Nutrient transport, shear strength and hydraulic characteristics of topsoils amended with mulch, compost and biosolids

Anthropogenic disturbance of soils can disrupt soil structure, diminish fertility, alter soil chemical properties, and cause erosion. Current remediation practices involve amending degraded urban topsoils lacking in organic matter and nutrition with organic amendments (OA) to enhance vegetative growth. However, the impact of OAs on water quality and structural properties at rates that meet common topsoil organic matter specifications need to be studied and understood. This study tested three commonly available OAs: shredded wood mulch, leaf-based compost, and class A Exceptional Quality stabilized sewage sludge (or biosolids) for nutrient (nitrogen and phosphorus) water quality, soil shear strength, and hydraulic properties, through two greenhouse tub studies. Findings showed that nitrogen losses to leachate were greater in the biosolids amended topsoils compared to leaf-compost, mulch amended topsoils, and control treatments. Steady-state mean total nitrogen (N) concentrations from biosolids treatment exceeded typical highway stormwater concentrations by at least 25 times. Soil total N content combined with the carbon:nitrogen ratio were identified to be the governing properties of N leaching in soils. Study soils, irrespective of the type of amendment, reduced the applied (tap) water phosphorus (P) concentration of ∼0.3 mg-P/L throughout the experiment. Contrary to the effects on N leaching, P was successfully retained by the biosolids amendment, due to the presence of greater active iron contents. A breakthrough mechanism for P was observed in leaf compost amended soil, where the effluent concentrations of P continued to increase with each rainfall application, possibly due to an saturation of soil adsorption sites. The addition of OAs also improved the strength and hydraulic properties of soils. The effective interlocking mechanisms between the soil and OA surfaces could provide soil its required strength and stability, particularly on slopes. OAs also improved soil fertility to promote turf growth. Presence of vegetative root zones can further reinforce the soil and control erosion.

Effect of Cultural Management and Plant Age on the Yield, °Brix, and Antioxidant Content of Aronia mitschurinii Grown in Maryland

Aronia mitschurinii is a fruiting plant that has the potential of becoming the next-generation superfood. The fruit contains high concentrations of flavonoids, polyphenols, and anthocyanins, which are known to be powerful antioxidants. The fruit is regarded for its potential to treat oxidative stress diseases like cancer. Recent studies have proven that this fruit contains significantly more antioxidants than the açai berry and even 40 times more than tomatoes. Here, we report results for developing and optimizing the horticultural management program for growing aronia on Maryland small farms to produce the crop with the highest possible antioxidant capacity, based on observations since 2009. This was achieved by analyzing how plant age, fertilizers, mineral soil amendments, and other factors like disease and pest pressure affect the antioxidant content. This data can help in improving sustainability of local farm businesses by providing them with new alternative and highly profitable crops to grow and process. Analysis and comparison of the fruit yield, soluble sugar content (°Brix), pH, total polyphenols, total anthocyanins, and total flavonoids of aronia based on two treatment levels of nitrogen fertilizer (3 g N plant^-1 year^-1 vs 14 g plant^-1 year^-1) and conventional and organic-based nitrogen are presented. Plants were fertilized with either 127 g (rows A and C) or 27 g (rows B and D) of Bartlett's Boost Natural at the base of each plant. This equated to 14 and 3 g of N, respectively. Average yields of plants given 14 g of organic N were only significantly higher than those given only 3 g of conventional N but not organic N. The yield in all plants increased year by year from 2009 and until 2019 and slightly decreased in 2020. Even though an increase in the anthocyanin content was noted for a lower N rate, the higher N rate would have produced more fruit and hence more anthocyanin per hectare. A higher nitrogen (N) rate positively affected the yield, but not always the phytochemical content. Organic N did not have a positive effect on the phytochemical content. Additionally, we report the cyanide content of aronia fruit in comparison to other fruits.

Extraction of Antioxidants from Aronia mitschurinii Juice Using Macroporous Resins

Antioxidants play a vital role in the human body by defending cells from damage caused by free radicals, highly reactive products of oxidation reactions. A major source of antioxidants is fruits and vegetables. Aronia mitschurinii, a breed created at the end of the 19th century by crossbreeding wild Aronia melanocarpa and Russian Mountain Ash, produces fruits with one of the highest known content of hydrophilic antioxidants. Aronia fruit contains a potent blend of anthocyanins, polyphenols, and flavonoids. The most popular way of consuming the fruit is through juicing. Yet, due to very high concentrations of tannins in the juice, very few food-related applications have been developed. Resin extraction of antioxidants provides an alternative for utilizing valuable phytochemicals from crops for applications in the food industry as nutraceutical supplements and more. To increase the market value of the plant, it is important to determine what resins can extract the optimum concentration of antioxidants from aronia juice, pulp, and whole berries. We have shown that macroporous resins such as Amberlite XAD 1180N, Amberlite XAD 7HP, Amberlite XAD 761, and Amberlite FPX66, which have been reported to be effective in extracting the anthocyanins and polyphenols from other fruit juices, skins of red grapes, and the wild breed, are also effective for use in juice, pulp, and whole fruits of Aronia mitchurinii. However, the extremely high content of antioxidants presents a challenge to obtaining high recovery; a notable change in the juice/resin ratio is required to obtain a higher recovery value. Our results showed that Amberlite FPX66 was the best at extracting anthocyanins, polyphenols, and flavonoids from aronia juice. A separate experiment conducted to determine how to optimize the efficiency of FPX66 extraction revealed that increasing the resin/juice ratio increased the percent recovery of anthocyanins from aronia juice. Moreover, we have compared recovery between juice, pulp, and whole aronia berries and batch versus column extraction.