The combined effects of thermal pruning, fungicide and fertilizer applications on lowbush blueberry

Management improves the growth and fruit yield of cultivated lowbush blueberries, but it remains to be seen how the pruning method, fertilizers, and fungicide applications affect soil fertility. This study investigates the impact of pruning, fungicide, and fertilization management practices on key soil parameters related to soil fertility, namely: soil organic matter (SOM) content, soil pH, nitrogen and phosphorus mineralization, nitrification, and phosphorus saturation index (PSI). A split–split–plot experiment was established, including two pruning methods (mechanical and thermal), two fungicide regimes (with or without), and three types of fertilizer applications (mineral, organic, or none). Mineral fertilizer applications significantly and strongly affected most soil fertility indicators, with increased nitrogen (+77 kg ha−1) and phosphorus (+117 kg ha−1) mineralization and SOM (+34 g kg−1), while reducing soil pH (−0.18) and nitrification (−46 kg ha−1). Thermal pruning decreased nitrification (−26 kg ha−1), soil pH (−0.12), and SOM concentration (−29 g kg−1). Fungicide applications showed no significant impact on soil fertility. While mineral fertilizer improves soil fertility, repeated application of organic fertilizer increases soil pH (+0.34), nitrification (+53 kg ha−1), phosphorus mineralization (+161 kg ha−1), and the soil phosphorus saturation index at undesirable levels (PSI > 2.8%) in lowbush blueberry production systems. The loss of SOM with thermal pruning is noteworthy and highlights the management impact and need for regular monitoring to maintain soil fertility in such fields.

Fertilizer and fungicide applications are commonly used in lowbush blueberry cropping systems (Vaccinium angustifolium Aiton and Vaccinium myrtilloides Michaux) to enhance fruit yield. Such crop inputs can significantly affect soil fungi, a topic that is not well documented, even though these organisms impact the development and survival of lowbush blueberries in natural forest ecosystems. We evaluated soil fungal biomass and community structure in a commercial lowbush blueberry field located in Lac-Saint-Jean, Québec, Canada. Since 2017, mineral fertilizers and fungicide (Proline 480 SC®) have been applied once every two-years. In-growth sandbags were incubated for 90 days during the 2019 and 2020 growing seasons to collect fungal hyphae biomass in vegetated and unvegetated areas. Soil samples were also collected to analyze the structure of the fungal community using next-generation sequencing. Our results showed that applying fungicide alone increased hyphal biomass in sandbags by 40%, whereas adding both fungicide and fertilizer or fertilizer alone did not change hyphal biomass compared to the control. The structure of the fungal community was only slightly affected by the applications of fungicide and fertilizer, with fungicide decreasing the relative abundances of plant pathogens and fertilizer negatively influencing saprotrophs. Low doses and infrequent applications could explain such weak effects. Among the 33 amplicon sequence variants that were positively associated with the presence of lowbush blueberry plants, eight Penicillium species, four Clavariaceae, two Serendipita species, and one ericoid mycorrhizal fungi (EMF) (Oidiodendron maius) were identified.

Combined primary and secondary papermill sludge (PS) is a good potential source of C and other nutrients to restore low organic matter sandy soils supporting native lowbush blueberry (Vaccinium angustifolium Ait.). A 3-yr field study was conducted to compare the effect of PS with mineral fertilizers (MF) on the blueberry yield and soil chemical properties and enzyme activities of a l’Afrique sand (Humo-Ferric Podzol) in the Saguenay-Lac Saint-Jean area (Quebec, Canada). The PS was applied in the spring of the sprout year at 0, 8.5, 17 and 34 Mg ha-1 and MF was applied at 0, 13, 26 and 52 kg N ha-1. The highest fresh fruit yields were obtained at 8.5 and 17 Mg PS ha-1. The 34 Mg PS ha-1 treatment produced berry yield comparable to the control. This PS rate reduced pH, but increased inorganic N, Mehlich-3 extractable P and Mn in the 0- to 15-cm soil layer. The NO3−-N content of the 15- to 30-cm and 30- to 60-cm soil layers was also increased by PS, suggesting leaching. The MF significantly affected soil inorganic N content only at 3 wk after its application in the first year. The PS rate linearly increased the soil acid phosphatase activity in the first year. The arylsulfatase activity was also higher in PS than in MF treatment, but was severely depressed by 34 Mg PS ha-1 in the last 2 yr. This study indicated that PS, when used at low rates, improves lowbush blueberry yield and the soil enzyme activity on this low fertility sand. Key words: Papermill sludge, lowbush blueberry, soil composition, soil enzyme

The flavor of blueberry fruit products is an important parameter determining consumer satisfaction. Wild lowbush blueberries are primarily processed into products, but their flavor chemistry has not been characterized. The objective of this study was to characterize the aroma chemistry of lowbush blueberries and compare it with that of highbush. Aroma volatiles of lowbush blueberries from four Canadian provinces and five highbush blueberry cultivars were isolated using headspace solid-phase microextraction (SPME) and characterized using gas chromatography-olfactometry (GC-O) and 2-dimensional gas chromatography-time of flight-mass spectrometry (GC×GC-TOF-MS). Lowbush fruit volatiles were composed of 48% esters, 29% aldehydes and 4% monterpenoids compared to 48% aldehydes, 26% monoterpenoids and 3% esters in highbush fruit. Twenty-three aroma-active peaks were identified in lowbush compared to forty-two in highbush fruit using GC-O. The most aroma-active compounds in lowbush fruit were ethyl 2-methylbutanoate, methyl 2-methylbutanoate, methyl 3-methylbutanoate, ethyl 3-methylbutanoate and ethyl propanoate compared to geraniol, (Z)-3-hexen-1-ol, 1-octen-3-one, α-terpineol and linalool in highbush fruit. The aroma volatile composition was more consistent among lowbush fruit samples than the five highbush cultivars. Aroma-active GC-O peaks were described more frequently as “floral”, “fruity”, “sweet” and “blueberry” in lowbush than in highbush fruit. Results suggest wild lowbush blueberries would provide “fruitier” and “sweeter” flavors to food products than cultivated highbush fruit.

Development and validation of a fungicide scoring system for management of late season soybean diseases in Argentina

Minimum and maximum leaf micronutrient concentrations in wild lowbush blueberry (Vaccinium angustifolium Ait.) were determined under the climatic and edaphic conditions of the Saguenay–Lac-Saint-Jean region (Quebec, Canada). The boundary-line approach was used to determine the relationship between leaf micronutrient concentrations and yield. The data were obtained from nitrogen and phosphorus fertilization trials conducted from 2001 to 2008 on 13 commercial lowbush blueberry fields in the Saguenay-Lac-Saint-Jean region. On average, more than 80% of the samples met the new minimum leaf micronutrient concentrations. Minimum leaf concentrations were revised downward for aluminum (Al), copper (Cu), iron (Fe), and zinc (Zn) compared to actual reference values. Minimum leaf boron (B) and manganese (Mn) concentrations were revised upward. Maximum leaf concentrations for all micronutrients were also revised downward. Minimum and maximum leaf concentrations were 26.2–73.5, 32.2–52.9, 3.2–6.5, 27.8–61.4, 873–1394, and 11.0–17.3 mg kg−1 for Al, B, Cu, Fe, Mn, and Zn, respectively. The determination of these new minimum and maximum leaf micronutrient concentrations established sufficiency ranges for the growing conditions in the region.

A soil pH of 4.8 is often cited as being optimal for wild lowbush blueberry (Vaccinium angustifolium Ait.), but commercial fields range from 3.9 to 5.3. To determine if soil pH below the optimum is detrimental, two 1.2 x 2.4 m treatment plots within each of eight clones were established in a commercial field in Lamoine, Maine in 1994. One plot was randomly selected to receive 784 kg of sulfur per ha to create an extremely low soil pH of 4.0. Pretreatment 1994 yield data verified comparable fruit production of the two plots. Soil pH was significantly lower in sulfur-treated plots compared to control plots in 1995, 1997, 1998, and 1999. In 1998 the control pH was 4.6 and the sulfur-treated plots were 4.0. Despite this difference in soil pH, there were no differences between treatment plots in stem density (number of stems per unit area), stem length, branching, or flower buds/stem. In sulphur-treated plots, only minor increases in leaf N, P, and K concentrations and minor decreases in leaf Ca and B concentrations were found in 1997 samples. There were no differences in normal alternate-year yield of control or sulfur-treated plots in 1996, 1998, or 2000. Based on these results, soil pH as low as 4.0 does not appear to adversely affect growth or yield of lowbush blueberry.

Understanding of the genetic relationship within wild lowbush blueberry (Vaccinium angustifolium Ait.) germplasm is important to establish a broad genetic base for safeguarding and for future use of the existing genetic resources. The objective of this study was to assess the genetic variability within 43 wild lowbush blueberry clones, collected from 10 communities of four Canadian provinces, and the cultivar ‘Fundy’ by using inter simple sequence repeat (ISSR) markers, with the hope to establish a reference set of lowbush blueberry germplasm for blueberry conservation, breeding and research. Thirteen primers generated 242 polymorphic ISSR‐PCR bands. A substantial degree of genetic similarity was found among the wild collections. Cluster analysis by the unweighted pair‐group method with arithmetic averages (UPGMA) separated the 41 genotypes into two main clusters, and identified the three remaining clones as outliers. Furthermore, within one main cluster, the genotypes tended to form sub‐clusters that were in agreement with the principal coordinate (PCO) analysis. Geographical distribution contributed to 27% of total variation as revealed by analysis of molecular variance (AMOVA). The ISSR‐PCR method was simple, fast and relatively inexpensive to produce useful DNA fragments and detected a sufficient degree of polymorphism to differentiate among lowbush blueberry clones, making this technology valuable for germplasm management and the more efficient choice of parents in current blueberry breeding program.

This study aimed to evaluate the effect of forms of application of foliar fertilizers and fungicides to control fungus causing white maize spot, Phaeosphaeria maydis , and the growth and development of hybrids maize. The design had randomized blocks, with the use two sources hybrids maize with different reaction to white maize spot: resistant and susceptive and application with moisture of foliar chemical fungicide + cobalt foliar + molybdenum foliar + manganese and control treatment, without application consisting of four treatments and five replications. In the treatments with application of moisture were done on vegetative maize growth stage V8 (stage that determine that the number of kernel rows), VT (stage that arrives when the last branch of the tassel is completely visible) and reproductive maize growth stage R2 (kernels are white on the outside and resemble a blister). The evaluation of variables of growth of maize plants: grain dry mass, cob dry mass, leaf dry mass, culm dry mass and modificated leaf ear and total plant dry mass. Harvest was carried out when the grains were 20% humidity. The application of fungicides and foliar fertilizers increased the leaves, culm, ear modificated, cobs and shoot dry mass plants maize. The application of fungicides and foliar fertilizers providing returning of 11.409,5 kg ha -1 of shoot dry mass plants with increased of 1.296 kg ha -1 on soil(12,81%). In the susceptive hybrid maize the application of fungicides and foliar fertilizers provide higher dry mass grains and shoot of plants.

The main management strategy for coffee leaf rust (Hemileia vastatrix) in conilon coffee is based on the application of fungicides using a fixed schedule without considering the epidemiological aspects of the disease. In order to turn chemical control less subjective and more efficient, two systems of coffee leaf rust management were tested: 1) application of systemic fungicide based on the intensity of the disease present in each conilon clone of the “Conilon Vitoria” variety, according to the disease incidence; threshold of 5 % incidence of the disease was adopted to spray the fungicide, and 2) application of systemic fungicide to the soil, followed by foliar application in the beginning of the rainy season. The experiments were performed in two municipalities of the Espirito Santo State, Nova Venecia e Castelo. Monthly evaluations of disease incidence were performed between September 2010 and August 2011. The results showed that chemical control of coffee leaf rust in conilon coffee should be performed differently, for each clone, of the clonal Vitoria variety. The 5 % threshold of the disease incidence was reached at different time of the coffee grower season. The strategy to apply systemic fungicide to the leaves, to control conilon leaf rust, based on the disease incidence of 5 % was more effective than soil application system. Application of systemic fungicide to the soil did not control the disease. In conclusion, monitoring the incidence of coffee leaf rust in all the clones is an important strategy to decide the appropriate time to apply fungicides.

Lowbush blueberries (Vaccinium angustifolium Ait.) in two commercial fields were treated with a preemergent soil application of ZnSO4 at 0.34 g Zn/m2 or a prune-year or crop-year foliar application of Zintrac (1.76 g Zn/L) in a RCB design with five treatments and nine blocks, using 1.5 x 15-m treatment plots. Prune-year foliar Zintrac treatments were applied 20 June and 30 June at 53.8 mL·m-2 or 20 June at 107.6 mL·m-2. A crop-year application of Zintrac at 53.8 mL·m-2 was made on 26 June at only one location. Composite leaf tissue samples taken 14 July of the prune year indicated that two applications of Zintrac at 53.8 mL·m-2 raised Zn concentrations at both locations more than a single application at twice the rate. Soil application of ZnSO4 did not raise leaf Zn concentrations compared to the control at either location. Crop-year leaf samples taken 6 July at the site that received the crop-year foliar treatment indicated no carryover effect of prune-year Zn treatments on leaf Zn concentration, but crop-year foliar application of Zn from Zintrac did raise leaf Zn concentrations compared to the controls. The characteristics of stems sampled in the fall of the prune year at each location (stem density, stem length, flower bud formation) were not meaningfully affected by any of the prune-year treatments. Blueberry yield was not affected by any of the treatments at either location. These data suggest that control plot leaf Zn concentrations of about 15 ppm in both fields were adequate. Raising the leaf Zn concentrations to about 80 ppm with two applications of Zintrac at 53.8 mL·m -2 had no effect on growth or yield.

SUMMARY Many commercial lowbush blueberry (Vaccinium angustifolium Ait.) fields border the Bay of Fundy and the Gulf of St. Lawrence. Qualitative producer observations in these areas indicate that salt spray from the marine environment during winter months reduces yield of the lowbush blueberry. To quantitatively examine the effects of ocean spray on the lowbush blueberry, the amount of salt deposited on stems of this species was assessed at several commercial sites in the Canadian provinces of Prince Edward Island and Nova Scotia between 1998 and 2000. Randomly selected areas of commercial fields were protected with 1.8 m × 0.45 m (5.9 ft × 1.48 ft) shelters covered with 4 mil plastic film. Data on growth, yield, and salt deposition on shoots were recorded from both protected and exposed plants. Results varied according to location, weather conditions, and snow cover. Tree line wind protection and snow cover appeared to reduce the severity of salt spray-induced damage to the lowbush blueberry. In general...

A long-term introduction experiment conducted in 2009–2016 revealed that in the harshest weather conditions of the northern part of Belarus associated with a difficult environmental situation on a trial area, including weakly-decomposed acid sphagnum peat and the deficiency of artificial watering, lowbush blueberry (Vaccinium angustifolium Ait.) due to the significant tolerance to abiotic factors of the environment completely fulfills its bioproductive potential. It is clear, in particular, through the formation of a continuous berry bush cover and its high resistance to cold. A sustainable cultivated phytocenosis forms. It protects a peat substrate from fires, water and wind erosions, and has a high level of positive dynamism of berry productivity during the whole period of record. It proves the appropriateness of the ecological-biological type of the species to the extreme weather and ecological conditions of the experiment. However, lowbush blueberry needs an optimization of mineral nutrition. The implementation of this condition is a guaranty of successful introduction of the plant on the cutover raised-bog peatlands in the North of Belarus.

Nowadays, due to high population pressure more fragile lands are put into farming which then leads to low crop yield, loss of biodiversity and above all contributing to increased greenhouse gas emissions. This two year study (2020-2021) evaluated the potential of legume green manure (GM) species in improving soil fertility and barley yield, and their ability to effectively sequester soil organic carbon (SOC) towards reducing greenhouse gas emissions. The GM crops; lupine and vetch were planted during the main rainy season on the land that previous barley crop was harvested and left bare and fallow. The green manures crops were chopped and ploughed under at their 50% flowering stage and the main test crop, barley was introduced during the next cropping season. The treatments included (i) vetch GM, (ii) vetch GM + 23N + 20P, (iii) lupine GM, (iv) lupine GM + 23N + 20P, (v) fallow, (vi) fallow + 46N + 20P laid down in RCBD design with three replications. The N rate used was half when integrated with the GM species but full dose with the fallow system, whereas P was full dose. Results showed that barley grain & biomass yields were increased by 3.7 to 39.8% and 10.66 to 38.58%, respectively due to the application of the GM crops. The highest grain yield (4.1 t ha-1) and biomass yield (10.1 t ha-1) were recorded from vetch + NP application while the least grain yield (2.94 t ha-1) & biomass yield (7.24 t ha-1) were registered from the traditional fallow system. Green manure addition has brought 25 to 95.41% SOC relative change in the top 0-20cm soil depth compared with the traditional fallow system. Since both GM species are legumes, they added more N to the soil alongside with storing more C in the soil so that C: N ratio was also not affected. The highest carbon sequestered was from sole application of vetch GM (26.18 t C ha-1 yr-1) followed by vetch + NP applications (22.82 t C ha-1 yr-1). Lupine GM alone sequestered 9.24 t C ha-1 yr-1 and lupine + NP sequestered 6.86 t C ha-1 yr-1. The carbon balance in the fallow and fallow + NP combinations were negative (-0.98 and -1.40 t C ha-1 yr-1, respectively) indicating that there was C loss to the atmosphere. Therefore, application of vetch and lupine GMs with and/or without inorganic fertilizer integration had positively contributed towards improving the yield of barley and sequestering more C as compared to the local fallow practice.

This article presents the results of research on the use of a new granular organomineral fertilizer for growing plants of half-highbush cultivars of the lowbush blueberry (Vaccinium angustifolium Ait.). The purpose of the research is studying the effect of a new granular organomineral fertilizer on the agrobiological characteristics of V. angustifolium plants on a peatland in the conditions of the north of the European part of Russia. The developed composition of organomineral fertilizer (NPK 8:8:8, Fe 0.5%, Zn 0.2%, Cu 0.4%) differs from existing fertilizers in a more balanced ratio of micro- and macroelements and the content of vermicompost containing spore forms of bacteria Bacillus subtilis H-13, B. mucilaginosus, and Azotobacter chroococcum. The use of a new organomineral fertilizer on high-moor peat (pH 2.9) contributed to the highest yield of V. angustifolium fruits (190.2 g/bush), which is 1.2 times more than other mineral fertilizers (NPK, etc.). The best morphophysiological indicators of V. angustifolium plants (leaf area, total and working surface of the roots, root weight) when using the developed organomineral fertilizer were noted in September. An increase of 1.2–1.3 times in the collection of dry matter and sugars in fruits was revealed, compared with other fertilizer options, while the vitamin C content practically did not change. New organomineral fertilizer contributes to the optimal supply of the necessary micro- and macroelements throughout the growing season and increases the productivity of V. angustifolium plants when growing depleted peat deposits in the natural and climatic conditions of the European part of Russia.