Calvin Chong

Evaluation of Compost Leachates for Plant Growth in Hydroponic Culture

Abstract Compost run-off leachates are usually rich in nutrients and can potentially be recycled in plant culture. Seedlings of tomato (Lycopersicon esculentum Mill. ‘Roma VF’) and marigold (Tagetes erecta L. ‘Crackerjack’) were grown for five weeks in each of six hydroponic treatment solutions: full and half strength Hoaglands solution; leachates from spent mushroom compost (SMCL) and pond-collected runoff from a commercial composting operation (RCL); and these leachates amended with extra nitrogen (N) and phosphorus (P) (SMCL+NP and RCL+NP, respectively). The leachates were low in content of N and P, but rich in potassium (K), magnesium (Mg), calcium (Ca), sodium (Na), and various microelements. Top dry weight of tomato seedlings was highest in the two Hoaglands solutions, intermediate in RCL+NP, and lowest in the other solutions. With marigold, top dry weight in SMCL+NP was similar to that in the two Hoaglands solutions, intermediate in SMCL, and lowest in the RCL+NP and RCL solutions. The poor tomato performance on the SMCL+NP regime was the result of a high proportion of NH4-N ( < 50%), which over time lowered pH and caused nutritional disorders. Imbalance in tissue nutrient (low content of N and P and high content of K, Mg, Ca, and Na) from plants grown in the unamended SMCL and RCL solutions indicates a need to balance these nutrients in the leachates before it is recycled.

Response of Four Container Grown Woody Ornamentals to Immature Composted Media Derived from Waxed Corrugated Cardboard

Four containerized deciduous ornamental shrubs [deutzia (Deutzia gracilis L.), silverleaf dogwood (Cornus alba ‘Elegantissima’), red-osier dogwood (Cornus sericea L.), and ninebark (Physocarpus opulifolius L.)] were grown during each of two separate growing seasons using 12 different immature (nonaged) composts as media (year one, 12 weeks from start of windrowing; year two, 16-weeks) and also two control nursery mixes (100 percent ground pine bark; and 80:15:5 by volume of pine bark:sphagnum peat:top soil). The compost formulations (volume basis) consisted of spent mushroom substrate (50 percent), waxed corrugated cardboard, 0 percent, 25 percent, or 50 percent), and/or pulverized wood wastes (50 percent, 25 percent, and 0 percent). Supplemental N was added to some composts as poultry manure (18 kg·m−3), soybean wastes (24·kg·m−3), or both at the same application rates. Despite the immaturity of the compost media and the presence of high initial contents of soluble salts primarily from the spent mushroom...

Uniformity of Spent Mushroom Substrate (SMS) and Factors in Applying Recommendations for Use

SMS may be obtained from a number of locations and from crops produced in different ways. Consequently such material may be variable in terms of physical structure and chemical analysis. This is important when choosing blends of material for subsequent reuse, including recomposting. Ranges for maximum and minimum values of plant nutrient properties of fresh SMS are outlined. In particular, pH (8.2-7.3), conductivity (2,380-1,410 μS cm−1) and C:N ratio (9-15:1) each vary from sample to sample. Nitrogen availability varies both in terms of organic- and inorganic-N and in the ratio of nitrate-N to ammonium-N. This appears to be a function of duration of cropping and subsequent storage conditions.Methods for determination and interpretation of plant nutrient content of SMS are discussed. The need for greater standardisation of salt extraction procedures and presentation of published data is discussed.Changes in composting procedures and Agaricus bisporus substrate recipes demand continuing research into the b...

Response of Container-Grown Nursery Crops to Raw and Composted Paper Mill Sludges

Growth and nutrient uptake of three container grown nursery crops were compared using different potting media, including bark mixed with varying amounts, 0, 33, 67, and 100% by volume, of raw paper mill sludge and Phase I (fresh) and Phase II (aged) sludge composts. Species grown were: Tartarian dogwood (Cornus alba L.), Coral Beauty cotoneaster (Cotoneaster dammeri C. K. Schneid.), and Variegata Nana weigela [Weigela florida (Bunge) A.DC.]. Each compost consisted of ca. 40% paper mill sludge. Despite differences in response of species to the amount and source of sludge, plants grew well in media containing Phase I and II composts and produced plants of marketable size at harvest. Media with >33% raw sludge resulted in fewer marketable plants and had a greater volume reduction with increasing amounts of sludge. This was also accompanied by declining shoot and root dry weight. Media containing Phase I compost showed less volume reduction than those with raw sludge, and yielded growth comparable to that obt...

Variability of Soluble Salts Using Different Extraction Methods on Composts And Other Substrates

Soluble salts represent dissolved inorganic ions in solution and are typically measured in terms of electrical conductivity (EC). Often soluble salt measurements from different studies or laboratories cannot be cross-referenced or there is much confusion when comparing these results. The soluble salts from 13 composts and horticultural substrate materials were extracted using six different methods: saturated medium extract; pour-through, a water displacement method; and water suspensions using various ratios (by volume) of water:substrate (1:1, 1:2, 2;1, 5:1). EC ranged from 0.1 (peat and perlite) to 23.1 dS m−1 (turkey litter compost). A linear regression model was developed to allow cross-referencing between extraction methods of measurements of soluble salts concentration of the composts and substrates.

Characteristics of Composts Derived from Waxed Corrugated Cardboard

The characteristics of 12 composts containing, by volume, spent mushroom substrate (SMS, 50 percent), waste waxed corrugated cardboard (WCC, 0 percent, 25 percent or 50 percent), and/or pulverized wood wastes (WW, 50 percent, 25 percent or 0 percent) were measured during two separate windrow composting periods (12-16 weeks). Supplemental N was added to some of the composts in the form of poultry manure, and/or soybean processing wastes. During the first eight to 10 weeks, composts containing 50 percent WCC tended to reach and maintain the highest temperatures, but subsequently cooled most rapidly. Microbial activity (CO2 evolution) also was initially highest in these composts but fell by the twelfth week to levels comparable to composts containing lower levels of WCC. The paraffin wax in WCC containing composts was almost completely degraded (>95 percent). After 12 weeks of composting N (1.2-1.6 percent DW), P (0.30-0.55 percent), and K (0.9-1.2 percent) concentrations were within typical ranges and N and...

Relationship of Soluble Salts Content in MSW Compost Media and Rooting of Evergreen Cuttings

Municipal solid waste (MSW) compost media with various levels of soluble salts were used for rooting stem cuttings of nine evergreen landscape shrubs: Buxus sempervirens L. ‘Green Gem’; Juniperus chinensis L. ‘Hetzii; J. chinensis ‘Mint Julep’; J. chinensis ‘Pfitzeriana Aurea’; J. horizontalis Moench ‘Bar Harbor’; J. horizontalis ‘Blue Chip’; J. sabina L. ‘Blue Danube’; Taxus x media Rehd. ‘Densiformis’; and Thuja occidentalis L. Rooting occurred during the winter in greenhouse compartments supplied with bottom-heated benches filled with 100% sphagnum peat or 100% perlite, or peat or perlite mixed with 15, 30, 45, 60 or 75% by volume of MSW compost. The electrical conductivity (salt) levels were similar in MSW compost with peat or with perlite (range, 0.05-0.60 dS·m−1 with 0-75% compost) and positively correlated with levels of MSW (r = 0.88, P≤0.001). With few exceptions, cuttings rooted similarly in MSW with peat or perlite. Depending on taxa, increasing salt levels had various degrees of diminutive, neutral, and enhancing effect on rooting response, expressed in terms of percent rooting, root number per cutting, and root length (longest root per cutting). Four taxa (J. horizontalis ‘Bar Harbor’ and ‘Blue Chip’, J. sabina ‘Blue Danube’, and T. occidentalis) were tolerant of the salt levels tested (positively influenced or unaffected). The other five taxa were intolerant (adversely affected).

Evaluation of Compost Leachate for Growing Nursery Trees on a Waste-Rehabilitated Field Site

Compost run-off leachates are potential sources of irrigation water and nutrients. The objective of this study was to evaluate and compare growth response between nursery tree species irrigated with pond-collected compost leachate. Leachate was deficient in nitrogen (NO3 -N < 0.02 mg L−1) and phosphorus (0.40 mg P L−1) and excess in potassium (316 mg K L−1) also slight to moderate excess in sodium (138 mg Na L−1. One- or two-year-old seedling whips of black locust (Robinia pseudoacacia L.), Carolina poplar (Populus x canadensis Moench), green ash (Fraxinus pennsylvanica March), hybrid poplar (Populus angulata x nigra L. var. plantierensis (Simon-Louis) Schneid.)] and silver maple (Acer saccharinum L.), and 2-year-old whips of hybrid poplar grown from hardwood cuttings, were planted in a field site rehabilitated with various organic wastes (wood chips, corrugated cardboard, and spent mushroom substrate-derived compost.) During each of two growing seasons (1998 and 1999), the leachates were applied 2-3 times weekly at two rates: Irrig I -fulfill crop water requirements with a 5% leaching fraction, i.e. about 12 L m−2, and Irrig II with a leaching fraction of 20%, i.e. 17 L m−2. There were also unirrigated (control) plots. All plots were fertilized with two levels of combined N and P fertilizer, 100 kg N+ 44 kg P ha−1 (1 NP) and 200 kg N + 88 kg P ha−1 (2 NP). Trunk diameter of all taxa and height of some taxa increased due to wastewater irrigation but there was no influence to application rates. With few exceptions, trunk diameter and tree height were larger with the higher NP application. Sodium accumulated consistently in leaves of all taxa due to irrigation treatments but the highest concentrations of 1.25 mg g−1 were below recommended toxic values (<2.5 mg g−1). Other foliar nutrients (N, P, K, Ca and Mg) showed inconsistent, little, or no accumulation, due to leachate irrigation and/or NP fertilizer. Throughout the study, there was no visual sign of nutrient toxicity or deficiency.

Rooting of Deciduous Woody Stem Cuttings in Peat- and Perlite-amended MSW Compost Media

Terminal stem cuttings of seven deciduous woody taxa [coralberry (Symphoricarpos × chenaultii Rehd. ‘Hancock’), snowberry (Symphoricarpos albus (L.) S.F. Blake), European cranberry bush (Viburnum opulus L.), lilac (Syringa velutina Kom.), purple osier (Salix purpurea L. ‘Nana’), purple-leaf sandcherry (Prunus × cistena N.E. Hansen), and winged spindle-tree (Euonymus alata (Thunb.) Siebold. ‘Compacta’)] were rooted under outdoor lath (50% shade) and mist in rooting media consisting of 0, 15, 30, 45, 60, and 75% by volume of MSW compost mixed with sphagnum peat or perlite. Rooting performance, expressed in terms of percent rooting, mean root number per rooted cutting, and length of the longest root per cutting, was regressed on level of compost. When there were differences due to amendments, most taxa rooted better with perlite than with peat due largely to more favourable water (36-50%) and air (16-26%) porosities with perlite than with peat (water, 60-60%; air, 12-15%). Cranberry bush, an exception, roote...

Paper Mill Waste Mixed with Compost and Other Ingredients as Container Nursery Substrates

Growth performance of container-grown dogwood (Cornus alba L. ‘Sibirica’), forsythia (Forsythia x intermedia Zab ‘Lynwood’), ninebark (Physocarpus opulifolius L.), and weigela (Weigela florida (Bunge) A. DC. ‘Variegata Nana’) were evaluated in 20 waste-derived substrates classified into five groups. Each group had 0, 20, 40 or 60% (by volume) of paper mill biosolids in binary mixtures with bark (PB group), tertiary mixtures with topsoil and sand (PTS group), and quaternary mixtures with bark, topsoil and sand (PBTS group). There were also similar binary and quaternary mixtures with compost instead of bark (PC and PCTS groups, respectively). With few exceptions, top dry weights of all four species increased (linear or curvilinear responses) with increasing rate of biosolids, and were higher in the compost-amended PC and PCTS (forsythia, 72-99 g/plant, range over all rates of biosolids; ninebark, 97-116; dogwood, 45-60; and weigela, 18-25) than in bark-amended PB and PBTS (forsythia, 26-71; ninebark, 32-80; dogwood, 33-56; and weigela, 7.7-18) substrates. Top dry weights in a control nursery mix (80:15:5 by vol bark:peat:topsoil) used by nurseries were: forsythia, 70; ninebark, 110; dogwood, 51; and weigela, 48. While none of the weigela plants attained size comparable to that of the control, top dry weights of other species reached or exceeded their control counterparts in PC and PCTS substrates over most or all rates of biosolids (all species); in PB and PBTS with 40-60% of biosolids (forsythia and dogwood); and in PTS with the highest rate of biosolids(forsythia, 91; and ninebark, 140). Higher retention of nutrients in the substrates and/or more favorable bulk densities and air-filled porosities, primarily due to the biosolids, contributed to increased growth and/or foliar nutrient status of the plants.