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The main purpose of this study was to improve the accuracy and reliability of nutrient analysis on soilless substrates by comparing two different saturated medium extract (SME) methods, using either water (SMEW) or DTPA (diethylenetriamine-pentaacetic acid, SMED) as extractants. A series of analyses were performed to compare ion levels quantified from either SMEW or SMED. Substrate pH, electrical conductivity (EC) and nutrient data were analyzed from a survey of substrate components (coconut coir, peat, bark, perlite, vermiculite), and blended greenhouse propagation substrates using the SMEW and SMED methods. In addition, a series of SMEW and SMED extracted samples were sent to three commercial soil testing laboratories for nutrient analysis. The objectives of these analyses were to (1) validate that published relationships between SMEW and SMED methods were consistent with correlation curves for pH, EC and nutrient levels across a wide range of soilless substrates, (2) compare statistical variability of results from SMEW and SMED methods and (3) compare variability in results between different laboratories. The results validated that previously published standards for interpreting SMEW extractions can be used for SMED method for macronutrients and EC due to an approximately 1:1 relationship for test results between extraction methods. Up to 2 orders of magnitude higher levels of micronutrients were extracted for iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu) using SMED compared with SMEW, with low correlation between extractants. Concentrations of ions from SMED extractions were less variable than SMEW for micronutrient analysis but were comparable for macronutrient analysis. Results from this study were combined with published research to provide suggested ranges using SMED for soilless substrates. [ABSTRACT FROM AUTHOR]

Strawberries (Fragaria × ananassa) are a globally cultivated fruit crop known for their economic significance and versatility in both fresh markets and processed food industries. Their high consumer demand and market value contribute to substantial profitability for producers. In recent years, due to increasing costs of production and occurrence of extreme weather events, the use of controlled environment agriculture (CEA) and hydroponics for strawberry production has become popular in several Asian, European, and American countries. There are two main types of hydroponic systems: substrate- and water-culture. Substrate-culture systems are the common choice for CEA strawberry production, whereas water-culture systems are usually used for crops like leafy greens and herbs. Both systems have been independently studied for CEA strawberry production, but direct comparisons between them are still limited. The objective of this study was to compare the performance of substrate and water-culture systems for CEA strawberry production regarding yield and resource use efficiencies. ‘Florida Brilliance’ and ‘Florida Beauty’ strawberries were grown in a greenhouse in one substrate-culture, with plants grow in soilless media, and three water-culture systems: nutrient film technique (NFT), vertical tower (stacked nutrient flow), and aeroponics (nutrient misted roots). The system inputs (water, energy, and area) and outputs (yield, biomass, etc.) were quantified during the 129-day experiment. Fruit yield was used to calculate water (WUE), energy (EUE), and area (AUE) use efficiencies. Based on yield and resource use efficiencies, the substrate system performed the best, with the vertical tower system also showing promising performance. The results of this experiment can help growers understand the tradeoffs between hydroponic systems to maximize both profits and sustainability for CEA strawberry production.

Humic substances are a type of biostimulant used in greenhouse production to promote plant growth and health. Our goal was to evaluate the effect of three commercially available biostimulants containing humic and/or fulvic acids (HumaPro, FulviPro, and Micromate) on the performance and tissue nutrient concentration of Solanum lycopersicum L. 'Bush Beefsteak' grown in a peat-based substrate. We conducted four experiments testing application rate and fertility level (50 and 100 mg⋅L–1 N) (Exp. 1), application rate and frequency (Exp. 2), direct Micromate incorporation into the substrate (Exp. 3), and FulviPro application method (drench vs. foliar spray) (Exp. 4). Plants were fertilized with 20N-1.3P-15.7K. Experiments 2, 3, and 4 were conducted under low fertility (50 mg⋅L–1 N). Micromate promoted growth when applied as a weekly drench at 40 g·L−1 or when incorporated into the substrate (20 g in 1 L of the substrate). Micromate-treated plants showed high P, S, and Si in the shoot and root tissues. FulviPro showed a negative effect when applied as a drench at higher rates, but foliar application increased greenness (Green Leaf Index). The negative effects of FulviPro might be due to the over-accumulation of Fe and Mn when applied as a drench. [ABSTRACT FROM AUTHOR]

Inappropriate waste disposal imposes significant health risks in densely populated urban environments and schools, necessitating sustainable waste management. Therefore, a study was carried out at Al-Jazaer School, Kuwait, to evaluate rotary drum composting (RDC) of organic school waste comprising used paper, dry leaves, and vegetable food wastes in a 1:4:20 ratio. Feedstock comprising 42% organic school wastes, 42% horse manure, and 16% sawdust produced mature compost with a C:N ratio of 20.55 on the 43rd day of composting. Distinct mesophilic, thermophilic, cooling, and curing phases were observed during composting. Mature compost recorded a moisture content of 54.3%, pH 8.56, EC of 2.71 mS/cm, total nitrogen of 0.77%, total organic carbon of 18.25%, carbon content of 15.86%, and sulfur content of 0.14%. Soilless growing media comprising peat moss, perlite, and rotary drum compost in three proportions (1:1:1, 1:1:2, and 1:1:3), and peat moss, perlite, and commercial organic compost in a 1:1:3 ratio were evaluated for greenhouse vegetable production. The performance of cucumbers (Cucumis sativus cv. Ramos) raised in the lowest proportion of in-house prepared rotary drum compost (1:1:1 ratio) was comparable with that raised in the highest proportion of commercial compost (1:1:3). The study revealed the potential of RDC for decentralized sustainable waste management at the small-community scale and the suitability of compost from school wastes for soilless culture. [ABSTRACT FROM AUTHOR]

Various soilless substrate components have been evaluated for many years to identify sustainable resources that do not negatively impact plant growth. Biochar is a carbon-based material that has been evaluated for use as an alternative aggregate in peat-based soilless substrates. In addition, the use of carbon adsorption for compound removal is widely used in groundwater remediation, municipal water filtration, and volatile organic compounds. Experiment one aimed to determine the impact of coarse biochar (<6 mm) on paclobutrazol efficacy when incorporated at 15% or 30% by volume in a peat-based substrate when compared with a perlite-amended substrate at the same incorporation volumes. In Expt. 1, a single paclobutrazol drench application of 0, 0.5, 1.0, 2.0, and 4.0 mg·L21 was applied to 'Princettia Red' and 'Princettia White' poinsettias (Euphorbia pulcherrima × Euphorbia cornastra). In Expt. 2, two different biochar particle sizes of coarse (<6 mm) and extra coarse (>6 mm) were examined at the same incorporation volumes as Expt. 1 and compared with a perlite-amended substrate at the same incorporation volumes. However, during Expt. 2, continual drench applications at times of irrigation of 0.0, 6.25, 12.5, 25.0, 50, and 100 lg·L21 (ppb) paclobutrazol were applied to pansy (Viola ×wittrockiana) 'Matrix Blue Blotch' and begonia (Begonia ×hybrida) 'Big Red Bronze Leaf'. The efficacy of paclobutrazol drenches for controlling growth in all species was unaffected by the substrate composition regarding aggregate type or aggregate incorporation rate. Thus, even though biochar is often used for bioremediation and wastewater treatment, it did not negatively impact the efficacy of paclobutrazol drenches at the concentrations used. This research suggests that when biochar is used as an amendment to peatmoss it will not influence paclobutrazol drench efficacy when incorporated up to 30% by volume for the examined species. [ABSTRACT FROM AUTHOR]

Humic substances are components of soil organic matter that influence soil structure and fertility. Humic and fulvic acids can be extracted from soil and other organic sources, and are used as biostimulants to promote plant growth and increase nutrient availability and uptake. The goal of this study was to determine whether selected humic and fulvic acid-based commercial products would promote growth and flowering of petunia (Petunia ×hybrida) 'Picobella Blue' grown in soilless media with low or optimal fertilizer rates. Plants were grown in 11.4-cm pots filled with peat-based media [80:20 peat:perlite (v/v); pH 5.4]. Three biostimulant products were evaluated at different rates and application frequencies: Huma Pro, a liquid humic acid biostimulant; Fulvi Pro, a liquid fulvic acid biostimulant; andMicromate, a powder containing both humic and fulvic acids. In Expt. 1, Huma Pro and Fulvi Pro were drenched weekly onto the growing media at a rate of 5, 10, or 20 mL·L-1; Micromate was drenched weekly at a rate of 5, 10, 20, or 40 g·L-1. Plants were fertilized with either 50 mg·L-1 nitrogen (N) (low fertility) or 100 mg·L-1 N (optimal fertility) from Jack's Professional 20N-1.3P-15.7K Petunia FeED each irrigation. Control plants received fertilizer but no biostimulant treatments. In Expt. 2, biostimulant treatments were drenched once at transplant, biweekly, or weekly at a rate of 1.25, 2.5, 5, or 10 mL·L-1 for Huma Pro and Fulvi Pro; and at 5, 10, 20, or 40 g·L-1 for Micromate. All plants received constant liquid feed at the lower fertilizer rate of 50 mg·L-1 N. In Expt. 1, plants fertilized with 100mg·L-1 N and treated with 20 g·L-1 Micromate had the best performance. The average shoot dry weight was 32% greater than that of the control plants. Micromate (20 g·L-1)-treated plants had an average of five more flowers per plant, and they flowered 4 days earlier than untreated control plants. In Expt. 2, plants treated with 40 g·L-1 of Micromate weekly had the greatest shoot dry weight compared with the other treatments. Weekly Micromate treatments (40 g·L-1) resulted in plants with an average of 13 more flowers per plant, which flowered 7 days earlier than control plants. Plants treated with Fulvi Pro and Huma Pro at 20 mL·L-1 had a significantly greater concentration of potassium in shoot tissue, whereas Micromate treatments at 20 and 40 g·L-1 resulted in a greater concentration of phosphorous in the shoots. The humic and fulvic acids in Micromate improved petunia crop quality by promoting vegetative growth, increasing flower numbers, and reducing the time to flower. [ABSTRACT FROM AUTHOR]

Humic substances are a type of biostimulant used in greenhouse production to promote plant growth and health. Our goal was to evaluate the effect of three commercially available biostimulants containing humic and/or fulvic acids (HumaPro, FulviPro, and Micromate) on the performance and tissue nutrient concentration of Solanum lycopersicum L. ‘Bush Beefsteak’ grown in a peat-based substrate. We conducted four experiments testing application rate and fertility level (50 and 100 mg⋅L–1 N) (Exp. 1), application rate and frequency (Exp. 2), direct Micromate incorporation into the substrate (Exp. 3), and FulviPro application method (drench vs. foliar spray) (Exp. 4). Plants were fertilized with 20N-1.3P-15.7K. Experiments 2, 3, and 4 were conducted under low fertility (50 mg⋅L–1 N). Micromate promoted growth when applied as a weekly drench at 40 g·L−1 or when incorporated into the substrate (20 g in 1 L of the substrate). Micromate-treated plants showed high P, S, and Si in the shoot and root tissues. FulviPro showed a negative effect when applied as a drench at higher rates, but foliar application increased greenness (Green Leaf Index). The negative effects of FulviPro might be due to the over-accumulation of Fe and Mn when applied as a drench.

The objective was to quantify the extractable micronutrient levels from container substrate components and limestone and their potential contribution as fertilizer sources for crop growth. Samples of horticultural limestone (29 samples) and substrate components [peat (48 samples), perlite (10), vermiculite (14), bark (15), and coconut coir (6)] were analyzed for micronutrient content with the SME (Saturated Medium Extract) method using either water (SMEW) or diethylenetriamine pentaacetate (SMED) as extractants for the substrate components, or following acid digestion of limestone samples. Samples were obtained from commercial substrate and greenhouse companies throughout the U.S. and Canada. Peat included 36 peat samples from two peat bogs in Alberta Canada to evaluate whether species composition, decomposition, and bog location affected micronutrient content. Increasing von Post decomposition increased SMEW and SMED Mn level and SMED Zn. As percent Sphagnum fuscum increased, extractable Fe and Mn levels increased for both extractant types, and SMEW extractable Zn increased. Based on established SME guidelines for acceptable to optimum nutrient levels for soilless substrates, peat and bark could potentially provide sufficient Fe and Mn to contribute to plant requirements. Average Fe content in limestone was 0.11%, and Mn content was 0.012%. Based on SMED extractions and lime analysis, Fe supplied by 100% peat and lime could potentially provide Fe at levels comparable with commercial pre-plant fertilizers if these Fe sources are plant-available. Substrate-pH affected solubility of Fe, Mn and Zn in peat. As substrate-pH increased, Fe and Zn solubility in peat decreased with both SMEW and SMED. The SMEW-extractable Mn decreased with increasing pH, in contrast to SMED-extractable Mn which increased as pH increased. Analysis of raw materials using SMED (substrate components) or complete digestion (limestone) is advised for substrate companies to proactively identify batches of components that may affect crop nutrition. Given this high level of potential contribution of Fe by peat and lime, it is likely that these uncontrolled sources contribute to nutrient uptake in horticultural production. However, further research is required to compare extractable micronutrients with actual plant uptake. [ABSTRACT FROM AUTHOR]

The practice of cultivating crops in a controlled environment using a soilless culture method is seeing an increasing level of popularity. The aforementioned challenges include addressing climate change, combating pests and diseases, mitigating falling soil fertility, and ensuring constant production and quality. One of the potential crops that could be grown with such a method is soybean. Soybean cultivation in a controlled environment using soilless culture still needs more information, especially regarding nutrient solution management of certain soybean varieties. Thus, this study investigated the impact of nutrient concentrations and variety on soybean growth, yield, and chemical composition. This research was carried out in a plant growth chamber using expanded clay aggregate as a soilless substrate. The treatments were four nutrient concentrations: 0% (control), 50%, 100%, and 150%, and two different varieties: Martina and Johanna. The findings of this research revealed that there were significant differences in nutrient treatments on all parameters measured. Application of nutrient concentration at 50% resulted in the most profound root size for both varieties. Applying 100% nutrient concentration produced a higher 100-grain weight for the Johanna variety. Application of nutrient concentration at 150% resulted in the highest shoot weight and shoot:root ratio for both varieties, with varietal differences. Furthermore, applying nutrient concentration at 150% also produced the highest grain yield/pot, protein yield, and lipid yield for both varieties. Thus, the nutrient concentration between 100% and 150% gave a positive effect and can be applied for planting Martina and Johanna using this system. [ABSTRACT FROM AUTHOR]

Dormant containerized blackberry plants grown as long canes are forced into protected environments, such as plastic tunnels or greenhouses, to schedule harvesting for important market weeks. The time needed to produce a crop is mainly a function of temperature. In this study, the objectives were to quantify the effects of temperature on plant development rates for long-cane blackberry and develop simple models predicting the time from forcing dormant plants to first open flowers and ripe fruit as a function of average daily temperature (ADT). The crop time and ADT at the first-flower and -fruit stages were measured for the cultivars 'Loch Ness', 'Osage', 'Ponca', and 'Prime-Ark® 45′ grown as long canes during a greenhouse and high-tunnel experiment, and the days to flowering and fruiting were converted to rates by calculating the reciprocal. Nonlinear models relating flowering and fruiting rates to ADT were developed for each cultivar using a combination of the experimental data and base (6 °C), optimum (25 °C), and maximum (35 °C) temperature parameters derived from a previous blackberry heat unit study. Model accuracy was evaluated by comparing the predicted to observed times to first flower and fruit per cultivar. Average daily temperature was shown to have a main influence on crop timing, as shown by a strongly positive and near 1:1 relationship between predicted and observed days to flowering/fruiting. However, there was significant variability depending on the cultivar and model accuracy within ±7 days, ranging from 50% ('Prime-Ark® 45) to 90% ('Loch Ness') for the flower models and from 60% ('Prime-Ark® 45) to 100% ('Loch Ness') for the fruit models. To the best of our knowledge, this study is the first to characterize the relationship between temperature and crop timing for soilless long-cane blackberry, and it provides a framework for modeling temperature effects on crop timing for these systems. The authors discuss further methods to improve model accuracy and precision for commercial use. These models can also be used for general training purposes to help educate growers on how temperature influences crop scheduling during long-cane blackberry production. [ABSTRACT FROM AUTHOR]

Soilless cultivation systems in a controlled environment are increasingly being used due to several global issues such as climate change, pest and disease problems, declining soil fertility quality and limited agricultural land. Soybean is one of the potential crops that can be grown using the soilless planting system in a controlled environment. Therefore, a study was conducted to investigate the effect of nutrient concentrations on the early development of two soybean varieties. Four different nutrient concentrations (0%, 50%, 100% and 150%) were applied, and two soybean varieties (Martina and Johanna) were tested. This study was designed in a split-plot experimental design where the nutrient concentration was the main plot and the variety was the sub-plot. The data record was started after fertilization. The plant growth data were collected for five weeks. All the data were analyzed statistically using SPSS V.23 software. The results of the study found that the nutrient concentration affected the number of leaves and leaf area. The number of leaves was higher in the treatment using 100% and 150% nutrients. Meanwhile, the leaf area increased with increasing nutrient concentration from 0% to 150%. The nutrient concentration then interacted with the variety in influencing the plant height. The plant height of the Martina variety was higher than the Johanna variety when 0% and 100% nutrients were applied. The variety also affected the leaf area and interacted with the number of weeks in affecting the SPAD readings and number of leaves. Thus, the two tested varieties (Johanna and Martina) have distinct early growth patterns that differ from one another as affected by the nutrient concentrations and plant age (number of weeks). [ABSTRACT FROM AUTHOR]

Raspberry fruits are a valuable source of bioactive compounds. The study used the modification of the substrate (coconut fibre), consisting of the use of various organic and mineral additives, in the soilless cultivation of raspberries. The additives influenced the biosynthesis of bioactive compounds in the raspberry fruits by modifying the sorption properties and the abundance of the substrate. The influence of the additives on the content of polyphenols was determined as well as their profile (UPLC-MS), antioxidant potential (ABTS), vitamin C content, and the activity of selected enzymes that are markers of stress and resistance to abiotic factors. In the study, a significant effect of these additives was observed on the biosynthesis of polyphenols in raspberry fruit. The highest increase in the content of these compounds in relation to the control sample (substrate—100% coconut fibre), namely 37.7%, was recorded in the case of fruit produced on coconut substrate enriched with sheep wool. These fruits were also characterised by a significantly different profile of these compounds. These changes were caused by readily available ammonium nitrogen and free amino acids in the decomposition of proteins contained in the sheep wool. This was confirmed by the recorded content of chlorophyll SPAD in the plant leaves and the activity of selected enzymes, which proves a low level of stress and good condition of the plants. [ABSTRACT FROM AUTHOR]

The use of wood-derived materials in soilless substrates for horticultural crop production is increasing; however, there is little information about the effects of wood on the incidence and severity of soilborne diseases of container-grown plants. The objectives of this research were to compare three differently processed wood substrate components blended with sphagnum peat and to investigate the effect of the peat:wood blend ratio on damping-off disease caused by Rhizoctonia solani using radish as a model system. In objective one, raw sphagnum peat was blended with three types of processed pine wood, screw-extruded, twin disc-refined, and hammer-milled, at a volumetric ratio of 70:30 and compared to a 70:30 peat:perlite mix. Radish plants grown in the hammer-milled wood and disc-refined wood had significantly lower damping-off disease severity compared to plants grown in the peat–perlite control. In objective two, sphagnum peat was blended with the three types of processed wood at a volumetric ratio of 90:10, 80:20, and 70:30 and compared to a 70:30 peat–perlite mix. The effect of the blend ratio varied by wood processing type. Higher percentages of Forest Gold and pine tree substrate resulted in lower disease severity. In both objectives, radish plants grown in any of the substrate treatments containing wood infested with R. solani tended to have lower disease severity compared to plants in the control. Results of this study indicate that the blending of processed pine wood-derived components into peat may enhance the natural suppression of damping-off disease of radish. Further research is needed to elucidate the mode of action of wood-derived materials on disease suppression in container-grown crops and to study the effects for other plant pathogens and crop species. [ABSTRACT FROM AUTHOR]

Dormant containerized blackberry plants grown as long canes are forced into protected environments, such as plastic tunnels or greenhouses, to schedule harvesting for important market weeks. The time needed to produce a crop is mainly a function of temperature. In this study, the objectives were to quantify the effects of temperature on plant development rates for long-cane blackberry and develop simple models predicting the time from forcing dormant plants to first open flowers and ripe fruit as a function of average daily temperature (ADT). The crop time and ADT at the first-flower and -fruit stages were measured for the cultivars ‘Loch Ness’, ‘Osage’, ‘Ponca’, and ‘Prime-Ark® 45′ grown as long canes during a greenhouse and high-tunnel experiment, and the days to flowering and fruiting were converted to rates by calculating the reciprocal. Nonlinear models relating flowering and fruiting rates to ADT were developed for each cultivar using a combination of the experimental data and base (6 °C), optimum (25 °C), and maximum (35 °C) temperature parameters derived from a previous blackberry heat unit study. Model accuracy was evaluated by comparing the predicted to observed times to first flower and fruit per cultivar. Average daily temperature was shown to have a main influence on crop timing, as shown by a strongly positive and near 1:1 relationship between predicted and observed days to flowering/fruiting. However, there was significant variability depending on the cultivar and model accuracy within ±7 days, ranging from 50% (‘Prime-Ark® 45) to 90% (‘Loch Ness’) for the flower models and from 60% (‘Prime-Ark® 45) to 100% (‘Loch Ness’) for the fruit models. To the best of our knowledge, this study is the first to characterize the relationship between temperature and crop timing for soilless long-cane blackberry, and it provides a framework for modeling temperature effects on crop timing for these systems. The authors discuss further methods to improve model accuracy and precision for commercial use. These models can also be used for general training purposes to help educate growers on how temperature influences crop scheduling during long-cane blackberry production.

Soilless cultivation systems in a controlled environment are increasingly being used due to several global issues such as climate change, pest and disease problems, declining soil fertility quality and limited agricultural land. Soybean is one of the potential crops that can be grown using the soilless planting system in a controlled environment. Therefore, a study was conducted to investigate the effect of nutrient concentrations on the early development of two soybean varieties. Four different nutrient concentrations (0%, 50%, 100% and 150%) were applied, and two soybean varieties (Martina and Johanna) were tested. This study was designed in a split-plot experimental design where the nutrient concentration was the main plot and the variety was the sub-plot. The data record was started after fertilization. The plant growth data were collected for five weeks. All the data were analyzed statistically using SPSS V.23 software. The results of the study found that the nutrient concentration affected the number of leaves and leaf area. The number of leaves was higher in the treatment using 100% and 150% nutrients. Meanwhile, the leaf area increased with increasing nutrient concentration from 0% to 150%. The nutrient concentration then interacted with the variety in influencing the plant height. The plant height of the Martina variety was higher than the Johanna variety when 0% and 100% nutrients were applied. The variety also affected the leaf area and interacted with the number of weeks in affecting the SPAD readings and number of leaves. Thus, the two tested varieties (Johanna and Martina) have distinct early growth patterns that differ from one another as affected by the nutrient concentrations and plant age (number of weeks).

A comprehensive understanding of the distribution and water movement of the substrate in root areas is crucial to the design and management of drip irrigation systems, which is a significant step to maximizing crop water use efficiency by understanding the hydrodynamics in soilless substrates. In this study, an improved HYDRUS-2D model by the dynamic root growth model was used to simulate water movement under the condition of drip irrigation and the water uptake process of the root, and then, compared with the observed data. Substrate water content under drip irrigation was also measured with the calibrated ECH20-EC5 sensors. The situation of substrate water movement was analyzed under the conditions of different depths, different initial water content, and different irrigation amount. The substrate water movement under different drip irrigation conditions was explored. The results showed that incorporating the defined initial and boundary conditions and the hydraulic characteristics of the substrate into the model enabled HYDRUS model to predict the movement and position of water in unsaturated porous media by solving Richards equation. Under drip irrigation, the substrate wetting body was approximately a quarter ellipse, and the water would continue to move to the area where the wetting front did not reach within 1 h after irrigation. The simulation results of the improved HYDRUS-2D model agreed well with those observed by the ECH2O-EC5 sensors, and the model could provide a basis for precision irrigation of soilless substrate culture under drip irrigation. [ABSTRACT FROM AUTHOR]

Peat and coir are commonly used for substrate production of highbush blueberry (Vaccinium sp.). Perlite is also typically added to improve drainage and stability of the media. The purpose of the present study was to determine how various combinations of each affect growth and nutrition in highbush blueberry. Two cultivars, ‘Liberty’ northern highbush blueberry (V. corymbosum L.) and ‘Jewel’ southern highbush blueberry (interspecific hybrid of V. corymbosum L. and V. darrowii Camp.), were grown for 3 months in media containing 0%, 10%, 20%, or 30% perlite, by volume, and a 1:0, 2:1, 1:2, or 0:1 ratio of peat and coir. At 95 days after transplanting, total dry weight of the ‘Liberty’ plants was greatest in pure peat and progressively less as more coir or perlite was added to the media. Total dry weight of ‘Jewel’ also declined with increasing amounts of perlite but, in this case, was unaffected by the ratio of peat and coir. The response of the plants to perlite did not appear to be a function of pH or nutrition and was most likely related to the effects of perlite on media water relations. Response to peat and coir, on the other hand, may have been due to nutrition and salinity of the media. In both cultivars, a higher amount of peat in the media improved uptake of N, P, Mg, and S and decreased uptake of K, B, Zn, and Na. Coir, on the other hand, contained higher concentrations of Na and Cl than peat. These findings suggest that the use of high amounts of perlite in the media could be detrimental when growing highbush blueberry in substrate, and some cultivars may grow better in peat than in coir.

The use of wood-derived materials in soilless substrates for horticultural crop production is increasing; however, there is little information about the effects of wood on the incidence and severity of soilborne diseases of container-grown plants. The objectives of this research were to compare three differently processed wood substrate components blended with sphagnum peat and to investigate the effect of the peat:wood blend ratio on damping-off disease caused by Rhizoctonia solani using radish as a model system. In objective one, raw sphagnum peat was blended with three types of processed pine wood, screw-extruded, twin disc-refined, and hammer-milled, at a volumetric ratio of 70:30 and compared to a 70:30 peat:perlite mix. Radish plants grown in the hammer-milled wood and disc-refined wood had significantly lower damping-off disease severity compared to plants grown in the peat–perlite control. In objective two, sphagnum peat was blended with the three types of processed wood at a volumetric ratio of 90:10, 80:20, and 70:30 and compared to a 70:30 peat–perlite mix. The effect of the blend ratio varied by wood processing type. Higher percentages of Forest Gold and pine tree substrate resulted in lower disease severity. In both objectives, radish plants grown in any of the substrate treatments containing wood infested with R. solani tended to have lower disease severity compared to plants in the control. Results of this study indicate that the blending of processed pine wood-derived components into peat may enhance the natural suppression of damping-off disease of radish. Further research is needed to elucidate the mode of action of wood-derived materials on disease suppression in container-grown crops and to study the effects for other plant pathogens and crop species.

The objective of this study was to evaluate silicon (Si) foliar spray and substrate drench effects on plant growth and morphology for container-grown edible crops during greenhouse production, as well as resistance to plant wilting during post-production. In the first greenhouse experiment, basil received Si foliar sprays at 0, 50, 100, 200, and 400 mg·L–1 Si. In the second greenhouse experiment, Si was applied as either a foliar spray (500 mg·L–1 Si) or substrate drench (100 mg·L–1 Si) with six edible crop species. Supplemental Si increased shoot Si levels but had minimal effects on plant growth and morphology, except for parsley, which resulted in distorted growth and phytotoxicity. In the first experiment, 200 and 400 mg·L–1 Si foliar sprays increased plant resistance to wilt by 2.2 and 2.5 d, respectively; however, this was not observed in the second experiment. All species accumulated Si with the control (no Si) treatments, indicating trace amounts of Si were taken up from the substrate, fertilizer, spray surfactant, and irrigation water. Only cucumber was classified as a Si “accumulator” with a high capacity for Si uptake. Results emphasize the need to conduct preliminary trials with supplemental Si to avoid issues of phytotoxicity. [ABSTRACT FROM AUTHOR]

Soilless substrates are routinely amended with dolomite and sulfate-based micronutrients to improve fertility, but the effect of these amendments on phosphorous (P) in substrate pore-water during containerized crop production is poorly understood. The objectives of this research were as follows: compare the effects of dolomite and sulfate-based micronutrient amendments on total P (TP), total dissolved P (TDP), orthophosphate P (OP), and particulate P (PP; TP − TDP) concentrations in pour-through extracts; to model saturated solid phases in substrate pore-water using Visual MINTEQ; and to assess the effects of dolomite and micronutrient amendments on growth and subsequent P uptake efficiency (PUE) of Lagerstroemia L. ‘Natchez’ (crape myrtle) potted in pine bark. Containerized crape myrtle were grown in a greenhouse for 93 days in a 100% pine bark substrate containing a polymer-coated 19N–2.6P–10.8K controlled-release fertilizer (CRF) and one of four substrate amendment treatments: no dolomite or micronutrients (control), 2.97 kg·m−3 dolomite (FL); 0.89 kg·m−3 micronutrients (FM); or both dolomite and micronutrients (FLM). Pour-through extracts were collected approximately weekly and fractioned to measure pore-water TP, TDP, and OP and to calculate PP. Particulate P concentrations in pour-through extracts were generally unaffected by amendments. Relative to the control, amending pine bark with FLM reduced water-extractable OP, TDP, and TP concentrations by ≈56%, had no effect on P uptake efficiency, and resulted in 34% higher total dry weight (TDW) of crape myrtle. The FM substrate had effects similar to those of FLM on plant TDW and PUE, and FM reduced pore-water OP, TDP, and TP concentrations by 32% to 36% compared with the control. Crape myrtle grown in FL had 28% lower TDW but pour-through OP, TDP, and TP concentrations were similar to those of the control. Chemical conditions in FLM were favorable for precipitation of manganese hydrogen phosphate (MnHPO4), which may have contributed to lower water-extractable P concentrations in this treatment. This research suggests that amending pine bark substrate with dolomite and a sulfate-based micronutrient fertilizer should be considered a best management practice for nursery crop production.

Two massive wastes are cigarette butts (CB) and stone wool (SW), both representing a threat to the environment. Although the cellulose acetate filters (CAF) in CB are long-term degradable, SW soilless substrates are not. Here, a soilless substrate for growing ornamental plants was manufactured with CAF and compared to commercial SW substrate. CB treatment consisted of a washing in boiling water with a dramatic reduction of pollutants in CAF. Then, cleaned filters were separated, dried, carded to fibers, and subsequently compacted into plugs. The trace pollutants in recycled CAF substrate did not negatively affect the germination of Spartium junceum L. and Lavandula angustifolia Miller seeds as well as the root development of Salvia officinalis L. and Salvia rosmarinus Schleid. stem cuttings. Plants grown in recycled CAF showed a differential species-dependent change of pigments in comparison with those in SW, without compromising their photosynthesis performance. Overall, the results demonstrated that these plants can be well established and grow in recycled CAF, as comparable to SW substrate. This study highlights a novel and promising solution in CAF recycling by turning this litter into an efficient soilless substrate for growing ornamental plants, thus limiting the use of SW and indirectly decreasing its industrial waste flow.

Objectives were 1) to quantify acidic and basic effects on the root zone pH for eight vegetable and herb species grown in peat-based substrate and hydroponic nutrient solution and 2) to determine the applied NH4+:NO3- ratio expected to have a neutral pH reaction for each species during its vegetative growth phase. In one experiment, plants were grown for 33 days in substrate (70% peat:30% perlite by volume), and were fertilized with a nutrient solution containing 7.14 milli-equivalents (mEq)·L-1 N and NH4+:NO3- ratios ranging from 0:100 to 40:60. During the second experiment, the same species were grown in hydroponic nutrient solutions at 7.14 mEq·L-1 N with NH4 +:NO3- ratios ranging from 0:100 to 30:70, and data were collected over a 6-day period. In substrate, species increased root zone pH when supplied 0:100 solution, except for cucumber, which did not change substrate pH. Increasing the NH4 +:NO3- ratio to 40:60 increased acidity and decreased pH across species. Similar trends were observed in hydroponics, in which the most basic response occurred across species with 0:100, and the most acidic response occurred with 30:70. Arugula was the only species that increased root zone pH with all three NH4 +:NO3- ratios in substrate and hydroponics. In substrate and hydroponics, mEq of acidity (negative) or basicity (positive) produced per gram dry weight gain per plant (mEq·gL1) correlated positively with mEq·gL1 net cation minus anion uptake, respectively, in which greater cation uptake resulted in acidity and greater anion uptake resulted in basicity. In hydroponics, the greatest net anion uptake occurred with 0:100, and increasing the NH4 +:NO3- ratio increased total cation uptake across species. Cucumber had the most acidic effect and required less than 10% of N as NH4 +-N for a neutral pH over time, arugula was the most basic and required more than 20% NH4+-N, and the remaining species had neutral percent NH4 +-N between 10% and 20% of N. Increasing the NH4+:NO3- ratio decreased Ca2+ uptake across all species in hydroponics, which could potentially impact tip burn and postharvest quality negatively. Controlling root zone pH in substrate and hydroponic culture requires regular pH monitoring in combination with NH4 +:NO3- adjustments and other pH management strategies, such as injecting mineral acid to neutralize irrigation water alkalinity or adjusting the limestone incorporation rate for substrate. [ABSTRACT FROM AUTHOR]

The objective of these experiments was to determine if preemergence herbicides perform similarly across pine bark that was aged for varying lengths of time including 0, 4, 8, and 12 months after bark removal from harvested trees. Three preemergence herbicides were evaluated for three separate weed species, including 1) Cardamine flexuosa With. (bittercress) with isoxaben, 2) Digitaria sanguinalis (L.) Scop. (large crabgrass) with prodiamine, and 3) Oxalis stricta L. (woodsorrel) with dimethenamid-P. Leaching of herbicides through substrates was evaluated for prodiamine. Weed growth in the various substrates was variable, but few differences were detected in weed growth among the pine bark substrates evaluated. For isoxaben and prodiamine, weed control was similar among the pine bark substrates in most cases when label rates were applied. Although some differences were detected in prodiamine performance across different pine bark ages, a high level of control was achieved in all cases at rates well below manufacturer recommendations. Prodiamine leaching was minimal in all substrates. It would be recommended that growers test substrates for physical properties before use so that irrigation and other production inputs could be modified if needed. In most cases, growers should expect similar performance of preemergence herbicides regardless of pine bark substrate age. [ABSTRACT FROM AUTHOR]

Nursery production of birch (Betula nigra L.) trees commonly occurs in containers using a soilless substrate such as pine bark or peat moss. Birch trees have been reported to suffer from pH-induced micronutrient deficiencies in landscapes; thus, they are recommended to be planted in low-pH soils (<6.5). Little research has addressed the influence of substrate pH on birch trees during container production. Therefore, the objective of this research was to determine if substrate pH influences birch tree growth and development. Birch (Betula nigra 'NBMTF') liners were transplanted into 11.4 L plastic nursery containers filled with an 80 pine bark: 20 sphagnum peat moss (v:v) amended with either 0.6 kg.m−3 of elemental sulfur (S) or 0, 1.8, 3.5, or 7.1 kg.m−3 dolomitic lime. Substrate pH ranged from 4.8 to 7.3. There were only a few and minor differences in leaf chlorophyll content and no differences in plant growth. Differences in leachate and plant tissue nutrient concentration occurred for some elements, although these differences were not enough to affect plant growth. Container-grown birch trees can be grown over a wide range of substrate pH (4.8 to 7.3) with little or no effect on their growth. [ABSTRACT FROM AUTHOR]

Floriculture species differ in their effect on substrate-pH and the resulting substrate micronutrient availability in container production. The objective was to quantify effects of floriculture plant species on substrate-pH. In a growth chamber factorial experiment, 15 floriculture species were grown in 70%:30% by volume peat:perlite substrate and fertilized with nutrient solutions containing 100 mg⋅L-1 N and NH4+-N:NO3--N nitrogen ratios of 0:100, 20:80, or 40:60. The relationship between substrate-pH and milliequivalents (meq) of acid or base per unit volume of substrate was quantified by titration with hydrated dolomitic lime or HCl. After 33 days, species and solution type effects on substrate-pH and estimated meq of acid or base produced were evaluated. Final substrate-pH ranged from 4.83 for geranium in 40:60 solution to 6.58 for lisianthus in 0:100 solution, compared with an initial substrate-pH of 5.84. This change in substrate-pH corresponded with a net meq of acid or base produced per gram of tissue dry mass gain (NMEQ) ranging across solutions and species from 1.47 of base for lisianthus in the 0:100 solution to 2.10 of acid for coleus in the 40:60 solution. With the 0:100 solution, geranium produced the greatest NMEQ of acid (0.07), whereas lisianthus produced the greatest NMEQ of base (1.47). Because all N in the 0:100 solution was in the NO3- anion form, meq of both anions and cations taken up by plant roots could be calculated based on tissue analysis. With the 0:100 solution, species that took up more anions than cations into plant tissue tended to have a more basic effect on substrate-pH, as would be expected to maintain electroneutrality. Data were used to estimate the percent NH4+-N of total N in a nutrient solution that would be neutral (results in no substrate-pH change) for each species. This neutral percent NH4+-N of total N ranged from ≈0% (geranium) to 35% (pentas). Species were separated into three clusters using k-means cluster analysis with variables related to NMEQ and anion or cation uptake. Species were clustered into groups that had acidic (geranium and coleus), intermediate (dusty miller, impatiens, marigold, new guinea impatiens, petunia, salvia, snapdragon, and verbena), or basic (lisianthus, pansy, pentas, vinca, and zinnia) effects on substrate-pH. Evaluating the tendency to increase or decrease substrate-pH across a range of floriculture species, and grouping of plants with similar pH effects, could help predict NH4+:NO3- ratios for a neutral pH effect and assist growers in managing substrate-pH for container production. [ABSTRACT FROM AUTHOR]

Recently developed capacitance soil moisture sensors are suitable for measuring volumetric water content (VWC, v/v) of soilless substrates in real time, useful for substrate moisture based-automated irrigation systems of horticultural crops. For capacitance sensors, a substrate-specific calibration is required for accurate VWC measurements, but sensor manufacturers typically provide only a general calibration for potting soil. However, the general calibration for potting soil is not indicative of the variety of soilless substrates. We investigated and compared the physical properties of various coir dust and perlitemix ratios (1:0, 8:2, 6:4, 4:6, 2:8, 0:1, v/v), and conducted individual substrate-specific VWC calibrations in the range from 0.1 m³⋅m-3 to near container capacity. Sensor outputs [in mV and analog-to-digital converter (ADC)] of various VWC levels of the specific substrates were collected with four EC-5 and GS3 sensors (Decagon Devices Inc., Pullman, WA) connected to a data logger with 2.5-V and 12-V excitation, respectively. Substrates with greater relative perlite contents had larger particles, and both the water-holding capacity and electrical conductivity (EC) were lower than the substrate mixes with more coir dust. All tested substrate mixes had linear relationship between EC-5 sensor output and VWC with high R² (>0.93) except in the case of 100% perlite, and their slopes were significantly different across the substrate mixes (P = 0.03). However, most of the substrate mixes had similar calibrations with estimated VWC differences within 0.06 m³⋅m-3. TheGS3 sensor had the best fit with a logarithmic relationship between sensor output (in ADC) and VWC, and the slopes among the substrate mixes were not significantly different (P = 0.13). Furthermore, the soilless substrate calibration provided by the company differed from the substrate-specific calibration, resulting in considerable error (up to 0.18 m³⋅m-3 difference), during the measurement of the actual VWCs. Therefore, sensor- and substrate-specific calibration is required for accurate VWC measurements with capacitance sensors. [ABSTRACT FROM AUTHOR]

The effects of organic soilless substrates on growth and yield of ginger were studied. In soilless production system, many types of growing media or substrates such as rockwool, perlite, vermiculite and peat have been used to grow many kinds of crops. Alternative substrates that are cheaper and locally available such as coconut fibres and burnt paddy husks should be used as alternative media. The main objective of the study was to determine the most suitable organic growth substrate for cultivation of ginger using fertigation technique. The study was conducted under the side-netted rain shelter equipped with an irrigation system to supply fertiliser solution at a regulated time schedule. Five combinations of growth substrates were evaluated: 100% coir dust; 100% burnt paddy husks; 70% coir dust + 30% burnt paddy husks; 30% coir dust + 70% burnt paddy husks; and 50% coir dust + 50% burnt paddy husks. The ginger plants were selected randomly and the rhizomes were harvested 3 - 9 months after sowing. Plants grown in 100% coir dust gave the best growth performance and yield compared to the other treatments. They produced the highest shoot height (123 ± 23 cm), shoot fresh weight (1,340 ± 235 g) and rhizome yield (5,480 ± 325 g per plant). The lowest rhizome yield (2,570 ± 135 g) was obtained from plants planted in 30% coir dust + 70% burnt paddy husks. Hence, it can be concluded that the ginger plants cultivated in 100% coir dust substrate using fertigation technique gave the best plant growth and yields. [ABSTRACT FROM AUTHOR]

• Yield and fruit quality varied significantly by genotype. • Yields ranged from 0.4 kg/bush to 2.5 kg/bush in the first two years. • Substrate composition nor container size made a difference on vegetative or reproductive growth. • Yield and fruit quality was not affected by either substrate or container size. • Differences among genotypes indicated breeding for this intensive system might be needed. Southern highbush blueberry (SHB) production is continuing to expand worldwide. Innovative horticulture practices including container-based cultivation, evergreen management, high-density planting, and high-tunnel production have been explored to maximize the productivity and profitability of SHB production. However, there is a lack of information on the feasibility of integration of all these practices to establish an intensive production system in Florida. We aimed to test and optimize this intensive system by evaluating container size, substrate composition, and genotype. Two container sizes (50.5 L and 40.4 L), five different combinations of pine bark, coco coir, and perlite, and five SHB genotypes were tested in this study. Plant vegetative growth, yield, and berry quality were measured for two years. There were no impacts of substrate composition and container size on vegetative or reproductive growth during the two-year production period studied. Plant height and canopy width varied among genotypes due to their canopy architecture. Yields of each genotype ranged from 1.0 kg/bush to 2.5 kg/bush in the first year and ranged from 0.4 kg/bush to 2.1 kg/bush in the second year. Significant differences in the performance of five genotypes tested in this study indicated that is necessary to breed cultivars specifically for this intensive system. [ABSTRACT FROM AUTHOR]

Highlights: [•] Biochar is the solid, carbon-rich residual from the pyrolysis of biomass. [•] Biochars were produced from wood pellets and pelletized wheat straw. [•] Both biochars proved acceptable as peat replacements in potting substrates at levels up to 15%. [Copyright &y& Elsevier]

This research work was conducted to investigate the possibility of usingWashingtonia robustaH. Wendl. pruning waste as growing media and raw material for particleboard production. In the growing media experiment, variable factors were the particle size (0.25–4, 2–4, 1–2, and 0.25–1 mm), and in the particleboard experiment, the variables wereg the particle size (2–4, 1–2, and 0.25–1 mm), press temperature (120 and 140oC), and press pressure (15.7 and 21.0 kg cm−2). The main physical and chemical properties of the growing media were determined and the experimental panels were tested for their mechanical and physical properties according to the procedures defined by European Union (EN) standards. With respect to agricultural value, theW. robustapruning waste had low macro- and microelement contents [except in the case of potassium (K)] and high carbon (C) / nitrogen (N) ratio values (C/N ratio >130), and the majority of the studied physical properties were not inside the interval of values for an ideal substrate. On the other hand, in general, the physical and mechanical properties of the particleboards from theW. robustapruning waste were appropriate according to the EN standards for particleboards. These properties were more significantly affected by the particle size than by the board manufacturing conditions. [ABSTRACT FROM AUTHOR]

Abstract: Soilless substrates are primarily used in the production of containerized greenhouse and nursery crops. Sphagnum peat moss is a primary constituent of these substrates and its harvest from endangered ecosystems has become a worldwide concern. Ethanol-extracted, coarse-ground corn (Zea mays L. ‘Silver Queen’) tassels were used as a peat replacement for potting substrates. Replacing peat moss with increasing levels of ground tassel (up to 50%, v/v) elevated pH and electrical conductance, while having variable effects on substrate physical properties (bulk density, percent solids, air porosity, container capacity, and total porosity). Two identical greenhouse experiments separated by time were conducted using tomato (Solanum lycopersicum L. ‘Red Robin’) plants grown in 6.0-L pots. In the first experiment, all substrates were similar for total tomato yield per plant and number of fruit per plant, with only the 50% tassel substrate having significantly lower values. There were no differences for plant height or average fruit weight among substrates. No differences were found for any of these variables in the second experiment. This research indicates that extracted ground tassels may be utilized as a suitable replacement for peat in greenhouse substrates for tomatoes. [ABSTRACT FROM AUTHOR]

Abstract: Commercial potting media often contain substantial amounts of peat that was mined from endangered bog and fen ecosystems. The main objectives of this study were to assess (1) whether the amendment of 0, 20, 40, 60, 80 and 100% (v/v) of vermicompost (VC) to a fertilized commercial peat potting substrate has effects on the emergence, growth and biomass allocation of tomato seedlings (Lycopersicon esculentum Mill.) under greenhouse conditions, (2) whether possible impacts on seedlings can affect tomato yields and fruit quality even when transplanted into equally fertilized field soil, and (3) whether effects are consistent among different tomato varieties. Amended VC was produced in a windrow system of food and cotton waste mainly by earthworms Eisenia fetida Sav. Vermicompost amendments significantly influenced, specifically for each tomato variety, emergence and elongation of seedlings. Biomass allocation (root:shoot ratio) was affected by VC amendments for two varieties in seedling stage and one field-grown tomato variety. Marketable and total yields of field tomatoes were not affected by VC amendments used for seedling husbandry. However, morphological (circumference, dry matter content, peel firmness) and chemical fruit parameters (contents of C, N, P, K, Ca, Mg, l-ascorbic acid, glucose, fructose) were significantly affected by VC amendments in seedling substrates; these effects again were specific for each tomato variety. Overall, vermicompost could be an environmentally friendly substitute for peat in potting media with similar or beneficial effects on seedling performance and fruit quality. However, at least for tomatoes, variety-specific responses should be considered when giving recommendations on the optimum proportion of vermicompost amendment to horticultural potting substrate. [Copyright &y& Elsevier]

Two experiments were completed to determine whether the form and concentration of iron (Fe) affected Fe toxicity in the Fe-efficient species Pelargonium xhortorum 'Ringo Deep Scarlet' L.H. Bail. grown at a horticulturally low substrate pH of 4.1 to 4.9 or Fe deficiency in the Fe-inefficient species Calibrachoa xhybrida 'Trailing White' Cerv. grown at a horticulturally high substrate pH of 6.3 to 6.9. Ferric ethylenediaminedi(o-hydroxyphenylacetic) acid (Fe-EDDHA), ferric ethylenediamine tetraacetic acid (Fe-EDTA), and ferrous sulfate heptahydrate (FeSO4⋅7H2O) were applied at 0.0, 0.5, 1.0, 2.0, or 4.0 mg⋅L-1 Fe in the nutrient solution. Pelargonium showed micronutrient toxicity symptoms with all treatments, including the zero Fe control. Contaminant sources of Fe and Mn were found in the peat/perlite medium, fungicide, and lime, which probably contributed to widespread toxicity in Pelargonium. Calibrachoa receiving 0 mg Fe/L exhibited severe Fe deficiency symptoms. Calibrachoa grown with Fe-EDDHA resulted in vigorous growth and dark green foliage, with no difference from 1 to 4 mg⋅L-1 Fe. Using Fe-EDTA, 4 mg Fe/L was required for acceptable growth of Calibrachoa, and all plants grown with FeSO4 were stunted and chlorotic. Use of Fe-EDDHA in water-soluble fertilizer may increase the upper acceptable limit for media pH in Fe-inefficient species. However, iron and Mn present as contaminants in peat, irrigation water, or other sources can be highly soluble at low pH. Therefore, it is important to maintain a pH above 6 for Fe-efficient species regardless of applied Fe form or concentration, in order to avoid the potential for micronutrient toxicity. [ABSTRACT FROM AUTHOR]

Two massive wastes are cigarette butts (CB) and stone wool (SW), both representing a threat to the environment. Although the cellulose acetate filters (CAF) in CB are long-term degradable, SW soilless substrates are not. Here, a soilless substrate for growing ornamental plants was manufactured with CAF and compared to commercial SW substrate. CB treatment consisted of a washing in boiling water with a dramatic reduction of pollutants in CAF. Then, cleaned filters were separated, dried, carded to fibers, and subsequently compacted into plugs. The trace pollutants in recycled CAF substrate did not negatively affect the germination of Spartium junceum L. and Lavandula angustifolia Miller seeds as well as the root development of Salvia officinalis L. and Salvia rosmarinus Schleid. stem cuttings. Plants grown in recycled CAF showed a differential species-dependent change of pigments in comparison with those in SW, without compromising their photosynthesis performance. Overall, the results demonstrated that these plants can be well established and grow in recycled CAF, as comparable to SW substrate. This study highlights a novel and promising solution in CAF recycling by turning this litter into an efficient soilless substrate for growing ornamental plants, thus limiting the use of SW and indirectly decreasing its industrial waste flow. [ABSTRACT FROM AUTHOR]

• Greater than 55% of input nitrogen remained in the substrate at end of production. • Five percent of input nitrogen was utilized by plant shoots. • Infiltration into soil below growing beds was less than 2.5% of input nitrogen. • Runoff nitrogen accounted for 6.5% of input nitrogen. • Unaccounted nitrogen was 27.7% of input nitrogen and is attributed to denitrification. To reduce nitrate contamination of groundwater in intensive agricultural production areas, crop producers should identify nitrogen (N) inputs and outputs to calculate potential N available for leaching into groundwater. However, poor understanding of N fate in container plant production may result in inaccurate estimation of potentially leachable N. To improve understanding of container-applied N fate, an experiment was conducted to measure N inputs and outputs from a woody ornamental plant (Lagerstroemia indica 'Whitt II') production system fertilized with controlled-release and surface-applied fertilizer. Two experimental bed types, polyethylene-lined and unlined, were installed at a production nursery in California. Measured N inputs included: the substrate, with fertilizer and roots, and irrigation water N. Outputs included: N remaining in the substrate and plant shoots at the end of the production cycle, nitrous oxide-N gas lost from the substrate and bed soil, and aqueous N lost in runoff during the production cycle. There was a significant difference in runoff N losses from the lined and unlined beds. The difference in runoff N lost between bed types was the amount of N infiltrating into the soil below the growing bed surface. The majority of input N either remained in the growing substrate (57%) at end of production cycle or was taken up by the plant shoots (5%). Nitrous oxide-N lost from the growing substrate and the bed soil was 1.5% and 0.01% of input N, respectively. Runoff and soil infiltration N accounted for 6.5% and 2.4% of input N, respectively. Unaccounted N was 27.7% of input N and is attributed to complete denitrification. Future work should address the amount of aqueous N lost from the growing substrate to reduce surface and groundwater contamination. [Display omitted] [ABSTRACT FROM AUTHOR]

The present study aimed to evaluate fresh spent mushroom substrate (SMS) as a growing medium in soilless strawberry cv. 'Honeoye' production. Fresh SMS after commercial production of Agaricus bisporus, Lentinus edodes, and Pleurotus ostreatus was used as a peat substitute in 15 and 25% (v/v), for strawberry cultivation in an unheated plastic tunnel. In the experiment, seven different substrates were studied, including peat (100%) as control and six substrate combinations (prepared by mixing SMSs with peat). The study was carried out in a randomized complete block design in five replicates. The results indicated that the electrical conductivity (EC), pH, and nutrient content varied among the studied substrates. The experiment also demonstrated that the substrates significantly influenced strawberry yield, leaf area, and fresh and dry plant weights. However, no significant differences were observed for selected photosynthetic parameters (Fv/Fm, Fv/F0, and PIabs) and Normalized Difference Vegetation Index (NDVI) values among the evaluated substrates. Differences were recorded for the Photochemical Reflectance Index (PRI) and Modified Chlorophyll Absorption in Reflectance Index (MCARI) values. The present investigation revealed that fresh SMSs can be an effective and inexpensive peat substitute in 15 and 25% (v/v). Therefore, such easy and immediate utilisation of SMSs could overcome associated disposal problems. [ABSTRACT FROM AUTHOR]

• Biochar was produced from Eastern red cedar wood. • Biochar was infused with both inorganic and organic fertilizers. • Tomato seed germination was suppressed by biochar incorporated at the highest rate. • Growth of tomato transplants with biochar were similar to a commercial control. Most soilless substrates currently used by the greenhouse and nursery industries for transplants use lightweight materials including peat moss, vermiculite and perlite. Because these materials lack sufficient nutrients, slow-release synthetic fertilizers are added which have sustained release patterns that are sufficient to maintain optimal plant growth until the plants are placed in gardens. Biochar has physical and chemical properties (e.g., light weight, high water and nutrient absorption capacity) which allow it to be both a significant component of soilless potting substrates as well as acting as a slow-release fertilizer when preconditioned with nutrients, either from inorganic or organic sources. Biochar produced in a kiln from Eastern red cedar (ERC, Juniperus virginiana L.) wood was found to have high porosity, potentially allowing it to absorb large amounts of nutrients and subsequently re-release the nutrients over an extended period of time, allowing it to be utilized in slow-release fertilizers for transplant substrates. Experimental slow-release fertilizers were produced from ERC biochar that were infused under a vacuum with both a commercial synthetic hydroponic fertilizer and an organic fish-emulsion liquid fertilizer. Seed germination, seedling growth and transplant growth parameters of tomato (Solanum lycopersicum L. 'Red Robin') plants grown in a commercial peat moss-based potting substrate supplemented with 5, 10 and 20 % (v%/v%) of both organic and inorganic fertilizer-infused ERC biochar were examined, utilizing commercially-available slow-release chemical fertilizers as the control. When utilized as a starter substrate, seed germination was significantly inhibited in both 20 % ERC biochar substrates. When used as a transplant substrate, fresh weights of tomato plants grown with 10 and 20 % inorganic biochar fertilizer, and dry weights of these treatments as well as the 20 % organic biochar fertilizer were similar to the control. Final plant heights with both 20 % inorganic and organic ERC biochar fertilizers were equal to the control, with SPAD values (indicating chlorophyll content and nitrogen status of the plants) was highest in plants grown in 20 % inorganic biochar. These results indicate that ERC biochar has potential as a slow-release fertilizer for both starter and transplant substrates when preconditioned with both inorganic and organic fertilizers, although the higher levels of preconditioned ERC biochar should not be used in starter substrates. [ABSTRACT FROM AUTHOR]