College of Agriculture & Natural Resources
Permanent URI for this communityhttp://hdl.handle.net/1903/1598
The collections in this community comprise faculty research works, as well as graduate theses and dissertations.
Browse
6 results
Search Results
Item THE USE OF ORGANIC WASTE PRODUCTS AS SOIL AMENDMENTS FOR TURFGRASS ESTABLISHMENT: EFFECTS AND REGULATORY INFLUENCES(2024) Morash, Jennifer Dawn; Lea-Cox, John; Plant Science and Landscape Architecture (PSLA); Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The use of organic waste products as soil amendments in highly disturbed urban soil is poised to grow due to rising fertilizer costs, waste-management issues, and greater emphasis on creating sustainable circular economies. Despite the advantages of using waste products as organic amendments to enhance fertility, their incorrect use may result in short-term unintended consequences such as nutrient losses or the immobilization of plant-essential nutrients, which could diminish efforts to establish vegetation on disturbed soil. To avoid these consequences, transportation authorities – cited as the largest users of compost in some states – have implemented measures to improve product specifications. This research details the efforts of one such organization, the Maryland Department of Transportation State Highway Administration (MDOT SHA), and the results of an initiative to increase the quality of manufactured topsoil and compost use through agency topsoil specifications. After determining which products were most likely to be incorporated into manufactured topsoil (finely shredded wood mulch and composted leaf yard waste), two greenhouse microcosm experiments were conducted to evaluate plant growth responses and the efficiency of nutrient uptake compared to leachate losses when those amendments were used in accordance with MDOT SHA specifications. Composted yard waste provided excellent results while wood mulch suppressed growth in the short-term studies. A biosolids treatment was included in the experiments due to widespread availability and growing interest. Biosolids improved soil fertility and plant growth. However, the difference between nitrogen (N) uptake and leachate mass losses required a second set of experiments, to quantify the effects of four biosolids amendments on plant growth, nutrient uptake, and leachate losses. Treatments were applied at the rate recommended by UMD for turfgrass establishment (2.54 cm, incorporated) and included fresh biosolids, biosolids that were stockpiled for two years, two blended products made from either the fresh or aged biosolids and fine wood mulch, an inorganic fertilizer, and a control. Aging and wood fines reduced N leaching losses but at the expense of N inputs to soil. The cumulative N leachate mass loss from the new biosolids treatment was 63 times greater than the cumulative fertilizer total. Aging did not reduce phosphorus (P) leaching losses but wood fines did by diluting the concentration of P in blends. However, biosolids mostly retained P in the soil and cumulative fertilizer losses were 2 times higher. Overall, growth measurements showed that biosolids enhanced growth during the first and second growing seasons. However, based on the results of this research, 2.54 cm of pure biosolids is not required to enhance turfgrass establishment. An application of 1.27 cm of pure biosolids or 2.54 cm of a biosolid/wood fine blend should provide comparable enhanced turfgrass growth results while reducing overall nutrient leachate losses.Item Biosolids and Compost For Urban Soil Restoration and Forestry(2022) Keener, Emily Cathryn; Pavao-Zuckerman, Mitchell A; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Elements of urban soil quality such as compaction and low organic matter are underexamined, important challenges to urban afforestation. In this Beltsville, Maryland field experiment, I examined biosolids and compost as amendments to improve soil quality and planted tree survival in a degraded urban proxy soil and identified correlations between soil properties and tree survival. Organic amendments increased organic matter content, decreased bulk density, and had no effect on tree survivorship compared to controls. Effects on soil were more profound and lasting with compost than with biosolids. Soil organic matter and bulk density were correlated with tree survival early in the study and microbial respiration was correlated with tree survival throughout the study. High tree mortality was driven by transplant shock, limiting insights from tree response data. This study highlights the importance of soil quality and good planting practices in future research.Item High Quality Biosolids: Assessment of Nitrogen Mineralization and Potential for Improving Highway Soils(2019) Zhu, Chenglin; Felton, Gary K; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Biosolids production is increasing with increase in human population. Over the years, the quality of biosolids has been improving with the upgrading of most wastewater treatment plants (WWTP) as dictated by a need to meet discharge limits in receiving water bodies. Applying biosolids to agricultural soils to improve crop production has been practiced for decades. With increased regulation on land application in agricultural lands, biosolids industry has been exploring ways to use biosolids in specific situations such as highway roadside soils to improve soil properties. Roadside soils are known to be compacted and contaminated due to vehicular traffic and typically have low organic matter and nutrients. The objective of this study was to investigate the efficacy of high quality biosolids (i.e. Bloom) to improve soil physical and chemical properties. Results showed that Bloom and its mixture can significantly improve soil bulk density and hydraulic conductivity. Bloom-amended soils had a higher nitrogen mineralization rate than the control (2.45 times faster in simulated roadside soil and 1.21 times faster in agricultural soil) and compost amended soil. Further, soils amended with cured Bloom had relatively slower N mineralization than those applied with uncured Bloom since the curing process will decrease organic matter (OM) content and facilitate the loss of N as ammonium. The take home message is that bloom is more effective than inorganic fertilizer in terms of improving soil physical properties for roadside soils and bloom mixed with sand and sawdust is more effective than pure bloom. Bloom addition can significantly increase soil organic nitrogen mineralization. Further study and analysis will be needed to conclude on the effect of deer compost on soil physical properties and the mineralization rate of Orgro amended soil.Item BLOOM BIOSOLIDS: WHAT IS THEIR MICROBIAL COMMUNITY AND HOW DO THEY AFFECT SOIL AND PLANT HEALTH?(2019) Baballari, Eni; Yarwood, Stephanie; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Biosolids are rich in nutrients and organic matter, and are known to improve and maintain productive soils and stimulate plant growth. D.C. Water’s new Class A biosolids product, Bloom, was evaluated for its impact on plant and soil health. Using molecular tools, Bloom was examined for the presence of functional genes that would indicate the presence of microbes capable of improving plant growth (i.e.nitrifiers, N- fixers). Using greenhouse and laboratory experiments, we determined Bloom’s effect on plant growth, carbon and nitrogen cycling. Bloom has both nitrifying and N-fixing microbes, but their gene numbers vary depending on the stage of production. We show that plants, such as cucumber and tomato, grown in soil amended with Bloom produce more leaves and stems and have higher aboveground biomass, and soybeans produced more bean pods. Lastly, we found that N-mineralization is higher in soil amended with Bloom, even after one growing season, providing increased nutrients.Item FATE AND TRANSPORT OF NITROGEN AT A DEEP ROW BIOSOLIDS APPLICATION HYBRID POPLAR TREE FARM(2012) Maimone, Diana; Felton, Gary K; Biological Resources Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This study evaluates deep row applied biosolids as a nutrient source for hybrid poplar trees grown on a gravel mine reclamation site in Brandywine, Maryland from November 2003 to April 2009. The study included biosolids application rates of 386, 773, and 1,159 dry Mg/ha (172, 345, and 517 dry ton/ac.) and hybrid poplar tree densities of 0, 716, and 1,074 trees/ha (0, 290, and 435 trees/ac.). Soil water samples taken from suction lysimeters located 15 - 120 cm (6 - 48 in.) vertically below the biosolids were analyzed for total ammoniacal-nitrogen (TAN) and nitrate-nitrogen (NO3-N). The majority (96.3%) of NO3-N values were less than EPA drinking water MCL of 10 mg/L. No NO3-N values within the tree plots exceeded 2 mg/L. The TAN concentrations increased with application rates, but decreased with distance from the biosolids, except there was no difference between 60 cm (24 in.) and 120 cm (48 in.).Item Fate and Transport of Nitrogen at a Deep Row Biosolids Application Hybrid Poplar Tree Farm(2006-08-10) Buswell, Carrie Ursula; Felton, Gary K; Biological Resources Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This study focused on a gravel mine reclamation site using biosolids in deep rows as a nutrient source and hybrid poplar trees as the stabilizing crop. Biosolids application rates of 481, 962, and 1443 dry Mg/ha and tree densities of 0, 716, and 1074 trees/ha and controls (0 dry Mg/ha - 0 trees/ha) were studied. Total nitrogen, ammonium, nitrite and nitrate in soil water samples from pan and suction lysimeters under and around the biosolids rows were evaluated. Total nitrogen was predominantly in the form of ammonium. Ammonium concentrations in more than half the samples were above 100 mg/L, reflecting the average biosolids concentration of 2,300 mg/kg. No significant differences (a = 0.05) were determined between application rates or tree densities, but ammonium concentration significantly decreased with distance below the biosolids row. Nitrite and nitrate nitrogen concentrations were predominantly non-detects or less than 1 mg/L, indicating that nitrification was not occurring.