Field experiments were conducted in two winter successive seasons (2020-2021 and 2021-2022) at the Soil Improvement and Conservation Research Department, Sakha Agricultural Research Station, Kafr Elsheikh Governorate. Egypt (located 6 meters above sea level, with latitude of 31° 05' 38" N and longitude of 30° 56' 53" E) The experiments aimed to evaluate the response of wheat yield and its components as well as some soil properties to some soil amendments i. e. fulvic acid (FA) and phosphogypsum (PG) under irrigation conditions that using irrigation saline water. A split-plot design with three replications was applied; six salinity levels of irrigation water were applied in the main plots, while three soil amendments including (without amendment, FA and PG) were tested in the sub-plots.
The results revealed that increasing irrigation water salinity led to significant reductions in wheat plant height, spike length, and 1000-grain weight, while the application of FA and PG mitigated these effects, enhancing these growth parameters. Similarly, grain yield, straw yield, and biological yield significantly decreased with higher salinity levels but were improved with the application of FA and PG The nutrient content (N, P, and K) in wheat plant grain also decreased with increased salinity but improved with the use of FA and PG.The relationships between grain yield as well as straw yield and salinity levels under some amendments were expressed in six equations namely:
Grain yield:
Linear: GYL = 2800 – 66.207x R2 = 0.9385
Quadratic: GYQ =2741.1 -16.062x -6.0098x2 R2 = 09681
Straw yield:
Linear :SYL = 3508.1-154.28x R2 = 0.9611
Quadratic: SY Q = 3506.1 - 152.59 x -0.2024 x2 R2 = 0.9611
Where: GYL , GYQ, SYL and SYS, are the grain and straw yield (kgfed-1)for linear and quadratic relationship under irrigation water salinity, x is irrigation water salinity level (dSm-1).
These fitted equations indicated that with respect to grain yield PG is more effective at lower salinity levels (below 6.59 dS/m), while FA is preferable at higher salinity levels (above 6.59 dS/m), however, resulting in a yield reduction Moreover, the results revealed that increasing irrigation water salinity led to significant reductions in wheat plant height, spike length, and 1000-grain weight, while the application of FA and PG mitigated these effects, enhancing these growth parameters. The nutrient content (N, P, and K) in wheat plant grain also decreased with increased salinity but improved with the use of FA and PG. emphasizing the critical importance of managing salinity and soil amendments for optimal wheat productivity.
Conclusively, from the fitted equations of the relationships between grain yield and salinity levels under some amendments the study indicated that PG is more effective at lower salinity levels (below 6.59 dS/m), while FA is preferable at higher salinity levels (above 6.59 dS/m)..