Planting density: Key strategy for optimizing soil health and fruit antioxidant activity in a calafate orchard

Matías Betancur1, 2, Jorge Retamal-Salgado3*, María Dolores López1, Rosa Vergara-Retamales2, and Mauricio Schoebitz1*
Limited information exists regarding the impact of planting density on soil fertility, plant productivity, and the phenolic content of calafate (Berberis microphylla G. Forst.) fruits. This study aimed to assess the effects of planting density on the soil, plants, and fruits in a calafate orchard. Four treatments were employed: High-density (HD; 6667 plants ha-1), traditional density (TD; 3333 plants ha-1), medium density (MD; 2222 plants ha-1), and low density (LD; 1667 plants ha-1). In the soil, TD exhibited a 28% increase in basal respiration compared with MD, and a 29% increase in urease compared with HD. Additionally, TD enhanced soil N availability by 57%, ammonium availability by 58%, and Mn availability by 33% compared to LD. Photosystem II experienced an increase with MD and LD (p > 0.05), surpassing TD and HD by 3%. The LD significantly outperformed the other treatments in terms of yield per plant, reaching up to 873 g. Conversely, despite its lower yield per plant, HD produced larger and heavier fruits, albeit at the expense of phenolic content. However, HD and MD, averaging 2.1 t ha-1, generated more fruit per unit area than LD and TD did. Notably, planting density did not affect the fruit antioxidant capacity. These findings suggest that TD planting density in calafate preserves the biological and chemical functions of the soil, while maintaining the antioxidant capacity of calafate fruit.
Keywords: Basal respiration, Berberis microphylla, berberis, berries, polyphenols, stomatal conductance.
1Universidad de Concepción, Facultad de Agronomía, 4030000, Concepción, Chile.2Universidad Adventista de Chile, 3780000, Chillán, Chile.3Instituto de Investigaciones Agropecuarias, INIA Quilamapu, 3800062, Chillán, Chile.*Corresponding author (jorge.retamal@inia.cl; mschoebitz@udec.cl).