PubMed · 2026-04-21
Spraying cluster bean plants with natural compounds like humic acid, salicylic acid, or ascorbic acid—combined with different nitrogen fertilizers—boosts photosynthesis and seed yield, but how well these combinations work depends heavily on whether crops are grown in a humid or arid climate.
Combinations of nitrogen source and foliar biostimulant (humic acid, salicylic acid, or ascorbic acid) significantly affected both photosynthetic efficiency and seed yield in cluster bean.
Climate strongly moderated treatment outcomes — the semi-humid site (Khorramabad) and the arid site (Mashhad) produced measurably different responses to the same nitrogen-biostimulant pairings.
Five nitrogen treatments were compared (including a zero-nitrogen control and urea at 69 kg N/ha), revealing that no single combination was universally optimal across both climatic conditions.
