Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/3/2008
Publication Date: 9/16/2008
Citation: Grieve, C.M., Poss, J.A., Carter, C.T., Shouse, P.J. 2008. Modeling Growth of Matthiola incana in Response to Saline WasteWaters Differing in Nitrogen Level. HortScience. 43:1787-1793. Interpretive Summary: As water quality and quantity become more limited in many parts of the world, creative management approaches are sought to make more efficient use of degraded, generally saline, waters. The reuse of nutrient-rich run-off from floricultural production represents an opportunity for producers to greatly reduce fresh water consumption and to prevent surface and groundwater contamination. Little information is available, however, on the influence that these degraded water may have on the growth and quality of floral crops. With stock (Matthiola incana), a as the test species, a commercially-important cut flower, this study was conducted in outdoor sand tanks to demonstrate plant response to the interactive effects of saline water amended with different concentrations of fertilizer nitrogen (N). Stem length was recorded routinely over the growing period. At final harvest dimensions of the flowering stems were measured. Stock was insensitive to the various concentrations of N in the irrigations waters. Salinity, however, significantly slowed plant development, and the plants irrigated with non-saline water were the first to reach marketable stage. Quality of flowers produced in all treatments was rated as superior. The study demonstrates that growers can economically produce stock with degraded waters and can use their high-quality water resources for more salt sensitive crops.
Technical Abstract: The capture and reuse of nutrient-rich greenhouse effluents may be an environmentally-sound option for floriculture production which would conserve fresh water resources and reduce off-site pollution of surface and groundwaters. This study was initiated in 24 outdoor lysimeters to determine interactive effects of salinity and varying concentrations of nitrogen on the growth, yield and ion relations of stock (Matthiola incana (L.) R. Br.) cultivar ‘Cheerful White’. The experiment was a 4 × 4 factorial, partially-replicated design with four irrigation water salinities (2, 5, 8, 11 dS m-1) and four nitrate concentrations (2.5, 3.6, 5.4 and 7.1 mmol L-1; N = 35. 50, 75 and 100 ppm). Plant heights were measured thrice weekly. Measurements at final harvest were: stem and inflorescence lengths, stem and floret diameters, number of axillary buds and florets, shoot and root fresh weights. Time course of stem elongation was quantified as a function of thermal time with a phasic growth model. Salinity significantly delayed initiation of the exponential growth phase, shortened its duration, and reduced the rate of development. The overall effect was to delay time to harvest of marketable stems. Although length of the flowering stems decreased with increasing salinity, marketable stems (~60 cm) were produced in all treatments. Interactive effects of salinity and N on leaf ion relations were not significant, although a strong interactive trend for leaf-N was observed. Sodium, Mg and Cl concentrations in leaves increased with increasing salinity; Ca and K decreased. In response to increasing external N, both K and Cl decreased; Na increased, while Ca and Mg were unaffected.