A pot experiment with summer cover crops and soil amendments was conducted in two consecutive years to elucidate the effects of these cover crops and soil amendments on `Clemson Spineless 80' okra (Abelmoschus esculentus) yields and biomass production, and the uptake and distribution of soil nutrients and trace elements. The cover crops were sunn hemp (Crotalaria juncea), cowpea (Vigna unguiculata), velvetbean (Mucuna deeringiana), and sorghum sudangrass (Sorghum bicolor × S. bicolor var. sudanense) with fallow as the control. The organic soil amendments were biosolids (sediment from wastewater plants), N-Viro Soil (a mixture of biosolids and coal ash, coal ash (a combustion by-product from power plants), co-compost (a mixture of 3 biosolids: 7 yard waste), and yard waste compost (mainly from leaves and branches of trees and shrubs, and grass clippings) with a soil-incorporated cover crop as the control. As a subsequent vegetable crop, okra was grown after the cover crops, alone or together with the organic soil amendments, had been incorporated. All of the cover crops, except sorghum sudangrass in 2002-03, significantly improved okra fruit yields and the total biomass production (i.e., fruit yields were enhanced by 53% to 62% in 2002-03 and by 28% to 70% in 2003-04). Soil amendments enhanced okra fruit yields from 38.3 to 81.0 g/pot vs. 27.4 g/pot in the control in 2002-03, and from 59.9 to 124.3 g/pot vs. 52.3 g/pot in the control in 2003-04. Both cover crops and soil amendments can substantially improve nutrient uptake and distribution. Among cover crop treatments, sunn hemp showed promising improvement in concentrations of calcium (Ca), zinc (Zn), copper (Cu), iron (Fe), boron (B), and molybdenum (Mo) in fruit; magnesium (Mg), Zn, Cu, and Mo in shoots; and Mo in roots of okra. Among soil amendments, biosolids had a significant influence on most nutrients by increasing the concentrations of Zn, Cu, Fe, and Mo in the fruit; Mg, Zn, Cu, and Mo in the shoot; and Mg, Zn, and Mo in the root. Concentrations of the trace metal cadmium (Cd) were not increased significantly in either okra fruit, shoot, or root by application of these cover crops or soil amendments, but the lead (Pb) concentration was increased in the fruit by application of a high rate (205 g/pot) of biosolids. These results suggest that cover crops and appropriate amounts of soil amendments can be used to improve soil fertility and okra yield without adverse environmental effects or risk of contamination of the fruit. Further field studies will be required to confirm these findings.
Qingren Wang, Yuncong Li and Waldemar Klassen
George E. Fitzpatrick and Stephen D. Verkade
Three compost products made from urban waste materials, municipal solid waste (MSW), yard trash (YT), and a co-compost made from 1 part sewage sludge and 3 parts yard trash (S-YT), were used as growing media for production of dwarf oleander (Nerium oleander L.) in 25 cm. diameter containers. In one test the composts were used as stand-alone growing media and in a second test they were blended with pine bark (PB) and sand (S) in 2 ratios: 4 compost: 5 PB: 1 S and 1 compost: 1 PB: 1 S. The S-YT co-compost produced plants with the highest biomass in both tests. Reduced growth of dwarf oleander in each test was associated with the degree to which the media compacted during the 5.5 month production period. The MSW compost compacted an average 8.5 cm. per container when used as a stand-alone medium, while the S-YT mixes compacted much less, typically < 4.0 cm.
Garrett Goyette and Wallace Pill
The utility of Ironrich (IR), a tertiary mineral co-product from TiO2 production, as a growth medium component was investigated. All complementary bulking components (10 to 50% volume) gave reduced shoot fresh weights of tomato, impatiens or perennial ryegrass relative to Fairgrow (FG, co-composted solid waste and sewage sludge). Shoot fresh weights of impatiens and tomato grown in 50% IR with FG were similar to those grown in commercial peat-lites. When provided 200 mg N litre-1 daily, chard shoot fresh weights, beet root fresh weights, and tomato fruit fresh weights from plants grown in 50% IR plus 50% FG were not significantly different from those grown in 50% silt loam plus 50% FG. Tissue Cd, Cr, Ni, and Pb concentrations from plants grown in 50% combinations of FG with IR or silt loam were below the limits of detection. IR plus FG with N-P-K fertilization provided a satisfactory greenhouse growth medium. We project that IR + FG will constitute a satisfactory synthetic topsoil.
David Devenney, John Frett, Wallace Pill and Gary Smith.
Ten 10 wildflower species grew satisfactorily in a 1:1 (vol.) mix of Ironrich (IR, mineral co-product of the titanium dioxide industry) and Fairgrow (FG, co-composted sewage sludge and solid waste). Shoot fresh weights in the low fertility IR and in the high fertility FG averaged 35% and 157%, respectively, those grown in IR+FG. Wildflower establishment in 10cm-deep outdoor seedbeds of IR, FG, or IR+FG were compared to those in soil (control) plots. Maximum percentage seedling emergence and emergence rate and synchrony were lower in FG than in IR, values in IR+FG being intermediate and similar to those for control plots. Shoot fresh weights, however, were greater from the IR+FG than from IR, FG or the control plots. Total shoot dry weights of wildflowers from 1 m2 subplots after 3 months were FG > IR = IR+FG > control, being respectively 8.4, 8.5, 5.1 and 1.1% those of total shoot dry weights of weeds.
Catherine S.M. Ku, John C. Bouwkamp and Frank R. Gouin
Treatment combinations of four cultivars, 26 mixes, and three fertigation treatments were evaluated in a completely randomized design. Poinsettia cultivars included `V-14 Glory', `Red Sails', `Lilo Pink', and `Annette Hegg'. The 26 mixes were 25%, 33%, and 50% of eight compost sources blended with 1 peat: 1 perlite (v/v), and Sunshine mix and Pro-Gro were the control. The eight compost sources were yard waste, lime and polymer dewatered biosolid, municipal solid waste (MSW), co-composted MSW 1 and 2, crab waste, and poultry litter. Fertigation treatment was began on first, second, or third week after potting. Fertigation solution was 250 mg/L N from 21N–2.2P–15.8K. The controls produced premium quality plants with 38 cm in canopy diameter, 11 total number of branches, and 28 cm in shoot height. Poultry litter, yard waste, polymer dewatered biosolid, crab waste, and MSW produced good quality plants with canopy diameter ranging from 30 to 35 cm. The canopy diameter with 25% compost treatments were 6% to 20% greater than those with 50% compost treatments. Total number of branches, shoot height, canopy diameter, and plant grade with first week fertigation were only 3% greater than those with fertigation delayed 1 or 2 weeks.
Compost is organic matter that has undergone partial thermophilic, aerobic decomposition. This environmentally safe process is called composting. The combination of raw materials and the chosen composting method yields a wide range of characteristics, such as organic matter (OM) content, nutrient content, potential for disease suppressiveness and other physical, chemical, and biological properties. The objectives of this review are describing the horticultural outlets for composts, defining compost characteristics important for the above uses, and describing composting procedures and raw materials leading to these characteristics. The two main horticultural uses of composts are as soil amendment and as an ingredient in container media. Soil-applied composts improve soil fertility mainly by increasing soil organic matter (SOM) that activates soil biota. Compost's nutrient content, and especially that of nitrogen (N), should be high (>1.8%). Composts having these characteristics are produced of raw materials rich in both OM and N, while minimizing their loss during composting. Typical raw materials for this purpose include animal manures, offal, abattoir residues, sewage sludge, and grass clippings. Various composting methods can yield the required results, including turned windrows, aerated static piles, and in-vessel composting. Composts are also used for substrates as low-cost peat substitute, potentially suppressive against various soilborne diseases. These composts must be stable and non-phytotoxic. Physical properties of compost used as substrate are important. Hydraulic conductivity, air porosity, and available water should be high. Reconciling the physical and biological demands may be difficult. Materials such as softwood bark, wood shavings, various types of shells or hulls, and coconut coir are characterized by good physical properties after composting. However, being relatively resistant to decomposition, these materials should be subjected to long and well-controlled composting, which may be shortened using N and N-rich organic matter such as animal manures. High temperatures [>65 °C (149.0 °F)] may cause ashing, which leads to reduced porosity. In addition to ligneous materials, composts serving as growing media may be produced from numerous organic wastes, such as manures, food industry wastes, etc. These materials are better composted in aerated static piles, which tend to minimize physical breakdown. Animal excreta are of special value for co-composting as they contain large, diverse populations of microorganisms, which accelerate the process.
M. Ozores-Hampton, H.H. Bryan, B. Schaffer and E.A. Hanlon
The effects of municipal solid waste (MSW) materials on growth, yield, and mineral element concentrations in tomato (Lycopersicon esculentum Mill.) (1991 and 1992) and squash (Cucurbita maxima Duch. Ex Lam.) (1992 and 1993) were evaluated. Agrisoil compost (composted trash), Eweson compost (co-composted trash and sewage sludge), or Daorganite sludge (chemically and heat-treated sewage sludge) were incorporated into calcareous limestone soil of southern Florida. The control had no MSW material added to the soil. The effect of MSW on crop growth, yield, and mineral element concentrations varied considerably between years for tomato and squash. In 1991, tomato plants grown in soil amended with Eweson or Daorganite had a greater canopy volume than plants in the control treatment. Tomato plants grown in Daorganite had greater total fruit weight (1991) than plants in Agrisoil and more marketable fruit (1992) than control plants. In both years, tomato plants in Agrisoil had higher root Zn concentrations than plants in the other treatments. In 1992, tomato plants in Eweson had lower root Mn concentrations than plants in the other treatments, whereas Mg concentrations in the roots were higher in the Daorganite treatment than in Eweson. Tomato plants in Agrisoil had higher Pb concentrations in the roots than plants in all other treatments. In 1991, leaves of tomato plants in Agrisoil had lower Ca concentrations than leaves of plants in the control treatment. In 1992, leaf Zn concentrations were greater for tomato and squash in Agrisoil than in the control or Daorganite. In 1992, canopy volume and yield of squash were greater for plants in Daorganite than for plants in the control and other MSW treatments. Although canopy volume and total squash fruit weight did not differ among treatments in 1993, plant height was greater for squash plants in the MSW treatments than for those in the control. In 1993, leaf Mg concentrations were greater for squash grown in Daorganite than for plants in the control or Agrisoil. In 1993, fruit Cd concentration was higher for plants with Eweson than for plants in the control or Agrisoil. However, the fruit Cd concentration in squash grown in Eweson compost (1.0 mg/kg dry weight) was far below a hazardous level for human consumption. Our results indicate that amending calcareous soils with MSW materials can increase growth and yield of tomato and squash with negligible increases in heavy metal concentrations in fruit.
Nikolaos Ntoulas, Panayiotis A. Nektarios and Glykeria Gogoula
ameliorate the OMWW pollutant load ( Ehaliotis et al., 1999 ). Of these techniques, the most promising bioremediation technique is the co-composting of the solid and liquid residues of the olive mill processes ( Flouri et al., 1990 ; Mari et al., 2003
Ronnie W. Schnell, Donald M. Vietor, Richard H. White, Tony L. Provin and Clyde L. Munster
.E. Purcell, L.C. 2001 Quantifying turfgrass cover using digital image analysis Crop Sci. 41 1884 1888 Sims, J.T. 1990 Nitrogen mineralization and elemental availability in soils amended with Co-composted sewage sludge J. Environ. Qual. 19 669 675 Vietor, D
Nikolaos Ntoulas, Panayiotis A. Nektarios, Thomais-Evelina Kapsali, Maria-Pinelopi Kaltsidi, Liebao Han and Shuxia Yin
OMWC and was produced from co-composting olive stones, olive leaves, and olive mill wastewater (Biocyclic Compost; Samira Eisenbach, Kalamata, Greece). Peat was a Lithuanian sphagnum peat with a corrected pH of 5.5 and served as a control. Physical and