Plant Performance and Soil Microbial Responses to Irrigation Management: A Novel Study in a Calafate Orchard

Abstract

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.

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

“…This study signifies a notable progression in the assessment of planting density in calafate orchards, as it illustrates the role of planting density in enhancing soil microbial and enzymatic activity, thereby influencing the antioxidant activity of calafate fruit (Betancur et al, 2022;. Nevertheless, due to their moderate interrelationships, a comprehensive analysis of these factors is warranted.…”

“…The lack of dehydrogenase response could also be explained by the high OM content in the soil at the beginning of the study. Although there was a higher OM content in HD, previous studies in the same area indicated that OM levels higher than 9% reached a threshold where there was no change in the activity of this enzyme (Betancur et al, 2022;. However, it is important to note that the response of these enzymes is more pronounced with fertilization treatments in soils with low fertility because it promotes the formation of organo enzyme complexes that improve their stability (Nannipieri et al, 2012).…”

“…Weed control was performed over the row using a 100 µm thick black polypropylene geotextile mulch (Protekta, Santiago, Chile). Irrigation was carried out annually from August to March, replenishing 100% of the daily potential evapotranspiration (ET0) of the crop, according to Betancur et al (2022).…”

“…The FDAse increases its sensitivity to changes in soil moisture in the short term (Guntiñas et al, 2013). Although lower planting densities may result in lower evaporative soil moisture, it is likely that constant water replenishment and summer ground cover mitigated these losses in the short term (Betancur et al, 2022;. However, the lack of response in acid phosphatase between planting density treatments can be attributed to the high OM content of the soil in all treatments, with high buffer capacity and alkaline mineral content, such as Ca, Mg, and K, which maintained a neutral pH (Yang et al, 2022), with a lower response than in acidic conditions, where this enzyme improves its action.…”

Preharvest Applications of Oxalic Acid and Salicylic Acid Increase Fruit Firmness and Polyphenolic Content in Blueberry (Vaccinium corymbosum L.)

“…Data were expressed as mg 100 g −1 FW [36], a compound found in greater proportion in blueberry [31]. The DPPH antioxidant capacity was performed as described by Betancur et al [37], the extract was diluted, and the DPPH solution was incorporated and kept in the dark for 1 h at room temperature. The readings in the spectrophotometer were determined at 515 nm, and the standard curve used was 0.0008× + 0.0272 and R 2 = 0.99.…”