Container Nursery Production Research Articles

Fall fertilization during nursery production increases nitrogen status of Purshia tridentata seedlings: implications for outplanting

During container nursery production of Purshia tridentata (antelope bitterbrush), we found that three fall fertilization applications successfully loaded plants with nitrogen (N) with little effect on plant biomass. Using 15N‐labeled fertilizer to track N movements, we observed that N‐loaded seedlings attained luxury consumption and ultimately translocated more N toward roots. In trees, such N‐loading efforts have been reported to increase seedling survival and growth after outplanting by improving initial root growth. This leads to enhanced access to water and nutrients that increases overall plant competitiveness and performance. Our results add, in general, to the paucity of information concerning fall fertilization of shrubs, and specifically that this technique offers promise to enhance the quality of antelope bitterbrush seedlings. This could improve overall planting success of this important shrub native to western United States rangelands. Increasing the effectiveness of planting antelope bitterbrush, which can often improve restoration trajectories more than direct seeding or reliance on natural regeneration of this species, could accelerate the pace and scope of critical habitat restoration. Restoration is needed as antelope bitterbrush abundance has been reduced across the landscape because of conversion to agriculture, invasion by nonnative annual grasses, and an increase in fire frequency and intensity, among other reasons. In addition, this species provides browse for ungulates and critical habitat for at‐risk species, such as Centrocercus urophasianus (greater sage‐grouse). Although N loading antelope bitterbrush has potential to improve outplanting performance, the resulting higher nutrient status of this preferred browse species may lead to elevated browsing during seedling establishment.

Effect of Substrate Stratification on Growth of Common Nursery Weed Species and Container-grown Ornamental Species

Substrate stratification is a method of filling nursery containers with “layers” of different substrates, or different textures of the same substrate. Recently, it has been proposed as a means to improve drainage, substrate moisture dynamics, and optimize nutrient use efficiency. Substrates layered with larger particle bark as the top portion and smaller particle bark as the bottom portion of the container profile would theoretically result in a substrate that dries quickly on the surface, thereby reducing weed germination, but that would also retain adequate moisture for crop growth. The objective of this study was to evaluate the effect of stratified substrates on the growth of common nursery weeds and ornamental crops. This study evaluated the use of coarser bark (<0.5 or 0.75 inches) as the top substrate and finer bark (<0.38 inches) as the bottom substrate with the goal of reducing the water-holding capacity in the top 2 to 3 inches of the substrate to reduce weed germination and growth. Results showed that substrate stratification with more coarse bark on the top decreased the growth of bittercress (Cardamine flexuosa) by 80% to 97%, whereas liverwort (Marchantia polymorpha) coverage was reduced by 95% to 99%. Substrate stratification initially reduced the growth of ligustrum (Ligustrum japonicum) and blue plumbago (Plumbago auriculata), but there was no difference in the shoot or root dry weights of either species in comparison with those of nonstratified industry standard substrates at the end of 24 weeks. The data suggest substrate stratification could be used as an effective weed management strategy for container nursery production.

Leachate and Irrigation Sensor Development and Performance in Container Nursery Production

HighlightsUsing leaching fraction to schedule irrigation is recommended yet no automated measurement system exists.Sensors were developed to automatically measure leachate and irrigation within a sensor network.There was no difference between sensor measured and manually captured volume for sensors deployed in a nursery.After deployment in commercial nurseries, sensors accurately measured leachate and irrigation within 10% margin.Abstract. Nursery crops are often over-irrigated, resulting in wasted water and agrochemical inputs. Irrigating based on leaching fraction is recommended, yet an automated system for measuring and recording nursery container effluent (leachate) does not exist. The objective of this research was to develop and test a sensor-based system for real-time leachate and irrigation measurement in outdoor commercial nurseries. Sensors were developed to automatically measure irrigation and leachate volume in container nurseries that use overhead irrigation with the goal of facilitating the development of an automated leaching fraction-based irrigation system. Sensors were built using readily available components, including tipping bucket mechanisms calibrated to either 4.7 or 8.2 mL per tip, and were designed and constructed to function with commonly used 3.8-, 11.4-, and 14.5-L nursery containers. Sensor networks were developed in order to collect data from the sensors. Sensors were deployed at three commercial nurseries and tested using closed- and open-loop tests. Initially, a closed-loop test was performed on a subset of the sensors to test the integrity of the sensor-container system when subjected to an overhead irrigation delivery system. Following closed-loop tests, sensors were subjected to tests utilizing directed applications of water to compare sensor measurements with the volume of water applied and to compare sensor measurements over time (pre- and post-season). There was no difference between leachate measured by sensors and leachate captured and measured manually in closed-loop tests (p = 0.0570). In directed applications, sensors measured water flow with less than 3% margin at the beginning of the season (p = 0.0485) and less than 10% margin at the end of the season (p = 0.0390) regardless of container size. Pre- and post-season comparisons showed equivalence at the 10% margin for the 4.7-mL tipping bucket size (p = 0.0043) and at 5% for those calibrated to 8.2 mL per tip (p = 0.0198). Sensors deployed in commercial nurseries accurately measured leachate and irrigation within a 10% margin in real-time, on an individual plant scale, making them a viable option for a leaching fraction-based irrigation schedule. Keywords: Container effluent, Container-grown plants, Leaching fraction, Irrigation schedule, Sensor network.

Reducing Water and Pesticide Movement in Nursery Production

Ornamental nurseries produce a large number of plants in a concentrated area, and aesthetics are a key component of the product. To produce crops in this manner, high inputs of water, nutrients, and pesticides are typically used. Container nursery production further increases the inputs, especially water, because container substrates are designed to quickly drain, and the most effective method of irrigating large numbers of plants in containers (up to a certain size) is the use of overhead irrigation. Because irrigation and pesticides are broadcast over the crop, and because the crop is limited to the container, a large proportion of water or pesticides may land on nontarget areas, creating runoff contaminant issues. Water is the primary means of pesticide movement in nursery production. This review discusses water and pesticide dynamics and management strategies to conserve water and reduce pesticide and water movement during container nursery production.

Understanding Irrigation Water Applied, Consumptive Water Use, and Water Footprint Using Case Studies for Container Nursery Production and Greenhouse Crops

The understanding, calculation, and comparison of water footprint (WF) among specialty crop growers are confounded by geography, species, and process. This study builds on published models of representative plant production systems developed using life cycle assessment. These models include container production using recycled water in the mid-Atlantic, southeastern, and Pacific northwestern regions of the United States and greenhouse production implementing rainfall capture and overhead and ebb/flood irrigation strategies. Production systems using recycled water compare favorably in consumptive water use (CWU) with those that do not, regardless of the water source. Production systems in geographic locations with high water availability compare favorably with production systems in locations with high water scarcity in WF, but not necessarily CWU.

Fertilizer Source and Irrigation Depth Affect Nutrient Leaching During Coleus Container Production

Abstract Nutrient leaching during nursery container production can have negative effects on plant growth and the environment. The objective of this study was to evaluate effects of fertilizer source at two irrigation depths on nutrient leaching during coleus [Plectranthus scutellarioides (L.) Codd] ‘Solar Sunrise' container production to develop best management practices. Coleus received no fertilizer, a controlled-release fertilizer (CRF), or a water-soluble fertilizer (WSF) applied at 0.30 kg N and P per m3 (0.02 lb per ft3) and were irrigated at 1.9 or 3.8 cm.day−1 (0.7 or 1.5 in.day−1) for 56 days after planting (DAP). Leachate was analyzed every 7 DAP for inorganic N and dissolved total P (DTP). At 56 DAP, root biomass, leaf quality, and plant growth index were similar between CRF and WSF treatments at both irrigation depths. Highest inorganic N and DTP losses occurred within 21 DAP. Application of WSF resulted in higher cumulative N and DTP losses compared to CRF applications. Coleus irrigated at 3.8 cm.day−1 and fertilized with WSF resulted in higher DTP losses compared to CRF applications regardless of irrigation depth. Reducing irrigation reduced inorganic N leaching for each fertilizer source. Application of CRF provided consistent growth while curbing nutrient losses across both irrigation depths compared to WSF. Index words: controlled-release fertilizer, water-soluble fertilizer, nursery producers, best management practices. Chemicals used in this study: Micronutrients mix (Micromax®); controlled-release fertilizer (Osmocote® Classic); water-soluble fertilizer (Grower's Special). Species used in this study: Coleus [Plectranthus scutellarioides (L.) Codd] ‘Solar Sunrise'.

The challenge of using date branch waste as a peat substitute in container nursery production of lettuce (Lactuca sativa L.)

PurposePeat-based substrates constitute the preferred media in conventional and organic nursery production. Nevertheless, in recent years, there has been a growing interest in environmental impacts associated with peat extraction that has increased with the demand of these non-renewable substrates. The re-use of organic wastes as substrate seems to be good solution to substitute commercial peat. This study evaluates date-palm peat (wastes of date-palm branches base locally known as “Kornef”) as an alternative nursery substrate.MethodsThe research was conducted in a completely block randomized design with a linear substitution (0, 25, 50, 75 and 100%) of peat with date-palm waste peat for transplant production of lettuce (Lactuca sativa L.). Different physicochemical parameters (porosity, bulk density, pH, and CEC) of cultivation substrates were measured. The growth parameters (leaves number, leaves area, length, chlorophyll values, fresh and dry weight of seedlings) were evaluated at the end of growth period (when the seedling reached the commercial transplanting size).ResultsThe results showed that date-palm waste peat is an appropriate media for nursery production, showing similar properties with commercial peat and best plant response with 25 and 50% substitution.ConclusionsIn view of low cost, availability and large area of date-palm cultivation in Tunisia and over the world, it seems that peat can be replaced with substrate of date-palm wastes in the horticulture sector.

A cost analysis for using recycled irrigation runoff water in container nursery production: a Southern California nursery case study

In the U.S., container plant growers use high-quality water sources which can be expensive. The use of recycled irrigation runoff water could save growers money. The objective of this study was to compare the cost of recycled irrigation water with the cost of untreated municipal water at a nursery in Southern California over multiple years. Water cost for municipal (Western) supplied water ranged from $2.26 to $2.91 per 1000 gallons (3785 L). Water capturing and recycling system construction and infrastructure costs accounted for a large portion of recycled water cost. However, water provider rebates and a Natural Resource Conservation Service (NRCS) grant reduced total and per volume recycled water costs. Without considering rebates from water providers and a NRCS grant, the cost of recycled water was between $0.92 and $1.21 per 1000 gallons (3785 L). With consideration of rebates and the grant, the cost of recycled water ranged between $0.43 and $0.53 per 1000 gallons (3785 L). Thus, recycled water is a viable alternative to many high cost water sources and public funds facilitate adoption of recycled water for irrigation by containerized plant growers.

Geocomposite use in container nursery production of selected ornamental shrubs

Geocomposite, which is an innovative technology of superabsorbent material (hydrogels) occurring in a form of openwork discs closed in black agrotextile, reduces the negative impact of soil/substrate on the absorption capacity of hydrogel with simultaneous reduction of the negative impact of the hydrogel on the physical soil/substrate parameters. The aim of this research was to assess the influence of geocomposite use with different fertilizers and their doses (3 g Osmocote Plus 3-4M, 1.5 g Osmocote Plus 3-4M, 3×1 g YaraMila Complex) on biomass production of Prunus pumila var. depressa (Pursh) Bean and Diervilla lonicera Mill. cultivated in containers in an unheated foil tunnel. Fresh and dry biomass of both species was higher with the use of geocomposite, which did not affect root/shoot ratios for either taxa. For both species, fresh and dry shoots weight was the highest with 3 g Osmocote. The highest fresh and dry root weights and root/shoot ratios of Prunus was noted in 1.5 g Osmocote, while the fertilization had no effect on total weight of this plant. Diervilla obtained the highest fresh and dry root and total weight with 3 g Osmocote. The highest fresh and dry root/shoot ratio was noted in 1.5 g Osmocote. For both species, the highest fresh and dry biomasses were achieved by the use of geocomposite in combination with 3 g Osmocote fertilizer. The lowest fresh and dry shoot weights were obtained by both species with 1.5 g Osmocote fertilization without the use of geocomposite. The lowest fresh and dry root/shoot ratios occurred in treatments using 3 g of Osmocote without geocomposite application. The results of this research show that geocomposite use in container nursery production of ornamental shrubs had a positive influence on shoot and root growth.

Efficacy of Bio-based Liquid Mulch on Weed Suppression and Water Conservation in Container Nursery Production1

Abstract To assess the effectiveness of bio-based liquid mulch at different application rates and binder loading types for weed suppression and evaporation reduction in container nursery production, a study was conducted outdoors in the summer of 2015 in Ontario, Canada. Three application rates [0.5 1.25, or 2.0 kg·m−2 (0.20 lb·ft−2)] and two binder loading types (AMP753 with 3.5% binder loading or AMP153 with 7% binder loading) of the liquid mulch were used in the trial. The evaporation rates (ER) from the container growing substrate were quantified daily for three 7-day cycles. All mulched treatments reduced total ERs starting from the second cycle compared to the no-mulch control, with the exception of the treatment binder loading type 3.5% with 0.5 kg·m−2 mulch. All mulched treatments had an equivalent effect at reducing weed numbers compared to the control. The 1.25 and 2.0 kg·m−2 rates were more effective for weed control than the low application rate (0.5 kg·m−2) and there were no differences between binder loading types. No negative effects on overall plant health, flower or branch number, total aboveground biomass, leaf area, or plant growth index were observed on Hydrangea paniculata ‘Jane' from the applied mulch. A major shortcoming with the product as tested was that it dried and shrunk within a couple of days of application. This caused a gap of approximately 10 to15 mm (0.39-0.59 inch) between the wall of the pots and the actual dried mulch. The 1.25 kg·m−2 rate of either binder loading type (3.5% or 7%) could be recommended if the shrinking issue of this mulch could be resolved. Index words: Evaporation, witchgrass, Powell's amaranth, green foxtail, little lime hardy hydrangea. Chemicals used in this study: Bio-based Liquid Mulch. Species used in this study: witchgrass (Panicum capillare L.), Powell's amaranth (Amaranthus powellii S. Watson), green foxtail (Setaria viridis (L.) Beauv.), common groundsel (Senecio vulgaris L.), little lime hardyhydrangea (Hydrangea paniculata L. ‘Jane').

Dimethenamid Persistence and Leaching Potential in a Soilless Mix1

Abstract Dimethenamid and the granular combination product pendimethalin plus dimethenamid are herbicides registered for use in nursery production and landscape maintenance. The objectives of this study were: (1) to compare the effectiveness of sprayed dimethenamid and the granular combination of pendimethalin plus dimethenamid in container nursery production, (2) to determine the impact of formulation on leaching of dimethenamid in soilless media versus field soil and (3) to determine the influence of irrigation volume on herbicide leaching. Dimethenamid is less mobile in pine bark than field soil, while pendimethalin is more mobile in pine bark. The leaching profile for the granular pendimethalin plus dimethenamid combination product was similar to dimethenamid in field soil and similar to pendimethalin in pine bark. There was no significant difference in herbicide movement in pine bark or field soil after doubling the irrigation volume from 17.8 cm (7 in) to 35.6 cm (14 in). Compared to pendimethalin, dimethenamid leaches less in pine bark, explaining its greater effectiveness for weed control in container production. Index words: Herbicide leaching, soilless mix, pine bark, ornamentals, adsorption. Species used in this study: southern crabgrass [Digitaria ciliaris (Retz.) Koel.]; spotted spurge [Chamaesyce maculata (L.) Small]. Chemicals used in this study: dimethenamid (Tower); dimethenamid plus pendimethalin (FreeHand); pendimethalin (Pendulum 2G).

Efficacy of Bio-based Liquid Mulch on Weed Suppression and Water Conservation in Container Nursery Production1

Abstract To assess the effectiveness of bio-based liquid mulch at different application rates and binder loading types for weed suppression and evaporation reduction in container nursery production, a study was conducted outdoors in the summer of 2015 in Ontario, Canada. Three application rates [0.5 1.25, or 2.0 kg·m−2 (0.20 lb·ft−2)] and two binder loading types (AMP753 with 3.5% binder loading or AMP153 with 7% binder loading) of the liquid mulch were used in the trial. The evaporation rates (ER) from the container growing substrate were quantified daily for three 7-day cycles. All mulched treatments reduced total ERs starting from the second cycle compared to the no-mulch control, with the exception of the treatment binder loading type 3.5% with 0.5 kg·m−2 mulch. All mulched treatments had an equivalent effect at reducing weed numbers compared to the control. The 1.25 and 2.0 kg·m−2 rates were more effective for weed control than the low application rate (0.5 kg·m−2) and there were no differences between binder loading types. No negative effects on overall plant health, flower or branch number, total aboveground biomass, leaf area, or plant growth index were observed on Hydrangea paniculata ‘Jane' from the applied mulch. A major shortcoming with the product as tested was that it dried and shrunk within a couple of days of application. This caused a gap of approximately 10 to15 mm (0.39-0.59 inch) between the wall of the pots and the actual dried mulch. The 1.25 kg·m−2 rate of either binder loading type (3.5% or 7%) could be recommended if the shrinking issue of this mulch could be resolved. Index words: Evaporation, witchgrass, Powell's amaranth, green foxtail, little lime hardy hydrangea. Chemicals used in this study: Bio-based Liquid Mulch. Species used in this study: witchgrass (Panicum capillare L.), Powell's amaranth (Amaranthus powellii S. Watson), green foxtail (Setaria viridis (L.) Beauv.), common groundsel (Senecio vulgaris L.), little lime hardyhydrangea (Hydrangea paniculata L. ‘Jane').

Mulch Type and Depth Influences Control of Three Major Weed Species in Nursery Container Production

Two commonly used management practices for weed control in container plant production are hand pulling and herbicide applications. There are problems associated with these methods including crop phytotoxicity and environmental concerns associated with off-target movement of herbicides. Other nonchemical weed control methods could reduce herbicide-based environmental concerns, mitigate herbicide-resistance development, and improve the overall level of weed control in container nursery production. Readily available tree-mulch species, eastern red cedar (Juniperus virginiana), ground whole loblolly pine (Pinus taeda), chinese privet (Ligustrum sinense), and sweetgum (Liquidambar styraciflua) were harvested, chipped, and evaluated at multiple depths with and without the herbicide dimethenamid-p. Pine bark mini-nuggets were also evaluated. Mulches were applied at depths of 1, 2, and 4 inches and evaluated over three 30-day periods for their effectiveness in suppressing spotted spurge (Chamaesyce maculata), long-stalked phyllanthus (Phyllanthus tenellus), and eclipta (Eclipta prostrata). After 30 days, herbicide/mulch combinations, as well as mulch treatments alone, had reduced weed fresh weight 82% to 100% with 1 inch of mulch. By 168 days after treatment, dimethenamid-p had lost all efficacy, and mulch depth was the only factor that still had significant effects, reducing spotted spurge fresh weight by 90%, 99.5%, and 100% with depths of 1, 2, and 4 inches, respectively. The economics of mulch weed control will depend on variables such as available time, nursery layout, location, and availability of resources, equipment, among others. Regardless of variable economic parameters, data from this study reveals that any of these potential mulch species applied at a depth of at least 2 inches will provide long-term weed control in nursery container production.

The influence of geocomposites on the biomass production, the nutritional status of plants and the substrate characteristics in the container nursery production of Rosa cv. White Meidiland and Berberis thunbergii cv. Green Carpet

The influence of geocomposites on the biomass production, the nutritional status of plants and the substrate characteristics in the container nursery production of Rosa cv. White Meidiland and Berberis thunbergii cv. Green Carpet

Effects of pruning and plant growth regulators on branching and growth of azalea

Many woody plants do not branch well during nursery container production. Various plant growth regulators (PGRs) have been used to promote branching. The objective of this study was to evaluate the effects of dikegulac sodium (Atrimmec) and cyclanalide (Tiberon 2.8SC) in combination with or without pruning on branching and growth of two cultivars of azalea (Rhododendron sp.). For azalea 'Midnight Flare', Atrimmec at 3100 mg L-1 applied twice and Tiberon 2.8SC at 100 mg L-1 applied twice or 200 mg L-1 applied once significantly increased branching in 8 weeks after the initial treatment (WAIT), regardless of pruning treatment. However, by 20 and 30 WAIT, there were no significant differences on the number of shoots per plant among all the treatments. For azalea 'Katherine Alison', at 8 and 20 WAIT, plants which received pruning and were treated with two applications of Atrimmec at 3100 mg L-1 had significantly more shoots than plants that did not receive pruning but were treated with one application of Atrimmec at 3100 mg L-1. By 30 WAIT, there were no significant differences between the number of shoots per plant among all the treatments. No phytotoxicity was observed. For both azalea cultivars, at 8 WAIT, plants which received pruning had a significantly lower plant growth index (PGI) than plants that did not receive pruning. At 20 and 30 WAIT, pruning generally did not have a significant effect on PGI.

Leaching Behavior of Two Pendimethalin Formulations in a Soilless Growing Medium

Pendimethalin is commonly applied for PRE weed control in container nursery production. Field and laboratory trials were conducted to determine herbicide effectiveness and leaching of two pendimethalin formulations in pine bark, the primary component used in the growing medium of container-grown plants in the South. The microencapsulated (ME) formulation of pendimethalin gave lower control of southern crabgrass and leached deeper than the emulsifiable concentrate (EC) formulation in pine bark. The EC formulation controlled southern crabgrass 93% compared with only 70% with the ME formulation at 4.48 kg ai ha−1. After applying 3.4 kg ai ha−1pendimethalin and 17.8 cm of irrigation water, the ME formulation showed greater leaching into the 3- to 6- and 6- to 9-cm depths than the EC formulation on the basis of a southern crabgrass bioassay. Using a microwave extraction method, only 0.91 mg kg−1pendimethalin was found in the 3- to 6-cm pine bark depth compared with 4.0 mg kg−1for the ME formulation. Below the 6-cm depth, no pendimethalin was detected when the EC formulation was applied, but 0.5 ppm was found for the ME formulation. No pendimethalin was detected in effluent collected from irrigation water for the EC; however, 3.0 mg kg−1was collected from leachate for the ME formulation. Pendimethalin ME is leaching much deeper than the EC formulation in the pine bark profile, which results in lower weed control. This extensive leaching of ME formulation may be due to capsule movement with the irrigation water, combined with a delayed release of pendimethalin, which then binds to the pine bark much lower in the container profile.

TRACE GAS EMISSIONS FROM NURSERY CROP PRODUCTION USING DIFFERENT FERTILIZATION METHODS©

Research on agriculture’s role in mitigation of greenhouse gas (GHG) emissions has been conducted in row crop, forestry, and animal production systems, but there has been little focus on contributions from specialty industries such as horticulture. Our objective was to determine efflux patterns of CO2, CH4, and N2O associated with three different fertilization methods (dibble, incorporated, and topdressed) commonly used in nursery container production. Dibbling fertilizer reduced CO2 emissions when compared to incorporation or topdressing. Dibbling and topdressing reduced N2O emissions (68 and 70%, respectively) when compared to the incorporated treatment. These data begin to provide evidence of mitigation strategies which can be implemented in container plant production to help growers adapt to possible future legislation, improve the environmental impact from the industry, and benefit financially from potential carbon trading or offset programs.

Wetland Technologies for Nursery and Greenhouse Compliance with Nutrient Regulations

The need to protect our water resources and increasing public awareness of the importance of cleaner water for ecological and human health reasons are driving regulations limiting nutrient release from traditionally exempt, non-point source agricultural contributors. Modification of production practices alone may not be adequate to meet regulated nutrient criterion limits for irrigation and stormwater runoff entering surface waters. Three constructed wetland technologies are well suited to help agricultural producers meet current and future regulations. The first two technologies, surface- and subsurface-flow constructed wetlands, have been in use for over 40 years to cleanse various types of wastewater, whereas floating treatment wetlands are an emerging remediation technology with potential for both stormwater and agricultural runoff treatment applications. The mechanisms driving removal of both nitrogen (N) and phosphorus (P) in constructed wetland systems are discussed. Surface-flow constructed wetlands remediate N contaminants from both container nursery and greenhouse production wastewater, whereas P remediation is variable and tied most closely to active plant growth as the constructed wetland ages. Subsurface-flow constructed wetlands effectively remediate N from production wastewater and can be tailored to increase consistency of P remediation through selection of P-sorbing root-bed substrates. Floating treatment wetlands effectively remediate both N and P with a designed surface area of a pond covered depending on the target effluent concentration or regulated total maximum daily load. The choice of treatment technology applied by growers to meet regulated water quality targets should be based on both economic and site-specific considerations.

Alternatives to Synthetic Herbicides for Weed Management in Container Nurseries

Weed management is one of the most critical and costly aspects of container nursery production. This is most effectively achieved through preventative practices, primarily with preemergent herbicides. But there are valid reasons for managing weeds with alternatives to synthetic herbicides, including sanitation, exclusion, prevention, hand weeding, mulching, and the use of cover crops, heat, and nonsynthetic herbicides. This 6-page fact sheet was written by Gary W. Knox, Matthew Chappell, and Robert H. Stamps, and published by the UF Department of Environmental Horticulture, September 2012. ENH1203/EP464: Alternatives to Synthetic Herbicides for Weed Management in Container Nurseries (ufl.edu)

Effects of Fertilizer Placement on Trace Gas Emissions from Nursery Container Production

Increased trace gas emissions of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) are widely believed to be a primary cause of global warming. Agriculture is a large contributor to these emissions; however, its role in climate change is unique in that it can act as a source of trace gas emissions or it can act as a major sink. Furthermore, agriculture can significantly reduce emissions through changes in production management practices. Much of the research on agriculture’s role in mitigation of greenhouse gas (GHG) emissions has been conducted in row crops and pastures as well as forestry and animal production systems with little focus on contributions from specialty crop industries such as horticulture. Our objective was to determine efflux patterns of CO2, CH4, and N2O associated with three different fertilization methods (dibble, incorporated, and topdressed) commonly used in nursery container production. Weekly measurements indicated that CO2 fluxes were slightly lower when fertilizer was dibbled compared with the other two methods. Nitrous oxide fluxes were consistently highest when fertilizer was incorporated. Methane flux was generally low with few differences among treatments. Results from this study begin to provide data that can be used to implement mitigation strategies in container plant production, which will help growers adapt to possible emission regulations and benefit from future GHG mitigation or offset programs.