International Symposium on
Drylands Ecology and Human Security
Saline Water Drip Irrigated Sorghum Varieties Response
B.A., Ould Ahmed, T., Yamamoto, M., Inoue, M., Irshad
In this study saline-water drip irrigated sorghum varietal response under limited available soil water in dune sand was assessed using salinity response function. In a randomized complete block design experiment; three sorghum varieties (sorghum bicolor (L), BK 16, and EC 90) were grown in drip irrigated saline-water, at four salinity levels (5.47, 7.32, 9.38, and 12.50 dS m-1) plus quality water of 0.11 m-1 as the control. Four salinity response models were used to assess their ability to discriminate salinity-induced grain yield differences under very limited available soil water. Salinity response analysis indicated the four models were equally good in fitting the grain yield data, but the modified discount model produced the consistently best fitting for the tested varieties. The coefficients for the model parameters indicated that a varietal yield difference to salinity stress was best discriminated by the values of the parameters. Analysis of the data indicated the impact of salinity stress on varieties were best discriminated by the parameters; salinity threshold (Ct), salinity tolerance index (ST-index), and the salinity at which 50 % grain reduction (C50) occurred. The analysis indicated the variety BK 16 was the most tolerance to salinity stress.
Keywords: Drip irrigation; Crop response model; Saline water; Salt tolerance; Sorghum varieties