Sphagnum peat has been the standard base component for most container growing substrates in the United States since the 1950s. It is an ideal container substrate because it has low bulk density, high water-holding capacity, good aeration porosity, low soluble salts, acceptable pH, and high uniformity across batches (Schmilewski, 1983; Stamps and Evans, 1999). As nursery and greenhouse growers seek to adopt more environmentally and economically sustainable practices, interest has grown in the use of local, recycled organic materials as partial or complete substitutes for peat in container substrates (Fitzpatrick, 2001; Raviv, 2005). Because these materials have typically entered the waste stream, their use as container substrates reduces solid waste production and the subsequent need for disposal.
Alternative components include various composted materials (Carlile, 2008; Corti et al., 1998) using feedstocks such as yard debris and pruning waste, animal manures, biosolids, agricultural green waste, woody debris, municipal solid waste, and food waste. In general, substrates made from these materials have greater bulk density, soluble salts, and pH; lower porosity and available water capacity; and less uniformity than peat-based substrates (Corti et al., 1998). Despite these shortcomings, numerous studies have shown that container substrates with acceptable quality can be made using composts, supplying nutrients and producing plants of equivalent and sometimes better growth and quality compared with standard substrates (Bugbee, 2002; Clark and Cavigelli, 2005; Estévez-Schwarz et al., 2009; Grigatti et al., 2007; Hummel et al., 2000, 2001; Tittarelli et al., 2009). High salt content and lack of uniformity frequently have been the greatest problems to overcome in developing alternative container substrates (Bugbee, 2002; Ozores-Hampton et al., 1999).
Bark, another component of container substrates often used at rates as high as 60% to 100% by volume, is decreasing in availability and rising in cost (Buamscha et al., 2007; Lu et al., 2006). The demand for sustainable alternatives to bark has prompted research to develop substrates composed of whole pine trees (Fain et al., 2008; Jackson and Wright, 2009) and clean chip residual (Boyer et al., 2009). Other uncomposted materials may also have potential as inexpensive and sustainable peat substitutes (Ingelmo et al., 1998), but many of these materials have had little study. Some uncomposted recycled organic materials currently in use or with potential as substrate components include coir (Stamps and Evans, 1999), poultry feather fiber (Evans, 2004), rice hulls (Evans and Gachukia, 2004), and a noncomposted residential refuse (Kahtz and Gawel, 2004).
Reducing water and fertilizer use and managing leachate are also key to sustainable container production systems (Biernbaum, 1992; Uva et al., 1998). Research has demonstrated the efficiencies of subirrigation with recirculation in reducing water, fertilizer, and labor inputs while maintaining plant growth and quality (Argo and Biernbaum, 1995; Klock-Moore and Broschat, 1999; Molitor, 1990; Morvant et al., 1998, 2001; Neal and Henley, 1992; Uva et al., 1998). Subirrigation relies on water uptake through capillary action, and substrates suitable for subirrigation systems must readily absorb water by capillarity (Reed, 1996). Gabriëls et al. (1986) stress the importance of substrate physical parameters, especially aeration, in subirrigation systems. Most of the research on subirrigation systems has been done using substrates with peatmoss as a primary component. Incorporation of recycled organic materials into sustainable container production systems requires testing their efficacy as substrates for subirrigated crops.
This project compares a range of locally available peat substitutes for greenhouse production of chrysanthemum fertilized at two N rates using conventional overhead irrigation and a capillary mat subirrigation system. Alternative substrates include biosolids compost, an uncomposted class A biosolids (U.S. Environmental Protection Agency, 1994) blend, dairy manure compost, and solids from an anaerobic dairy manure digester. Our objectives were to 1) determine the growth and quality response of chrysanthemum grown at two N rates to the different substrates under overhead and subirrigation systems; and 2) determine the effect of the substrates and N on leachate water quality under the two irrigation systems.
Argo, W.R. & Biernbaum, J.A. 1995 The effect of irrigation method, water-soluble fertilization, preplant nutrient charge, and surface evaporation on early vegetative and root growth of poinsettia J. Amer. Soc. Hort. Sci. 120 163 169
Biernbaum, J.A. 1992 Root-zone management of greenhouse container-grown crops to control water and fertilizer use HortTechnology 2 127 132
Boyer, C.R., Gilliam, C.H., Fain, G.B., Gallagher, T.V., Torbert, H.A. & Sibley, J.L. 2009 Production of woody nursery crops in clean chip residual substrate J. Environ. Hort. 27 56 62
Broschat, T.K. 2008 Effectiveness of pasteurized poultry litter as a partial substitute for controlled-release fertilizers in the production of container-grown ornamental plants HortTechnology 18 671 677
Buamscha, M.G., Altland, J.E., Sullivan, D.M., Horneck, D.A. & Cassidy, J. 2007 Chemical and physical properties of douglas fir bark relevant to the production of container plants HortScience 42 1281 1286
Chen, Y., Inbar, Y., Raviv, M. & Dovrat, A. 1983 The use of slurry produced by methanogenic fermentation of cow manure as a peat substitute in horticulture—Physical and chemical characteristics Acta Hort. 150 553 561
Clark, S. & Cavigelli, M. 2005 Suitability of composts as potting media for production of organic vegetable transplants Compost Sci. Util. 13 150 156
Corti, C., Crippa, L., Genevini, P.L. & Centemero, M. 1998 Compost use in plant nurseries: Hydrological and physicochemical characteristics Compost Sci. Util. 6 35 45
Estévez-Schwarz, I., Seoane, S., Núñez, A. & López-Mosquera, M.E. 2009 Characterization and evaluation of compost utilized as ornamental plant substrate Compost Sci. Util. 17 210 219
Evans, M.R. & Gachukia, M. 2004 Fresh parboiled rice hulls serve as an alternative to perlite in greenhouse crop substrates HortScience 39 232 235
Fain, G.B., Gilliam, C.H., Sibley, J.L., Boyer, C.R. & Witcher, A.L. 2008 Whole tree substrate and fertilizer rate in production of greenhouse-grown petunia (Petunia ×hybrid Vilm.) and marigold (Tagetes patula L.) HortScience 43 700 705
Fitzpatrick, G.E. 2001 Compost utilization in ornamental and nursery crop production systems 135 150 Stoffella P.J. & Kahn B.A. Compost utilization in horticultural cropping systems Lewis Boca Raton, FL
Giles, J., Chong, C. & Lumis, G. 2005 Response of container-grown ninebark to crude and nutrient-enriched recirculating compost leachates HortScience 40 1507 1512
Grigatti, M., Giorgioni, M.E. & Ciavatta, C. 2007 Compost-based growing media: Influence on growth and nutrient use of bedding plants Bioresour. Technol. 98 3526 3534
Hummel, R.L., Johnson, C.R., Riley, R. & Smith, S. 2001 Yard trimmings compost as a growing medium component and nutrient source for chrysanthemum and fuchsia production Comb. Proc. Int. Plant Prop. Soc. 51 295 299
Hummel, R.L., Kuo, S., Winters, D. & Jellum, E.J. 2000 Fishwaste compost medium improves growth and quality of container-grown marigolds and geraniums without leaching J. Environ. Hort. 18 93 98
Inbar, Y., Chen, Y. & Hadar, Y. 1985 The use of composted slurry produced by methanogenic fermentation of cow manure as a growth media Acta Hort. 172 75 82
Ingelmo, F., Canet, R., Ibanez, M.A., Pomares, F. & Garcia, J. 1998 Use of MSW compost, dried sewage sludge and other wastes as partial substitutes for peat and soil Bioresour. Technol. 63 123 129
Ingram, D.L., Henley, R.W. & Yeager, T.H. 1990 Diagnostic and monitoring procedures for nursery crops Univ. of Fla. Coop. Extn. Serv. Circ. 556
Jackson, B.E. & Wright, R.D. 2009 Pine tree substrate: An alternative and renewable substrate for horticultural crop production Acta Hort. 819 265 272
Klock-Moore, K.A. & Broschat, T.K. 1999 Differences in bedding plant growth and nitrate loss with a controlled-release fertilizer and two irrigation systems HortTechnology 9 206 209
Lu, W., Sibley, J.L., Gilliam, C.H., Bannon, J.S. & Zhang, Y. 2006 Estimation of U.S. bark generation and implications for horticultural industries J. Environ. Hort. 24 29 34
Molitor, H.D. 1990 The European perspective with emphasis on subirrigation and recirculation of water and nutrients Acta Hort. 272 165 173
Morvant, J.K., Dole, J.M. & Cole, J.C. 1998 Irrigation frequency and system affect poinsettia growth, water use, and runoff HortScience 33 42 46
Morvant, J.K., Dole, J.M. & Cole, J.C. 2001 Fertilizer source and irrigation system affect geranium growth and nitrogen retention HortScience 36 1022 1026
Neal, C.A. & Henley, R.W. 1992 Water use and runoff comparisons of greenhouse irrigation systems Proc. Fla. State Hort. Soc. 105 191 194
Ozores-Hampton, M., Vavrina, C.S. & Obreza, T.A. 1999 Yard trimming–biosolid compost: Possible alternative to sphagnum peat moss in tomato transplant production Compost Sci. Util. 7 42 49
Reed, D.W. 1996 Closed production systems for containerized crops: Recirculating subirrigation and zero-leach systems 221 245 Reed D.W. Water, media and nutrition for greenhouse crops Ball Publishing Batavia, IL
Stamps, R.H. & Evans, M.R. 1999 Growth of Dracaena marginata and Spathiphyllum ‘Petite’ in sphagnum peat- and coconut coir dust-based growing media J. Environ. Hort. 17 49 52
Thompson, W.H., Leege, P.B., Millner, P.D. & Watson, M.E. 2001 Test methods for the examination of composting and compost USDA Washington, DC
Tittarelli, F., Rea, E., Verrastro, V., Pasucal, J.A., Canali, S., Ceglie, F.G., Trinchera, A. & Rivera, C.M. 2009 Compost-based nursery substrates: Effect of peat substitution on organic melon seedlings Compost Sci. Util. 17 220 228
U.S. Environmental Protection Agency. 1994. A plain English guide to the EPA Part 503 biosolids rule. EPA/832/R-93/003.
Uva, W.L., Weiler, T.C. & Milligan, R.A. 1998 A survey on the planning and adoption of zero runoff subirrigation systems in greenhouse operations HortScience 33 193 196
Williams, K.A. & Nelson, P.V. 1992 Low, controlled nutrient availability provided by organic waste materials for chrysanthemum J. Amer. Soc. Hort. Sci. 117 422 429
Wilson, S.B., Stoffella, P.J. & Graetz, D.A. 2003 Compost amended media and irrigation system influence containerized perennial Salvia J. Amer. Soc. Hort. Sci. 128 260 268