ARCHIVED REPORTS_2024 REPORTS - Laserfiche WebLink

Home Browse Search

Account No.:Date Received 4010538 - 1/1 - 10748 Sample i.d. Group:Sample I.d. No.1/1 4010538 INTERPRETATION:Page two of three Is Your Compost Stable? Respiration Rate 8.5 Moderate-selected use mg CO2-C/g OM/day The respiration rate is a measurement of the biodegradation rate of the organic matter in the sample (as received). The respiration rate is determined by measuring the rate at which CO2 is released under optimized moisture and temperature conditions. Is Your Compost Mature? AmmoniaN:NitrateN ratio Composting to stabilize carbon can occur at such a rapid rate that sometimes phytotoxins remain in 71 immature the compost and must be neutralized before using in high concentrations or in high-end uses. This Ammonia N ppm step is called curing. Typically ammonia is in excess with the break-down of organic materials resulting 530 immature in an increase in pH. This combination results in a loss of volatile ammonia (it smells). Once this toxic Nitrate N ppm ammonia has been reduced and the pH drops, the microbes convert the ammonia to nitrates. A low 7.5 immature ammonia + high nitrate score is indicative of a mature compost, however there are many exceptions. For example, a compost with a low pH (<7) will retain ammonia, while a compost with high lime content can lose ammonia before the organic fraction becomes stable. Composts must first be stable before curing indicators apply. Cucumber Bioassay 93.3 Percent Cucumbers are chosen for this test because they are salt tolerant and very sensitive to ammonia and organic acid toxicity. Therefore, we can germinate seeds in high concentrations of compost to measure phytotoxic effects without soluble salts being the limiting factor. Values above 80% for both percent emergence and vigor are indicative of a well-cured compost. Exceptions include very high salts that affect the cucumbers, excessive concentrations of nitrates and other nutrients that will be in range when formulated to make a growing media. Is Your Compost Safe Regarding Health? Fecal Coliform < 1000 / g dry wt.Fecal coliforms can survive in both aerobic and anaerobic conditions and is common in all initial compost piles. Most human pathogens occur from fecal matter and all fecal matter is loaded in fecal coliforms. Therefore fecal coliforms are used as an indicator to determine if the chosen method for pathogen reduction (heat for compost) has met the requirements of sufficient temperature, time and mixing. If the fecal coliforms are reduced to below 1000 per gram dry wt. it is assumed all others pathogens are eliminated. Potential problems are that fecal coliform can regrow during the curing phase or during shipping. This is because the conditions are now more favorable for growth than during the composting process. Salmonella Bacteria Less than 3 3 / 4g dry wt.Salmonella is not only another indicator organism but also a toxic microbe. It has been used in the case of biosolids industry to determine adequate pathogen reduction. Metals Pass The ten heavy metals listed in the EPA 503 regulations are chosen to determine if compost can be applied to ag land and handled without toxic effects. Most high concentrations of heavy metals are derived from woodwaste feedstock such as chrome-arsenic treated or lead painted demolition wood. Biosolids are rarely a problem. Does Your Compost Provide Nutrients or Organic Matter? Nutrients (N+P2O5+K2O) 3.2 Average nutrient content This value is the sum of the primary nutrients Nitrogen, Phosphorus and Potassium. Reported units are consistent with those found on fertilizer formulations. A sum greater than 5 is indicative of a compost with high nutrient content, and best used to supply nutrients to a receiving soil. A sum below 2 indicates low nutrient content, and is best-used to improve soil structure via the addition of organic matter. Most compost falls between 2 and 5. Feb24A No. 1 29 Jan. 24 5, 6, 7, 8