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Dr. Hye-Ji Kim
Department Horticulture & Landscape Architecture, Purdue University, West Lafayette, IN 47907, USA.

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0 Aquaponics
0 Hydroponics
0 Nitrogen
0 Plant Nutrition
0 Plant Physiology

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Aquaponics
Hydroponics
Nitrogen
Phosphorus
water use
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Crop yield and quality

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Journal article
Published: 04 August 2021 in Horticulturae
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Aquaponics is a circulating and sustainable system that combines aquaculture and hydroponics and forms a symbiotic relationship between fish, plants, and microorganisms. We hypothesized that feed alone could support plant growth, but the symbiosis with fish adds some beneficial effects on plant growth in aquaponics. In this study, we created three closed culture systems, namely, aquaponics, hydroponics without nitrogen (N) and phosphorus (P), and aquaculture, and added the same amount of feed containing N and P to all the treatments in order to test the hypothesis. Accumulation of NO3 and PO43− was alleviated in aquaponics and hydroponics as a result of plant uptake. Lettuce plants grown in aquaponics grew vigorously until 2 weeks and contained a constant level of N in plants throughout the production period, whereas those in hydroponics grew slowly in the early stage and then vigorously after 2 weeks with a late increment of N concentration. These results suggest that catfish help with the faster decomposition of the feed, but, in hydroponics, feed can be slowly dissolved and decomposed owing to the absence of the fish. The bacterial community structures of the culture solution were investigated using 16S rRNA gene amplicon sequencing. At the class level, Actinobacteria, Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria were the major microbial groups in the solutions. Aquaponics prevented the pollution of tank solution and maintained a higher water quality compared with hydroponics and aquaculture, suggesting that aquaponics is a more sustainable cultivation system even in a small-scale system.

ACS Style

Kenji Yamane; Yuuki Kimura; Keita Takahashi; Isamu Maeda; Masayuki Iigo; Atsuo Ikeguchi; Hye-Ji Kim. The Growth of Leaf Lettuce and Bacterial Communities in a Closed Aquaponics System with Catfish. Horticulturae 2021, 7, 222 .

AMA Style

Kenji Yamane, Yuuki Kimura, Keita Takahashi, Isamu Maeda, Masayuki Iigo, Atsuo Ikeguchi, Hye-Ji Kim. The Growth of Leaf Lettuce and Bacterial Communities in a Closed Aquaponics System with Catfish. Horticulturae. 2021; 7 (8):222.

Chicago/Turabian Style

Kenji Yamane; Yuuki Kimura; Keita Takahashi; Isamu Maeda; Masayuki Iigo; Atsuo Ikeguchi; Hye-Ji Kim. 2021. "The Growth of Leaf Lettuce and Bacterial Communities in a Closed Aquaponics System with Catfish." Horticulturae 7, no. 8: 222.

Journal article
Published: 02 April 2021 in Horticulturae
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Our previous study reported that fresh produce grown in aquaponic and hydroponic systems can pose potential food safety hazards due to an accidental introduction of contaminated fish and cross-contamination between the systems. In this study, we examined the effects of plant species and age on the likelihood and level of internalization of Shiga toxin-producing Escherichia coli (STEC) in aquaponic and hydroponic systems. Four plant species, basil (Ocimum basilicum L. cv. Genovese), cilantro (Coriandrum Sativum L.), lettuce (Lactuca sativa cv. Cherokee), and kale (Brassica oleracea var. sabellica), received root damage treatment as seedlings before transplanting or mature plants at three weeks after transplanting by cutting off 1-cm tips of one-third of the roots. Enrichments and selective media were used for the isolation, and presumptive positive colonies were confirmed by PCR for the presence of stx1 gene in plant tissues, recirculating water, and fish feces collected at four weeks after transplanting. In hydroponic systems, STEC was found neither in the solution nor in the roots and leaves of all four plant species, possibly through improved sanitation and hygiene practices. However, consistent with our previous findings, STEC was found in the water, on the plant roots, and in the fish feces in aquaponic systems, even after thorough sanitation prior to the study. Regardless of plant age, STEC was internalized in the roots of all plant species when the roots were damaged, but there was no difference in the degree of internalization with STEC among plant species. STEC was present in the leaves only when seedlings received root damage treatment and were grown to maturity, indicating that root damage allows STEC to internalize in the roots within a week, but a longer period is required for STEC to internalize into the leaves. We concluded that root damage on seedlings can cause the internalization of E. coli O157:H7 in the edible parts of leafy vegetables and herbs in soilless production systems.

ACS Style

Yi-Ju Wang; Amanda J. Deering; Hye-Ji Kim. Effects of Plant Age and Root Damage on Internalization of Shiga Toxin-Producing Escherichia coli in Leafy Vegetables and Herbs. Horticulturae 2021, 7, 68 .

AMA Style

Yi-Ju Wang, Amanda J. Deering, Hye-Ji Kim. Effects of Plant Age and Root Damage on Internalization of Shiga Toxin-Producing Escherichia coli in Leafy Vegetables and Herbs. Horticulturae. 2021; 7 (4):68.

Chicago/Turabian Style

Yi-Ju Wang; Amanda J. Deering; Hye-Ji Kim. 2021. "Effects of Plant Age and Root Damage on Internalization of Shiga Toxin-Producing Escherichia coli in Leafy Vegetables and Herbs." Horticulturae 7, no. 4: 68.

Reply
Published: 25 February 2021 in Horticulturae
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Recently, the Aquaponic Association (AA) published a statement through multiple outlets in response to our article entitled “The Occurrence of Shiga Toxin-Producing E. coli in Aquaponic and Hydroponic Systems”

ACS Style

Yi-Ju Wang; Amanda Deering; Hye-Ji Kim. Reply to Comment on “The Occurrence of Shiga Toxin-Producing E. coli in Aquaponic and Hydroponic Systems”. Horticulturae 2021, 7, 37 .

AMA Style

Yi-Ju Wang, Amanda Deering, Hye-Ji Kim. Reply to Comment on “The Occurrence of Shiga Toxin-Producing E. coli in Aquaponic and Hydroponic Systems”. Horticulturae. 2021; 7 (3):37.

Chicago/Turabian Style

Yi-Ju Wang; Amanda Deering; Hye-Ji Kim. 2021. "Reply to Comment on “The Occurrence of Shiga Toxin-Producing E. coli in Aquaponic and Hydroponic Systems”." Horticulturae 7, no. 3: 37.

Journal article
Published: 16 July 2020 in Journal of Cleaner Production
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Aquaponics is known to be one of the most efficient agriculture production systems by far; however, limited quantitative data are available on the level of efficiency, particularly in comparison to its counterpart, hydroponics. This study compared aquaponics with hydroponics to assess nitrogen (N) and phosphorus (P) distributions, N- and P-use efficiency (NUE and PUE), and potential environmental impacts. Cherry tomato, basil, and lettuce were cultured in recirculating tilapia (Oreochromis niloticus)-based aquaponic or stand-alone hydroponic systems over a 3-month period. N and P mass balances were developed by using N and P concentrations in fish feed, solid waste, wastewater, fish biomass, and plant biomass for aquaponic systems, and chemical fertilizer, wastewater, and plant biomass for hydroponic systems, which were to estimate N and P loss from each system via denitrification and P precipitations, respectively. In aquaponics, 59–70% of total N input was estimated to be lost via denitrification (45–50%), wastewater (14–20%), and solid waste (0.7–2%) and 30–41% was assimilated into biomass (21–24% fish; 9–17% plants). In hydroponics, 76–87% was estimated to be lost via denitrification (69–78%) and wastewater (7–15%), and only 14–24% was assimilated into biomass. Similarly, 38–54% of total P input in aquaponics was lost via wastewater (22–28%), precipitations (8–25%), and solid waste (2–7%) and 46–62% was assimilated into biomass (35–45% fish; 11–25% plants). In hydroponics, 79–89% of total P input was lost via wastewater (52–74%) and precipitations (15–27%), and only 11–21% was assimilated into plant biomass. Plant species had a significant impact on N and P distribution, and tomato was most effective in removing N from wastewater and reducing denitrification via higher biomass production compared to basil and lettuce. NUE was lower for aquaponics than for hydroponics when only edible plant parts were taken into consideration, but 71–114% higher when both fish and plant biomass were considered. Meanwhile, PUE was higher for aquaponics than for hydroponics even only when edible parts were considered and 336–369% higher when the biomass of both crops was considered. Our N and P mass balance analyses demonstrated for the first time that aquaponics is more efficient than hydroponics. Greater N and P losses in hydroponics were mainly due to higher N and P inputs, causing 2 times higher N loss via gas emission and up to 3 times higher P loss via inorganic P in wastewater compared to aquaponics. Therefore, reducing nutrient inputs is critical in improving NUE and PUE for both aquaponics and hydroponics, which should be combined with proper crop choice, operation conditions, and management practices to further improve the efficiency of the systems.

ACS Style

Teng Yang; Hye-Ji Kim. Comparisons of nitrogen and phosphorus mass balance for tomato-, basil-, and lettuce-based aquaponic and hydroponic systems. Journal of Cleaner Production 2020, 274, 122619 .

AMA Style

Teng Yang, Hye-Ji Kim. Comparisons of nitrogen and phosphorus mass balance for tomato-, basil-, and lettuce-based aquaponic and hydroponic systems. Journal of Cleaner Production. 2020; 274 ():122619.

Chicago/Turabian Style

Teng Yang; Hye-Ji Kim. 2020. "Comparisons of nitrogen and phosphorus mass balance for tomato-, basil-, and lettuce-based aquaponic and hydroponic systems." Journal of Cleaner Production 274, no. : 122619.

Journal article
Published: 29 April 2020 in Water
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Aquaponic nutrient studies often use various types of water containing high levels of mineral nutrients for water supply, making it difficult to accurately determine deficient nutrients limiting crop yield and quality across the systems. To avoid interference with background nutrients, we used reverse osmosis water in this study. The objectives were to identify critical nutrients that affect the yield and quality of cherry tomato-, basil-, and lettuce by characterizing nutrient composition and concentration in aquaponic systems in comparison to hydroponic systems. Daily release rate (mg L−1) of macronutrients derived from fish feed (41% protein, 1.1% phosphorus, 1% fish weight) was in decreasing order of SO4–S (16) > PO4–P (2.4) > NO3–N (1.0) > K (0.8) > Cl (0.5) > NH4–N (0.4) > Ca (0.2) > NO2–N (0.13) > Na (0.11) > Mg (0.02), in which daily inputs of Mg and Ca in aquaponics were found to be only 1–2% and 4–6%, respectively, of those in hydroponics. Subsequently, the average concentrations of all nutrients were significantly lower in aquaponics than in hydroponics during a 3-month production except for Cl, NH4–N, NO2–N, and Na. The concentration of Mg remained below 5 mg L−1 in all aquaponic systems, while the concentration of Ca rapidly decreased in tomato-based aquaponics, especially during fruiting. SPAD value (chlorophyll content) was associated with concentrations of leaf N, Mg, and/or Ca. Specifically, lower SPAD value was correlated with lower leaf Mg and Ca for tomato and lower leaf Mg for basil but neither Mg nor Ca for lettuce. The aquaponic solution contained nearly six-times higher Na than the hydroponic solution, resulting in three-times higher Na concentration in the edible portion of the crops. Compared to a lettuce-based aquaponic system, tomato- and basil-based systems retained more desirable water quality parameters (i.e., stable pH, lower temperature), had lower electrical conductivity (EC) via greater biomass production and, therefore, more efficient nutrient removal, and had lower feed conversion rate and higher fish biomass increment. Regardless of crop species, vegetative shoot biomass was significantly reduced in aquaponics than in hydroponics. However, the marketable yield of tomatoes was similar between aquaponics and hydroponics, while those of basil and lettuce were reduced in aquaponics by 56% and 67%, respectively, in comparison to hydroponics. Our results highlighted potential solutions to design proper nutrient management practices essential for the development of successful aquaponic production systems. Considering that ingested fish feed does not provide sufficient levels of Mg and/or Ca for crop production, it is suggested to supplement Mg before crop transplanting and Ca before fruiting of fruity crops to improve crop growth and quality in aquaponic systems, especially when high-quality water is used for water supply.

ACS Style

Teng Yang; Hye-Ji Kim. Characterizing Nutrient Composition and Concentration in Tomato-, Basil-, and Lettuce-Based Aquaponic and Hydroponic Systems. Water 2020, 12, 1259 .

AMA Style

Teng Yang, Hye-Ji Kim. Characterizing Nutrient Composition and Concentration in Tomato-, Basil-, and Lettuce-Based Aquaponic and Hydroponic Systems. Water. 2020; 12 (5):1259.

Chicago/Turabian Style

Teng Yang; Hye-Ji Kim. 2020. "Characterizing Nutrient Composition and Concentration in Tomato-, Basil-, and Lettuce-Based Aquaponic and Hydroponic Systems." Water 12, no. 5: 1259.

Journal article
Published: 02 February 2020 in Horticulturae
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Aquaponics is a rapidly growing food-production system integrating aquaculture and hydroponic crop production through an energy-intensive water recirculation process. Crop performance and yield in aquaponics are affected by essential and toxic nutrient levels in the root zone, which can be regulated by water flow rate. This study was conducted to examine the effects of hydraulic loading rate (HLR) on water quality and crop growth and yield in recirculating aquaponic systems set at three different loading rates: high (3.3 m3/m2/day; HFR, which is 12 times lower than recommended loading rate), medium (2.2 m3/m2/day; MFR), and low (1.1 m3/m2/day; LFR). Crop species varying in growth rate were examined for their optimal HLR: fast-growing Chinese cabbage (Brassica rapa) and lettuce (Lactuca sativa); medium-growing mustard (Brassica juncea) and chia (Salvia hispanica); and slow-growing basil (Ocimum basilicum) and Swiss chard (Beta vulgaris). Compared to LFR, HFR decreased water and leaf temperatures and total ammonium nitrogen (TAN) but increased dissolved oxygen and pH in aquaponic solution up to one and two weeks after transplant, respectively. HFR increased NO3–N concentration by 50 and 80%, respectively, compared to MFR and LFR, while reducing the exposure duration of roots to ammonia (NH3–N) and its peak concentration through rapid dissipation of the toxic compound. Lower electrical conductivity (EC) in HFR during the last two weeks of production was associated with higher plant nutrient uptake and greater biomass production. The leaf greenness, photosynthetic rate (Pn), and total plant N were significantly higher at HFR than LFR. Fish growth rate, fresh weight, and feed-conversion efficiency were also increased by HFR. The growth of fast-growing crops including total fresh weight, shoot fresh weight, leaf area, and Pn was not different between HFR and MFR, while HLR had less significant effects on the growth and performance (i.e., shoot fresh weight and whole plant photosynthesis) of slow-growing crops. In conclusion, the flow rate is an important component in aquaponic crop production as it affects spatial and temporal water characteristics and subsequently determines the growth and yield of the crops. HLR at 3.3 m3/m2/day was sufficient across the crops allowing better chemical and physical properties of the aquaponic solution for maximum yield and quality. HLR should be maintained at least at 2.2 m3/m2/day for the production of fast-growing crops but can be lowered for slow-growing crops.

ACS Style

Teng Yang; Hye-Ji Kim. Effects of Hydraulic Loading Rate on Spatial and Temporal Water Quality Characteristics and Crop Growth and Yield in Aquaponic Systems. Horticulturae 2020, 6, 9 .

AMA Style

Teng Yang, Hye-Ji Kim. Effects of Hydraulic Loading Rate on Spatial and Temporal Water Quality Characteristics and Crop Growth and Yield in Aquaponic Systems. Horticulturae. 2020; 6 (1):9.

Chicago/Turabian Style

Teng Yang; Hye-Ji Kim. 2020. "Effects of Hydraulic Loading Rate on Spatial and Temporal Water Quality Characteristics and Crop Growth and Yield in Aquaponic Systems." Horticulturae 6, no. 1: 9.

Journal article
Published: 02 January 2020 in Horticulturae
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Food safety concerns have been raised over vegetables and herbs grown in aquaponics and hydroponics due to the reuse of wastewater and spent nutrient solutions. This study was conducted to determine the occurrence of foodborne pathogens in greenhouse-based aquaponic and hydroponic systems. Fish feces, recirculating water, roots, and the edible portions of lettuce, basil, and tomato were collected at harvest, and microbiological analyses were conducted for the bacterial pathogens Shiga toxin-producing Escherichia coli (STEC), Listeria monocytogenes, and Salmonella spp. Enrichments and selective media were used for the isolation, and presumptive positive colonies were confirmed by PCR. STEC was found in fish feces, in the water of both systems, and on the surface of the roots of lettuce, basil, and tomato regardless of the system. However, contaminated water did not lead to the internalization of STEC into the roots, leaves, and/or fruit of the plants. Meanwhile, L. monocytogenes and Salmonella spp. were not present in any samples examined. Our results demonstrated that there are potential food safety hazards for fresh produce grown in aquaponic and hydroponic production systems.

ACS Style

Yi-Ju Wang; Amanda J. Deering; Hye-Ji Kim. The Occurrence of Shiga Toxin-Producing E. coli in Aquaponic and Hydroponic Systems. Horticulturae 2020, 6, 1 .

AMA Style

Yi-Ju Wang, Amanda J. Deering, Hye-Ji Kim. The Occurrence of Shiga Toxin-Producing E. coli in Aquaponic and Hydroponic Systems. Horticulturae. 2020; 6 (1):1.

Chicago/Turabian Style

Yi-Ju Wang; Amanda J. Deering; Hye-Ji Kim. 2020. "The Occurrence of Shiga Toxin-Producing E. coli in Aquaponic and Hydroponic Systems." Horticulturae 6, no. 1: 1.

Journal article
Published: 28 November 2019 in Agronomy
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This study was conducted to examine plant biomass and phosphorus (P) accumulation and partitioning in response P availability and to determine the optimal P concentration during growth phases of two plant species with contrasting growth characteristics: geranium (Pelargonium × hortorum Bailey) “Bullseye Scarlet”, a flowering plant, and coleus (Solenostemon scutellarioides (L.) Codd) “Chocolate Mint”, a foliage plant. Plants were grown in inert media (1:1 mixture of perlite and vermiculite) with complete nutrient solutions containing a range of P concentrations considered low (3 and 5 mg/L), intermediate (10 and 15 mg/L), and high (20 and 30 mg/L). Higher P rates logarithmically increased shoot and root dry mass of geranium and coleus plants regardless of the growth phase, but linearly enhanced flower dry mass of reproductive geranium plants resulting from the accelerated flower development. During the vegetative phase, the intermediate-P increased the shoot biomass production of geranium plants, but high-P was more effective for coleus plants. During the reproductive phase, however, the intermediate-P increased shoot biomass production of both geranium and coleus plants to the level achieved by high-P. The change from vegetative to reproductive phase increased the relative biomass to flowers, roots, and shoots of reproductive geranium plants and roots and shoots of reproductive coleus plants in decreasing orders, resulting in an increased root-to-shoot ratio. The P content of all plant parts showed a logarithmical increase with higher P rates for reproductive geranium plants but a linear increase for reproductive coleus plants. During the reproductive phase, a higher proportion of acquired P was allocated to flowers of low-P geranium plants than the roots of high-P coleus. Our results demonstrate that geranium plants require intermediate-P throughout the growth phases, while coleus plants require high-P during the vegetative phase and intermediate-P during the reproductive phase. P-use efficiency (PUE) ranged from 5 to 15% in high-P, which was improved with intermediate-P by 36 to 70%. To further improve PUE, the application method also needs to be taken into consideration such that the fertigation volume is reduced during the vegetative phase and increased before the reproductive phase.

ACS Style

Jiayin Zhang; Seunghyun Choi; Jingping Fan; Hye-Ji Kim. Biomass and Phosphorus Accumulation and Partitioning of Geranium and Coleus in Response to Phosphorus Availability and Growth Phase. Agronomy 2019, 9, 813 .

AMA Style

Jiayin Zhang, Seunghyun Choi, Jingping Fan, Hye-Ji Kim. Biomass and Phosphorus Accumulation and Partitioning of Geranium and Coleus in Response to Phosphorus Availability and Growth Phase. Agronomy. 2019; 9 (12):813.

Chicago/Turabian Style

Jiayin Zhang; Seunghyun Choi; Jingping Fan; Hye-Ji Kim. 2019. "Biomass and Phosphorus Accumulation and Partitioning of Geranium and Coleus in Response to Phosphorus Availability and Growth Phase." Agronomy 9, no. 12: 813.

Journal article
Published: 08 November 2019 in Scientia Horticulturae
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Off-season greenhouse tomatoes have a poor reputation relative to their in-season, field-grown counterparts. Previously, we reported that supplemental intracanopy far-red (700–800 nm, FR) radiation in addition to red (600–700 nm, R) light with light-emitting diodes (LEDs) significantly decreased fruit water content compared to R LEDs alone and high-pressure sodium (HPS) lamps, the most common supplemental lighting used in commercial greenhouses. We hypothesize that supplemental R + FR LEDs during production improves fruit quality attributes (i.e., physicochemical properties, mineral concentrations, and sensory properties) in greenhouse tomatoes compared to R LEDs and HPS lamps. Both intracanopy LED lights increased fruit yield and biomass compared to HPS lamps. R LEDs increased dry matter ratio and improved overall physicochemical proprieties such as total soluble solids (TSS), titratable acidity (TA), and pH; however, R + FR LEDs had more significant effects on all measured attributes than did R LEDs. Similarly, R LEDs increased potassium, magnesium, and calcium content in whole fruit by 30, 74, and 40% compared to HPS lamps, and the addition of FR to R LEDs further increased sodium (Na) content and concentration. Consumer sensory panelists rated higher for sensory attributes (aroma, sweetness, acidity, and texture) of R + FR LED-supplemented tomatoes on a hedonic scale compared to R LED-supplemented ones. Importantly, HPS lamp-supplemented tomatoes had the least desirable quality attributes even when compared at the same ripe stage as LED-supplemented ones. Energy use efficiency (EUE) was not different between R + FR LEDs and R LEDs, which was 5 times higher than that of HPS lamps. Our results demonstrate for the first time that fruit quality attributes of greenhouse tomatoes can be improved by supplemental intracanopy lighting with R + FR LEDs to a degree that consumer panelists could perceive the differences. Therefore, we conclude that supplemental R + FR LEDs is indispensable for improving fruit quality of greenhouse tomatoes during off-season production.

ACS Style

Hye-Ji Kim; Teng Yang; Seunghyun Choi; Yi-Ju Wang; Meng-Yang Lin; Andrea M. Liceaga. Supplemental intracanopy far-red radiation to red LED light improves fruit quality attributes of greenhouse tomatoes. Scientia Horticulturae 2019, 261, 108985 .

AMA Style

Hye-Ji Kim, Teng Yang, Seunghyun Choi, Yi-Ju Wang, Meng-Yang Lin, Andrea M. Liceaga. Supplemental intracanopy far-red radiation to red LED light improves fruit quality attributes of greenhouse tomatoes. Scientia Horticulturae. 2019; 261 ():108985.

Chicago/Turabian Style

Hye-Ji Kim; Teng Yang; Seunghyun Choi; Yi-Ju Wang; Meng-Yang Lin; Andrea M. Liceaga. 2019. "Supplemental intracanopy far-red radiation to red LED light improves fruit quality attributes of greenhouse tomatoes." Scientia Horticulturae 261, no. : 108985.

Research report
Published: 16 October 2019 in Horticulture, Environment, and Biotechnology
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This study was conducted to investigate the effects of physical properties of peat-based substrate mixtures partially substituted with parboiled rice hulls (PRH) on plant growth and performance. Thirteen substrate mixtures were formulated by substituting 0, 20, 30, 40, 50, 60, or 70% peat with either parboiled ground rice hulls (GRH) or whole rice hulls (WRH) (by volume) in commercial potting mix (CPM) containing 70% peat, 20% perlite, and 10% vermiculite. All substrate mixtures consisted of mainly medium-sized (2.0–0.25 mm) particles. However, regardless of the mixing ratio, GRH significantly increased the medium-sized particles especially with diameters of 2.0–0.71 mm, while WRH increased both the medium- and coarse-sized (> 2.0 mm) particles. A higher mixing ratio of PRH increased air space and decreased container capacity but to a greater extent by WRH compared to GRH. Similarly, bulk density was increased with a higher mixing ratio of both types of PRH, but to a greater degree by GRH. Total porosity of GRH-containing substrates was similar to that of CPM within the range of 30–70%. The substrate mixtures containing PRH did not have the same physical properties as the CPM at any mixing ratio, but the values of some GRH-containing mixtures were within or close to the suggested ranges for greenhouse substrates. Considering the maximum substitution of PRH for peat, the substitution with 40% GRH (GRH-40) was selected for a plant growth study in comparison to CPM. Petunia (Petunia × hybrida) ‘Easy Wave Neon Rose’ and zinnia (Zinnia elegans) ‘Benary’s Giant Golden Yellow’ were grown in pots containing CPM and GRH-40 at two irrigation levels: high (25–30%, by volume) and low (20–25%). Overall, shoot DW of both plant species was reduced in GRH-40, but root DW was maintained similar to those in CPM. The low irrigation level more significantly reduced shoot DW of petunia grown in CPM than in GRH-40, relative to their counterparts with the high irrigation level (20 and 7%, respectively); however, root growth of plant species grown in GRH-40 was either maintained or tended to be maintained even at the low irrigation level compared to their high irrigation counterparts. The water use efficiency of plants grown in GRH-40 was not significantly different from those in CPM regardless of irrigation level. These results indicate that GRH-40 provides desirable physical properties and water release characteristics, allowing more available water for plants under low irrigation levels than CPM. We concluded that substituting peat with 40% GRH in a commercial potting mix is a sustainable approach to produce petunia and zinnia.

ACS Style

Seunghyun Choi; Lizhen Xu; Hye-Ji Kim. Influence of physical properties of peat-based potting mixes substituted with parboiled rice hulls on plant growth under two irrigation regimes. Horticulture, Environment, and Biotechnology 2019, 60, 895 -911.

AMA Style

Seunghyun Choi, Lizhen Xu, Hye-Ji Kim. Influence of physical properties of peat-based potting mixes substituted with parboiled rice hulls on plant growth under two irrigation regimes. Horticulture, Environment, and Biotechnology. 2019; 60 (6):895-911.

Chicago/Turabian Style

Seunghyun Choi; Lizhen Xu; Hye-Ji Kim. 2019. "Influence of physical properties of peat-based potting mixes substituted with parboiled rice hulls on plant growth under two irrigation regimes." Horticulture, Environment, and Biotechnology 60, no. 6: 895-911.

Journal article
Published: 02 July 2019 in Scientia Horticulturae
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Sustainable nutrient management is of critical importance to achieve high crop yield and quality and to improve nutrient use efficiency in agricultural production systems but has not been fully established for aquaponics. The objective of this study was to determine the effects of feeding regime on water quality, crop performance and yield, and nitrogen (N) use efficiency in recirculating aquaponic systems. The same amount of total N (120 g) was applied to aquaponics with different feeding regimes: aquaponic increasing feeding (AIF; the standard feeding regime), uniform feeding (AUF), and intermediate feeding (AMF), for one-month production of six vegetable and herb species. Crops grown in AIF and AUF showed contrasting results in yield and SPAD value (chlorophyll content), and therefore were further evaluated for nutrient profile in aquaponic solution and crop growth and performance compared to those in hydroponics (HYD), using eight leafy vegetable (Chinese cabbage, Mizuna, Swiss chard, lettuce, pac choi), herb (basil, chia), and fruity vegetable (cherry tomato) species. AUF improved water quality by reducing average concentrations of harmful compounds (i.e., NO2–N and Na) compared to AIF and crop growth and yield similar to those of HYD. Particularly, AUF tended to increase concentrations of mineral nutrients (i.e., NO3–N, PO4–P, Ca, and Mg) in aquaponic solution during the first week after transplanting, while decreasing the concentrations of harmful compounds in comparison to AIF. Regardless of feeding regime, aquaponics reduced fine root growth in leafy vegetables and herbs, compared to hydroponics. Overall, vegetables and herbs grown in AUF had a greater photosynthetic rate (Pn) from the first to the second week after transplanting and throughout production period and showed higher SPAD value and leaf total N content to the level similar to or slightly lower than HYD. Consequently, AUF increased N use efficiency (NUE) of the system by 30% and up to 600% compared to those in AIF and HYD, respectively. In conclusion, aquaponic crop production and N use efficiency can be increased by uniform feeding regime as it improves water quality and nutrient availability for better seedling establishment, consequently enhancing quality and/or yield of vegetables and herbs in aquaponics.

ACS Style

Teng Yang; Hye-Ji Kim. Nutrient management regime affects water quality, crop growth, and nitrogen use efficiency of aquaponic systems. Scientia Horticulturae 2019, 256, 108619 .

AMA Style

Teng Yang, Hye-Ji Kim. Nutrient management regime affects water quality, crop growth, and nitrogen use efficiency of aquaponic systems. Scientia Horticulturae. 2019; 256 ():108619.

Chicago/Turabian Style

Teng Yang; Hye-Ji Kim. 2019. "Nutrient management regime affects water quality, crop growth, and nitrogen use efficiency of aquaponic systems." Scientia Horticulturae 256, no. : 108619.

Journal article
Published: 10 February 2019 in Agronomy
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Plant-derived protein biostimulants exhibit hormone-like activities promoting plant growth and yield, yet detailed investigations on hormonal function have remained limited. This study was conducted to investigate the effects of vegetal-derived-biostimulant on morphological and metabolic changes in cuttings of three herbaceous species demonstrating different rooting ability, basil (Ocimum basilicum L.), tomato (Solanum lycopersicum L.), and chrysanthemum (Chrysanthemum indicum L.), in comparison to auxin. Unrooted cuttings were applied with or without biostimulant (100, 1000, 5000, and 10000 mg L−1) or auxin [1% indole-3-butyric acid (IBA) plus 0.5% 1-naphthaleneacetic acid (NAA); 100, 200, 300, and 500 mg L−1] as a basal quick-dip, stuck into inert media, and evaluated at 20 days after placement under intermittent mist. Both compounds increased adventitious rooting in all cuttings. Biostimulant required a significantly higher threshold for a series of adventitious rooting responses than auxin, and the maximum effectiveness was achieved at 5000 mg L−1 for biostimulant and 100, 200, and 300 mg L−1 for auxin in basil, tomato, and chrysanthemum, respectively. Adventitious rooting responses (dry mass and length) to biostimulant showed a gradual logarithmic rise as a function of increasing dosages, which was not in agreement with biphasic dose-response of auxin. Biostimulant significantly increased or tended to increase fine roots in all tested cuttings, which was not consistent with auxin. Relatively high levels of endogenous brassinosteroids (BRs) were present in non-treated cuttings of basil, tomato, and chrysanthemum in decreasing order. Both compounds had no effects or concomitantly increased or decreased BR levels in plant tissues, with fewer effects on basil and tomato, containing high BR levels, but more prominent effects on chrysanthemum, containing relatively low BR levels. Contrasting effects of biostimulant and auxin were found in antioxidant activities, which were promoted by biostimulant but inhibited by auxin either in roots or shoots. These results indicate that the hormonal effects of vegetal-derived biostimulant are primarily exerted by BR-mediated processes while involving interaction with auxin. Both the biostimulant-derived BRs and auxin were suggested to modulate endogenous BR pool via overlapping and interdependent regulatory functions, inducing morphological and metabolic changes during adventitious rooting of cuttings in a plant species-specific manner.

ACS Style

Hye-Ji Kim; Kang-Mo Ku; Seunghyun Choi; And Mariateresa Cardarelli. Vegetal-derived Biostimulant Enhances Adventitious Rooting in Cuttings of Basil, Tomato, and Chrysanthemum via Brassinosteroid-mediated Processes. Agronomy 2019, 9, 74 .

AMA Style

Hye-Ji Kim, Kang-Mo Ku, Seunghyun Choi, And Mariateresa Cardarelli. Vegetal-derived Biostimulant Enhances Adventitious Rooting in Cuttings of Basil, Tomato, and Chrysanthemum via Brassinosteroid-mediated Processes. Agronomy. 2019; 9 (2):74.

Chicago/Turabian Style

Hye-Ji Kim; Kang-Mo Ku; Seunghyun Choi; And Mariateresa Cardarelli. 2019. "Vegetal-derived Biostimulant Enhances Adventitious Rooting in Cuttings of Basil, Tomato, and Chrysanthemum via Brassinosteroid-mediated Processes." Agronomy 9, no. 2: 74.

Journal article
Published: 19 October 2018 in Environmental and Experimental Botany
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We investigated the effects of light spectral and thermal properties on biomass allocation among vegetative and reproductive structures in tomato (Solanum lycopersicum L. ‘Merlice’) plants during growth and development and to determine its underlying mechanisms. Plants were grown in a greenhouse under a DLI of 3.4 mol m2 day−1 with/without supplemental lighting and a 16-h photoperiod, provided at equal photosynthetic photon flux density (PPFD of 230 μmol m‒2 s‒1 either from overhead high-pressure sodium (HPS) lamps or intracanopy light-emitting diode (LED) arrays: red light alone (R100; 100% of photosynthetically active radiation (%PAR)), red plus low far-red (R100+FR21), red plus high far-red (R100+FR41), and red plus blue (R61+B39). Supplemental lighting substantially increased total biomass and fruit yield, but to a greater extent by LED lighting regardless of spectrum. However, spectral contribution to leaf morphological traits and biomass allocation pattern varied greatly among the light treatments. HPS-supplemented plants had higher leaf temperature, photosynthetic rate (Pn), and transpiration rate (E) in the upper foliar canopy (161 to 240 cm from the base of the shoot) and contained higher water content in all tissues, particularly in roots by 2-fold, compared to LED-supplemented plants. They also had thinner, smaller leaves and allocated a higher fraction of total biomass to vegetative tissues, demonstrating their allocation strategies for effective transpiration and heat dissipation. Meanwhile, LED-supplemented plants allocated biomass preferentially to reproductive structures at the expense of vegetative tissues. Inclusion of higher FR or B with R light decreased leaf biomass fraction relative to total biomass but increased leaf dry mass and leaf thickness. Particularly, supplemental FR light significantly lowered the water content of leaves and fruits compared to B light. Long-term exposure of tomato plants to low R:FR was associated with reductions in leaf area, chlorophyll content, and vegetative shoot biomass fraction, increases in leaf thickness and fruit biomass, and acceleration of flowering and fruiting. Light-induced biomass allocation changed between vegetative and reproductive structures during plant growth and development. FR light had the most pronounced effect in this regard by significantly shifting dry-mass accumulation to fruits, via more efficient photosynthetic mechanisms and conserved water use. We conclude that light spectral and thermal properties affect biomass allocation among plant parts during tomato growth and development, and such responses involve morphological and physiological changes in tomato plants, ultimately affecting crop performance and yield.

ACS Style

Hye-Ji Kim; Meng-Yang Lin; Cary A. Mitchell. Light spectral and thermal properties govern biomass allocation in tomato through morphological and physiological changes. Environmental and Experimental Botany 2018, 157, 228 -240.

AMA Style

Hye-Ji Kim, Meng-Yang Lin, Cary A. Mitchell. Light spectral and thermal properties govern biomass allocation in tomato through morphological and physiological changes. Environmental and Experimental Botany. 2018; 157 ():228-240.

Chicago/Turabian Style

Hye-Ji Kim; Meng-Yang Lin; Cary A. Mitchell. 2018. "Light spectral and thermal properties govern biomass allocation in tomato through morphological and physiological changes." Environmental and Experimental Botany 157, no. : 228-240.

Journal article
Published: 01 November 2017 in International Biodeterioration & Biodegradation
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ACS Style

Sumeth Wongkiew; Brian N. Popp; Hye-Ji Kim; Samir Kumar Khanal. Fate of nitrogen in floating-raft aquaponic systems using natural abundance nitrogen isotopic compositions. International Biodeterioration & Biodegradation 2017, 125, 24 -32.

AMA Style

Sumeth Wongkiew, Brian N. Popp, Hye-Ji Kim, Samir Kumar Khanal. Fate of nitrogen in floating-raft aquaponic systems using natural abundance nitrogen isotopic compositions. International Biodeterioration & Biodegradation. 2017; 125 ():24-32.

Chicago/Turabian Style

Sumeth Wongkiew; Brian N. Popp; Hye-Ji Kim; Samir Kumar Khanal. 2017. "Fate of nitrogen in floating-raft aquaponic systems using natural abundance nitrogen isotopic compositions." International Biodeterioration & Biodegradation 125, no. : 24-32.

Journal article
Published: 01 November 2016 in HortScience
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Modern intensive agriculture has led to biodiversity loss by restricting the number of crops, resulting in a limited range of nutrients available to the community. Alternative specialty crops can contribute to crop diversification in agricultural production systems and enhance human health and well-being by providing a diverse array of food crops. Rapid demographic changes in the U.S. population has created higher demands for and sales potential of fruits and vegetables, and has brought new market opportunities for farmers in the United States to grow alternative specialty crops. The introduction of alternative specialty crops has many inherited advantages including economic benefits to farmers through multiple facets: diversifying crop with value-added crops, improving resilience to climate variability, maintaining yields with less resources, and boosting crop resistance to pests and diseases. However, there are challenges associated with the introduction and establishment of new crops, which include lack of information on candidates, cultural practices, and marketing as well as policy and institutional barriers. Farmers may face risk from poor economic returns and their businesses are likely to fail if proper management and marketing information are not available. This paper explores the opportunities and challenges associated with introduction of alternative specialty crops, and discuss how to mitigate potential problems associated with the introduction and establishment of alternative specialty crops.

ACS Style

Hye-Ji Kim. Opportunities and Challenges of Alternative Specialty Crops: The Global Picture. HortScience 2016, 51, 1316 -1319.

AMA Style

Hye-Ji Kim. Opportunities and Challenges of Alternative Specialty Crops: The Global Picture. HortScience. 2016; 51 (11):1316-1319.

Chicago/Turabian Style

Hye-Ji Kim. 2016. "Opportunities and Challenges of Alternative Specialty Crops: The Global Picture." HortScience 51, no. 11: 1316-1319.

Journal article
Published: 20 September 2014 in BMC Genomics
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Litchi is an evergreen woody tree widely cultivated in subtropical and tropical regions. Defective flowering is a major challenge for litchi production in time of climate change and global warming. Previous studies have shown that high temperature conditions encourage the growth of rudimentary leaves in panicles and suppress litchi flowering, while reactive oxygen species (ROS) generated by methyl viologen dichloride hydrate (MV) promote flowering and abortion of rudimentary leaves. To understand the molecular function of the ROS-induced abortion of rudimentary leaves in litchi, we sequenced and de novo assembled the litchi transcriptome. Our assembly encompassed 82,036 unigenes with a mean size of 710 bp, and over 58% (47,596) of unigenes showed significant similarities to known sequences in GenBank non-redundant (nr) protein database. 5,865 unigenes were found to be differentially expressed between ROS-treated and un-treated rudimentary leaves, and genes encoding signaling components of plant hormones such as ABA and ethylene were significantly enriched. Our transcriptome data represents the comprehensive collection of expressed sequence tags (ESTs) of litchi leaves, which is a vital resource for future studies on the genomics of litchi and other closely related species. The identified differentially expressed genes also provided potential candidates for functional analysis of genes involved in litchi flowering underlying the control of rudimentary leaves in the panicles.

ACS Style

Xingyu Lu; Hyeji Kim; Silin Zhong; Houbin Chen; Zhiqun Hu; Biyan Zhou. De novo transcriptome assembly for rudimentary leaves in Litchi chinesis Sonn. and identification of differentially expressed genes in response to reactive oxygen species. BMC Genomics 2014, 15, 1 -14.

AMA Style

Xingyu Lu, Hyeji Kim, Silin Zhong, Houbin Chen, Zhiqun Hu, Biyan Zhou. De novo transcriptome assembly for rudimentary leaves in Litchi chinesis Sonn. and identification of differentially expressed genes in response to reactive oxygen species. BMC Genomics. 2014; 15 (1):1-14.

Chicago/Turabian Style

Xingyu Lu; Hyeji Kim; Silin Zhong; Houbin Chen; Zhiqun Hu; Biyan Zhou. 2014. "De novo transcriptome assembly for rudimentary leaves in Litchi chinesis Sonn. and identification of differentially expressed genes in response to reactive oxygen species." BMC Genomics 15, no. 1: 1-14.