Soil Salinity Effects on Absorption of Nitrogen, Phosphorus, and Protein Synthesis by Coastal Bermudagrass1
- G. W. Langdale and
- J. R. Thomas2
The interaction of artificially salinized soil and N-P fertilization on dry-matter production and protein synthesis of coastal bermudagrass [Cynodon dactylon (L.) Pers.] was studied in a greenhouse environment. Saline solutions were prepared in concentration multiples with the same ionic ratios as the available irrigation water to develop four treatments with electrical conductivities (EC) of O, 4.8, 9.6, and 14.4 mmhos/cm. After salinewater equilibration of a Brennan fine sandy loam soil (Typic Haplustalf), fertilizer treatments were applied in a factorial arrangement with N rates of O, 67, 133, and 200 mg/kg of soil and P rates of O, 20, 40, and 60 mg/kg of soil.
No response was obtained from P fertilization. Significant interactions occurred for both dry-matter and protein- N yields with soil salinity and N supply treatments. Soil salinities of 5.3 and 6.6 mmhos/cm yielded the most dry matter and protein N, respectively, in the presence of N fertilizer. Reduction in soluble N (nonprotein) occurred at the most efficient levels of protein-N synthesis. Although N requirements decreased as soil salinity increased, N fertilization offset effects of salinity up to 9.6 mmhos/cm. Dry-matter and protein syntheses were seriously restricted at the 14.4 mmhos/cm salinity level; however, salinity levels did not restrict N absorption by coastal bermudagrass.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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