Biochemical changes that undergo during the harvest season in 2020 (between 28 July and 11 September) were evaluated by a comparative study of two Aronia cultivars. The experiment was conducted at the Research Institute for Fruit Growing Pitesti, Arges County, Romania, on ‘Melrom’ and ‘Nero’ cultivars. Dry matter, total soluble content, pH, vitamin C, and biologically active components such as anthocyanins and phenolics variations were assessed from 28 July to 11 September 2020, for berries harvested every five days. ‘Melrom’ cultivar berries had significantly higher dry weight content, 251.43 g kg-1. ‘Nero’ showed a significantly higher vitamin C (1.87 g /kg-1 DW), total anthocyanins content (29.71 g cyanidin 3 – glucoside kg-1 DW), and juice pH (3.87). As harvest time main effect over the two cultivars taken together, dry weight, anthocyanins, total soluble content, and juice pH content increased significantly during the harvest season with 43.32%, 54.10%, 36.33%, and 17.98%, respectively, whereas significant losses of vitamin C, by 26.21%, and total phenolics compounds, by 27.90%, were recorded. Overall, early harvested fruits contained higher levels of moisture, vitamin C, and phenolics compounds, although the last crops provided less acidic fruits, with higher total soluble solids and anthocyanins content.

The berries are rich in polyphenols, vitamins, and other bioactive compounds, and exhibit antioxidant, antimicrobial, anti-inflammatory and anticancer activities. In this work, antioxidant activity (AA) and a phenolic profile of berries fruits belonging to the Aronia melanocarpa (Michx.) Elliott, ʹMelromʹ cv., Lonicera caerulea var. kamtschatica, ʹKamiʹ cv., and Sambucus nigra L., ʹElromʹ cv. were studied. All three cvs. were previously patented by the Research Institute for Fruit Growing Pitesti, Romania. Alcoholic extracts from berries were obtained by four methods: continuous, maceration, ultrasounds and microwaves-assisted. The antioxidant content of extracts was evaluated by an HPLC method. AA was determined by DPPH free radical scavenging method. Total phenol, flavonoid, and anthocyanin contents were determined by spectrophotometric methods. The AA values were reported as equivalents (µg mL-1 extract) caffeic and gallic acids, morin, quercetin, rutin, and are in concordance with the results of the chromatographic method. In addition, the chromatographic method allowed identifying the p-coumaric acid, caffeic acid, chlorogenic acid, rutin, and epicatechin. The experimental results have shown that analyzed fruit extracts have high antioxidant activity, due mainly to flavonoids and anthocyanins in high concentration. Therefore, extracts from mentioned berries can be used in different nutraceutical products with high antioxidant potential.

This study shows the influence of compost fertilization derived from sludge obtained from wastewater treatment on the nutrition of an eight-year-old apple orchard, ʹJonathanʹ cv. A field experiment was conducted to demonstrate the beneficial and negative aspects of (urban) sludge compost fertilization in apples and to assess the risk of soil contamination with heavy metals from municipal sewage sludge compost. The experimental factor was the compost with the following gradations: V1 = 0 t/ha, V2 = 20 t/ha, V3 = 40 t/ha, V4 = 60 t/ha, V5 = 80 t/ha. After two years (2019-2021) from soil fertilization with compost, the nitrogen content of the leaves increased in the treatment with the maximum fertilization dose (80 t/ha) by 30% compared to the unfertilized control, while the phosphorus content of leaves increased by 80% compared to non-fertilization control. The potassium content of the leaves increased by 36% in the 80 t/ha treatment compared to the unfertilized control, but still remained at a deficit level. The results showed that growth and yield were improved by using sewage sludge compost. However, sewage sludge compost applications have not significantly altered the heavy metal content of plant tissues. The concentration of heavy metals in the soil did not exceed the maximum permissible thresholds according to standards established in other EU countries, where compost from sewage sludge is considered product, not waste. However, the calculation of the Igeo index (geoaccumulation index of heavy metal in soil) showed certain levels of soil pollution already installed with Cd Zn, Pb in all variants fertilized with compost.

Different fertilization systems cause changes in the content of mobile forms of Al (aluminum) in the soil, due to changes in pH. The toxicity Al is one of the major limitations that inhibits the growth and development of plants in acidic soils. In acidic soils (pH <5.0), phytotoxic aluminum (Al3+) rapidly inhibits root growth and subsequently affects the absorption of water and nutrients by plants. Stationary fertilization experiments with wastewater sludge compost treatments to blueberry plants were evaluated. In the spring of 2020, an experiment with increasing doses of compost of 0, 20, 40, 60, 80 t /ha in vegetation pots, under soil water controlled conditions, was organized. Three years after compost fertilization, a 4.2 pH level (strong acid) was experimentally induced in the soil of all vegetation vessels planted with blueberries. The content of phytotoxic forms of aluminum increased with increasing dose of compost, compared to unfertilized control. At the induction of the soil pH of 4.2, in the variant fertilized with the maximum dose of compost (80 t/ha) the mobile and phytotoxic content of Al increased 30 times compared to the same experimental variant from the pre-acidification conditions. In the same time, under the newly created conditions, the mobile phosphorus content in the soil decreased dramatically. In the compost maximum fertilization dose, the mobile phosphorus content from the soil was significantly lower than the unfertilized control.

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