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- Author or Editor: Dewayne Ingram x
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Life cycle assessment (LCA) was used to analyze the global warming potential (GWP) and variable costs of production system components for an 11.4-cm container of wax begonia (Begonia ×semperflorens-cultorum Hort) modeled in a gutter-connected, Dutch-style greenhouse with natural ventilation in the northeastern United States. A life cycle inventory of the model system was developed based on grower interviews and published best management practices. In this model, the GWP of input products, equipment use, and environmental controls for an individual plant would be 0.140 kilograms of carbon dioxide equivalents (kg CO2e) and the variable costs would total $0.666. Fifty-seven percent of the GWP and 43% of the variable costs would be due to the container and the portion of a 12-plant shuttle tray assigned to a plant. Electricity for irrigation and general overhead would be only 13% of GWP and 2% of variable costs. Natural gas use for heating would be 0.01% of GWP and less of the variable costs, even at a northeastern U.S. location. This was because of the rapid crop turnover and only heated for 3 months of a 50-week production year. Life cycle GWP contributions through carbon sequestration of flowering annuals after being transplanted in the landscape would be minor compared with woody plants; however, others have documented numerous benefits that enhance the human environment.
Trees were grown for 2 years as a function of three container volumes (10, 27, and 57 liter) the first year and six shifting treatments (10 liter both years, 10 to 27 liter, 10 to 57 liter, 27 liter both years, 27 to 57 liter, or 57 liter both years) the second year when containers were spaced 120 cm on center, Height and caliper were greatest for magnolias grown in 27- or 57-liter containers both years. Caliper was greater for trees shifted from 10-liter containers to the larger container volumes compared to trees grown in 10-liter containers both years, Trees grown in 10-liter containers both years tended to have few roots growing in the outer 4 cm at the eastern, southern, and western exposures in the grow medium, During the second year, high air and growth medium temperatures may have been primary limiting factors to carbon assimilation during June and August. Using large container volumes to increase carbon assimilation and tree growth may be even more important when daily maximum air temperatures are lower during late spring or early fall compared to midsummer.
Three scenarios for production of Buxus microphylla var. japonica [(Mull. Arg.) Rehder & E.H. Wilson] ‘Green Beauty’ marketed in a no. 3 container on the west coast of the United States were modeled based on grower interviews and best management practices. Life cycle inventories (LCIs) of input products, equipment use, and labor were developed from the protocols for those scenarios and a life cycle assessment (LCA) was conducted to determine impact of individual components on the greenhouse gas emissions (GHGs) and the subsequent carbon footprint (CF) of the product at the nursery gate and in the landscape. CF is expressed in global warming potential (GWP) for a 100-year period in units of kilograms of carbon dioxide equivalents (kg CO2e). The GWP of the plant from Scenario A (propagation to no. 1 to 3 container) was 2.198 kg CO2e with variable costs of $4.043. Scenario B (propagation to field to no. 3 container) would result in a GWP of 1.717 kg CO2e with variable costs of $2.880 and take a year longer in production than the other two models. The GWP of Scenario C (propagation to no. 1 to no. 2 to no. 3 containers) would be 3.364 kg CO2e with variable costs of $5.733. Containers, transplants/transplanting, irrigation, and fertilization input products and associated activities accounted for the greatest portion of GHG and variable costs in each scenario. Pruning, assembling/load trucks, pesticides, and chlorination were other important components to variable costs of each scenario but had little impact on GWP. Otherwise, the major contributors to GWP are also major contributors to cost.
A model production system for a 15.2-cm poinsettia (Euphorbia pulcherrima) in the north Atlantic region of the United States was developed through grower interviews and best management practices and analyzed using a life cycle assessment (LCA). The model system involved direct sticking of unrooted cuttings. The propagation phase was 4 weeks, followed by 9 weeks of irrigation using a boom system and 4 weeks of flood-floor irrigation. The carbon footprint, or global warming potential (GWP), for the plant was calculated as 0.474 kg carbon dioxide equivalent (kg CO2e), with a variable cost of $1.030. Major contributors to the GWP were the substrate and filling pots, fertilization, the container, irrigation, and overhead electricity. The major contributors to variable costs were the unrooted cuttings and labor to prepare and stick ($0.471). Furthermore, the substrate and filling containers and irrigation were notable contributors. Material inputs accounted for 0.304 kg CO2e, whereas equipment use was estimated to be 0.163 kg CO2e, which comprised 64.2% and 35.8% of total GWP, respectively. Material inputs accounted for $0.665 (64.6%) of variable costs, whereas labor accounted for 19.6% of variable costs for this model. Water use per plant was 77.2 L with boom irrigation for the 9 weeks during production spacing (32.8 plant/m2) and represented 64% of the total water use. LCA was an effective tool for analyzing the components of a model system of greenhouse-grown, flowering, potted plants. Information gained from this study can be used by growers considering system alterations to improve efficiency.
Life cycle assessment (LCA) was used to analyze the production system components of a 20-cm Chrysanthemum grown for the fall market in the north Atlanta region of the United States. The model system consisted of 2 weeks of mist in a greenhouse followed by 9 weeks on an outdoor gravel bed equipped with drip irrigation. The carbon footprint, or global warming potential (GWP), was calculated as 0.555 kg CO2e and the variable costs incurred during the modeled production system (from rooting purchased cuttings to loading the truck for shipment) totaled $0.846. Use of plastics was important in terms of GWP and variable costs with the container contributing 26.7% of the GWP of the product and 12.2% of the variable costs. The substrate accounted for 44.8% of the GWP in this model but only 12.1% of the variable costs. Consumptive water use during misting was determined to be 3.9 L per plant whereas water use during outdoor production was 34.8 L. Because propagation is handled in various ways by Chrysanthemum growers, the potential impact of alternative propagation scenarios on GWP and variable costs, including the purchase of plugs, was also examined.
Abstract
Quercus virginiana Mill., Magnolia grandiflora L., Liquidambar styraciflua L., Ulmus parvifolia Jacq. ‘Drake’, Lagerstroemia indica L., Ilex opaca Ait. ‘East Palatka’, and Pinus elliottii Engelm. were transplanted from 3-liter containers into 36-cm-diameter fabric Field-Gro containers, directly in the field into 36-cm-diameter auger-dug holes, or into 36-cm-diameter × 33-cm-tall black plastic containers. After 1 year, measured growth parameters of the Magnolia, Ulmus, Lagerstroemia, and Pinus were not affected by production system. Dry weight of Quercus and Liquidambar roots in the “harvest zone” were greater for trees grown in the fabric Field-Gro containers than those grown directly in the field. Quercus height and total carbohydrate content of Quercus and Magnolia primary root samples were increased by the fabric container. The above-ground container system clearly was inferior to the field-grown systems for production of the Quercus and Liquidambar under the conditions of this study.
Abstract
Root systems of ‘Grande Name’ banana (Musa spp. L., AAA Group), Ixora coccinea L., Dracaena marginata L., and ‘Carrizo’ citrange [Citrus sinensis L. (Osbeck) × Poncirus trifoliata L.(Raf.)] were exposed to temperatures of 28°, 34°, and 40°C for 6 hr daily for 90 days. Root zone temperature did not affect dry weight of shoots or roots of ixora or citrus, but the 40° treatment increased the shoot to root ratio, S:R. Banana shoot dry weight decreased linearly with increasing root zone temperature, but root dry weight was not affected. The 40° root temperature regime reduced root dry weight in dracaena but not shoot dry weight. Absolute concentrations of sugars and starch in shoots and roots of the 4 test plants did not differ with root temperature, but the ratio of sugars to starch in roots was reduced in ixora and increased in banana by the 40° treatment.
The production components of an evergreen shrub (Ilex crenata ‘Bennett’s Compacta’) grown in a no. 3 container in an east coast U.S. nursery were analyzed for their costs and contributions to carbon footprint, as well as the product impact in the landscape throughout its life cycle. A life cycle inventory was conducted of input materials, equipment use, and all cultural practices and other processes used in a model production system for this evergreen shrub. A life cycle assessment (LCA) of the model numerated the associated greenhouse gas emissions (GHG), carbon footprint, and variable cost of each component. The LCA also included the transportation and transplanting of the final product in the landscape as well as its removal after a 40-year useful life. GHG from input products and processes during the production (cutting-to-gate) of the evergreen shrub were estimated to be 2.918 kg CO2e. When considering carbon sequestration during production weighted over a 100-year assessment period, the carbon footprint for this model system at the nursery gate was 2.144 kg CO2e. Operations, combining the impact of material and equipment use, that contributed most of GHG during production included fertilization (0.707 kg CO2e), the liner and transplanting (0.461 kg CO2e), the container (0.468 kg CO2e), gravel and ground cloth installation (0.222 kg CO2e), substrate materials and preparation (0.227 kg CO2e), and weed control (0.122 kg CO2e). The major contributors to global warming potential (GWP) were also major contributors to the cutting-to-gate variable costs ($3.224) except for processes that required significant labor investments. Transporting the shrub to the landscaper, transporting it to the landscape site, and transplanting it would result in GHG of 0.376, 0.458, and 0 kg CO2e, respectively. Variable costs for postharvest activities were $6.409 and were dominated by labor costs (90%).
The components for two production systems for young foliage plants in 72-count propagation trays were analyzed using life cycle assessment (LCA) procedures. The systems differed by greenhouse type, bench size and arrangement, rainwater capture, and irrigation/fertilization methods. System A was modeled as a gutter-connected, rounded-arch greenhouse without a ridge vent and covered with double-layer polyethylene, and the plants were fertigated through sprinklers on stationary benches. System B was modeled as a more modern gutter-connected, Dutch-style greenhouse using natural ventilation, and moveable, ebb-flood production tables. Inventories of input products, equipment use, and labor were generated from the protocols for those scenarios and a LCA was conducted to determine impacts on the respective greenhouse gas emissions (GHG) and the subsequent carbon footprint (CF) of foliage plants at the farm gate. CF is expressed in global warming potential for a 100-year period (GWP) in units of kilograms of carbon dioxide equivalents (kg CO2e). The GWP of the 72-count trays were calculated as 4.225 and 2.276 kg CO2e with variable costs of $25.251 and $24.857 for trays of foliage plants grown using Systems A and B, respectively. The GWP of most inputs and processes were similar between the two systems. Generally, the more modern greenhouse in System B was more efficient in terms of space use for production, heating and cooling, fertilization, and water use. While overhead costs were not measured, these differences in efficiency would also help to offset any increases in overhead costs per square foot associated with higher-cost, more modern greenhouse facilities. Thus, growers should consider the gains in efficiency and their influences on CF, variable costs (and overhead costs) when making future decisions regarding investment in greenhouse structures.