Because fresh water supplies are limited in many parts of the world, using alternative water sources for irrigating horticultural crops may become necessary. Alternative water sources (hereafter called nonpotable water) include recycled water, treated municipal effluent (reclaimed water) and brackish groundwater, which generally contain higher levels of salts compared with potable water. Previous research has demonstrated the possibility of using nonpotable water for irrigating high-value horticultural crops (Grieve et al., 2005, 2006; Shannon et al., 2000; Shillo et al., 2002) and for landscape irrigation (Devitt et al., 2005; Marosz, 2004; Niu and Rodriguez, 2006a, 2006b; Wu et al., 2001), although a wide range of salt tolerance among these ornamental plants was observed.
Depending on salt tolerance, some plants became more compact with little visual damage when irrigated with low to moderate salinity compared with nonsaline control (Niu and Rodriguez, 2006a, 2006b; Wu et al., 2001). For landscape plants, maximizing growth is not essential and indeed, excessive shoot vigor is often undesirable. To maintain a compact growth habit, ornamental plants traditionally have either been pruned or treated with growth regulators (Cameron et al., 2004). Therefore, nonpotable water may play an important role for landscape irrigation where potable water supply is limited. Salinity stress in some instances has positive effects on crop yield and quality in some floricultural crops (Grieve et al., 2006). For example, number of flowers, stem weight, and stem diameter of lisianthus were increased when salinity stress was imposed during the final stage of vegetative growth compared with the control (Shillo et al., 2002). Salinity stress during early reproductive stage resulted in shorter, more robust peduncles with larger inflorescences in carnation (Baas et al., 1995).
Lupinus havardii is an annual native to a narrow geographic range along the Rio Grande River in southwest Texas and has shown potential to be grown as a specialty cut flower (Davis et al., 1994; Picchioni et al., 2001). It has fragrant and attractive blue racemes with a length of 40 to 55 cm supporting 25 to 30 fully opened flowers (Mackay and Davis, 1998). In Texas, L. texensis is a hardy winter annual and is the best-known, most widely distributed member of the Lupinus genus (Davis et al., 1994). Transplants of L. texensis are produced for spring and fall sales, but those grown during late summer and early fall are the best for garden performance in warmer regions in the United States (Davis et al., 1994). There is no information available on the impact of saline irrigation on the growth and development of these two species. The objectives of this study were to determine the salinity threshold for marketable production of L. havardii and L. texensis and assess the effects of increasing levels of salinity on growth of these species.
Baas, R., Nijssen, H.M.C., Van Den Berg, T.J.M. & Warmenhoven, M.G. 1995 Yield and quality of carnation (Dianthus caryophyllus L.) and gerbera (Gerbera jamesonii L.) in a closed nutrient system as affected by sodium chloride Scientia Hort. 61 273 284
Cameron, R.W.F., Wilkinson, S., Davies, W.J., Harrison-Murray, R.S., Dunstan, D. & Burgess, C. 2004 Regulation of plant growth in container-grown ornamentals through the use of controlled irrigation Acta Hort. 630 305 312
Carter, C.T., Grieve, C.M., Poss, J.A. & Suarez, D.L. 2005 Production and ion uptake of Celosia argentea irrigated with saline wastewaters Scientia Hort. 106 381 394
Davis, T.D., George, S.W., Mackay, W.A. & Persons, J.M. 1994 Development of Texas bluebonnets into floricultural crops HortScience 29 1110, 1211
Devitt, D.A., Morris, R.L., Fenstermaker, L.K., Baghzouz, M. & Neuman, D.S. 2005 Foliar damage and flower production of landscape plants sprinkle irrigated with reuse water HortScience 40 1871 1878
Grieve, C.M., Poss, J.A., Grattan, S.R., Shouse, P.J., Lieth, J.H. & Zeng, L. 2005 Productivity and mineral nutrition of Limonium species irrigated with saline wastewaters HortScience 40 654 658
Khurram, S. & Miyamoto, S. 2005 Seedling growth, leaf injury and ion uptake response of cold-resistant palm species to salinity J. Environ. Hort. 23 193 198
Marosz, A. 2004 Effect of soil salinity on nutrient uptake, growth, and decorative value of four ground cover shrubs J. Plant Nutr. 27 977 989
Picchioni, G.A., Valenzuela-Vazquez, M. & Armenta-Sanchez, S. 2001 Calcium-activated root growth and mineral nutrient accumulation of Lupinus havardii: Ecophysiological and horticultural significance J. Amer. Soc. Hort. Sci. 126 631 637
Shannon, M.C., Grieve, C.M., Lesch, S.M. & Draper, J.H. 2000 Analysis of salt tolerance in nine leafy vegetables irrigated with saline drainage water J. Amer. Soc. Hort. Sci. 125 658 664
Shillo, R., Ding, M., Pasternak, D. & Zaccai, M. 2002 Cultivation of cut flower and bulb species with saline water Scientia Hort. 92 41 54
Wu, L., Guo, X. & Harivandi, A. 2001 Salt tolerance and salt accumulation of landscape plants irrigated by sprinkler and drip irrigation systems J. Plant Nutr. 24 1473 1490