Suaeda glauca is an annual halophyte growing in saline–alkali environment in North China. To evaluate the potential of producing S. glauca as a vegetable at moderate NaCl concentrations, plants were grown in nutrient solutions with 6, 8, and 10 mm NaCl, and with 200 mm NaCl as a control. Results showed that main stem length, true leaf number, side branch number, and canopy width of plants in 6–10 mm NaCl were not significantly different from those in 200 mm. Also, no significant differences in fresh and dry weights of individual plants, marketable yield, and water use efficiency of the plants were observed between 6–10 and 200 mm NaCl treatments. Despite remarkable decreases in sodium uptake, similar water consumptions by the plants were obtained in 6–10 vs. 200 mm NaCl. The results suggest that S. glauca is a potential candidate for hydroponic production as a vegetable at moderate NaCl salinity, since growth attributes and biomass accumulation were not reduced when grown at lower salinity levels, despite with decreased sodium uptake.
Yun Kong and Youbin Zheng
Yun Kong and Youbin Zheng
Salicornia bigelovii is a halophyte that is capable of growing under high salinity. To evaluate the potential of producing S. bigelovii hydroponically as a vegetable at moderate NaCl concentrations, plants were grown in nutrient solutions with 6, 8, and 10 mm NaCl, and with 200 mm NaCl as a control. Results showed that plants had a reduced main stem length, canopy width, stem diameter, and root system length in 6 to 10 mm NaCl compared with those in 200 mm. Also, fresh weight increase, fresh and dry weights of individual plants, marketable yield, and water use efficiency of the plants grown in solutions with 6 to 10 mm NaCl were significantly lower than those grown in 200 mm. Associated with the reduced growth attributes, remarkable decreases in sodium uptake by the plants were also obtained in 6 to 10 vs. 200 mm NaCl. The results suggest that S. bigelovii is not a good candidate for hydroponic production as a vegetable at moderate NaCl salinity resulting from reduced growth attributes, which are possibly associated with decreased sodium uptake.
Yun Kong and Youbin Zheng
To evaluate the potential of producing purslane (Portulaca oleracea L.) as a sodium (Na)-removing vegetable hydroponically at moderate NaCl salinity, two cultivars (Green and Golden) were grown in solutions with added 0, 6, 8, and 10 mm NaCl (the actual Na+ concentrations ≈2, 8, 10, and 12 mm, respectively). At harvest, 26 days after transplanting, apparent growth and biomass accumulation were not negatively affected by 6 to 10 mm added NaCl compared with 0 mm added NaCl. However, with the increase of added NaCl concentration from 0 to 6 to 10 mm, the sodium removal showed a 1- to 3-fold increase up to 0.26 to 0.41 mmol/plant, and 225.7 to 300.2 mmol·kg−1 dry weight (DW) or 0.90 to 1.32 mmol·L−1 H2O, respectively. ‘Green’ produced greater biomass and removed more sodium per plant than ‘Golden’. ‘Golden’ had more of a dwarfed and compact canopy than ‘Green’. Sodium removal rate (mmol/plant/day) was the highest during the first 7 days after transplanting, but the fresh weight increase rate (g/plant/day) increased gradually as growth progressed. Results suggest that it is possible to hydroponically produce purslane in nutrient solutions with 8 to 12 mm Na+. Despite the high sodium-removal capability, purslane cannot be used to reduce Na+ concentrations in NaCl-rich hydroponic solutions. The biomass yield and the sodium removal of individual plants were affected by different cultivars and time after transplanting.
Yun Kong, David Llewellyn, Katherine Schiestel, Martha Gay Scroggins, David Lubitz, Mary Ruth McDonald, Rene Van Acker, Ralph C. Martin, Youbin Zheng and Evan Elford
There is a potentially large market for locally produced organic bitter melons (Momordica charantia L.) in Canada, but it is a great challenge to grow this warm-season crop in open fields (OFs) due to the cool and short growing season. To test the feasibility of using high tunnels (HTs) for organic production of bitter melons in southern Ontario, plant growth, fruit yield and quality, and pest and disease incidence were compared among three production systems: OF, HT, and high tunnel with anti-insect netting (HTN) at Guelph in 2015. The highest marketable fruit yield was achieved in HTN (≈36 t·ha−1), followed by HT (≈29 t·ha−1), with the lowest yield obtained in OF (≈3 t·ha−1). Compared with OF, there were several other benefits for bitter melon production in HT and HTN: increased plant growth, advanced harvest timing, reduced pest numbers and disease incidence, and improved fruit quality traits such as increased individual fruit weight and size, and reduced postharvest water loss. In addition to higher yield, HTN had fewer insect pests and disease incidence compared with HT. The results suggest that HTs can be used for organic production of bitter melon in southern Ontario and regions with similar climates. Also, the addition of anti-insect netting to HTs is beneficial to production if combined with an effective pollination strategy.