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Strawberries are only seasonally available in Nebraska (NE). If an affordable heated structure can be designed, then opportunity exists to increase on-farm income by producing strawberries off-season during high-value market periods. A series of university greenhouse trials were conducted from 2010 to 2012. The varieties Evie-2 and Seascape were identified as being most productive under a low technology growing scheme. A new research project, which ran from fall to late spring (2013–2014), was designed to determine if this production scheme would translate to a commercial grower. Varieties Seascape and Evie-2 (each at two grades indicated by +) and San Andreas plants were grown simultaneously at the university research greenhouse and a cooperative specialty crop grower greenhouse, similar structures and production timelines. Top performers for both experiment locations were 'Evie-2ʹ, and 'Evie-2+' plants, with average harvest berry weights (marketable) per plant (pp) of over 0.454 kg, and 'Seascape' with 0.390 kg. 'Seascape+' plants performed well at the cooperator location (0.399 kg pp), but not at the university location. 'San Andreas' plants performed well at the university location with 0.454 kg pp but not at the cooperator location. Productivity was greatest during the winter-spring season, which accounted for more than 82% of the total berry mass harvested at the cooperator site and 88% at the university site. The results support the concept that the growing system used within a controlled university research setting is representative of the crop productivity a specialty crop grower might expect, particularly when strawberries are grown in late winter and early spring. However, securing low fuel costs, eliminating delivery and having a secondary market for culls is key for profitability. [ABSTRACT FROM AUTHOR]

In this paper, the thermal performance of capillary mat cooling systems is evaluated through actual measurements under different ventilation rates. The results showed that the indoor air temperature drop rates of the ceiling, wall and floor cooling are 1.42–2.44°C/h, 0.69–1.11°C/h, 0.29–0.58°C/h, respectively, in the response phase, which can provide a reference for predictive control strategy of radiant system. Then the cooling capacity of the capillary mat is validated. The radiant heat transfer coefficient of the cooling capillary mat is about 5.80 W/m2 k. When the supply water temperature dropped from 20°C to 16°C, the total heat flux can experience an increase of 10%–30%. The heat flux for cooling ceilings is the largest, followed by cooling walls, which is 7%–17% lower; and cooling floors, which is 75%–90% lower. Orthogonal experiments illustrated that the water supply temperature and air supply volume have a significant influence on the indoor thermal environment of the hybrid systems, followed by the air supply temperature. In general, the dynamic performance of the radiant cooling system in the response phase can provide an effective reference for different control strategy considering the significant thermal inertia. [ABSTRACT FROM AUTHOR]

The present study examined the modulatory effects of natural fiber substrates (agave fiber, coconut fiber and peat moss) and synthetic alternatives (capillary mat and cellulose sponge) on the nutritive and phytochemical composition of select microgreens species (coriander, kohlrabi and pak choi) grown in a controlled environment. Polyphenols were analyzed by UHPLC-Q-Orbitrap-HRMS, major carotenoids by HPLC-DAD, and macro-minerals by ion chromatography. Microgreens grown on peat moss had outstanding fresh and dry yield but low dry matter content. Natural fiber substrates increased nitrate and overall macro-mineral concentrations in microgreens compared to synthetic substrates. The concentrations of chlorophylls, carotenoids and ascorbate were influenced primarily by species. On the contrary, variability in polyphenols content was wider between substrates than species. Out of twenty phenolic compounds identified, chlorogenic acid and quercetin-3-O-rutinoside were most abundant. Hydroxycinnamic acids and their derivatives accounted for 49.8% of mean phenolic content across species, flavonol glycosides for 48.4% and flavone glycosides for 1.8%. Peat moss provided optimal physicochemical conditions that enhanced microgreens growth rate and biomass production at the expense of phenolic content. In this respect, the application of controlled stress (eustress) on microgreens growing on peat moss warrants investigation as a means of enhancing phytochemical composition without substantial compromise in crop performance and production turnover. Finally, nitrate deprivation practices should be considered for microgreens grown on natural fiber substrates in order to minimize consumer exposure to nitrate.

The four experiments described here are part of a 5-year program focused on determining whether day-neutral and short-day strawberries would be suitable for commercial off-season/winter (temperate climate) production in greenhouses. All research was performed using container-grown plants fertigated through a capillary mat production system with heat supplied under the benches. The first experiment focused on stolon development. The second experiment investigated the influence of stolon removal on berry production and included the removal of flowers for the first three weeks. The third and fourth experiments were conducted as a comparison of university research (experiment 3) versus a commercial operation (experiment 4). In experiment one, of 13 cultivars, ‘AC Wendy’ plants produced significantly more stolons than the other cultivars. In experiment two, stolon production peaked at weeks 12 and 13, with ‘Chandler’ plants producing significantly more stolons (starting at week 9) than the other cultivars. At week 13, ‘Seascape’ plants produced more total berry weight than the other cultivars. The influence of stolon removal on total berry weight varied, with ‘Evie-2+’ plants (large crowns) producing higher total berry weight with the stolons on as compared to ‘Evie-2’ plants, which produced higher total berry weight with the stolons removed. In experiment 2, fruit production was low and was probably a result of deflowering for three weeks. Consequently, it may not be advisable to deflower during the ‘off-season’ for greenhouse-grown strawberries. In the final two experiments, which involved a commercial cooperator as well as the university greenhouse, it was found that of the five cultivars trialed, the same cultivars at both sites produced the maximum total berry weight. Stolon production differed at the two locations, but the optimal time for stolon removal was similar. Thus, it is recommended that for winter greenhouse production, stolons be removed initially at week 8 and then at weeks 11–12 of the production cycle. [ABSTRACT FROM PUBLISHER]

The effect of rain shelters on the performance of the day-neutral strawberry ( Fragaria × ananassa ) Monterey cultivar was studied in northern Québec in trials extending over 2 years. The main objective of the study was to evaluate the benefits of growing strawberry crops under plastic rain shelters in terms of yield, fruit quality, disease incidence and economical returns for soilless strawberry production. Five treatments were carried out and these included four − under rain shelters cultivation (T1 to T4) and one under open-air conditions (the Control, C). Under rain shelters conditions, plants were grown in either peat (PE; T1 treatment) or peat-sawdust (PS25; T2 treatment) substrates. Early forcing of bare-root plants (T3) in combination with a rain shelter cover was also carried out in an attempt to generate consistent early yields by the end of July as such would allow producers to capture a niche market for strawberries in Québec. Finally in T4, the PE substrate was laid onto a capillary mat to determine the potential of sub-surface water retention technology to minimize water use. In comparison to the Control treatment, protected cultivation led to a significantly lower incidence of strawberry mildew [ Sphaerotheca macularis (Wall. ex Fries)] and consistently higher marketable yields which largely compensated for the initial costs associated with the rain shelters. When grown under greenhouse conditions, forced plants had a significant production peak earlier, coinciding with the period of high prices for fresh strawberries in 2013. However, the economical analysis revealed that this method was not always profitable. Balancing economical and environmental considerations, the conditions of the T4 treatment were found to be best for generating both consistent water savings and profits (CAD $ 724–1356 per 0.1 ha) compared to the Control. Taken together, our results highlight the potential for rain shelters for soilless strawberry production, and should be a more profitable and environmentally friendly cultivation method for strawberry producers. [ABSTRACT FROM AUTHOR]

In many areas of the US, fresh locally grown berries are not available during the winter. With this in mind, a research study comprised of three experiments was conducted focused on cultivar selection for berry yield, number, sweetness and phytonutrient content. Using a capillary mat system with under bench heating within a double-layer polyethylene greenhouse, strawberries were grown in the Great Plains Region of the US during the winter. During experiment 1, 12 cultivars were grown; berries were weighed, counted and analyzed for sugars and phytonutrients. ‘Albion’ plants produced a high number/mass of berries, had relatively high sugar content but a lower level of phytonutrients when compared to other cultivars. Sugar and phytonutrients concentrations overlapped across cultivars and thus, one cultivar could not be statistically singled out as best. As all cultivars flowered and fruited, two additional 8-month-long experiments were conducted. It took only 7 weeks from potting of dormant crowns for most cultivars to produce fruit. Certain cultivars fruited more successfully during certain months than others, but this was not associated with response time. For example,’ ‘Albion’, ‘Chandler’, ‘Darselect’, ‘Evie-2′ and ‘Seascape’ plants consistently produced fruit October to early January while ‘AC Wendy’, ‘Cavendish’, ‘Honeoye’ and ‘Strawberry Festival’ plants mainly produced berries in March/April. Summed over experiment 2, ‘Albion’, ‘ Cavendish’, ‘Chandler’, ‘ Evie-2’, ‘Portola’ and ’Seascape’ plants produced the greatest mass of berries. ‘AC Wendy’ and ‘Darselect’ berries contained some of the highest levels of sugars while berries from ‘Chandler’, ‘Darselect’, ‘Evie-2′, ‘Seascape’ and ‘Strawberry Festival’ had some of the highest phytonutrient values. In the third experiment, of the 8 selected cultivars, ‘Evie-2′, ‘Evie−2+’ and ‘Portola’ plants had the highest total yield and average berry mass/plant. ‘Seascape’ and’ Chandler’ plants were second in total production. Glucose, fructose and sucrose levels varied across cultivars with ‘Chandler’ and ‘Seascape’ berries possessing the lowest level of total sugars. Phytonutrient values varied among cultivars with some having better flavonoids (‘Seascape’), phenols (‘Seascape’ and ‘Chandler’) and ant oxidant capacity (‘Seascape’, ‘Evie-2’ and ‘Cavendish’). Measurement of soluble solids concentration varied by week among the cultivars with ‘Seascape’, ‘Seascape+”, and “Albion” berries possessing higher levels than other cultivars such as ’Cavendish’. Overall, under these winter greenhouse conditions using capillary mat fertigation and an under-bench heat delivery system, strawberries were successfully produced for the off-season market. [ABSTRACT FROM AUTHOR]

Experiments were carried out to investigate the performance of a low-temperature radiant floor heating system with different heat storage materials (sand and phase change material) and heating pipes (polyethylene coils and capillary mat) in the floor structure of a test room. Detailed temperatures in both floor structural layers and the air of the room were measured for four different combinations of these thermal mass and heating pipes during charge and discharge operations. The results showed that the floor structure with capillary mat provides more uniform temperature profile in vertical direction of the test room and needs much shorter time (nearly half) to attain the same room temperature than the cases with polyethylene (PE) coils during the charging process. Also, after the heat source was closed, the floor structures using phase change material (PCM) as thermal mass release heat about 2 times longer than the cases using sand. A CFD simulation is also performed which confirms the measured data during the charging and discharging processes. The results indicate the advantages of using PCM – capillary mat combination for low – temperature floor panel typical of solar – hot – water heating system. [ABSTRACT FROM AUTHOR]

Over the past decade, citrus production has sharply decreased in Florida because of citrus greening or Huanglongbing (HLB), a disease that reduces fruit yield and quality and eventually kills the citrus trees. With the increased mortality and need to resetting trees, the demand for healthy trees from citrus nurseries has risen drastically in the last few years. To meet the demand and accelerate tree growth, the citrus nursery industry should use modern horticultural practices such as more efficient irrigation methods, fertigation, and more vigorous rootstocks. This study evaluated the effect of subirrigation systems in tree production time, water and fertilizer inputs, and plant growth of commercial citrus rootstocks cultivated in treepots. We tested five irrigation methods [three ebb-and-flow subirrigation systems triggered at specific volumetric water contents (θ, 0.24, 0.36, and 0.48 m3 m−3), capillary mats, and a conventional drip irrigation system], and six commercial rootstocks (Kuharske, UFR-2, UFR-16, US-802, US-812, and X-639). The experiment was arranged in a split-plot design, with the main plot consisting of the five irrigation methods and sub-plots the different rootstocks. Ebb-and-flow subirrigation benches conserved 98% more water than conventional drip irrigation. Rootstocks grown under ebb-and-flow systems reached adequate stem diameter for grafting four weeks before the drip irrigation. Pummelo hybrids used in this study (UFR-16, UFR-2, and US-802) were 55% taller, 24% thicker, and 150% heavier on biomass production than the other varieties tested, irrespective of the irrigation method utilized. Although the substrate electrical conductivity was higher in all subirrigation methods, the values were below 1 dS cm−1, not causing symptoms of osmotic stress in plants. Our results show that the ebb-and-flow subirrigation system at θ of 0.24 m3 m−3 is the best option for accelerating citrus growth in treepots with peat: perlite substrate and to conserve water in Florida nurseries in comparison to capillary mats and drip irrigation. • Ebb-and-flow subirrigation was successfully automated for citrus rootstock growth. • Ebb-and-flow benches used less water than capillary mats and drip irrigation. • Rootstocks were ready for grafting earlier at the substrate threshold θ of 0.24 m3 m−3. • Accelerated growth of citrus in treepots at the substrate threshold θ of 0.24 m3 m−3. [ABSTRACT FROM AUTHOR]

As nursery and greenhouse growers adopt more sustainable production practices, interest has grown in local, recycled organic materials (ROM) as partial or complete substitutes for peat in container substrates. Chrysanthemum xmorifolium Ramat. 'Shasta' was grown in substrates formulated from ROM: 1) 100% Groco, an anaerobically digested biosolids composted with sawdust; 2) 100% Tagro, a thermophilically digested class A biosolid mixed with sawdust and sand; 3) 100% dairy compost, the solids screened from dairy manure slurry and then composted; 4) 100% dairy fiber, the solids fraction from an anaerobic dairy manure digester; 5) 50% Groco: 50% douglas-fir bark (mixed by volume); 6) 50% Tagro: 50% bark; 7) 50% dairy compost: 50% bark; 8) 50% dairy fiber: 50% bark; and 9) the control, a commercial peat-perlite mixture. Soluble fertilizer [200 mg⋅L-1 nitrogen (N)] was applied every second day (high N) or every fourth day (low N). Water was applied through capillary mat subirrigation or overhead sprinkler surface irrigation. Surface irrigation and high N produced shoot dry weight, shoot growth index (SGI), quality, and flower bud counts similar to controls in all ROMs but Groco. Groco SGI was similar to the control but the other parameters were lower. Surface-irrigated, low N shoot dry weight, SGI, and flower buds in all ROM equaled or exceeded the control and quality was similar to or better than controls in all but dairy compost:bark. Subirrigated and high N substrate comparisons indicated that growth, quality, and flower bud measurements were similar to the control except for Groco in which performance was reduced. Low N rate subirrigation produced dry weight, SGI, quality, and flower buds similar to or better than the control in all bur the Groco and dairy compost:bark substrates. The generally inferior performance in Groco is likely the result of its low water-holding capacity. In substrates with higher available N (Groco, Tagro, Tagro:bark, and dairy fiber), plant growth parameters generally did not respond to doubling the applied N; in the other substrates, including the control, growth generally increased in response to additional N. Measured differences in leaf color across treatments were not large. Root growth of plants in the experimental substrates was similar to the control in both irrigation systems. Substrate effects on leachate nitrate-N were small and inconsistent. When properly constituted, biosolids and dairy manure can be used as substrates under reduced fertilization with both surface and subirrigation systems. [ABSTRACT FROM AUTHOR]

The present study examined the modulatory effects of natural fiber substrates (agave fiber, coconut fiber and peat moss) and synthetic alternatives (capillary mat and cellulose sponge) on the nutritive and phytochemical composition of select microgreens species (coriander, kohlrabi and pak choi) grown in a controlled environment. Polyphenols were analyzed by UHPLC-Q-Orbitrap-HRMS, major carotenoids by HPLC-DAD, and macro-minerals by ion chromatography. Microgreens grown on peat moss had outstanding fresh and dry yield but low dry matter content. Natural fiber substrates increased nitrate and overall macro-mineral concentrations in microgreens compared to synthetic substrates. The concentrations of chlorophylls, carotenoids and ascorbate were influenced primarily by species. On the contrary, variability in polyphenols content was wider between substrates than species. Out of twenty phenolic compounds identified, chlorogenic acid and quercetin-3-O-rutinoside were most abundant. Hydroxycinnamic acids and their derivatives accounted for 49.8% of mean phenolic content across species, flavonol glycosides for 48.4% and flavone glycosides for 1.8%. Peat moss provided optimal physicochemical conditions that enhanced microgreens growth rate and biomass production at the expense of phenolic content. In this respect, the application of controlled stress (eustress) on microgreens growing on peat moss warrants investigation as a means of enhancing phytochemical composition without substantial compromise in crop performance and production turnover. Finally, nitrate deprivation practices should be considered for microgreens grown on natural fiber substrates in order to minimize consumer exposure to nitrate. [ABSTRACT FROM AUTHOR]

• Application of capillary mat as ground heat exchanger. • Validation of experimental results with numerical simulation. • Current installed system can provide heat transfer rate for higher thermal load. • Potential advantages of capillary mat over HDPE pipes are discussed. The ground heat exchanger is an important part of a ground source heat pump system. The site selection and arrangement affect the thermal performance of the entire system. A horizontal (shallow) ground heat exchanger has lower initial cost than a borehole heat exchanger. However, it has a larger physical footprint and its thermal performance is strongly affected by surface heat flux and rainfall infiltration. The capillary mat heat exchanger comprises small parallel capillary tubes and provides larger effective heat transfer area per unit footprint installation area. Additionally, it is more easily prepared and installed. This paper reports experimental result and numerical validation of ground source heat pump cooling application using shallow horizontal capillary mat ground heat exchangers. From the experiment, it was found that the installed capillary mat heat exchangers provide sufficient heat rejection rate for the heat-pump's thermal load. A numerical model for capillary mat heat exchangers is developed and the numerical result are validated using experimental data, within 1.54% root-mean-square error. A new and simple numerical relationship is also proposed to express the rate of heat transfer from capillary pipes to the surrounding soil. The extended numerical simulation found that currently installed ground heat exchangers can provide higher thermal load. The estimation of the pressure drop suggests that for a given pressure drop and flow rate, a single capillary mat having a surface area of 13.18 m2 is equivalent to a 40-m high-density polyethylene pipe with a standard diameter of 3.2 cm and a surface area of 8.05 m2. [ABSTRACT FROM AUTHOR]