Alleviation The Deleterious Impact of Water Stress on Sorghum Bicolor (L.) Plants Using Biostimulant Humic Acid

Abstract

This investigate was conducted during the summer seasons of 2021 and 2022 to study the beneficial role of humic acid as biostimulant for reducing the harmful effect of water deficit on sorghum plant. Results show that water deficit at 75% FC and 50% FC caused decreases in vegetative growth parameters; grains yield and yield components, carbohydrate content of the yielded grains accompanied by increases in total soluble sugar and proline of the dry leaf tissues and protein content of the yielded grains. Regarding the interaction between water deficit and humic acid treatments, it was noted that humic acid at 50 mg/L and 100 mg/L markedly increased vegetative growth parameters, total soluble sugar and protein of the dry leaf tissues, grains yield and yield components, carbohydrate content and protein content of the yielded grains of sorghum grown under 95% FC, 75% FC and 50% FC relative to corresponding controls. It was noted that humic acid at 50mg/L and 100mg/L significantly increased weight of the yielded grains/plant by 11.46% and 34.50% respectively in plant irrigated with 95%FC, and by 17.25% and 24.37% respectively in plants irrigated with 75% FC and by 9.16% and 38.50% respectively in plants irrigated with 50% FC relative to corresponding controls. Clearly, humic acid treatment at 100mg/L was more effective than humic acid at 50mg/L under all conditions.