Combined effects of KNO3 and salinity on yield and chemical composition of lettuce and Chinese cabbage

Abstract

The effect of N and K nutrition on the salt tolerance of lettuce (Lactuca sativa L. cv. 'Salinas') and Chinese cabbage (Brassica campestris L., Pekinensis cv. Kazumi) was evaluated in three greenhouse experiments under a controlled aero-hydroponic system of cultivation. Three levels of KNO3 (1, 5 and 10 mM) were tested in all the experiments with rapidly circulated saline and nonsaline nutrient solutions. Two experiments, carried out between January and March 1989, with lettuce (Exp. I) and Chinese cabbage plants (Exp. III), consisted of two salinity levels, EC= 1.75 and 6.0 dS m-l, the former representing a nonsaline nutrient solution. In the third experiment with lettuce (Exp. II., conducted between March and May 1989), three saline nutrient solutions having EC levels of 4.7, 7.75 and 10.75 dS m-1 were compared to the nonsaline solution. The nutrient solutions were salinized with NaC1 and CaC12, in a 4:1 molar ratio. The highest yields of fresh weight of both crops were obtained from the 5 mM KNO 3 under both saline and non-saline conditions. The 10 mM treatment caused yield reduction in Chinese cabbage, probably due to a severe tipburn disorder. The relatively high fresh weight yield obtained at the lowest (1 raM) KNO 3 level can be explained by the positive effect of circulation velocity on nutrient uptake. The threshold salinity damage value for the vegetative yield of lettuce plants fed by 5 or 10 mM KNO 3 was approximately 5 dSm -1 and the yield decreased by 6.5% per unit dS m-1 above the threshold. No yield improvement due to the addition of KNO 3 occurred under highly saline conditions (Exp. II). The fresh weight of Chinese cabbage obtained from the 'saline' 1 and 5 mM KNO 3 treatments was approximately 15% lower than the 'non-saline'-treatment (Exp. III). Salinity increased tipburn and the effect was not altered by the addition of KNO 3 . No significant interaction between nutrition (KNO 3 level) and salinity was found. The application of salts increased the concentration of Na and C1 * Contribution from Institute of Soils and Water, ARO, Volcani Center, PO Box 6, Bet Dagan 50250, Israel. No. 3092-E 1990 series Offprint requests to: A Feigin in plant tissue and reduced the levels of N and K; the opposite occurred in plants fed by the medium and high levels of KNO a .The yield and quality of leaf vegetables, such as lettuce and Chinese cabbage, grown on irrigated land can be considerably influenced by water composition. This is also true for greenhouse-grown crops when saline water is used for irrigation or, when grown in soil, where a high water table or the accumulation of fertilizer residues contributes to the development of saline conditions (Sonneveld 1988). Alleviation of salt stress in leaf vegetables is important not only to prevent yield losses but also to avoid quality deterioration due to physiological disorders such as tipburn van den Ende et al. 1975).As salt damage to crops involves not only total salt effect (osmotic effect) but also specific ion effects (Lauchli and Epstein 1984) it has b...

Salinity–mineral nutrient relations in horticultural crops

“…In contrast to the effect of Cl À on NO À 3 uptake, others have reported that increased NO À 3 in the substrate decreased Cl À uptake and accumulation in numerous annual horticultural crops (Bernstein et al, 1974;Kafkafi et al, 1982;Feigin et al, 1987;Martinez and Cerda Â, 1989). This effect is particularly relevant in tree or vine crops that are prone to Cl-toxicity.…”

“…Despite the lack of evidence indicating that N applied to saline soils or media above a level considered optimal under non-saline conditions improves plant growth or yield, a number of laboratory and greenhouse studies have shown that salinity can reduce N accumulation in plants (Cram, 1973;Pessarakli and Tucker, 1988;Feigin et al, 1991;Pessarakli, 1991;Al-Rawahy et al, 1992). This is not surprising since an increase in Cl À uptake and accumulation is often accompanied by a decrease in shoot-NO À 3 concentration.…”

“…This is not surprising since an increase in Cl À uptake and accumulation is often accompanied by a decrease in shoot-NO À 3 concentration. Examples of such an effect have been found in cucumber, Cucumis sativus L. (Martinez and Cerda Â, 1989), eggplant, Solanum melongena L. (Savvas and Lenz, 1996), melon, Cucumis melo L. (Feigin et al, 1987), and tomato (Kafkafi et al, 1982;Feigin et al, 1987;Martinez and Cerda Â, 1989). Many attributed this reduction to Cl À antagonism of NO À 3 uptake (Bar et al, 1997;Feigin et al, 1987;Kafkafi et al, 1982) while others attributed the response to salinity's effect on reduced water uptake (Lea-Cox and Syvertsen, 1993).…”

Effects of Irrigation with Saline Water on Crop Growth and Yield in Greenhouse Cultivation

“…Rameshwaran et al [12] investigated effects of different irrigation regimes with salinity treatments using a drip irrigation system for two pepper varieties in the greenhouse in Antalya, Turkey. Feigin et al [17] tested the response of lettuce and Chinese cabbage to the combination of a wide range of salinity and potassium nitrate levels in the greenhouse using an aero-hydroponic system. Garrido et al [18] evaluated physiological, phytochemical, and structural changes in lettuce by salt stress in a soilless system.…”

Morphological and Physiological Analysis of Salinity Stress Response of Carob (Ceratonia siliqua L.) in Morocco

“…These results are in agreement with the observations of Kaya et al 26 . According to Feigin et al 27 and Grattan and Grieve…”