Tiger nut (cyperus esculentus L ) is an underutilized crop belongs to family Cyperaceae , A field
experiment was performed during two successive summer seasons of 2022 and2023 to explore the effect of
applying sea weed (Ascophyllum nodosum)extract at (0,2,3.4 or 4g/L-1 )as soil drench or foliar spray at (0,1,2
g/L-1) and /or Chitosan soil drenched and sprayed both at (2cm/L-1) Humic acid as foliar spray at (2g /L-1 ) and
soil drenched at (4g/L-1) or Glutamic acid foliar spray at (1 and 2g/L-1 )on tiger nut tubers , its fixed oil yields
and constituents. Results showed that both methods of application sea weed extract positively influenced
growth and tuber productivity ,soil drench of seaweed extract at 4g/L-1 followed by 3g/L-1 showed an increases
in,fresh , dry weights / plant, tuber, fixed oil yields / plant and feddan whereas the foliar application of sea weed
by both rates 2g/L-1 followed by 1g/L-1 caused more promising effect than drenching application. The
combined of both methods of application 4g/L-1 and2g/L-1 followed by 3g/L-1 and 2g/L-1 significantly
ameliorated these impacts as they induced the highest values of vegetative growth traits, tuber and fixed oil
yields / plant or feddan . The highest values of the main oil component of unsaturated fatty acids, flavonoids
,flavonoid glucoside , terpenoids and aromatic acids. Apply sea weed (Ascophyllum nodosum) extract as soil
drench at 4g/L-1 and or 3g/L-1 with foliar sprayed sea weed 2g/L-1 is recommended to improve tiger nut
tubers, and their fixed oil productivity.