Compost Science Complete scientific data on compost process control and end product quality

CURRENT RESEARCH PROJECTS

CSU Winter, 2005, Vol. 13, No. 1, p. 4

CROP RESPONSE
Enhancement Of Vegetable Crop Growth With Biosolids And Yard Waste Compost
Investigators: J.J. Heitholt and J.J. Sloan, Texas Agricultural Experiment Station, Dallas, Texas
Objectives: To quantify growth of vegetable crops grown in north Texas on a calcareous soil treated with biosolids and municipal compost over a two-year period. Yield increases were most likely due to increased N, P and trace nutrients supplied by organic treatments.

Compost As Soil Conditioner And Effect On Pest Management And Turfgrass Growth
Investigators: Mili Mandal and Rakesh S. Chandran, West Virginia University, Morgantown, West Virginia
Objectives: To study use of compost in various agricultural systems/crops and its benefits, ability to improve soil properties and to manage pests. Laboratory experiments were performed at West Virginia University to observe the effect of poultry litter compost extract on the germination of 13 weed species. Three different concentrations of compost extracts were compared to distilled water (control) for weed seed germination. The highest concentration inhibited germination in Johnsongrass, small flower morning glory and ivy leaf morning glory. Medium concentration inhibited germination in giant foxtail by 90%. The study indicates the presence of water-soluble substances in the composting material that have inhibitory effects on seed germination.

Evaluating Rates Of Leaf Compost Amendments In Carrot And Beet Production
Investigator: Abigail A. Maynard, Connecticut Agricultural Experiment Station, New Haven, Connecticut
Objective: To determine the effect of different rates of leaf compost on the yield of carrots (Daucus carota L.) and beets (Beta vulgaris L.). Experiments were performed on Cheshire fine sandy loam. Unscreened leaf compost was applied at the rate of 50 T/A (one inch on the surface), 25 T/A and 10 T/A. Compost was rototilled into the soil to a depth of six inches. Compost was produced in a passive pile turned four or five times yearly for two years. In all three years of compost applications, virtually no difference was found in soil nutrients between the compost treatments and the control. However, differences were found in organic matter percentage and pH between the treatments in all three years.

Effects Of Pulp Fiber Residue Waste On Three Crops
Investigators: Sherif H. Fahym, Karen Gillam and Sheldon Hann, Agriculture and Agri-Food Canada, Potato Research Center, Fredericton, NB, Canada and University of New Brunswick, Faculty of Forestry and Environmental Management
Objectives: To evaluate the effect of raw pulp fiber residue waste from a thermo-mechanical pulping newsprint process on the yield of crops and total nitrogen budgets in a three-year alternating potato rotation system. When residue is used as an organic amendment, it acts as a reservoir to soil moisture and as a release regulator to nitrogen in the soil matrix.

ENVIRONMENTAL IMPACT
Compost Source And Rate Effects On Soil Macronutrient Availability Under Turf
Investigators: Alan L. Wright, Tony L. Provin, Frank M. Hons, David A. Zuberer and Richard H. White, Texas A&M University, College Station, Texas
Objectives: To investigate the influence of compost sources and application rates on concentrations of plant-available macronutrients in soil over 29 months after a one-time compost application to St., Augustine and Bermuda grass turf. Compost application augmented soil organic, C,P, Ca and S concentrations after three months, but further increases from 3 to 29 months were seldom observed. Utilization of turfgrass sod production systems for compost application should take into account plant species composition and the related impacts of plant uptake. Macronutrient concentrations were significantly correlated with both total organic C and dissolved organic C (DOC). Formation of organic matter cation complexes appeared to influence macronutrient dynamics in soil, and may contribute to leaching and runoff losses.

MATERIALS AND METHODS
How Soil Biological Activity Is Influenced By Green Compost (GC) And Farmyard Manure (FYM)
Investigators: A. Saviozzi, R. Cardelli, P. N'kou, R. Levi-Minzi and R. Riffaldi, Department of Agricultural Chemistry and Biotechnology, University of Pisa, Pisa, Italy
Objectives: To evaluate the influence of FYM and GC at two application rates on the quality of soil. A two-month aerobic incubation was carried out and changes in chemical and biochemical activity were monitored. Results indicate that soil pH and dissolved organic C were affected to modest levels over the 60-day incubation period by any of the two rates of both amendments.

MICROBIAL ECOLOGY
Impact On Molecular Bionomics Of Microbial Communities In Dairy Manure Compost
Investigators: Li Zigang and Huang Wei-yi, Microbiology Department, Nanjing Agricultural University, Nanjing, Jiangsu, P.R.C.
Objectives: To study the diversity of microorganisms in compost production on the basis of molecular biology and supply the data to judge chemical and physical stability of compost. Researchers focused on the role of bacteria as well as contribution of other fungi and yeasts during the process, particularly at the mesophilic stage.

Spectroscopic And Thermal Investigation On Hydrophobic And Hydrophilic Fractions Of Dissolved Organic Matter
Investigators: M.A. Provenzano, G. Gigliotti, A. Cilenti, F. Erriquens and N. Senesi, University of Bari, Italy; University of Perugia, Italy
Objectives: To investigate the fractions of DOM isolated from an urban waste compost, a sewage sludge and a dairy slurry using Fourier transform infrared spectroscopy, conventional fluorescence spectroscopy, tridimensional emission matrix and other methods. It was found that dissolved organic matter has a significant role in the soil system affecting transport of metals, colloids and microbial activity.

Effects Of Ambient Air Temperature On Temperature Of Sewage
Investigators: Qifei Huang, Chinese Research Academy of Environment Sciences, Beijing, China; Tongbin Chen, Ding Gao and Zechun Huang, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
Objectives: To study the effects of ambient air temperature on the composting temperature with varying volume ratios of sewage sludge and recycled compost to bulking agent. Results show how composting temperature is influenced by ambient air temperature and the influence is more significant when composting is in the temperature rising process. The investigators observed the effect of hysteresis in composting temperature's responses to ambient air temperature. Study investigated effects of ambient air temperature and how it impacts the composting temperature of aerated static pile systems.

Determination Of Compost Respiration Rates Using Pressure Sensors
Investigators: Samy S. Sadaka, Iowa State University, Nevada, Iowa; Tom L. Richard and Matt Liebman, Iowa State University, Ames, Iowa; Terrance D. Loecke, Michigan State University, Hickory Corner's, Michigan
Objective: To develop and evaluate the Pressure Sensor Method (PSM) for measuring compost respiration rates. Specifically, there were two goals: 1) To compare the compost respiration rates measured using (PSM) versus the end-point titration method; and 2) To study the effects of decomposition stage, volatile solids, pH and electrical conductivity on respiration rates. Investigators rated the Pressure Sensor Method as a reliable method in measuring respiration rate. Of secondary importance, it was shown that increasing composting time and/or lowering volatile solids decreased respiration rate. However, pH and electrical conductivity showed no clear trend with respiration rate.