A Moringa oleifera-based formulation for growth and mitigation of drought stress in tomato plants

Introduction Contemporary agriculture is undergoing a profound transformation aiming at reducing environmental pollution, improving food security, and tackling the climate crisis. To respond to these challenges, the European Commission launched in 2020 the Green Deal initiative, which has among its main goals for 2030 a reduction in the use of synthetic fertilizers and plant protection products, as well as an increase in organic cultivation. In the last three decades biostimulants of natural origin have contributed to reduce agriculture footprint. Methods The objective of the present research was to test the efficacy of a new formulation based on a hydrolysed Moringa oleifera aqueous extract in presence and absence of a stress (drought). The assays were carried out on tomato plants grown in a greenhouse. The tested formulation was applied either by foliar spray or soil drenching. The abiotic stress was induced by suspending irrigation until wilting point. Efficacy was assessed by measuring plant vegetative parameters as height, Normalised Difference Vegetation Index (NDVI), photosynthetic pigment content, and Relative Water Content (RWC), as well as production parameters as fruit set and cluster weight. Results and discussion The results highlighted an overall positive effect of the tested formulation on vegetative parameters when applied by spraying in absence of stress; however, a different behaviour was observed as far as the resistance against drought concerns, being the Moringa formulate more effective as soil drenching. The positive effect could be ascribed to the presence in the formulate of numerous bioactive molecules, including polyphenols, flavonoids, organic acids, amino-acid derivatives, nucleosides, lipids, and bioactive peptides. Although further in the field large-scale trials are needed, these preliminary data support the use of the formulation in sustainable agriculture.