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Fahed A. Al-Mana and Tarik M. El-Kiey

Production of five commercial cut flowers in different culture media, namelyI nutrient film technique (NFT), soilless media (perlite and an equal mix of perlite and peatmoss), and soil mix (2 sand: 1 loam by volume), was investigated in controlled fiberglass-house. Two rose varieties (Rosa hybrida var. Baccara and Madina); carnation (Dianthus caryophyllus var. William Sim); Chrysanthemum morifolium var. Delta, and Dahlia hybrida var. variabilis were used. Plants were watered as they needed by the same nutrient solution used for NFT.

Generally, growth and yield of Baccara and Madina roses, Chrysanthemum and Dhalia plants were superior in NFT than in the other media. On the contrary, the growth and yield of carnation plants were significantly greater in conventional soil or perlite and peatmoss mix than in NFT or perlite.

Flower crops grown in NFT generally reached harvest stage 5-10 days earlier than those grown in the other media except carnation plants. There were variations in the accumulation of N, P, K mg, ca, and Fe in plant leaves among the various culture media.

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Christopher S. Brown, William M. Cox, Thomas W. Dreschel, and Peter V. Chetirkin

A nutrient delivery system that may have applicability for growing plants in microgravity is described. The Vacuum-Operated Nutrient Delivery System (VONDS) draws nutrient solution across roots that are under a partial vacuum at ≈91 kPa. Bean (Phaseolus vulgaris L. cv. Blue Lake 274) plants grown on the VONDS had consistently greater leaf area and higher root, stem, leaf, and pod dry weights than plants grown under nonvacuum control conditions. This study demonstrates the potential applicability of the VONDS for growing plants in microgravity for space biology experimentation and/or crop production.

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Woodland Hurtt and John P. Sterrett

Abstract

Two- to 3-month-old seedlings (10 to 12 cm tall) were grown in solution culture to which varying levels of ancymidol or dikegulac were added. Height growth of green ash (Fraxinus pennsylvanica Marsh.) at 11 days after treatment was inhibited ≈50% by 12.5 mg·liter–1 dikegulac. Growth of green ash and silver maple (Acer saccharinum L.) at 7 days was inhibited 75% to 80% by 0.125 mg·liter–1 ancymidol. Growth responses of these seedlings were linearly related to the logarithm of dikegulac and ancymidol concentrations. Chemical names used: 2,3:4,6-bis-O-(1-methylethylidene)-α-L-xylo-2-hexulofuranosonic acid) (dikegulac); α-cyclopropyl-α-(4-methoxy-phenyl)-5-pyrimidinemethanol (ancymidol).

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Steven J. Bergsten, Andrew K. Koeser, and J. Ryan Stewart

hydroponics. Hydroponic culture of seedlings has been found to be effective for screening for salinity tolerance in agaves ( Nobel and Berry, 1985 ), other species ( Munns and James, 2003 ; Shaheen and Hood-Nowotny, 2005 ), and for other forms of

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Noah J. Langenfeld and Bruce Bugbee

biological demand requires greater inputs of oxygen to sustain homeostasis ( Ben-Noah and Friedman, 2018 ). The nutrient solution of liquid hydroponics benefits from levels of DO close to saturation near 8 mg⋅L –1 . This promotes healthy root respiration and

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Alejandro R. Puerta, Suguru Sato, Yutaka Shinohara, and Toru Maruo

.1080/00221589.1984.11515216 Jones J.B. Jr 1997 Hydroponics: A practical guide for the soilless grower St. Lucie Press Boca Raton, Fla Lee, S.K. Kader, A.A. 2000 Preharvest and postharvest factors influencing vitamin C content of horticultural crops Postharvest Biol. Technol. 20 207

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Richard V. Tyson, Eric H. Simonne, Danielle D. Treadwell, James M. White, and Amarat Simonne

.R. Harper, J.K. Takeda, F. Wade, E.D. Summerfelt, S.T. 2000 Economic evaluation of hydroponics and other treatment options for phosphorus removal in aquaculture effluent HortScience 35 993 999 Adler

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Carl E. Niedziela Jr., Paul V. Nelson, Daniel H. Willits, and Mary M. Peet

Commercial recommendations exist for using short-term salt-shocks on tomato (Lycopersicon esculentum Mill.) to improve fruit quality. Six experiments were conducted to 1) assess the influence of nutrient concentration and short-term salt-shocks on fruit quality and yield and 2) identify a vegetative predictor of subsequent fruit quality. The first objective was addressed in three nutrient film technique (NFT) experiments (Expts. 1-3). Four treatments were applied: two maintained constant at two baseline concentrations (0.25X and 1X-commercial level) and two provided salt-shock periods of 30 min, twice daily. There were no effects of baseline concentration or salt-shocks on total number and weight of marketable fruit. Fruit quality was better at the 1X baseline concentration as observed by higher titratable acidity (Expt. 2), higher percent dry matter (Expts. 2 and 3), higher soluble solids concentration (Expt. 2), and lower pH (Expts. 2 and 3), however, weight per marketable fruit was lower (Expt. 2). Salt-shocks had little effect on fruit quality, refuting its commercial potential. Salt-shocks decreased fruit pH (Expts. 1 and 3). However, titratable acidity increased at the 0.25X level and decreased at the 1X level (Expt. 3). In Expt. 2, but not in Expt. 3, citrate concentration in the fifth leaf from the apex of young vegetative plants was correlated with subsequent fruit quality. Three additional experiments in static hydroponics with vegetative plants showed no significant differences in leaf citrate levels due to a single, short-term salt-shock. Thus, citrate is not a good predictor of fruit quality.

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Jae-Woo Soh* and Yong-Beom Lee

Experiments were carried out to determine nutrient management system for butterhead lettuce `Omega' and leaf lettuce `Grand Rapids' in nutrient film technique (NFT), and to develop a rapid and reliable program for recirculation solution. The effects of controlling solutions with UOSL (Leaf Lettuce solution of the Univ. of Seoul, Korea; NO3 -N 10.55, NH4 -N 1.02, P 2.0, K 6.7, Ca 3.5, Mg 2.0, SO4 -S 2.0 me·L-1; Fe 2.0, Cu 0.1, B 0.5, Mn 0.3, Zn 0.3, Mo 0.05 ppm) were studied by greenhouse with managing by distilled water (DW), managing pH and EC (CM), managing by nutrient solution analysis (MN), managing by nutrient solution with leaf analysis (ML). The CO2 assimilation, transpiration rate, relative chlorophyll contents, leaf color, fresh weight and dry weight were highest in MN control in the butterhead `Omega' and in MN and ML control in the leaf lettuces `Grand Rapids'. The highest relative growth rate (RGR) was in MN ML in the butterhead `Omega' but those wasn't in the leaf lettuce `Grand Rapids'. Calculation program of adjustable solution was based on the main works by Visual Basic 5.0. The developed program could select an automatic and passive process considering the type of fertilizers, run-off rate, nutrient concentration, and water volume, for calculation. All of them were done successfully by the fast and precise calculation program.