Foliar bio-stimulant application at flower initiation optimizes chickpea productivity and grain quality in rainfed environments

Bio-stimulants are emerging as effective agents to improve crop performance under abiotic stress, particularly in rain-fed systems. This two-year field study evaluated the effects of foliar-applied bio-stimulant (Actibion) (1250 mL ha− 1) composed of various amino acids including aspartic acid (1.21%), glutamic acid (3.14%), proline (1.15%) at different growth stages—flower initiation (FI), pod initiation (PI), and both (FPI) on chickpea (Cicer arietinum L.) growth, yield, and grain quality under rain-fed conditions in Pakistan. Treatments were compared with water spray and an unsprayed control in a randomized complete block design. Foliar application at the flower initiation stage significantly enhanced key growth parameters, increasing plant height by ~ 22%, pod length by ~ 14%, leaf area index by ~ 23%, and chlorophyll content by ~ 19%, relative to control. Seed yield improved by over 50% across both seasons. Grain nutrient contents (N, P, K) and protein concentration also increased significantly with bio-stimulant application at FI. This treatment yielded the highest net economic returns, demonstrating both agronomic and financial benefits. These findings suggest that foliar application of bio-stimulant at flower initiation is a promising, sustainable approach to enhance chickpea productivity and nutritional quality under rain-fed conditions.