Location: Agricultural Systems ResearchTitle: Response of two wheat cultivars to supplemental nitrogen under different salinity stress
|SALEH, A - National Research Centre|
|EL-KAKER, A - National Research Centre|
Submitted to: Journal of Agricultural Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/16/2015
Publication Date: 7/30/2015
Citation: Saleh, A.L., El-Kaker, A.A., Alva, A.K. 2015. Response of two wheat cultivars to supplemental nitrogen under different salinity stress. Journal of Agricultural Science. 7(6):14-19. DOI: 10.5539/jas.v7n6p14.
Interpretive Summary: Soil salinity limits plant growth and yield due to an increase in osmotic potential of the soil solution which limits plant available water or inhibition of plant metabolism caused by increased salt content. Reclamation of saline soils is often expensive, therefore, many not be possible in some situations. Plant tolerance to salinity is most desirable approach to manage saline soils; however, availability of tolerant cultivars may be the primary limitation. Therefore, evaluations of management options to mitigate the negative effects of salinity are highly desirable. Supplemental nutrition in different forms can enhance physiological mechanisms of plant tolerance to abiotic stresses, including salinity stress. In this greenhouse study, effects of supplemental nitrogen, applied as farmyard manure (FYM) or as urea, were investigated on the response of a salt sensitive and a salt tolerant wheat cultivars under various levels of salinity stresses (control, 6, 9, and 12 deci-siemen/meter). Only at the low salinity level (6 deci-siemen/meter), supplemental N as FYM or urea mitigated the salinity stress in both cultivars as compared to that with no supplemental N. The above beneficial effects of supplemental N were greater in a salinity tolerant cultivar than that for a salinity sensitive cultivar. Further long term field investigations are recommended to evaluate these beneficial effects and soil quality improvements resulting from supplemental nitrogen, in particular the FYM source, and mechanisms of improved stress tolerance.
Technical Abstract: Effects of supplemental nitrogen (N), as either farmyard manure (FYM) or urea, on response of two wheat (Triticum aestivum) cultivars (a salt sensitive ‘Sakha 69’ and a salt tolerant ‘Sakha 93’) were investigated in a green house experiment under various salinity levels (control, 6, 9, or 12 dS m-1). Grain and straw yields of both cultivars decreased with an increase in salinity levels. Supplamental N application, using FYM or urea, mitigated the adverse effects of salinity only at the low salinity level (6 dS m-1). This effect was greater in a salt tolerant cultivar (Sakha 93) than that in a salt sensitive cultivar (Sakha 69). At the moderate and high salinity (9 and 12 dS m-1) levels the supplemental N had no beneficial effects in mitigating the salinity stress of both cultivars. The mean grain yields, across all salinity levels and cultivars, of the plants received FYM and urea were greater by 11, and 8%, respectively, as compared to that of the plants received no supplemental N. The corresponding values for straw were 12 and 7%. The concentrations of N, P and K in the grain and straw significantly decreased with increasing salinity levels. Concentrations of Na, Cl, and Ca in the grain and straw were greater in salt sensitive cultivar than those in a salt tolerant cultivar. Concentrations of these elements significantly increased with an increase in salinity levels. This study demonstrated that supplemental N, as either FYM or as Urea, can mitigate negative effects of mild salinity stress, and that this beneficial effect was greater in a salt tolerant cultivar as compared to that in a salt sensitive cultivar.