Soil salinity is a common problem in agricultural regions of the southwestern United States as a result of low rainfall, high evapotranspiration, and poor quality of irrigation water. High soil salinity leads to poor germination, delays stand establishment, and reduces subsequent growth and yield of chile peppers and onion (Corgan et al., 2000; Flynn et al., 2002; Phillips, 2003). Seed germination and seedling emergence are critical growth stages for successful stand establishment, which impacts ultimate crop yields. Anecdotal observation indicated that it is more difficult for chile pepper seeds to germinate and establish in mineral soils compared with commercial potting mix. Elevated soil salinity and/or inadequate water supply can further reduce seedling establishment.
In furrow-irrigated croplands, a common problem with saline water and soils for vegetable production is high seedling mortality (Miyamoto et al., 1986). Soil salinity at or near the soil surface increases exponentially with time when saline water is used for irrigation (USDA Staff, 1954). Miyamoto et al. (2010) reported that seed germination, seedling emergence, and seedling growth of onions were affected by soil property, salinity of irrigation water, and irrigation method. The dynamics of salt movements and distribution in various soils are poorly understood.
Chile peppers (Capsicum annuum) are important vegetables in the southwestern states of the United States and in many other countries of the world. Peppers are considered moderately sensitive to salt stress (Maas and Hoffman, 1977; Pasternak and Malach, 1994). Yield reduction of peppers begins when the electrical conductivity (EC) of saturated soil extraction is greater than 1.5 dS·m−1 (Maas and Hoffman, 1977). However, limited recent studies of mostly bell peppers have indicated that some genotypes are more tolerant to salinity than others (Aktas et al., 2006; Chartzoulakis and Klapaki, 2000). The objectives of this study were to quantify 1) the effect of salinity of irrigation water and soil type on seedling emergence in two soil types; and 2) the relative tolerance of four commercial pepper varieties belonging to four botanical types, New Mexico long green, jalapeño, cayenne, and bell pepper, by growing them in commercial potting mix and irrigating the seedlings with saline solutions at various salinities.
Chartzoulakis, K. & Klapaki, G. 2000 Response of two greenhouse pepper hybrids to NaCl salinity during different growth stages Sci. Hort. 86 247 260
Corgan, J. , Wall, M. , Cramer, C. , Sammis, T. , Lewis, B. & Schroeder, J. 2000 Bulb onion culture and management New Mexico State University, Cooperative Extension Service, Circular 563
Flynn, R. , Phillips, R. , Ulery, A. , Kochevar, R. , Liess, L. & Villa, M. 2002 Chile seed germination as affected by temperature and salinity New Mexico Chile Task Force, New Mexico State University, Cooperative Extension Service, Report 2
Miyamoto, S. , Niu, G. & Martinez, I. 2010 Salinity and specific ion effects on onion establishment in relation to disposal of desalting concentrates Desalination and Water Treatment 16 381 392
Miyamoto, S. , Piela, K. & Petticrew, J. 1986 Seedling mortality of several crops induced by root, stem or leaf exposure to salts Irrig. Sci. 7 97 106
Pasternak, D. & Malach, Y.D. 1994 Crop irrigation with saline water 599 622 Pessarakli M. Handbook of plant and crop stress Marcel Dekker New York, NY
Phillips, R. 2003 Chile pepper growers' notes New Mexico State University Cooperative Extension Service, New Mexico Chile Task Force Report 10
Shannon, M.C. , Grieve, C.M. & Francois, L.E. 1994 Whole-plant response to salinity 199 244 Wilkinson R.E. Plant environment interaction Marcel Dekker New York, NY
USDA Staff 1954 Diagnosis and improvement of saline and alkaline soils. USDA Agric. Handbook No. 60 Richards L.A. U.S. Gov. Print. Office Washington, DC