Plasticulture Production Research Articles

Effects of pre-emergence herbicide on targeted post-emergence herbicide application in plasticulture production

Effects of pre-emergence herbicide on targeted post-emergence herbicide application in plasticulture production

Evaluation of smart spray technology for postemergence herbicide application in row middles of plasticulture production

AbstractPostemergence herbicides used to control weeds in the space between raised, plastic-covered beds in plasticulture production systems are typically banded, and herbicides are applied to weeds and to where weeds do not occur. To reduce the incidence of off-targeted applications, the University of Florida developed a smart-spray technology for row middles in plasticulture systems. The technology detects weed according to categories and applies herbicides only where the weeds occur. Field experiments were conducted at the Gulf Coast Research and Education Center in Balm, FL, in fall 2021 and spring 2022. The objective was to evaluate the efficacy of postemergence applications of diquat and glyphosate in row middles in jalapeno pepper fields when banded or applied with smart-spray technology. The overall precision of the weed detection model was 0.92 and 0.89 for fall and spring, respectively. The actuation precision achieved was 0.86 and 1 for fall and spring, respectively. No significant differences were observed between banded and targeted applications either with glyphosate or diquat in terms of broadleaf, grass, and nutsedge weed density. No significant pepper damage was observed with either herbicide or application technique. The smart-spray technology reduced herbicide application volume by 26% and 42% in fall and spring, respectively, with no reduction in weed control or pepper yield compared to a banded application. Overall, the smart-spray technology reduced the herbicide volume applied with no reductions in weed control and no significant effects on crop yield.

Tomato and bell pepper tolerance to preemergence herbicides applied posttransplant in plasticulture production

AbstractPreemergence (PRE) herbicides are often banded over the entire top of raised beds for broadleaf and grass control in plasticulture vegetable production systems. However, broadleaf and grass weeds may emerge from the planting holes and tears in the plastic mulch. Banded application results in herbicides applied where no holes occur, and therefore, where they are not needed. Our objective is to identify herbicides that do not harm transplanted crops when directed at transplant holes after transplant (POST) with the aim to reduce off-target applications. Therefore, we evaluated tomato and pepper tolerance to PRE herbicides applied to transplant holes 2 wk after transplant and the subsequent effects on crop tolerance and weed density. Halosulfuron, S-metolachlor, metribuzin, and pendimethalin did not injure tomato transplants, reduce height, or reduce yield. Fomesafen caused some tomato injury (7%) but had no effect on other measured parameters in Trial I. All PRE herbicides injured peppers by ≥19%, although no effect on yield was observed. Overall, halosulfuron, S-metolachlor, metribuzin, and pendimethalin can be safely applied to tomato transplant holes 2 wk after transplant with no significant crop injury nor effects on final yield, but none of the evaluated herbicides are safe for use on pepper crops.

Weed Management Strategies for Tomato Plasticulture Production in Florida.

Florida is the top producer of fresh market tomatoes in the U.S., with an average production of 0.4 million metric tons. Tomatoes are commercially grown on plastic mulched raised beds in Southwest Florida, the primary production region in the state. Low tomato yield in plasticulture production is often associated with the poor control of nutsedge species. Nutsedge management, therefore, remains a critical production challenge for tomato growers in Florida. Sandy soil in this region promotes herbicide movement after heavy rainfall or irrigation, affecting weed suppression. This will also potentially impact the timely establishment of new tomato transplants and, consequently, the crop vigor if the herbicides get into the root zone. This review aims to present and discuss an overview of available options to safely manage major weeds of tomatoes, including nutsedge species, in plasticulture production. In addition, this review seeks to discuss an approach for utilizing herbicide adjuvants, such as spray deposition agents or oil binding agents, to improve herbicides' efficacy and tomato crop safety by enhancing their retention in plastic mulched raised beds.

Strawberry Crown Plugs Provide Flexibility and Improved Performance in Cold Climate Plasticulture Production

Annual plasticulture strawberry production has not been adopted as rapidly in cold climate regions as has occurred in warmer production areas due to uncertainty about potential benefits. Recent trials have demonstrated the potential of regionally adapted varieties in the annual plasticulture system in cold regions, but optimal production practices have not been determined. Summer planting of short-day varieties in these areas would increase flexibility for growers, allowing additional cropping options and improved land use management. The performance of six short-day strawberry varieties (Chandler, Clancy, Jewel, Ovation, Seneca and Ventana) was examined in a series of four annual production trials using cold-stored bare-root crowns for spring planting or a new type of planting stock termed a ‘crown plug’ for two summer plantings. Procedures for producing crown plugs from cold-stored crowns are described. The crown plug summer plantings significantly outperformed the spring planted bare-root plants across all varieties. The July planting established using crown plugs had higher yield and higher mean berry weight across all six varieties compared to the May bare-root planting (623 g/plant—12.5 g mean fruit weight vs. 330 g/plant—10.6 g mean fruit weight, respectively). In the July planting, ‘Seneca’, ‘Ventana’ and ‘Jewel’ exceeded the mean yield per plant for the planting as a whole and the other three varieties also produced more than previously reported for the May planting established with bare-root plants. The August crown plug planting was less productive than the July planting (623 g/plant vs. 498 g/plant, respectively) but was still more productive than both spring plantings. No difference was observed between the April and May plantings across the six varieties. Utilizing crown plugs also reduced the duration of weed control measures needed, improved efficiency of setting plants and limited the need for blossom and runner removal in the field, thus demonstrating labor cost savings that can offset the cost of crown plug production while also producing higher overall yield and mean fruit weight in the varieties in the trial. The summer plantings established with crown plugs demonstrated improved survival through a second winter dormancy period but produced relatively poor yield and berry size in the second harvest season. Crown plugs provide flexibility and improved productivity for growers utilizing annual plasticulture production in cold climate regions.

Performance of Strawberry Varieties Developed for Perennial Matted-Row Production in Annual Plasticulture in a Cold Climate Region

Annual plasticulture production of strawberries promises superior weed control, fruit quality and yields. However, strawberry varieties adapted for perennial, matted-row production and local markets in cold climate regions have not been widely tested for adaptation to an annual production cycle. Productivity of seven short-day varieties developed for matted-row and/or annual production was examined in an annual plasticulture system in two consecutive trials in central NY (lat. 42.87° N, long. 76.99° W) harvested in 2013 and 2014. ‘Flavorfest’ demonstrated good performance in Trial 1 with high yield (390 g/plant) and large fruit size (13.9 g mean berry weight). ‘Jewel’ was shown to be well adapted to the annual plasticulture system with consistently high yields (330 and 390 g/plant) that equaled or surpassed other varieties and had moderate fruit size. ‘Chandler’ performed similarly to previous trials conducted in warmer regions with yield (340 g/plant) and fruit size (9.8 g mean berry weight) similar to ‘Jewel’. ‘Clancy’ yielded less but was consistent from year to year. The late season varieties Seneca and Ovation showed marked variability between years, possibly due to drastically different temperatures during flowering and fruit development in Trial 1 compared to Trial 2. High temperatures in Trial 1 likely caused higher early fruit yield, a compressed season and a precipitous decline in fruit size in the later season, thus reducing yield in the late season. Survival after a second dormant period was poor resulting in a small second harvest and reduced fruit size. Overall, the system demonstrated many of the expected benefits but may be more sensitive to weather conditions in the region. While many varieties developed for matted-row production may work well in an annual plasticulture system, not all varieties are equally adapted. Performance of each variety should be determined independently before large scale adoption by growers.

Tolerance of ‘Camarosa’ Strawberry (Fragaria ×ananassa Duch.) to Extra-label Use of Single and Tank Mix Preemergence Herbicides in Annual Hill Plasticulture

Relatively few herbicides are registered in Alabama or in the southeastern United States for use in annual hill plasticulture production of strawberries. Acquisition of 24(c) special local needs status for certain herbicides could make more of these chemistries available to the strawberry industry. These herbicides, especially when applied as tank mixes pose potential risks to strawberry plant growth and fruit yield. Special local needs status for these herbicides has been granted for other states, but more evaluation of these products in Alabama soils under plastic mulch is needed. The objective of this study was to assess tank mix applications of preemergence herbicides with different modes of action on plant growth, crop yield, and fruit size of ‘Camarosa’ strawberry. A study was conducted at the Chilton Research and Extension Center in Clanton, AL, in 2018 and 2019. Pendimethalin (3.5 L·ha–1) and S-metolachlor (1.6 L·ha–1) were evaluated for potential phytotoxicity in ‘Camarosa’ strawberry when applied alone or in tank mixes with napropamide (8.6 kg·ha–1), sulfentrazone (0.3 L·ha–1), or terbacil (0.42 L·ha–1) by comparing them to a nontreated control. At 18 weeks after planting, pendimethalin tank mixed with napropamide reduced plant dry weight by 33% compared with the control, but this reduction was not significant. Additionally, tank mixes of pendimethalin with sulfentrazone, napropamide, and terbacil reduced shoot dry weight by 43%, 52%, and 43%, respectively, compared with pendimethalin alone. Pendimethalin + napropamide tank mix reduced relative growth rate by 95% compared with the control between 6 and 18 weeks after planting. All treatments were similar to the control in marketable yield. Differences in plant growth parameters did not appear to affect yield by the end of the experiment. All single applied treatments along with S-metolachlor tank mixed with napropamide and sulfentrazone; pendimethalin tank mixed with sulfentrazone and terbacil appeared to be safe for direct application to strawberry planting beds covered in polyethylene mulch.

Efficacy of metam potassium on Fusarium oxysporum, Macrophomina phaseolina, Meloidogyne javanica, and seven weed species in microcosm experiments.

Metam potassium (metam-K) is a soil fumigant widely used to control plant pathogens, nematodes, and weeds in Florida plasticulture production. The objective of the study was to determine the efficacy of metam-K against Fusarium oxysporum, Macrophomina phaseolina, Meloidogyne javanica, and seven important weed species under controlled conditions. The optimal rates generated in this study provide insight into the efficacy of metam-K for field application. F. oxysporum and M. phaseolina were similarly sensitive toward metam-K with a 90% effective concentration (EC90 ) of 478 and 493 μmol kg-1 soil, respectively. Meloidogyne javanica was the most sensitive pest with an EC90 of 25 μmol kg-1 which is similar to previous studies. Chenopodium album was the most sensitive weed seed with an EC90 of 260 μmol kg-1 . Geranium carolinianum and Medicago lupulina were the least sensitive weed species with EC90 values of 786 and 567 μmol kg-1 , respectively. It is apparent from these results that metam-K can effectively control important pests in Florida plasticulture production systems with the correct application rate and adequate exposure of pest to the fumigant.

Optimal rate of metam potassium for fusarium and purple nutsedge control when applied through the drip tape or with a minicoulter

Metam potassium (metam-K) is a commonly used pre-plant fumigant in Florida plasticulture production. Two field studies on the dose-response of metam-K were conducted at the Gulf Coast Research and Education Center, Wimauma, FL, using two different application techniques for the control of purple nutsedge. In the first field study, multiple metam-K rates of 0, 130, 195, 260, 325, 390, 455, 520 kg ha−1 were applied with a minicoulter and were compared to the few commonly used herbicides such as 0.2 kg ha−1 sulfentrazone, 1 kg ha−1 s-metolachlor, 0.4 kg ha−1 fomesafen and 0.6 kg ha−1 oxyflurofen sprayed on the bed top. Percent purple nutsedge control was measured in all plots. The second field study evaluated five different metam-K rates (130, 260, 390, 520, 650 kg ha−1) in four different water volumes (54, 108, 162, and 216 m3 ha−1) when applied through drip irrigation within the bed. Herbicides reduced purple nutsedge density by 8–92% 6 weeks after fumigation compared to the nontreated control. Metam-K rates >455 kg ha−1 were needed to maximize purple nutsedge control. Water volumes had no significant effect on purple nutsedge and Fusarium oxysporum fsp lycopersici (FOL) control when metam-K was drip injected. Metam-K rates required to achieve 90% control of purple nutsedge at 9 weeks after fumigation were 612 and 766 kg ha−1 respectively in fall and spring 2018. All rates of metam-K were effective against FOL inoculum placed at bed center and 16 cm away from bed center, however, they were less effective on FOL inoculum placed at bed edges. EC90 values for FOL at the bed edges were 500 kg ha−1 in spring 2018. Optimal metam-K rates for purple nutsedge control were 10–30% higher than label rates when using an minicoulter and 57–96% higher than label rates when drip applied.

Goosegrass Detection in Strawberry and Tomato Using a Convolutional Neural Network

Goosegrass is a problematic weed species in Florida vegetable plasticulture production. To reduce costs associated with goosegrass control, a post-emergence precision applicator is under development for use atop the planting beds. To facilitate in situ goosegrass detection and spraying, tiny- You Only Look Once 3 (YOLOv3-tiny) was evaluated as a potential detector. Two annotation techniques were evaluated: (1) annotation of the entire plant (EP) and (2) annotation of partial sections of the leaf blade (LB). For goosegrass detection in strawberry, the F-score was 0.75 and 0.85 for the EP and LB derived networks, respectively. For goosegrass detection in tomato, the F-score was 0.56 and 0.65 for the EP and LB derived networks, respectively. The LB derived networks increased recall at the cost of precision, compared to the EP derived networks. The LB annotation method demonstrated superior results within the context of production and precision spraying, ensuring more targets were sprayed with some over-spraying on false targets. The developed network provides online, real-time, and in situ detection capability for weed management field applications such as precision spraying and autonomous scouts.

Growth of ‘Seascape’ strawberry (Fragaria X ananassa Duch.) is altered by photoperiod and nitrogen conditioning

ABSTRACT The influences of photoperiod and nitrogen plug conditioning for summer planting of ‘Seascape’ strawberry (Fragaria x ananassa Duch.) for off-season plasticulture production were evaluated in two separate experiments in New Jersey, USA. In experiment one, plants were conditioned in the greenhouse under ND (natural daylength), LD (ND supplemented with 24 h incandescent radiation (Phillips Duramax Soft White A19 60 watt) or LD7W (ND supplemented with 24 h incandescent radiation (C9, 7 watt bulbs) followed by elevated nitrogen (800 ppm) for 0 to 4 weeks. In experiment two, plants were conditioned in the greenhouse under ND or LD followed by elevated nitrogen (800 ppm) for 4 weeks. In experiment one, flowering was enhanced by LD conditioning. The 24LD7W treatment was more effective than the 24LD treatment in eliciting a long day response at low levels of N (0 and 1 week of elevated N) but not at higher levels of N (2 to 4 weeks of elevated N). No treatment effects were observed for fruit production. In the second experiment, flowering was enhanced by LD or elevated N. Elevated nitrogen during conditioning slightly enhanced yield through 11 September while photoperiod during conditioning did not affect productivity. Runner production was minimal in both experiments.

Responses to nitrogen conditioning in ‘Albion’ strawberry (Fragaria X ananassa Duch.) for off-season plasticulture production are primarily qualitative rather than quantitative

The nature (qualitative vs. quantitative) of growth responses to nitrogen during photoperiod conditioning of ‘Albion’ strawberry (Fragaria x ananassa Duch.) plants for late summer / early fall off-season field production was evaluated in New Jersey, USA. For two different planting dates (14 June and 6 July), plants were conditioned in the greenhouse under ND (natural daylength), LD (natural daylength supplemented with 24 h incandescent radiation (Phillips Duramax Soft White A19 60 W) or LD7W (natural daylength supplemented with 24 h incandescent radiation (C9, 7 W bulbs) followed by elevated nitrogen (800 ppm) for 0–4 weeks. Plants were then established in field plasticulture. Flowering in July was enhanced by LD conditioning; however, these effects did not persist and have an impact on plant productivity. Qualitative responses to N included crown branching, runner production, fruiting precocity and early season yield. Results confirm the previous observation that conditioning plants prior to off-season plasticulture production in the Northeast US is not necessary if plants are established in the field by early July. The LD7W light treatment was more effective than the LD light treatment in eliciting photoperiod responses especially when nitrogen levels were low. Thus, the lower wattage bulbs may be an effective tool for managing photoperiod responses for off-season production when needed (later planting dates) with this cultivar.

Utility of glufosinate in postemergence row middle weed control in Florida plasticulture production

AbstractHerbicides are the foundation for row-middle weed control in Florida plasticulture production. Paraquat is commonly used as a burndown herbicide, and resistance issues have subsequently developed. Halosulfuron is mixed with PRE and POST herbicides to provide additional control of nutsedge. The objective of the study was to determine glufosinate efficacy on weeds emerging in the row-middle and suitability in mixture with halosulfuron for nutsedge control. For total weed control, the high dose of glufosinate (983 g ai ha–1) gave the highest overall control (98% and 64% at 4 wk after treatment for experiments 1 and 2, respectively), and the low rate of glufosinate (656 g ha–1) (67% and 39%) gave results comparable to paraquat (57% and 44%). The high glufosinate dose and paraquat gave comparable control of Brazil pusley (74% to 77% control). Glufosinate + halosulfuron mixture had lower efficacy on Brazil pusley than halosulfuron + paraquat mixture. Glufosinate application reduced grass densities, whereas paraquat did not. Increasing the glufosinate dose did not further decrease grass densities. Similar trends in grass control were also demonstrated in their respective mixtures. Mixing halosulfuron with glufosinate or paraquat did not provide consistent reductions in nutsedge densities, nor did adding paraquat or glufosinate further reduce densities compared with halosulfuron alone for the 4-wk study period. Both paraquat and glufosinate antagonized halosulfuron and reduced efficacy on nutsedge. Compared to controls, there was a reduction between expected and actual nutsedge control for paraquat and glufosinate (25% and 36%), respectively. For total weed control, glufosinate is a suitable alternative to paraquat for row-middle weed management in vegetable production.

Development and Evaluation of a Hole-Punch Applicator for Precision Application of Preemergence Herbicides in Plasticulture Production

AbstractPreemergence herbicides are typically applied by broadcasting to the top of raised beds before laying the plastic mulch in plasticulture production systems. Broadleaf and grass emergence is limited to transplant holes in the mulch. As a result, most herbicides are applied under the mulch in locations where weeds cannot emerge and herbicides are unnecessary. To reduce this excessive off-target application, a precision hole-punch sprayer was developed at the University of Florida for use in plasticulture production systems. The technology facilitates the application of herbicides during the hole-punch operation immediately before transplant. Application of napropamide andS-metolachlor in an application volume of 233 L ha−1of water using the precision hole-punch applicator had no effect on tomato and bell pepper growth and yield. Equipment accuracy ranged from 55% to 90%. Preemergence herbicide use was reduced by 88% to 92% with no reduction in weed control. The hole-punch applicator is an effective way to reduce PRE herbicide use in transplant vegetables grown using the plasticulture production system.

The effect of grafting on nitrogen use in determinate field-grown tomatoes

ABSTRACTGrafting tomato (Solanum lycopersicum L.) onto disease resistant rootstocks has grown in use in North America over the past two decades. Rootstocks have traditionally been bred and used for their resistance packages to numerous soil-borne diseases but some rootstocks appear to improve scion yield and vigour in comparison to non-grafted plants in conditions lacking disease challenge. In this study, the tomato rootstocks ‘Maxifort’ or ‘RST-106’ were used to determine if vigour improved ‘Tribute’ scion traits, especially yield, and if marketable yield could be maintained in grafted plants at reduced nitrogen fertiliser inputs. Plants were grown in an open-field plasticulture production system at five rates of nitrogen from 0 kg ha−1 to 224 kg ha−1 applied via drip irrigation. Marketable yield was significantly affected by nitrogen rate and rootstock in both years. ‘Tribute’ grafted onto ‘Maxifort’ rootstock had the greatest, most consistent impact and increased marketable yield 15% and 30% in 2013 and 2014, respectively, compared to the non-grafted ‘Tribute’. Our findings suggest that some rootstocks can increase scion growth and yield but do not differentially respond to decreased nitrogen rates.

Plant architecture of 'Albion' strawberry (<i>Fragaria</i> × <i>ananassa</i> Duch.) is not influenced by light source during conditioning

Architectural analysis describes the position and fate (vegetative or floral) of plant meristems to account for differences in meristem sensitivity to stimuli depending on developmental stage and position on the plant. To provide further insight into the flowering responses of long-day strawberries to nitrogen (N), photoperiod and light source, ‘Albion’ strawberry plants were conditioned with 100 or 800 ppm N under ND (natural daylength) or LD (long days, natural days plus 24-hr supplementary illumination provided by either 60- or 7-watt incandescent bulbs) and greenhouse growth was evaluated for a total of 10 weeks following conditioning. After greenhouse forcing, plants were dissected and their floral architecture evaluated. Additional plants were established in early July in off-season plasticulture production where fruit, crown and stolon production were evaluated. Both light sources were equally effective in eliciting long-day photoperiod responses. No photoperiod effect on floral precocity, leaf, crown, or runner production was observed during greenhouse forcing. Plants under ND tended to produce more inflorescences during the first 5 weeks while LD enhanced inflorescence and flower production during the last 3 weeks of forcing. In dissected plants, maximum floral initiation was observed in plants receiving elevated N under LD. LD inhibited branch crown formation, but had no effect on the number of vegetative, floral or stolon producing axillary meristems regardless of N treatment. LD conditioning enhanced early yield (through 4 September). Field stolon and branch crown formation was supressed in plants receiving low N with LD conditioning. Stolon and branch crown inhibition by LD conditioning was not observed with elevated N. Growth data combined with architectural mapping of meristems allows more conclusive statements regarding treatment effects on specific stages of floral physiology (i.e. induction, initiation, differentiation and development) compared to more generalized conclusions obtained with growth data alone. The separation of direct and indirect effects on floral physiology is possible with floral architectural analysis.

Plastic Biodegradable Mulches Reduce Weeds and Promote Crop Growth in Day-neutral Strawberry in Western Washington

Day-neutral strawberry (Fragaria ×ananassa) is typically grown in plasticulture production systems that use black polyethylene (PE) mulch for weed management and promotion of crop growth and yield. The objectives of this research were to evaluate several commercial plastic and paper biodegradable mulch (BDM) products [Bio360, Experimental Prototype (Exp. Prototype), and WeedGuardPlus] in comparison with standard black PE mulch and bare ground cultivation in day-neutral strawberry grown in an annual system in northwestern Washington. Mulch performance [as percent visual cover (PVC)], weed suppression, marketable yield, plant biomass, and fruit quality were evaluated in ‘Albion’ and ‘Seascape’ strawberry grown in 2014 and 2015. PVC measured at the end of the production season was lowest for the Exp. Prototype (8%) in 2014 and was greatest for Bio360 (90%), WeedGuardPlus (90%), and PE (98%). In 2015, PVC at the end of the production season was again lowest for Exp. Prototype (62%), followed by WeedGuardPlus (64%), Bio360 (93%), and PE mulch (97%). Overall, weed pressure was higher in 2015 relative to 2014 and was greatest in the bare ground treatment in both years of the study. By the end of the 2015 season, weed cover in the bare ground treatment was 95%, followed by WeedGuardPlus (50%), Exp. Prototype (34%), PE (25%), and Bio360 (15%). Yield showed year and cultivar effects and was higher in mulched treatments. Plant biomass showed varying effects; root biomass was lowest in ‘Seascape’ in 2015 under the bare ground treatment and greatest under Bio360, which was similar to PE mulch and WeedGuardPlus. Leaf biomass was lowest in the bare ground treatment and highest in mulched treatments (except in 2015, when leaf biomass was intermediate for plants grown with WeedGuardPlus). Crown biomass showed a similar trend and was overall greater for plants grown in mulched treatments except for Bio360 in 2014, which was the same as the bare ground treatment. Overall, fruit quality was maintained among strawberry grown with BDMs, with soluble solids concentration (SSC, %) and titratable acidity (TA) being the only variables to show treatment effects. SCC tended to be lower in fruit from bare ground plots. TA was different for ‘Seascape’ in 2015 with fruit from bare ground and Exp. Prototype treatments having higher TA than the PE treatment. This study demonstrates that BDMs can be comparable to PE mulch in terms of performance and impacts on crop productivity in day-neutral strawberry, suggesting that BDMs could be a viable alternative to PE mulch for strawberry growers in the Pacific Northwest.

Effect of Fumigation with 1,3-Dichloropropene and Chloropicrin on Fomesafen Dissipation in Eggplant Plasticulture Production

Fomesafen is a protoporphyrinogen oxidase (PROTOX) inhibitor that has the potential to be used as an alternative mechanism of action for PRE nutsedge and broadleaf weed control in Florida production of small fruit and vegetables. Fumigation in the raised-bed plasticulture system may increase herbicide persistence. Fomesafen persistence could dissuade Florida growers from using the herbicide for fear of injury to subsequent susceptible crops. Field experiments were conducted in Balm, FL, in 2015 and 2016 to investigate the effect of fumigation on fomesafen dissipation, eggplant tolerance, and purple nutsedge control. Treatments included fomesafen at 0.42 kg ai ha−1,S-metolachlor at 1.06 kg ai ha−1, and a nontreated control in either a fumigated bed injected with a combination of 39% 1,3-dichloropropene and 59.6% chloropicrin at 336 kg ha−1or no fumigant. Fomesafen concentration in the soil decreased by 83% and 96% from application to harvest in 2015 and 2016, respectively. Fumigation did not affect fomesafen dissipation in either year. At 2 wk after transplant (WATr), fomesafen caused 14% eggplant injury. Injury decreased to less than 5% at 6 WATr. Fomesafen andS-metolachlor treatments did not reduce eggplant height or yields compared with the nontreated control. Fumigation and fomesafen did not decrease purple nutsedge density; however,S-metolachlor applications resulted in a 48% reduction. Further research is needed to assess efficacy on broadleaf and grass weeds.

Conditioning alleviates reduced yield of smaller plugs of ‘Albion’ strawberry (Fragaria X ananassa Duch.) in off-season plasticulture production

ABSTRACTThe influences of plug size, planting density, and mulch colour on responses to photoperiod and nitrogen conditioning of ‘Albion’ strawberry (Fragaria x ananassa Duch.) plants were evaluated in off-season field production in New Jersey, USA. Three different sized plug plants (7.6 cm square pots, 24-cell plug trays, or 50-cell plug trays) were conditioned with natural days (ND, natural daylength) or long days (LD, natural daylength supplemented with 24 h incandescent radiation) for one week followed by ND plus 100 ppm nitrogen (N) for 4 weeks or LD plus 800 ppm N for 4 weeks. Plants were then established in plasticulture on black, white, or silver mulch. In a second experiment, plug plants (439 cm3) were conditioned with LD and nitrogen then established in plasticulture on black, white, or silver mulch at 3 planting densities (0.46, 0.23, and 0.16 m2•plant−1 (2, 4, and 6 plants•m−2)). Fruit were harvested from August through October in both experiments. Conditioning enhanced off-season fall production. White plastic enhanced survival, productivity, and fruit size and larger plugs were more productive than smaller ones. If smaller plugs are desired, conditioning prevents the reduction in yield observed with non-conditioned smaller plugs.

Transforming the food-water-energy-land-economic nexus of plasticulture production through compact bed geometries

Abstract Raised-bed plasticulture, an intensive production system used around the world for growing high-value crops (e.g., fresh market vegetables), faces a water-food nexus that is actually a food-water-energy-land-economic nexus. Plasticulture represents a multibillion dollar facet of the United States crop production value annually and must become more efficient to be able to produce more on less land, reduce water demands, decrease impacts on surrounding environments, and be economically-competitive. Taller and narrower futuristic beds were designed with the goal of making plasticulture more sustainable by reducing input requirements and associated wastes (e.g., water, nutrients, pesticides, costs, plastics, energy), facilitating usage of modern technologies (e.g., drip-based fumigation), improving adaptability to a changing climate (e.g., flood protection), and increasing yield per unit area. Compact low-input beds were analyzed against conventional beds for the plasticulture production of tomato (Solanum lycopersicum), an economically-important crop, using a systems approach involving field measurements, vadose-zone modeling (HYDRUS), and production analysis. Three compact bed geometries, 61 cm (width) × 25 cm (height), 45 cm × 30 cm, 41 cm × 30 cm, were designed and evaluated against a conventional 76 cm × 20 cm bed. A two-season field study was conducted for tomato in the ecologically-sensitive and productive Everglades region of Florida. Compact beds did not statistically impact yield and were found to reduce: 1) production costs by $150–$450/ha; 2) leaching losses by up to 5% (1 cm/ha water, 0.33 kg/ha total nitrogen, 0.05 kg/ha total phosphorus); 3) fumigant by up to 47% (48 kg/ha); 4) plasticulture's carbon footprint by up to 10% (1711 kg CO2-eq/ha) and plastic waste stream by up to 13% (27 kg/ha); 5) flood risks and disease pressure by increasing field's soil water storage capacity by up to 33% (≈1 cm); and 6) field runoff by 0.48–1.40 cm (51–76%) based on HYDRUS model simulations of 10-year, 2-h storm events in other major tomato production regions of California and Virginia. Re-designing the bed geometries in plasticulture production systems to be more compact is an example of win-win production optimization not only for traditional farms in rural areas but also for urban and peri-urban farms which are located closer to city centers. Compact beds could enable more plants per unit area, thus requiring less land area for the same production. Needing less area facilitates urban and peri-urban farming where land values can be high. Urban and peri-urban farming has several benefits, including reductions in transportation energy as production is closer to market and the ability for city wastewater to be reused for irrigation instead of freshwater withdrawals. Compact beds allow plasticulture to have smaller water, chemical, energy, carbon, waste, and economic footprints without impacting production. Improving agricultural systems in this way could enhance economic and environmental viability, which is essential for a sustainable food-water-energy-land-economic nexus.