Different concentrations of compost applied as organic fertilizer can modify productive, quality, and chemical parameters in several fruit tree species. The objective of this study was to determine the effect of increasing applications of compost on physiological, productive, and quality parameters in calafate fruit during the seasons of 2018–2019 and 2019–2020. The study was conducted on a commercial calafate orchard using a randomized complete block design with four treatments (CK: no compost application, T1: 5 Ton ha⁻¹, T2: 10 Ton ha⁻¹, and T3: 15 Ton ha⁻¹), each with four repetitions. The results did not show statistical significance for stomatal conductance (Gs), quantum yield of PSII, or photosynthetic active radiation (PAR) within treatments. As for fruit yield, a statistical difference was found between the control treatment and T1, which were lower than T2 and T3 in both seasons. The trees reached a higher leaf area index with T2 in both seasons. The highest antioxidant capacity was obtained with T3 and T2 for the first and second season, respectively. Polyphenols and total anthocyanin production showed statistical significance, with a higher content at the second season with T2. It is concluded that the dose under which yield, quality, and nutraceutical content of calafate fruit are optimized is the one used in T2, 10 Ton ha⁻¹.

Blueberry exports that imply transport times of more than 25 d deteriorate their quality. The use of elicitors in preharvest has shown positive effects on the quality of berries such as grapes. The objective of this study was to evaluate preharvest applications (21, 14, and 7 d before harvest) of oxalic acid (OA) and salicylic acid (SA) on fruit firmness and phenolic compounds in blueberry. The treatments of 0, 2, and 4 mM OA in ‘Kirra’ and 0, 2, and 4 mM SA are in ‘Stella blue’. With the earlier preharvest application, ‘Kirra’ presented better firmness than ‘Stella blue’; however, 2 mM OA and SA in both cultivars increased fruit firmness, maintaining its weight and diameter with respect to the control. It should be noted that the treatment with 2 mM SA generated a 100% increase in polyphenolic content and antioxidant capacity (p < 0.05) in ‘Stella Blue’, with values close to 140 mg gallic acid 100 g⁻¹ and 80 mg 100 g⁻¹ fresh weight (FW), respectively. In Kirra, OA treatments did not have a significant impact on the polyphenol content, but 4 mM OA increased by 100% and 20%, total anthocyanin and antioxidant capacity of blueberry fruit, respectively. Based on our results, three pre-harvest applications of OA and SA during the fruit development until the beginning of ripening improve fruit firmness by up to 20% at different times of harvest.

Mulch is widely used in blueberry cultivation for weed control; however, there is still uncertainty as to how the use of different types of mulch alters leaf photosynthetic behavior and the quality and productivity of blueberry fruit. The objective of our research was to evaluate the effect of different types of mulch on the physiological, quality and yield characteristics of blueberries. Three treatments were established: T1 (control), T2 (pine bark) and T3 (geotextile) in two cultivars: Ochlockonee and Legacy. The parameters measured were: the photochemical quantum yield of photosystem II (Y_II), the maximum photochemical efficiency of photosystem II (F_v/F_m), electron transport rate (ETR), fruit quality and yield parameters. The results show lower soil temperature in T1 during the morning (p < 0.05) compared to the two mulch treatments, which was the opposite during the afternoon, the temperatures were more stable and closer to the optimum (21 °C) in T2 and T3, with mulch favoring root and foliar development. On the other hand, the treatments with mulch favored a higher photosynthetic efficiency of photosystem II (Y_II) at the end of afternoon and were associated with an increased firmness of the fruit; the firmness of all fruits was higher than that in the control treatment (p < 0.05) in the Legacy cultivar, but without differences between them, with values of 73 and 75 gf mm⁻¹ for T2 and T3, respectively, and 67 gf mm⁻¹ for the Control. In addition, it was observed that the use of mulch only increased the fruit yield in the Legacy cultivar, both in T2 and T3, with both being superior to T1 (p < 0.05). It can be concluded that the use of mulch decreases soil temperature in the midday and late afternoon, improving the edaphoclimatic conditions during the development of the blueberry. In addition, plants with mulch have lower stomatal conductance, which promotes greater photosynthetic efficiency during the day, increasing both firmness and fruit yield.

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.

Calafate fruits have a high content of phenolic compounds and an antioxidant activity up to four times higher than that of blueberries. The establishment of a calafate orchard and irrigation responses on fruit and soil characteristics have been scarcely studied. Therefore, the objective of this study was to evaluate the effect of water replenishment rate: 0%, 50%, 100% and 150% of reference evapotranspiration (ET₀), on soil microbiological activity, plant physiological response, fruit yield and chemical composition in a calafate orchard. The results showed that irrigation at 50% ET₀ presented significant increases in soil urease, dehydrogenase and acid phosphatase activity. Likewise, irrigation at 50% ET₀ significantly increased stomatal conductance and plant chlorophyll index, which led to a significant increase in fruit yield being 60% higher compared to the other treatments. Despite the higher fruit yield, 50% ET₀ irrigation had a similar level of total anthocyanins and ORAC antioxidant capacity as the 100% ET₀ treatment. In contrast, 0% and 150% ET₀ treatments showed a higher degree of stress and got higher values for total anthocyanins and fruit antioxidant capacity. Irrigation rates 50% ET₀ increases fruit yield while maintaining fruit quality and optimizing water resources in commercial orchards of calafate.

Calafate (Berberis microphylla G. Forst) is an evergreen shrub with blue berries that grows naturally in Patagonia, in South America. It has beneficial nutraceutical characteristics for human health. The objective of the research was to evaluate the effect of different harvest dates of calafate clones in the south-central zone of Chile on the polyphenolic content, antioxidant capacity, quality parameters and fruit yield. To meet this objective, during three consecutive years, four wild calafate clones located in the town of San Ignacio, Chile, were selected. Where a harvest period was established from 110 to 140 days after full bloom (DAFBs), each of the harvests carried out were used for the following measurements: antioxidant capacity, determination of anthocyanin content, concentration of polyphenols, phenolic compounds, soluble solids, total titratable acidity, pH, fruit yield and quality. Among the main results, it can be highlighted that clone 2 was the one that obtained the highest concentration of soluble solids, with 38.0 °Brix at 140 DAFBs. Together, it was the one that obtained the highest content of total polyphenols and concentration of anthocyanins, with 1121 g GAE kg⁻¹ fw and 714 g cy-3-glu 100 g⁻¹ fw, respectively.