Cowpeat as a Substitute for Peat in Container Substrates for Foliage Plant Propagation

Abstract

<jats:p>This study evaluated the potential for using cowpeat, a composted dairy manure, as a component of container substrates for foliage plant propagation. Using a commercial formulation (20% perlite and 20% vermiculite with 60% Canadian or Florida peat based on volume) as controls, peat was replaced by cowpeat at 10% increments up to 60%, which resulted in a total of 14 substrates. Physical and chemical properties such as air space, bulk density, container capacity, total porosity, pH, carbon-to-nitrogen ratio, and cation exchange capacity of the cowpeat-substituted substrates were largely similar to those of the respective control. However, the electrical conductivity (EC) increased with the increased volume of cowpeat. The 14 substrates were used for rooting single-node cuttings of golden pothos (<jats:italic>Epipremnum aureum</jats:italic>) and heartleaf philodendron (<jats:italic>Philodendron scandens</jats:italic> ssp. <jats:italic>oxycardium</jats:italic>) and three-node cuttings of ‘Florida Spire’ fig (<jats:italic>Ficus benjamina</jats:italic>) and germinating seeds of sprenger asparagus (<jats:italic>Asparagus densiflorus</jats:italic>) in a shaded greenhouse. All cuttings rooted in the 14 substrates, and the resultant shoot and root dry weights of golden pothos and ‘Florida Spire’ fig 2 months after rooting did not significantly vary across seven Canadian peat- or Florida peat-based substrates. Shoot dry weights of heartleaf philodendron were also similar across substrates, but the root dry weight produced in the Canadian peat-based control substrate was much greater than that produced in the substrate containing 60% cowpeat. Root dry weight and root length produced in the Florida peat-based control substrate were also significantly greater than those produced in substrates substituted by 60% cowpeat. These results may indicate that cuttings of golden pothos and ‘Florida Spire’ fig are more tolerant of higher EC than those of heartleaf philodendron, as the substrate with 60% cowpeat had EC ≥ 4.16 dS·m<jats:sup>−1</jats:sup>. Seed germination rates of sprenger asparagus from cowpeat-substituted Canadian peat-based substrates were greater than or comparable to those of the control substrate. Seed germination rates were similar across the seven Florida peat-based substrates. The root-to-shoot ratios of seedlings germinated from both control substrates were significantly greater than those germinated from substrates substituted by cowpeat. This difference could be partially explained by the higher nutrient content in cowpeat-substituted substrates where shoot growth was favored over root growth. Propagation is a critical stage in commercial production of containerized plants. The success in using up to 60% cowpeat in rooting and seed germination substrates may suggest that cowpeat could be an alternative to peat for foliage plant propagation.</jats:p>

Plant Performance and Nutrient Losses during Containerized Bedding Plant Production Using Composted Dairy Manure Solids as a Peat Substitute in Substrate

“…Composted dairy manure solids were generated by Agrigy Co. (Clearwater, FL) at their Lake Okeechobee facility, where dairy manure solids were screened, composted in a large rotary drum composter at temperatures up to 65°C for 3 d, and allowed to cure in static piles (Nordstedt and Sowerby, 2003). Li et al (2009) reported a pH of 6.9, an EC of 4.8 dSÁm -1 , and a C:N ratio of 15.1 for composted dairy manure solids from the same source that were received at about the same time as our material. Vermiculite and perlite were purchased from Verlite Co. (Tampa, FL) and S&B Industrial Materials (Vero Beach, FL).…”

“…Seven substrates were formulated by mixing Canadian sphagnum peat (S), Florida reed-sedge peat (R), and/or composted dairy manure solids (C) in the following ratios by volume: 1) 3S:0R:0C; 2) 0S:3R:0C; 3) 2S:0R:1C; 4) 0S:2R:1C; 5) 1S:0R:2C; 6) 0S:1R:2C; and 7) 0S:0R:3C, each with 20% vermiculite and 20% perlite. Canadian sphagnum peat was purchased from Fafard, Inc. (Apopka, FL); Li et al (2009) reported a pH of 3.9, an electrical conductivity (EC) of 0.32 dSÁm -1 , and a C:N ratio of 56.8 for Canadian sphagnum peat from the same source purchased at about the same time as our material. Florida reed-sedge peat was purchased from Reliable Peat Co. (Okahumpta, FL); Li et al (2009) reported a pH of 6.9, an EC of 0.31 dSÁm -1 , and a C:N ratio of 18.3 for Florida reed-sedge peat from the same source purchased at about the same time.…”

“…Canadian sphagnum peat was purchased from Fafard, Inc. (Apopka, FL); Li et al (2009) reported a pH of 3.9, an electrical conductivity (EC) of 0.32 dSÁm -1 , and a C:N ratio of 56.8 for Canadian sphagnum peat from the same source purchased at about the same time as our material. Florida reed-sedge peat was purchased from Reliable Peat Co. (Okahumpta, FL); Li et al (2009) reported a pH of 6.9, an EC of 0.31 dSÁm -1 , and a C:N ratio of 18.3 for Florida reed-sedge peat from the same source purchased at about the same time. Composted dairy manure solids were generated by Agrigy Co. (Clearwater, FL) at their Lake Okeechobee facility, where dairy manure solids were screened, composted in a large rotary drum composter at temperatures up to 65°C for 3 d, and allowed to cure in static piles (Nordstedt and Sowerby, 2003).…”

“…Reuse of the manure solids could significantly reduce the need for land application, which itself represents significant potential for environmental degradation as a result of leaching and runoff of nutrients when manures are broadcast over a large area (Davis et al, 1997;Elliott et al, 2002;Flavel and Murphy, 2006). Composting manure solids results in a uniform and stable product that is likely to have the physical properties necessary to support plant growth (Li et al, 2009). Mature composts provided adequate levels of available inorganic nitrogen (N) and were not phytotoxic to plants (Cogger, 2005;Hue and Sobieszczyk, 1999;Zucconi et al, 1981).…”

“…Researchers have suggested that composted dairy manure solids may be an acceptable substitute for peat in container substrate (Gorodecki and Hadar, 1990;Li et al, 2009;Wang et al, 2004). Additions of composted dairy manure to soil improved growth of maize in pots compared with an untreated loamy-sand field soil (Irshad et al, 2002).…”