Novel Approach to Organic Mulching from Natural-Based Solutions to Enhance Soil Health and Functional Value of Calafate Fruit

Abstract

Mulching suppresses weeds, improves soil biology, and increases physical or bioactive fruit yield in fruit orchards. However, there is no information on its impact on calafate (Berberis microphylla G. Forst.) orchards, which produce berries with high antioxidant content. To address this gap, in 2021, an experiment was conducted to evaluate the effect of 5 years of mulching on soil, plants, and calafate fruit. Four mulching treatments were established: no mulch (control), geotextile, oat straw, and hazelnut shell. All mulches suppressed weeds (43%) and maintained more soil moisture (5%) than the control. Soil microbial activity increased only with hazelnut shell compared with the control, up to 46%. Only oat straw and hazelnut shell increased basal respiration and urease up to 31% and 15% more than the control. Oat straw produced the highest fruit yield with 0.44 t ha−1, while the lowest yield was produced by the control and hazelnut shell with 0.1 and 0.15 t ha−1, respectively. The geotextile with 0.35 t ha−1 of fruit produced no differences between treatments. The ORAC antioxidant capacity was only higher in the control and hazelnut shell, with a mean of 3272 µmol TE 100 g−1. Hazelnut shell mulch is recommended to improve the biological functions of the soil and the antioxidant capacity of the calafate fruit.