Effects of Microbial and Non-Microbial Biostimulants on Chickpea Growth, Yield, and Soil Properties in a Marginal Mediterranean Environment

Climate change is increasingly constraining agricultural productivity by intensifying drought, accelerating soil degradation, and increasing pest and disease pressure. In this context, biostimulants are emerging as sustainable tools to improve crop resilience and maintain yield under suboptimal conditions. This study evaluated the effects of microbial and non-microbial biostimulants on chickpea (Cicer arietinum L.) growth, grain yield, seed quality, root traits, and soil properties under low-fertility and water-limited conditions in a marginal field in southern Italy. Treatments included an untreated control and biostimulants based on microelements, arbuscular mycorrhizal fungi (AMF), microbial consortia, ozonated oil, and humic substances. Biostimulants significantly affected agronomic traits. Humic substances increased plant height, while microelements markedly enhanced reproductive performance, with pod number increasing from 13 in the control to 23 pods plant−1. Root traits were also improved, particularly under microbial, humic, and AMF treatments. Grain yield was highest in the ozonated oil treatment (430.6 kg ha−1), whereas seed nutritional composition showed only limited variation among treatments. Biostimulants also induced treatment-specific changes in soil fertility indicators. Overall, the results indicate that selected biostimulants can improve chickpea performance and modulate soil fertility under marginal conditions, although multi-year studies are needed to confirm the stability of these responses under variable environments.