Chlorophyll Fluorescence and Fruit Quality Response of Blueberry to Different Mulches

Abstract

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 (YII), the maximum photochemical efficiency of photosystem II (Fv/Fm), 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 (YII) 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.

Evaluation of the Effectiveness of Loose and Compressed Wood Chip Mulch in Field-Grown Blueberries—A Preliminary Study

“…Similar to the results of this study, Strike and Davis [32] reported that blueberry diameter and firmness were unaffected by the mulch type. Retamal-Salgado et al [37] also reported that the use of pine bark and geotextiles as mulch in blueberries only increased fruit yield without affecting fruit firmness and other fruit qualities. Whilst Pliszka et al [38] observed significant influences of mulches on the growth and yield of blueberry fruits, a study by Krewer et al [39] showed minimal impacts of mulch application in the first year.…”

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

“…Maximum fluorescence intensity (F m ) and minimum fluorescence intensity (F 0 ) of chlorophyll were measured with a portable fluorimeter model OS-30p (Opti-Sciences) on fully sun-exposed leaves, mature and annual shoots located in the second third of the shoot, considering a total of 18 measurements per treatment [30,31], at five times of the day, 09:00, 11:00, 13:00, 15:00, 17:00 h, during a clear day. These results allowed quantification of the maximum photochemical efficiency of photosystem II (F v /F m ) [32,33].…”

“…Immediately after harvest, fruit firmness and equatorial diameter were determined using FirmPro equipment (Happy Volt SPA, Santiago, Chile) [28,31,34]. Firmness was expressed as the force in grams (g) necessary to deform the fruit in 1 mm (gf mm −1 ).…”

“…Total anthocyanins were determined by a differential pH technique according to the methodology described by Pinto-Morales et al [27], where the molecular weight and molar absorbance of the anthocyanin pigment present in the highest proportion were used to calculate the total anthocyanin content. 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.…”

Propagation Methods and Mulching Modulate the Quantum Yield, Ionic Relations, and Production Components of Sour Passion Fruit under Salt Stress

“…Plastic mulching (PM) has been reported as a way of minimizing salt accumulation in the soil [23,24] and, consequently, toxicity to plants caused by irrigation water [7,25]. The use of mulching in arid and semiarid regions has been increasingly employed in agriculture as it maintains soil moisture at high levels and reduces temperature [26][27][28], especially in places where the only water source available shows considerable concentrations of soluble salts [29]. According to [30] Aragüés et al (2014), plastic mulching reduces the need for frequent irrigation as it prevents water loss through evaporation into the atmosphere.…”