Effects of form and concentration of nitrogen fertilizer on the salt tolerance of 'Tifway' bermudagrass

Abstract

Many factors influence the salt tolerance of plants. This study investigated the effects of form and concentration of nitrogen fertilizer on the salt tolerance of 'Tifway' bermudagrass grown under four salinity levels in a nutrient solution. The design was a 4 x 2 x 2 factorial in an RCB design. The four salinity levels were 0 (1.6 to 3.6), 10, 22, and 42 dS m⁻¹. Nitrogen was applied in the NH₄⁺ and NO₃⁻ form and at 52.5 and 210.0 mg N L⁻¹ of nutrient solution. The results indicated that NH₄⁺ improved the salt tolerance of 'Tifway' bermudagrass in terms of aesthetic value (color and leaf firing), osmotic adjustment (free amino acid content), and tolerance of specific ion effects (Na, Ca, and the Na:K ratio). The 210.0 mg N L⁻¹ concentration improved the root:shoot ratio of 'Tifway' bermudagrass and reduced salt ion accumulation in shoots.