The use of hydromulching increases yield and quality of drought-stressed artichokes (Cynara cardunculus subsp. scolymus L. (Heigi)) by improving soil properties and plant hormone homeostasis

There exist many research papers which pointed out the positive effects of using the mulching technique in stressful conditions, showing crop productivity and physicochemical quality improvement of the product. We hypothesized that a novel organic liquid mulching formulations (hydromulching) can be used in sustainable agricultural production under drought stress through both their direct influence on physicochemical and biological soil properties as well as by their effect on plant hormonal balance leading to the improvement of crop yield and quality. Artichoke plants were grown on bare soil (BS) or mulched with traditional polyethylene (PE) or with three different types of ecological hydromulching treatments obtained from recycled additives, namely: substrate used for mushroom cultivation (MS), rice hulls (RH) and wheat straw (WS); and were subjected to optimal (100% ETc) and reduced (70% ETc) irrigation regimes. Under water limitation, soil organic matter and carbon and mineral soil concentrations increased in the hydromulched soils (by 60% on average). Mulched treatments produced the highest crop yield (by 40% on average) attributed to increased artichoke head fresh weight, giving rise to the improvement of the important physical quality parameters in artichoke: color, firmness, and size. Furthermore, hydromulched treatments induced higher content of mineral nutrients in artichoke heads, while sugar concentrations were superior in non-mulched soil due to a major exposure to water stress. This may be related to the diminished carbohydrate metabolism activity under drought stress, including notable changes in the hormonal balance. The crosstalk of growth-promoting hormones (cytokinins) with the stress-related hormone factors (ethylene precursor 1-aminocyclopropane-1-carboxylic acid) has been shown to regulate adaptive responses such as sugar osmoregulation in artichoke heads under drought stress. Altogether, these results demonstrate that hydromulching is a sustainable alternative to plastic films to cope with drought stress by improving yield and physical quality characteristics of artichoke heads and maintaining their chemical and nutritional quality over bare soil.