Responses of growth, yield and chemical composition of tomato to phosphorus nutrition under different saline environments

Abstract

Growing crops on marginal and salt-affected soils with saline water will be more important for agricultural production in the future. The most prevalent anions in saline soils, chloride (Cl^-) and sulfate (SO₄^2-) have distinct effects on plant growth, metabolism, nutrient composition, productivity, and nutrient requirements. In order to ascertain the role of phosphorus in mitigating salinity stress in tomato plants, a pot experiment was conducted in a screen house under two types of saline environments chloride-dominated (Cl^-: SO₄^2- = 7:3) and sulfate-dominated (Cl^-: SO₄^2- = 3:7), with two comparable ECe levels (non-saline and 6 dS m⁻¹) and four graded phosphorus levels (0, 12.5, 25, 50 mg kg⁻¹soil). The significant increase in yield up to 50 ppm added P indicated that plants require more P under chloride salinity than sulfate salinity. In non-saline, chloride, and sulfate-dominated conditions, increased P from 0 to 50 ppm increased chlorophyll 'a‘ and 'b‘ values by 21.4, 19.8 and 23.8% and 10, 20 and 14%, respectively. The reduced photochemical efficiency due to salinity, was increased 32%, 30% and 13% as P level increased from 0 to 50 ppm in non-saline, Cl^--6 and SO₄^2—6 conditions, respectively. The TSS, ascorbic acid content and titrable acidity of tomato fruits was improved with mild salinity stress but reduced with added P. The plant N, P and K content increased significantly with each added P level irrespective of types of salinity. The plant composition indicated an antagonism between phosphorus and chloride ions and synergism between phosphorus and sulfate ions.

Keywords:

• Chloride salinity
• phosphorus
• sulphate salinity
• tomato

Acknowledgments

We are thankful to CCS Haryana Agricultural University, Hisar, Haryana, for providing necessary facilities for conducting this research.

Disclosure statement

No potential conflict of interest is reported.