Enhanced chickpea (Cicer arietinum L.) growth and yield attributes via agronomic modulation using nano-emulsion biofertilizer for sustainable crop productivity improvement

Chickpea ( Cicer arietinum L.) productivity is often constrained by inefficient nutrient management and declining soil fertility. This study evaluated the potential of integrating reduced mineral fertilization with nano-emulsion biofertilizers (NEB) to enhance growth, yield, and grain quality under field conditions. A two-factor field experiment was conducted during 2023–2024 at the Karunya Institute of Technology and Sciences, India. Treatments comprised four NPK levels (0, 50, 75, and 100% of 25:50:20 kg ha −1 ) combined with foliar applications of nano fertilizers ND (Nano-DAP), NU (Nano-Urea) and NEB (Nano Emulsion Biofertilizer; Rhizobium + Phosphorus Solubilizing Bacteria (PSB) consortium) applied at 30 and 45 days after sowing. Results revealed that 75% NPK integrated with NEB significantly improved growth traits, including plant height, number of branches, leaf area index, chlorophyll content, and dry matter production. Yield attributes such as pods per plant, grains per plant, and 100-seed weight were markedly enhanced, resulting in the highest grain yield (1143.97 kg ha −1 ) and stover yield (2024.09 kg ha −1 ), the combined application of 75% NPK + NEB increased grain yield by an average of 45.3% compared with the other treatments. Grain quality also improved significantly, with higher protein content (28.69%) and increased zinc and iron concentrations. Correlation and structural equation modeling indicated strong positive relationships between growth parameters and yield (R 2 = 0.80), with dry matter production and leaf area index acting as key determinants. The study demonstrates that substituting 75% of conventional fertilizers with NEB is an efficient and sustainable strategy to improve nutrient use efficiency, crop productivity, and grain nutritional quality, supporting environmentally resilient chickpea production system.