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Graphical abstract Basil (A) and tomato (B) total dry weight (mean ± standard deviation) in eight substrates formulated by mixing biochar (BC; 60%, 70%, 80% or 90%, by vol.) with either 5% (by vol.) vermicompost (VC) or composted chicken manure (CM) and the control. Highlights • Physical properties of biochar (60–90%) with 5% chicken manure compost or vermicompost mixes were in the recommended range for container plants. • Replacing peat-based substrate with 60% or 70% biochar and 5% chicken manure compost or vermicompost did not affect tomato and basil plant growth. • 90% biochar and 5% chicken manure compost mix suppressed plant growth due to high salt and pH. • Wholesale price for mixes with 5% chicken manure compost and 70% biochar is 54% of a peat-based substrate. Abstract Biochar (BC) has the potential to be used as alternative container substrate, which adds value to the bioenergy process. But high percentage of BC may suppress plant growth and there is limited research on BC and compost in container. High percentages of mixed hardwood BC (60%, 70%, 80% or 90%, by vol.) mixed with either 5% (by vol.) vermicompost (VC) or chicken manure compost (CM) were evaluated to substitute a peat-based commercial container substrate (Berger BM7), using basil (Ocimum basilicum) and tomato (Solanum lycopersicum) as test crops. Total porosity, container capacity, air space and bulk density of BC-compost mixes were all in or close to the recommended ranges for container substrates. High percentage of BC incorporation reduced the SPAD readings caused by BC's N-binding effect. BC-compost mixes had no effect on the plants' photosynthetic rates at 5 weeks after transplanting (WAT). At 8 WAT, the growth index (GI), shoot dry weight (DW) and fresh weight (FW), and root and total DW of basil plants in 80BC:5CM, 90BC:5VC and 90BC:5CM were reduced due to high salt and pH while those in other BC-compost mixes were similar to the control. The BC-compost mixes (except 90BC:5CM) did not negatively affect the GI, stem, root and total DW, and red and total fruit FW and DW of tomato plants. Therefore, 5% (by vol.) CM and VC was a good potential amendment candidate for replacing peat-based substrate with 60% and 70% BC to grow container plants. Mixture of 5% CM with 70% BC with the rest the Berger BM7 peat-based substrate is recommended since its wholesale price is estimated at 54% of that of 100% Berger BM7 substrate. These results benefit bioenergy companies by adding value to the byproduct BC and provide economical and sustainable container substrate alternatives for horticultural producers. [ABSTRACT FROM AUTHOR]

Highlights: [•] An experiment to investigate the relative salt tolerance of six garden roses. [•] At elevated salinity levels, all cultivars had growth reductions except ‘New dawn’. [•] The leaf sodium and chloride concentrations were lowest in ‘New Dawn’. [•] ‘New Dawn’ was more salt tolerant among the cultivars investigated. [•] ‘Caldwell Pink’, ‘Marie Pavie’, and ‘The Fairy’ were least salt tolerant. [Copyright &y& Elsevier]

Highlights: [•] The relative salt tolerance of six cultivars of Ricinus communis L. was compared in two separate experiments. [•] Seedling emergence was inhibited by salinity at 17.5dSm−1 in all cultivars except for ‘Memphis’. [•] Salinity at 1.9 and 10.5dSm−1 enhanced seedling emergence in some cultivars. [•] ‘Memphis’ was more tolerant to salinity stress among the six cultivars tested. [ABSTRACT FROM AUTHOR]

Abstract: Salt tolerance of five cultivars of Capsicum annuum L. Early Jalapeno, Golden Treasure, NuMex Sweet, NuMex Joe E. Parker, and Santa Fe Grande, two cultivars of C. chinense Jacq. Habanero and Pimienta De Chiera, and one accession of C. annuum, NMCA 10652, were evaluated in a field study. Seedlings were transplanted in late May to field raised beds containing loamy sand soils in a semi-arid environment. Plants were well irrigated throughout the experiment. Three saline solution treatments, prepared by adding NaCl, MgSO4, and CaCl2 to tap water at different amounts to create three salinity levels of 0.82dSm−1 (control, tap water), 2.5dSm−1, and 4.1dSm−1 electrical conductivity (EC), were initiated on 15th June and ended in late August. Among the eight varieties, NMCA 10652 had the highest survival percentage at 100% in the 4.1dSm−1 treatment, followed by ‘Early Jalapeno’, ‘NuMex Sweet’, ‘Pimienta De Chiera’, ‘Santa Fe Grande’, ‘Golden Treasure’, and ‘NuMex Joe E. Parker’. ‘Habanero’ had the lowest survival at 28%. Compared to control, final shoot dry weight of the plants irrigated with saline solution at 4.1dSm−1 was reduced by 92% in ‘Habanero’, followed by ‘Golden Treasure’ at 80%. For fruit fresh weight in 4.1dSm−1 vs. control, ‘Habanero’ had the highest reduction at 86%, followed by ‘Golden Treasure’ at 74%, while NMCA 10652 and ‘Santa Fe Grande’ had the least at 26% and 19%, respectively. NMCA 10652, the most tolerant to salinity, had the lowest leaf Na+ accumulation, while ‘Habanero’, the most sensitive to salinity, had the highest Na+ in the leaves. For leaf Cl−, ‘Early Jalapeno’ had the highest, while ‘Habanero’ had the lowest Cl− accumulation in the leaves. Generally, sensitive varieties accumulated more Na+ and/or Cl− in leaves, except for ‘Early Jalapeno’, which was relatively tolerant to salinity but had high Na+ and Cl− accumulation in leaves. [Copyright &y& Elsevier]

Abstract: In order to use reclaimed water to irrigate landscape plants and minimize damage and loss, salinity tolerance of commonly used landscape plants needs to be determined and characterized. Eight herbaceous perennials and groundcovers were obtained from a local nursery, transplanted to 2.6-L plastic containers and grown in the greenhouse for 2 weeks before saline irrigation at electrical conductivity (EC) of 0.8 (tap water), 3.2, 6.4, or 12dSm−1 were initiated. Plants were irrigated with measured amount of saline solutions to obtain 30% leaching when approximately 50% water had been depleted. After 12 weeks, four plants in each treatment were destructively harvested and dry weights of shoots and roots were determined. Three Penstemon species (P. eatonii A. Gray, P. pseudospectabilis M.E. Jones, and P. strictus Benth.) and Lavandula angustifolia Mill. at 6.4 and 12dSm−1 and most at 3.2dSm−1 did not survive. Shoot dry weight of Delosperma cooperi (Hook.f.) L. Bolus decreased by 25% at 12dSm−1, but there were no significant differences among the rest of the treatments. All plants of Teucrium chamaedrys L. survived but growth was reduced significantly with lower visual scores as salinity of irrigation water increased. Although growth was reduced in Gazania rigens (L.) Gaertn. as salinity increased, no other signs of stress or injury were observed. Ceratostigma plumbaginoides Bunge had reduced growth at 3.2dSm−1 and higher EC levels compared to the control, older leaves showed reddish pigmentation at 6.4dSm−1, whereas those at 12dSm−1 did not survive. Ion concentrations of shoot and root tissue at the end of the experiment on surviving plants were also affected by salinity levels and varied among species. Among the tested species, D. cooperi and G. rigen indicated a relatively high tolerance to salinity, T. chamaedrys and C. plumbaginoides were moderately tolerant, and the rest were less tolerant. [Copyright &y& Elsevier]

Highlights • Lighting environment at seedling stage influenced mature lettuce yield. • Nitrate content of lettuce was not affected by light treatment at seedling stage. • Broad spectrum LED with red to blue ratio of 2.2 was suitable for seedling growth. • Daily light integral of 11.5 mol m−2 d−1 was appropriate for seedling growth. Abstract In order to obtain high-quality lettuce seedlings, effects of photosynthetic photon flux density (PPFD), photoperiod and light quality at seedling stage on growth and quality of hydroponic lettuce were investigated at different growth stages. Hydroponic lettuce (Lactuca sativa L. cv. Frill ice) seedlings were grown under 12 combinations of two levels of PPFD (200 and 250 μmol m−2 s-1) and two photoperiods (14 and 16 h d-1) under three light quality: light-emitting diodes (LEDs) with red to blue ratio (R:B ratio) of 1.2 and 2.2, and fluorescent lamps with R:B ratio of 1.8 as control. After the 20-day treatment during seedling stage, lettuce seedlings were transplanted to a homogeneous lighting environment for another 20 days before harvest. Results showed that leaf length and ratio of leaf length to leaf width at 20 days after sowing decreased in a logarithmic way with increasing daily light integral and fluorescent lamps resulted in larger seedlings with bigger leaves and higher leaf and root dry weights compared to LEDs. Leaf and root fresh weights of harvested lettuces were higher in the seedlings grown under PPFD at 200 μmol m−2 s-1 with a 16 h d-1 photoperiod, regardless of light quality at seedling stage. Generally, vitamin C content of mature lettuce was lower in seedlings grown under LEDs with R:B ratio of 1.2 and no significant differences were observed in nitrate content among the three lighting sources. In consideration of mature yield and quality, lighting efficiency and electrical consumption of lighting sources, PPFD of 200 μmol m−2 s-1 with a photoperiod of 16 h d-1 provided by LEDs with R:B ratio of 2.2 was suitable for hydroponic lettuce (cv. Frill ice) seedling production. [ABSTRACT FROM AUTHOR]

Ongoing severe drought and increased demand for freshwater by municipal and industrial sectors have reduced the freshwater availability for agriculture in the far west Texas region. The region has enormous potential for developing alternative water sources for a bioenergy crop that requires less water and can grow on saline soils. In addition to improving farm income, this can help in producing 137 billion liters of bio-based transportation fuels goal set by the U.S. Congress by the year 2022. This study evaluated switchgrass ( Panicum virgatum L.) performance under treated urban wastewater irrigation on salt affected soils amended with gypsum and polymer using soil columns prepared from a salt affected land over six years under greenhouse conditions that mimicked the climatic conditions of the study region. Results indicated that switchgrass produced appreciable biomass even under highly saline and sodic conditions. Qualities of biomass under treated urban wastewater were comparable to that produced under freshwater irrigation. Expectedly, soil salinity increased with time at a greater rate under wastewater irrigation than freshwater. Soil SAR values were below threshold when adequate Ca was available to counter sodicity. In addition irrigation with treated wastewater improved nitrogen and potassium status in the root zone. This can reduce of cost of fertilization and increase farm profitability. [ABSTRACT FROM AUTHOR]

Mustard seed meals (MSMs) are by-products resulting from crushing mustard seeds to provide biofuel. MSMs have been applied as bio-herbicides due to the release of active glucosinolates hydrolysis products. Three experiments were conducted to determine the herbicidal activity of MSM ( Sinapis alba ‘IdaGold’ and Brassica juncea ‘Pacific Gold’) in two weed species, large crabgrass ( Digitaria sanguinalis ) and Palmer amaranth ( Amaranthus palmeri ). In petri dishes, MSMs were applied at 0, 50, 100, 200 or 300 g/m 2 . In greenhouse containers, MSMs were applied on the surface or incorporated with germination mix at 0, 1.5, 3.0 or 4.5 g/pot. In outdoor containers, MSMs were incorporated with germination mix at 0, 1.5 or 3.0 g/pot. In petri dishes, emergence percentage (EP) and emergence index (EI) of large crabgrass were lower in ‘Pacific Gold’ than ‘IdaGold’ under unsealed conditions, and EP and EI were lower under sealed than unsealed conditions at all rates. In greenhouse containers, the EP and EI of crabgrass were lower in ‘Pacific Gold’ than ‘IdaGold’ when applied on the surface at 3.0 and 4.5 g/pot, while EP and EI was lower in ‘Pacific Gold’ when applied at 1.5 to 4.5 g/pot under both two methods. The EP of amaranth was lower in ‘IdaGold’ than ‘Pacific Gold’ at 1.5 g/pot under both methods, while EI was lower in ‘Pacific Gold’ when applied on the surface than incorporated. In outdoor containers, EP and EI of crabgrass were lower in ‘Pacific Gold’ than ‘IdaGold’ at 3.0 g/pot. These results demonstrated that ‘IdaGold’ might have better herbicidal efficacy on Palmer amaranth (broadleaf weeds), whereas ‘Pacific Gold’ was more effective on large crabgrass (grass weeds). [ABSTRACT FROM AUTHOR]

[Display omitted] • Canola as a biofuel crop was evaluated under freshwater and treated wastewater irrigation. • Canola seed yields did not differ between fresh and wastewater irrigation. • Seed oil content, oil yield, ash, and mineral constituents remained unchanged. • Treated wastewater increased soil salinity and sodicity but less than canola threshold. • Gypsum + sulfur significantly reduced the sodicity hazard of TWW application. Treated urban wastewater (TWW) is seen as a potential alternative for agricultural irrigation in arid west Texas region, due to scarcity of Freshwater (FW) supplies. However, TWW can potentially cause soil salinization and affect soil quality and crop productivity. Therefore, crops that are salt-tolerant and less water-intensive are needed to sustain agriculture in this region. Canola (Brassica napus L.) as an edible oilseed and biodiesel/biofuel crop, is salt-tolerant and relatively less water-intensive than crops that are traditional to this area. This two–year field study evaluated the performance of canola under TWW irrigation in terms of its seed yield potential and seed quality (oil content, oil yield and salt constituents), along with quantifying changes in soil salinity and sodicity. Experimental design included a randomized block split-plot with water quality (FW and TWW) as the main-plot and soil amendment (gypsum + sulfur and no-amendment) as the subplot factor. Results show that TWW application did not significantly affect canola seed yields in any of the two years. On average, seed yields were 1975 kg ha−1 across all treatments and years. Seed oil content, oil yield and mineral constituents were also not affected by TWW irrigation. Nevertheless, average seed oil content was 42 % and oil yield was 849 kg ha−1. Other than the effects on soil salinity and sodicity, Gypsum + Sulfur application did not influence canola seed productivity and quality. Changes in soil salinity and sodicity were more prominent under TWW irrigation but the levels were below the thresholds after two years. Gypsum + Sulfur application significantly reduced soil sodicity, especially in TWW irrigated soils. These results highlight that TWW can be successfully used to grow canola as a biofuel feedstock in this arid region while following appropriate soil management practices to alleviate sodicity hazard of TWW in the long-term. [ABSTRACT FROM AUTHOR]

• Treated wastewater irrigation effects on bioenergy sorghum and soil quality were tested. • Wastewater irrigation did not affect biomass yields compared to freshwater irrigation. • Holocellulose and lignin contents decreased, and ash content increased over time in biomass. • Soil salinity and sodicity generally increased after wastewater application. • Gypsum and sulfur significantly reduced soil SAR in wastewater treatments. Prolonged drought in arid west Texas has resulted in freshwater scarcities in the Rio Grande basin, forcing growers to abandon agricultural lands. Augmenting freshwater scarcities with marginal quality treated urban wastewater could be an alternative strategy. However, higher salinity in wastewater could be detrimental to crops and soil quality. Therefore, developing information on crops that are salt tolerant and less water-intensive is important to sustain agriculture in this region. Sorghum is both drought and salt-tolerant and could potentially provide revenue due to increasing demand for its lignocellulosic biomass in biofuel industry. This two-year field study evaluated (i) the performance of bioenergy sorghum under wastewater irrigation in terms of its biomass yield potential and biomass quality relative to freshwater irrigation and (ii) wastewater irrigation effects on rootzone soil quality including soil salinity and sodicity. A split-plot experimental design was used with water type (fresh and wastewater) as the main-plot and soil amendments (non-amended and gypsum + sulfur) as the subplot factors. Results show that sorghum biomass yields were not significantly different between fresh and wastewaters in any of the years. Differences in biomass quality were observed overtime but as an indirect consequence of increased soil salinity and/or sodicity after wastewater irrigation. Soil quality changes were apparent with salinity and sodicity increasing over time with irrigation, but this effect was pronounced under wastewater irrigation. Application of gypsum and sulfur was able to significantly reduce soil sodicity, especially in wastewater irrigated plots. The results from this study highlight that treated wastewater can be successfully used to grow bioenergy sorghum in arid regions. However, appropriate soil management practices should be in place to counter the effects of high sodium in wastewater. These results have important implications in diversifying cropping pattern in this region while also help extend freshwater supplies through increased reuse of treated urban wastewater. [ABSTRACT FROM AUTHOR]

Soil organic matter plays a major role in determining the fate of the engineered nanomaterials (ENMs) in the soil matrix and effects on the residing plants. In this study, kidney bean plants were grown in soils varying in organic matter content and amended with 0–500 mg/kg cerium oxide nanoparticles (nano-CeO 2 ) under greenhouse condition. After 52 days of exposure, cerium accumulation in tissues, plant growth and physiological parameters including photosynthetic pigments (chlorophylls and carotenoids), net photosynthesis rate, transpiration rate, and stomatal conductance were recorded. Additionally, catalase and ascorbate peroxidase activities were measured to evaluate oxidative stress in the tissues. The translocation factor of cerium in the nano-CeO 2 exposed plants grown in organic matter enriched soil (OMES) was twice as the plants grown in low organic matter soil (LOMS). Although the leaf cover area increased by 65–111% with increasing nano-CeO 2 concentration in LOMS, the effect on the physiological processes were inconsequential. In OMES leaves, exposure to 62.5–250 mg/kg nano-CeO 2 led to an enhancement in the transpiration rate and stomatal conductance, but to a simultaneous decrease in carotenoid contents by 25–28%. Chlorophyll a in the OMES leaves also decreased by 27 and 18% on exposure to 125 and 250 mg/kg nano-CeO 2 . In addition, catalase activity increased in LOMS stems, and ascorbate peroxidase increased in OMES leaves of nano-CeO 2 exposed plants, with respect to control. Thus, this study provides clear evidence that the properties of the complex soil matrix play decisive roles in determining the fate, bioavailability, and biological transport of ENMs in the environment. [ABSTRACT FROM AUTHOR]

There is lack of information about the effects of foliar applied nanoparticles on fruit quality. In this study, three week-old soil grown cucumber seedlings were foliar-exposed to n CeO 2 , n CuO, and corresponding bulk counterparts at 50, 100, and 200 mg/L. Respective suspensions/solutions were sprayed to experimental units in a volume of 250 ml. Net photosynthesis rate ( Pn ), stomatal conductance ( Gs ), and transpiration rate ( E ) were measured 15 days after treatment application and in 74 day-old plants. Yield, fruit characteristics (size, weight, and firmness), Ce, Cu, and nutritional elements were also measured. Results showed a nano-specific decrement on Pn (22% and 30%) and E (11% and 17%) in seedling leaves exposed to n CeO 2 and n CuO at 200 mg/L, respectively, compared with control. n CeO 2 at 50 mg/L, b CeO 2 at 200 mg/L, and all Cu treatments, except n CuO at 100 mg/L, significantly reduced fruit firmness ( p ≤ 0.05), compared with control. However, n CuO at 200 mg/L and b CuO at 50 mg/L significantly increased fruit fresh weight ( p ≤ 0.05). At 200 mg/L, n CeO 2 and b CeO 2 reduced fruit Zn by 25%, while n CuO and b CuO reduced fruit Mo by 51% and 44%, respectively, compared with control. This study has shown that when the route of exposure is the foliage, differences in particle size are less significant, compared to root-based exposure. To the authors' knowledge, this is the first report on the effect of foliar application of n CeO 2 and n CuO upon yield and nutritional quality of cucumber. [ABSTRACT FROM AUTHOR]

Abstract: Orchids are currently the most valuable potted crop in the United States. To date, no studies focused on making possible the year-round greenhouse production of flowering nobile dendrobium orchids. This experiment was aimed at developing a strategy to defer flowering of nobile dendrobium orchids by holding them under low temperature. Mature Den. Red Emperor ‘Prince’ and Den. Sea Mary ‘Snow King’ were held at 10°C for various durations (0, 4, 8, 12 or 16 weeks) after vernalization (4 weeks at 10°C). Plants were forced in a greenhouse after holding. Time to flower, flower differentiation (flowering node percentage, number of aerial shoot and aborted bud) and flower quality (total flower number, flower diameter, flower number per flowering node and flower longevity) were determined. Increase of low temperature holding duration from 0 to 16 weeks extended time to flower up to 3 months and did not affect parameters of flower except producing larger flowers and reducing flower number per flowering node for Den. Red Emperor ‘Prince’. Notably, the flower longevity was not adversely affected. Defoliation was aggravated in Den. Red Emperor ‘Prince’ by longer duration of cooling and was considered a detrimental effect of low temperature holding. [Copyright &y& Elsevier]

Freshwater (FW) scarcity as a result of prolonged drought has reduced FW availability to agriculture in the arid west Texas region in order to meet demands from other sectors. Alternatively, there is enormous potential to utilize treated urban wastewater (TWW) for agricultural irrigation. However, the soil salinization potential of TWW is a concern as it can be detrimental to crops and soil quality. Alternative crops that are both less water-intensive and salt-tolerant are therefore needed to sustain this region's agriculture. Switchgrass is a perennial grass that is well adapted to grow on marginal lands and is a novel crop for lignocellulosic bioenergy feedstock. However, its performance when irrigated with TWW on arid soils of far west Texas is largely unknown. This field study evaluated the yield potential and composition of switchgrass biomass as affected by TWW along with soil quality changes, using a split-plot experimental design. Results indicate that biomass yields were not affected by TWW irrigation and there were no significant differences between TWW and FW across years. With respect to biomass composition, cellulose and lignin contents were lower, while ash content was significantly higher in TWW treatment. Theoretical ethanol production was not affected. Soil salinity and sodicity increased overtime but this increase was more prominent under TWW irrigation. However, application of gypsum and sulfur significantly reduced soil sodicity. These results indicate that switchgrass can tolerate soil salinity induced by TWW application and therefore can be successfully grown on these marginal arid soils as a bioenergy feedstock. • Bioenergy switchgrass and soil quality were evaluated under wastewater irrigation. • Biomass yields did not differ significantly between fresh and wastewater irrigation. • Wastewater increased biomass N and ash but decreased cellulose and lignin contents. • Soil salinity and sodicity increased with wastewater but less than switchgrass threshold. • Gypsum and sulfur can negate soil sodicity hazard with wastewater. [ABSTRACT FROM AUTHOR]

With the exponential growth of nanomaterial production in the last years, nano copper (Cu)-based compounds are gaining more consideration in agriculture since they can work as pesticides or fertilizers. Chinese scallions (Allium fistulosum), which are characterized by their high content of the antioxidant allicin, were the chosen plants for this study. Spectroscopic and microscopic techniques were used to evaluate the nutrient element, allicin content, and enzyme antioxidant properties of scallion plants. Plants were harvested after growing for 80 days at greenhouse conditions in soil amended with CuO particles [nano (nCuO) and bulk (bCuO)] and CuSO 4 at 75–600 mg/kg]. Two-photon microscopy images demonstrated the particulate Cu uptake in nCuO and bCuO treated roots. In plants exposed to 150 mg/kg of the Cu-based compounds, root Cu content was higher in plants treated with nCuO compared with bCuO, CuSO 4 , and control (p ≤ 0.05). At 150 mg/kg, nCuO increased root Ca (86%), root Fe (71%), bulb Ca (74%), and bulb Mg (108%) content, compared with control (p ≤ 0.05). At the same concentration, bCuO reduced root Ca (67%) and root Mg (33%), compared with control (p ≤ 0.05). At all concentrations, nCuO and CuSO 4 increased leaf allicin (56–187% and 42–90%, respectively), compared with control (p ≤ 0.05). The antioxidant enzymes were differentially affected by the Cu-based treatments. Overall, the data showed that nCuO enhances nutrient and allicin contents in scallion, which suggests they might be used as a nanofertilizer for onion production. Unlabelled Image • None of the Cu-based compounds produced visible signs of toxicity. • Allicin, Ca, Fe, Mg, and Mn contents were improved by nCuO, but not by bCuO. • Nano CuO increased root GPOX and leaf APOX, but reduced CAT in roots and leaves. • Cu was translocated to leaves dependent on the Cu compound exposure manner. • Cu uptake distribution from bCuO and nCuO treatments indicated an apoplastic pathway. [ABSTRACT FROM AUTHOR]