Greenhouse gas emissions as impacted by high wood fiber substrate in the production of three annual crops

Authors: MURPHY, ANNA-MARIE - Auburn University; Prior, Stephen - Steve; Runion, George; Torbert, Henry - Allen; SIBLEY, JEFF - Auburn University; FAIN, GLENN - Auburn University; PICKENS, JEREMY - Auburn University

Submitted to: Southern Nursery Association Research Conference
Publication Type: Proceedings
Publication Acceptance Date: 3/6/2019
Publication Date: 5/21/2019
Citation: Murphy, A., Prior, S.A., Runion, G.B., Torbert III, H.A., Sibley, J.L., Fain, G.B., Pickens, J.M. 2019. Greenhouse gas emissions as impacted by high wood fiber substrate in the production of three annual crops. Southern Nursery Association Research Conference. 63:51-56.

Interpretive Summary: The global climate may be altered by increases in greenhouse gases (GHG) associated with agriculture. Our objective was to determine the effects of nursery media on GHG emissions. Understanding the relationship between potting media and gas emissions could be used to estimate industry-wide trace gas emissions. Our data show that loss of CH4 were minimal across three media types for three different common annual plants. No treatment difference were noted for total N2O loss, and differences in total CO2 loss were related to plant size and substrate. Findings suggest that substrate composition could be altered to reduce emissions. There is still uncertainty regarding the overall impact of the nursery industry on climate change, however results from this study begin to provide baseline data for identifying best management practices that could help reduce GHG emissions.

Technical Abstract: Implementation of best management practices across the nursery and greenhouse industry differ based on varying availability of infrastructure, finances, natural resources (water, land, etc), and labor. Growers continually evaluate options with respect to both fertilizer and water application rates and methods, as well as weed, disease and insect control to make operational decisions. While climate change may not be an influencer in the decision-making process at this time, the potential exists for incentives aimed at reducing greenhouse gas emissions in the production of ornamental plants. Current programs have begun to emerge across the agronomic industry and offset incentive projects currently in place generally indicate four standards that must be met in order to qualify for payments: 1) Projects, or offset initiatives, must be additional, or occur from activities that would not have occurred in the absence of the incentive, 2) Initiatives must be quantifiable, 3) Initiatives must be permanent, and 4) Initiatives are subject to verification by a third-party inspection (9). The objective of this work aims to assist nursery and greenhouse producers in finding actionable practices to decrease greenhouse gas emissions with minimal changes to their best management practices, and to provide quantifiable evidence of those reductions. This study evaluated trace gas emission from three common annual plants [coleus (Solenostemon scutellarioides Thonn. ‘Redhead’); vinca (Catharanthus roseus L. ‘Cooler Grape’); and impatiens (Impatiens walleriana Hook. f. ‘Super Elfin XP White’)] grown on three different substrates [80:20 fine professional sphagnum peatmoss:coarse horticultural perlite (P:P) blend; 80:20 peatmoss:Wholetree (P:WT) blend; and 60:40 P:WT blend]. Gas flux patterns as influenced by treatments will be discussed. Our data show that loss of CH4 were minimal across three media types for three different common annual plants. No treatment difference were noted for total N2O loss, and differences in total CO2 loss were related to plant size and substrate. Findings suggest that substrate composition could be altered to reduce emissions. There is still uncertainty regarding the overall impact of the nursery industry on climate change, however results from this study begin to provide baseline data for identifying best management practices that could help reduce GHG emissions.