The influence of compost (derived from MSW and biosolids) maturity on seed germination of several weed species was evaluated. A bioassay was developed by extracting 20 g of compost of different maturities with various volumes of water, then measuring germination percentage of ivyleaf morningglory (Ipomoea hederacea) seeds placed on extract-saturated filter paper in a petri dish. A 20 g (dry weight) compost: 50 mL of water generated an extract that produced the widest percentage seed germination variation in response to composts of different maturity. Ivyleaf morningglory, barnyardgrass (Echinochloa crus-galli L.), purslane (Potulaca oleracea L.), and corn (Zea mays L) were selected as plant indicators to determine the compost maturity stage with maximum germination inhibition. Compost 8-week-old decreased percent germination, root growth, and germination index (combines germination rate and root growth), and increased mean days to germination (MDG) of each plant indicator. Immature 8 week-old compost extract effect on MDG and germination percent of 15 weed species was evaluated. Extract from 8-week-old compost inhibited germination in most weed species, except yellow nutsedge (Cyperus esculentus). Compost extracts derided from immature (3-day, 4-, and 8-week-old) compost resulted in delayed and reduced germination percent of important economic weed species.
Monica Ozores-Hampton, Thomas A. Bewick, Peter Stoffella, Daniel J. Cantliffe, and Thomas A. Obreza
Kimberly A. Klock-Moore and George E. Fitzpatrick
Analytical determination and confirmation of minimum compost processing times and minimum curing times can aid commercial growers in selecting compost materials that should give them more reliable and consistent results in their operations. Five-cubic-yard volumes of yard-trimmings were assembled into three 1.25-cubic-yard compost piles at 60-day intervals. At the conclusion of the experiment, there were three piles each of compost of the following ages: 10 months, 8 months, 6 months, and 2 months. Compost was collected from each pile and screened through a 0.75-inch screen. Bulk density, water-holding capacity, air-filled porosity, carbon to nitrogen ratio, electrical conductivity, and ATPase activity were determined on samples from each reference compost pile. A bioassay using beans also was performed. These data will be presented.
Tara A. O'Brien and Allen V. Barker
This research evaluated production of wildflower sods in soil and composts of mixed municipal solid waste, biosolids and woodchips, fall leaves, and mixed agricultural wastes. Soil or composts were laid on plastic sheeting in outdoor plots, and a mixture of wildflower seeds was sown in July and in September in separate experiments. Quality of sods was assessed in two growing seasons. Best sods with respect to seed germination, stand establishment, and intensity and diversity of bloom over two seasons occurred in mature biosolids compost and in agricultural waste compost. These composts were low in ammonium but rich in total N. Germination and growth of wildflowers were limited by high ammonium concentrations in immature biosolids composts. Nitrogen deficiency limited sod growth and quality in leaf composts. Poor N nutrition and weed competition restricted sod production in soil. Fertilization of soil promoted unacceptably large weed growth. Summer seeding or fall seeding resulted in good sods, but many annual flowers that appeared in the summer seeding were absent in the fall-seeded planting. Using plastic-lined plots was a convenient system for evaluating composts and other media in outdoor culture.
T.K. Hartz and C. Giannini
Windrows of municipal yard and landscape waste at three commercial composting sites in California were sampled at ≈3-week intervals through 12 to 15 weeks of composting to observe changes in physiochemical and biological characteristics of importance to horticulture. Initial C, N, P, and K content averaged 30%, 1.3%, 0.20%, and 0.9%, respectively. Carbon concentration declined rapidly through the first 6 to 9 weeks, while N, P, and K remained relatively stable throughout the sampling period. Few viable weed seeds were found in any compost. A high level of phytotoxicity, as measured by a tomato (Lycopersicon esculentum Mill.) seed bioassay, was observed at only one site; overall, the degree of phytotoxicity declined with compost age. Short-term net N immobilization (in a 2-week aerobic incubation) was observed in nearly all samples, with an overall trend toward decreased immobilization with increased compost age. In a 16-week pot study in which fescue (Festuca arundinacea Shreb.) was grown in compost-amended soil, net N mineralization averaged only 2% to 3% of compost total N content. Neither composting site nor duration of composting significantly affected either N mineralization rate or fescue growth. Growth of vinca (Catharanthus roseus Don.) in a blend of 1 compost : 1 perlite increased with increasing compost age. Overall, at least 9 to 12 weeks of composting were required to minimize the undesirable characteristics of immature compost.
Danielle D. Treadwell, George J. Hochmuth, Robert C. Hochmuth, Eric H. Simonne, Lei L. Davis, Wanda L. Laughlin, Yuncong Li, Teresa Olczyk, Richard K. Sprenkel, and Lance S. Osborne
bedding most likely inhibited growth, despite the successful use of horse compost in other applications ( Zubillaga and Lavado, 2006 ). Compost maturity can be tested with indices such as Solvita test (Woods End Research Laboratory, Mt. Vernon, ME). This
Paige L. Herring, Abbey C. Noah, and Helen T. Kraus
Compost maturity index. California Compost Quality Council, Nevada City, CA Davis, J.M. 1994 Growing herbs as a cash crop. 13 Jan. 2016. < https://newcropsorganics.ces.ncsu.edu/herb/growing-herbs-as-a-cash-crop/ > DeKalb, C.D. Kahn, B.A. Dunn, B.L. Payton
Yuncong Li, Edward Hanlon, George O'Connor, Jianjun Chen, and Maria Silveira
. Reliable methods to assess compost maturity, stability, and pathogen suppressivity are needed to characterize compost quality. Table 7. Yield responses of tomato to compost amendments from experiments conducted in Florida ( Li et al., 2000 ). Benefits of
Hong Su, He Zhang, Chaoxia Wang, Jianquan Huang, Jiayin Shang, Na Zhang, Dan Wang, and Kai Li
. Santana, D. Navas, M. Masaguer, A. Benito, M. 2017 Influence of pruning waste compost maturity and biochar on carbon dynamics in acid soil: Incubation study Eur. J. Soil Biol. 78 66 74 doi: 10.1016/j.ejsobi.2016.12.001 Tiquia, S.M. Lloyd, J. Herms, D
Lu Zhang and Xiangyang Sun
Gabhane, J. William, S.P.M.P. Bidyadhar, R. Bhilawe, P. Anand, D. Vaidya, A.N. Wate, S.R. 2012 Additives aided composting of green waste: Effects on organic matter degradation, compost maturity, and quality of the finished compost Bioresour. Technol. 114