Response of safflower (Carthamus tinctorius L.) to saline soils and irrigation: II. Crop response to salinity

Safflower was grown in previously salinized plots that varied in effective ECe from 1.8 to 7.2 dS m−1 (0–2.7 m depth) and irrigated with either high quality (ECi<1 dS m−1) or saline (ECi, 6.7 dS m−1) water. Differences in pre-dawn and mid-day plant water potential, between saline and non-saline treatments, were significant at several dates. Leaf area index (LAI) declined by one unit over this salinity range. Plant populations were not affected, however, plant height was reduced by 32 cm between saline and non-saline plots. Seed and oil yield were not affected by increasing ECe, but oil content and 1000 seed weight increased slightly. Harvest index increased with salt stress due to a reduction in the ratio of stem to total biomass. Bud weight per m2 was less affected by salinity. Safflower tolerated greater levels of salinity than previously reported. Below average temperatures and higher than average relative humidity in spring likely moderated the effects of salinity. Safflower is a viable alternative for use in rotations where saline soils and irrigation water limit production of non-tolerant crops.