/landscapes.
Page 1. Lysimeter Measurements of Nitrate and Chloride Losses from Soil Under Conventional and No... more Page 1. Lysimeter Measurements of Nitrate and Chloride Losses from Soil Under Conventional and No-tillage Corn I Donald D. Tyler and Grant W. Thomas 2 ABSTRACT Salt and water movement was studied using steel pan ...
Page 1. i Cost Analysis of Alternative Harvest and Storage Methods for Switchgrass in the Southea... more Page 1. i Cost Analysis of Alternative Harvest and Storage Methods for Switchgrass in the Southeastern US James A. Larson, Associate Professor Department of Agricultural and Resource Economics The University of Tennessee ...
Full carbon accounting for terrestrial ecosystems is intended to quantify changes in net carbon e... more Full carbon accounting for terrestrial ecosystems is intended to quantify changes in net carbon emissions caused by changes in land management. On agricultural lands, changes in land management can cause changes in CO2 emissions from fossil fuel use, agricultural lime, and decomposition of soil carbon. Changes in off-site emissions can occur from the manufacturing of fertilizers, pesticides, and agricultural lime. We are developing a full carbon accounting framework that can be used for estimates of on-site net carbon flux or for full greenhouse gas accounting at a high spatial resolution. Estimates are based on the assimilation of national inventory data, soil carbon dynamics based on empirical analyses of field data, and Landsat-derived remote sensing products with 30x30m resolution. We applied this framework to a mid-western region of the US that consists of 679 counties approximately centered around Iowa. We estimate the 1990 baseline soil carbon for this region to be 4,099 Tg C...
ABSTRACT The objective of this study was to estimate the storage dry matter (DM) losses for switc... more ABSTRACT The objective of this study was to estimate the storage dry matter (DM) losses for switchgrass bales that were preprocessed using an industrial baler technology prior to storage with three particles sizes of feedstock and two types of bale wraps. Mixed models were used to test difference in DM losses across the particle sizes, wrap materials, and storage days. Response functions were also estimated to determine DM losses for each particle size and wrap material at storage over time. DM losses were found to be different across particle size, wrap material, and storage period. Specifically, the DM losses were lower when the particle size of switchgrass baled decreased from full length to less than two centimeters. The results show switchgrass bales stored at the smallest particle size had lower DM losses than bales stored at the full length of feedstock. Also, applying additional film wrap that completely covers the net wrapped bale reduced DM losses relative to bales wrapped only in net. Furthermore, storage DM losses of preprocessed switchgrass bales increased linearly with days in storage. Our findings suggest that applying both net and film wrap to switchgrass bales composed by a particle size less than two centimeters can reduce DM losses during storage. Economic analysis indicates the price of switchgrass was also important in the choice of storage method for switchgrass. The results provide valuable insight into improving feedstock logistics and the feasibility of the advanced biofuels industry.
To manage lands locally for C sequestration and for emissions reductions, it is useful to have a ... more To manage lands locally for C sequestration and for emissions reductions, it is useful to have a system that can monitor and predict changes in soil C and greenhouse gas emissions with high spatial resolution. We are developing a C accounting framework that can estimate C ...
Page 1. i Cost Analysis of Alternative Harvest and Storage Methods for Switchgrass in the Southea... more Page 1. i Cost Analysis of Alternative Harvest and Storage Methods for Switchgrass in the Southeastern US James A. Larson, Associate Professor Department of Agricultural and Resource Economics The University of Tennessee ...
There is a dearth of research regarding the influence of family members on adolescent dating. Thi... more There is a dearth of research regarding the influence of family members on adolescent dating. This study explored messages that African American adolescents received from family members regarding dating attitudes, norms and behaviors. Qualitative interviews were conducted with sexually experienced urban African American heterosexual adolescents (N = 51) between the ages of 15-17. Analyses revealed that participants received a diversity of messages from a range of both nuclear and extended family members, and that these messages were organized around three temporal phases of dating: initiation, maintenance, and termination. Types and sources of messages are discussed, as well as implications for intervention development.
ABSTRACT Previous work has found yield-maximizing nitrogen (N) rates in switchgrass production an... more ABSTRACT Previous work has found yield-maximizing nitrogen (N) rates in switchgrass production and results have varied widely. Little attention, however, has been given to estimating profit-maximizing N rates. The objectives of this research were to determine the (1) yield- and (2) profit-maximizing N rates for producing switchgrass on four soil types/landscapes in Tennessee. Mixed models were used to perform an analysis of variance on the effects of four N rates on average yield and average net returns for switchgrass grown on the four soil types/landscapes. Data were analyzed from a switchgrass experiment conducted at Milan, Tennessee over a six-year period on: (1) a moderately- to well-drained level upland (WDLU), (2) a moderately- to well-drained flood plain (WDFP), (3) a moderate-to somewhat poorly-drained eroded sloping upland (MDSU), and (4) a poorly-drained flood plain (PDFP). The N rates that maximized average yield were 67, 134, 134, and 200 kg N ha−1 for the WDFP, WDLU, MDSU, and PDFP soil types/landscapes, respectively. The profit-maximizing N rate was estimated by soil type/landscape using three prices of switchgrass and three prices of N. Results demonstrated that yield- and profit-maximizing N rates can be different, and the yield- and profit-maximizing N rates across different across the soil types/landscapes. The profit-maximizing N rate was sensitive to the price of N and the price of switchgrass across all soil types/landscapes, but sensitivity to price changes were not equal for all soil types/landscapes.
Page 1. Lysimeter Measurements of Nitrate and Chloride Losses from Soil Under Conventional and No... more Page 1. Lysimeter Measurements of Nitrate and Chloride Losses from Soil Under Conventional and No-tillage Corn I Donald D. Tyler and Grant W. Thomas 2 ABSTRACT Salt and water movement was studied using steel pan ...
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