Phytotoxicity evaluation and response of wheat to agro-industrial waste composts

A greenhouse experiment was conducted in loamy sand soil to compare the effects of agro-industrial waste composts on yield and nutrient uptake by wheat. The raw materials of agro-industrial wastes and chemical fertilizers were used as controls. The yields were significantly higher with agro-industrial waste composts compared with their raw materials. Compost-fertilized grain yields were increased by 118% with poultry waste compost and by 97% with chemical fertilizes compared with unfertilized control. Agro-industrial waste composts applied with NK (recommended dose) fertilizers, except distillery effluent compost, produced a wheat grain yield comparable with that obtained with NPK (recommended dose) fertilizers, indicating a net saving of 100% of P fertilizer. Application of agro-industrial waste composts significantly increased NPK uptake by wheat and improved the post-harvest NPK status of soil compared with addition of their raw materials. Up to 60 days of composting, severe suppression of tomato seed germination was observed, which improved thereafter in all the composts. Our results suggest that the germination index >70% may be accepted as an indicator for disappearance of phytotoxic substances.     

Effects of fungivorous nematodes on corky root disease of tomato grown in compost-amended soil

Abstract

The effect of fungivorous nematodes, Aphelenchus avenae and Aphelenchoides spp., against corky root disease of tomato caused by Pyrenochaeta lycopersici was investigated. Three different greenhouse trials were conducted using soil naturally infested with P. lycopersici, alone or mixed with four different types of compost consisting of green manure, garden waste and horse manure (20% compost by volume). The fungivorous nematodes were propagated in cultures of the fungus Pochonia bulbillosa and inoculated (3 or 23 nematodes ml^?1 substrate) into the soil and soil-compost mixtures one day after transplanting of tomato seedlings. Greenhouse experiments were terminated after ten weeks and disease was measured from infected roots after harvesting. Aphelenchus avenae significantly reduced the disease severity when added to infested soil without compost in all experiments. Aphelenchoides spp. did not suppress the disease either in the presence or absence of compost. Among the composts tested, only a garden waste compost was found to be suppressive to the disease. Neither A. avenae nor Aphelenchoides spp. improved the suppressive effect of the compost.     

Effects of aeration and moisture during windrow composting on the nitrogen fertilizer values of dairy waste composts

The objective of this work was to evaluate the effects of turning and moisture addition during windrow composting on the N fertilizer values of dairy waste composts. Composted-dairy wastes were sampled from windrow piles, which received four treatments in a 2×2 factorial of turning (turning vs. no turning) and moisture addition (watering vs. no watering) at two stages of maturity (mature vs. immature). Composts were characterized for their chemical properties. An 84-day laboratory incubation of soils with addition of the composts at two levels was conducted to evaluate the inorganic N accumulation patterns from the variously treated composts. Chemical analyses of variously treated composts did not differ between compost treatments or maturity. In contrast, the inorganic N accumulation patterns differed between soils that received immature versus mature turned composted-dairy wastes. The results suggested that turning was a more important factor than moisture addition affecting the composting process. There was no significant difference in inorganic N accumulation patterns among soils that received different immature composts, while the N accumulation patterns observed for soils that received different mature composts depended on compost treatments. Soils amended with mature composts treated by frequent turning had higher N mineralization potentials (N₀), mineralization rate constants (K), and initial potential rates (N₀K) in comparison to soils with composts that had not been turned. Soils with mature composts treated by watering had a higher N₀, lower K, and therefore similar N₀K when compared to soils with composts that had not been watered. Soils that received mature composts treated by watering and frequent turning had higher N mineralization potentials and N₀ to total organic N ratios than soil alone, which suggested that intensive management of composting would ensure positive N fertilizer values of dairy waste composts, if the appropriate composting duration is completed.     

Application rate and composting method affect the immediate and residual manure fertilizer value in a maize–rice–rice–maize cropping sequence on a degraded soil in northern Vietnam

A field experiment was carried out in northern Vietnam to investigate the effects of adding different additives [rice (Oriza sativa L.) straw only, or rice straw with added lime, superphosphate (SSP), urea or a mixture of selected microorganism species] on nitrogen (N) losses and nutrient concentrations in manure composts. The composts and fresh manure were applied to a three-crop per year sequence (maize–rice–rice) on a degraded soil (Plinthic Acrisol/Plinthaquult) to investigate the effects of manure type on crop yield, N uptake and fertilizer value. Total N losses during composting with SSP were 20% of initial total N, while with other additives they were 30–35%. With SSP as a compost additive, 65–85% of the initial ammonium-N (NH₄-N) in the manure remained in the compost compared with 25% for microorganisms and 30% for lime. Nitrogen uptake efficiency (NUE) of fresh manure was lower than that of composted manure when applied to maize (Zea mays L.), but higher when applied to rice (Oriza sativa L.). The NUE of compost with SSP was generally higher than that of compost with straw only and lime. The mineral fertilizer equivalent (MFE) of manure types for maize decreased in the order: manure composted with SSP?>?manure composted with straw only and fresh manure?>?manure composted with lime. For rice, the corresponding order was: fresh manure?>?manure composted with SSP/microorganisms/urea?>?manure composted with lime/with straw alone. The MFE was higher when 5 tons manure ha^?1 were applied than when 10 tons manure ha^?1 were applied throughout the crop sequence. The residual effect of composted manures (determined in a fourth crop, with no manure applied) was generally 50% higher than that of fresh manure after one year of manure and compost application. Thus, addition of SSP during composting improved the field fertilizer value of composted pig manure the most.     

Characterization and Evaluation of Compost Utilized as Ornamental Plant Substrate

Two composts produced at different times of the year from garden waste, sewage sludge and wood ash were evaluated for use as ornamental plant substrates. The maturity and lack of phytotoxicity of both composts, as well as the absence of E. coli, were first confirmed by use of laboratory procedures and rapid test kits. A greenhouse experiment was then carried out with two ornamental species, Petunia sp. and Tagetes sp., to evaluate the suitability of the composts as plant substrates. The performance of the composts as well as mixtures of each with 25, 50 and 75% acid peat moss was compared with that of a commercial universal substrate. Addition of the peat to the composts improved some of the physical and chemical properties. However, the results of the pot experiments indicated that under the experimental conditions used, the compost produced from green waste was suitable for use as a plant substrate, without the need for addition of other components; this appears to be an effective way of utilizing the type of urban waste considered in the study.     

Soil Physical Properties and Organic Matter Fractions Under Forages Receiving Composts,Manure or Fertilizer

A field study was conducted to assess the benefits, with respect to soil physical properties and soil organic matter fractions of utilizing composts from a diversity of sources in perennial forage production. A mixed forage (timothy-red clover (Trifolium pratense L.) and monocrop timothy (Phleum pratense L.) sward were fertilized annually with ammonium nitrate (AN) at up to 150kg and 300 N ha^?1 yr^?1, respectively, from 1998-2001. Organic amendments, applied at up to 600 kg N ha^?1 yr^?1 in the first two years only, included composts derived from crop residue (CSC), dairy manure (DMC) or sewage sludge (SSLC), plus liquid dairy manure (DM), and supplied C to soil at 4.6 and 9.2 (CSC), 10.9 (SSLC), 10.0 (DMC) 2.9 (DM) Mg C ha^?1. Soil samples (0-5cm; 5-10cm;10-15cm) were recovered in 2000 and 2001. Improvements in soil physical properties (soil bulk density and water content) were obtained for compost treatments alone. Composts alone influenced soil C:N ratio and substantially increased soil organic carbon (SOC) concentration and mass (+ 5.2 to + 9.7 Mg C ha^?1). Gains in SOC with AN of 2.7 Mg C ha^?1 were detectable by the third crop production year (2001). The lower C inputs, and more labile C, supplied by manure (DM) was reflected in reduced SOC gains (+ 2.5 Mg C ha^?1) compared to composts. The distribution of C in densiometric (light fraction, LF; >1.7 g cm^?3) and particulate organic matter (POM; litter (>2000μm); coarse-sand (250-2000μm); fine-sand (53-250μm) fractions varied with compost and combining fractionation by size and density improved interpretation of compost dynamics in soil. Combined POM accounted for 82.6% of SOC gains with composts. Estimated compost turnover rates (k) ranged from 0.06 (CSC) to 0.09 yr^?1 (DMC). Composts alone increased soil microbial biomass carbon (SMB-C) concentration (μg C g^?1 soil). Soil available C (C_ext) decreased significantly as compost maturity increased. For some composts (CSC), timothy yields matched those obtained with AN, and SOC gains were derived from both applied-C and increased crop residue-C returns to soil. A trend towards improved C returns across all treatments was apparent for the mixed crop. Matching composts of varying quality with the appropriate (legume/nonlegume) target crop will be critical to promoting soil C gains from compost use.     

MSW Compost Reduces Nitrogen Volatilization During Dairy Manure Composting

Manures lose N through volatilization almost immediately after deposit. Attempts to control losses include the addition of a C source to stimulate nitrogen immobilization. Composting is a treatment process that recommends the addition of carbonaceous materials to achieve a C:N ratio of 30:1 to stimulate degradation and immobilize nitrogen. Dairies near cities may be able to reduce N loss from manures by composting with urban carbonaceous residues such as municipal solid waste (MSW) or MSW compost that, by themselves, have little agronomic value. Studies were conducted using a self-heating laboratory composter where dairy solids were mixed with MSW compost to determine the reduction of N loss during composting. One-to-one mixtures (v/v) of dairy manure solids and MSW compost were composted and NH₃ volatilization, CO₂ evolution and temperatures were compared to composting of manure alone. Addition of MSW compost resulted in increased CO₂ evolution and reduced N loss. Nitrogen loss from composting dairy manure alone was four to ten times greater than that from composting dairy manure mixed with MSW compost. Adjustment of the C:N ratio to 25 by adding MSW compost to manure appeared to be the major factor in reducing N losses.     

Long-term effects of compost amendment of soil on functional and structural diversity and microbial activity

We studied the effects of applying different composts (urban organic waste, green waste, manure and sewage sludge), mineral fertilizer and compost plus mineral fertilizer on chemical, biological and soil microbiological parameters over a 12‐year period. The organic C and total N levels in soils were increased by all compost and compost + N treatments. Microbial biomass C was significantly (P ≤ 0.05) increased for some compost treatments. In addition, basal respiration and the metabolic quotient (qCO₂) were significantly higher in all soils that had received sewage sludge compost. The Shannon diversity index (H), based on community level physiological profiling, showed a higher consumption of carbon sources in soils treated with compost and compost + N compared with the control. The utilization of different guilds of carbon sources varied amongst the treatments (compost, compost + N or mineral fertilizer). Cluster analysis of polymerase chain reaction‐denaturing gradient gel electrophoresis patterns showed two major clusters, the first containing the mineral fertilization and compost treatments, and the second, the composts + N treatments. No differences in bacterial community structure could be determined between the different types of compost. However, the results suggest that long‐term compost treatments do have effects on the soil biota. The results indicate that the effects on the qCO₂ may be due to shifts in community composition. In this study, it was not possible to distinguish with certainty between the effects of different composts except for compost derived from sewage sludge.     

Suppression of Strawberry Root Disease with Animal Manure Composts

Compost has been suggested as a nonchemical alternative to methyl bromide (MeBr) for control of root diseases. Its widespread availability and soil improvement properties are appealing to growers, but they need information on its use and effectiveness relative to the control of economically important root diseases in specific crops. Here, we report results from controlled-environment pot studies on the effects of manure composts on two major soilborne diseases of strawberry: red stele (RS) caused by Phythophthora fragariae, and black root rot (BRR), caused by a complex of fungi. Commercially available, on-farm-produced composts, based on either poultry/steer or dairy manure, were incorporated into two different, naturally infested soils at 5, 10, and 20% rates (v/v). Results show that significant control (36-79%) of RS in susceptible cultivar ‘Chandler’ occurred at all rates and with both types of compost in comparison with the unamended soil. Low rates (5%) of poultry/steer manure compost produced more disease control than equivalent or greater rates (10% and 20%) of dairy manure compost. However, the 20% rate had significantly greater soluble salts content than all other rates. At this 20% rate, root/shoot biomass accumulation and shoot health ratings were relatively low and equivalent to those from unamended soil, despite the improved content of soil organic matter, cation exchange capacity, and soil micronutrient content. The 5% amendment rate of poultry/steer manure compost provided more control than the 10% or 20% rates and more than the 5-20% rates of dairy manure compost. Soluble salts content in amended soils was significantly greater than in unamended soils, especially at 20% rates of poultry/steer compost. Leaf N from all treatments was deficient despite additional weekly supplemental fertilization. This deficiency coupled with increased soluble salt content at 20% poultry/steer compost amendments likely contributed to reduced root/shoot biomass accumulation and overall reduced plant vigor, thus increasing plant susceptibility to disease. In contrast to RS, BRR in all compost treatments was moderate in intensity and equivalent to the unamended soil, with slight but insignificant control at 5 and 10% rates of poultry/steer compost. Overall effects of the two manure compost amendments on BRR were inconclusive because no treatments, including the soil only, exhibited roots with extensive disease symptoms, despite cultural evidence of BRR pathogen colonization, especially by Rhizoctonia fragariae, during the course of this pot study. Effects of compost on appearance of BRR in strawberry should be pursued over a significantly longer time period than used here, possibly in field plots located on naturally infested soils subject to environmental stressors and seasonally realistic fertilization rates, because major BRR symptoms do not appear in the short-term even when fungal pathogens are present in the root.     

Nitrogen and Phosphorus Availability in Groundfish Waste and Chitin-Sludge Cocomposts

Seafood processing generates a substantial volume of wastes. This study examined the feasibility of converting the fish waste into useful fertilizer by composting. Groundfish waste and chitin sludge generated from the production of chitin were composted with red alder or a mixture of western hemlock and Douglas-fir sawdust to produce four composts: alder with groundfish waste (AGF); hemlock/fir with groundfish waste (HGF); alder with chitin sludge (ACS); and hemlock/fir with chitin sludge (HCS). The resulting AGF had a higher total N and a lower C:N ratio than the other three composts. A large portion of the total N in the AGF, HGF, and HCS composts was in inorganic forms (NH₄⁺-N and NO₃^?-N), as opposed to only two percent in the ACS compost. Alder sawdust is more quickly decomposed, which favored N retention and limited nitrification during the composting period. It was less favorable than the hemlock/Douglas fir sawdust for composting with chitin sludge. Corn growth on soil amended with compost was dependent upon both compost type and rate. Nitrogen and P availabilities in all composts except the ACS were high and compost addition enhanced corn yields, tissue N and P concentrations, and N and P up-take. Neither the total N concentration nor the C:N ratio of the composts was an effective measure of compost N availability in the soil. Because soil inorganic N test levels correlated well with the corn biomass, tissue N and N uptake, they should be an effective measure of the overall compost effects on soil N availability and corn growth response. Phosphorus concentration, which increased linearly with increasing compost rates, was related to soil P availability from compost additions and correlated well with corn biomass, tissue P concentration and P uptake under uniform treatments of N and K fertilizers. Composting groundfish waste with alder or hemlock/Douglas-fir sawdust can produce composts with sufficient amounts of available N and P to promote plant growth and is considered to be a viable approach for recycling and utilizing groundfish waste.     

Effects of Amendment of Calcimagnesic Soils With Olive Husk Compost In Tunisia

The amounts of olive husks produced in Mediterranean countries are very significant. Their treatment and disposal are becoming serious environmental problems. Increasing attention has been paid to finding a use for olive husks. A technological treatment is available to reduce their pollutant effects and to transform them into valuable products. The most suitable procedures are recycling instead of the detoxification of these wastes. It is possible to transform olive husks into organic fertilizers (composts) by composting with poultry manure. The compost has no phytotoxicity and may improve soil fertility and plant production. The composting process involves the microbial degradation of the polluting load of the solid wastes. Results of experiments using olive husk composts in crop production have shown that yields obtained with organic fertilization are similar, and sometimes higher, than those obtained with classic manure. Their bioavailability may be linked to the soil humic complexes originated by these organic fertilizers and to mineral components (active lime and clay). The composition of vegetable leaves improved similitude between compost and manure, normal concentrations but with deficiency in nitrogen, phosphorus and potassium.     

Recycling of Two-Phase Olive-Mill Cake “Alperujo” by Co-composting with Animal Manures

The use of poultry manure or goat/sheep manure in the co-composting of the two-phase olive-mill cake “alperujo” (ALP) with olive leaf (OL) is compared by studying organic-matter mineralization and humification processes during composting and the characteristics of the end products. For this, two different piles (P1 and P2) were prepared using ALP with OL mixed with poultry manure (PM) and goat/sheep manure (GSM), respectively, and composted by the turned windrow composting system. Throughout the composting process, a number of parameters were monitored, such as temperature, pH, electrical conductivity (EC), organic matter (OM), OM losses, total organic carbon (C_org), total nitrogen (N_t), C_org/N_t ratio, and the germination index (GI). In both piles, the temperature exceeded 55 °C for more than 2 weeks, which ensured maximum pathogen reduction. Organic-matter losses followed a first-order kinetic equation in both piles. The final composts presented a stabilized OM and absence of phytotoxins, as observed in the evolution and final values of the C_org/N_t ratio (C_org/N_t < 20) and the germination index (GI > 50 percent). Therefore, composting can be considered as an efficient treatment to recycle this type of waste, obtaining composts with suitable properties that can be safely used in agriculture.     

Evaluation of maturity of poultry manure compost by phospholipid fatty acids analysis

To study the influence of the physical properties of compost feedstock on some characteristics associated with maturity, two types of compost were made from poultry manure, rice husk, and rice bran. The bulk density of one type (PMC) was always higher than that of another type (NMC) during composting. In the case of PMC, the change in temperature, decrease in NH₄⁺, appearance of NO₃^–, and increase in germination indices (GI) with Japanese Komatsuna (Brassica campestris cv. Osome) were all more delayed than in NMC. As the composting process progressed, the proportion of branched (iso-, anteiso-, 10Me-) and saturated phospholipid fatty acids (PLFA) [BRANCHED FAMES (fatty acid methyl esters), biomarkers for gram-positive bacteria] gradually increased, then reached plateau. The high proportion of BRANCHED FAMES was maintained over a long storage period. The straight hydroxyl and saturated PLFAs (SOH-FAMES) initially increased, then disappeared with the progress of composting. The increase in BRANCHED FAMES and the decrease in SOH-FAMES were more delayed in PMC than NMC. The day on which the proportion of BRANCHED FAMES reached plateau and the proportion of SOH-FAMES dipped below 2 mol% coincided with the maturity stage based on the changes of physicochemical characteristics and GI. The composition of BRANCHED FAMES showed highly positive and negative correlation with GI and NH₄⁺, respectively. In the case of SOH-FAMES, inverse correlations were observed. This indicates that the proportion of BRANCHED FAMES and/or SOH-FAMES can be used as a tool for evaluating the maturity of poultry manure compost.     

Relating Compost Measures of Stability And Maturity to Plant Growth

Assessment of compost maturity is important for successful use of composts in agricultural and horticultural production. We assessed the “maturity” of four different sawdust-based composts. We composted sawdust with either cannery waste (CW), duck manure (DM), dairy (heifer) manure (HM) or potato culls (PC) for approximately one year. Windrows were turned weekly for the first 60 days of composting, covered for four winter months and then turned monthly for six more months. We measured compost microbial respiration (CO₂ loss), total C and N, C:N ratio, water soluble NO₃-N and NH₄-N, dissolved organic carbon (DOC), pH and electrical conductivity at selected dates over 370 days. Compost effects on ryegrass biomass and N uptake were evaluated in a greenhouse study. We related compost variables to ryegrass growth and N uptake using regression analysis. All composts maintained high respiration rates during the first 60 days of composting. Ammonium-N concentrations declined within the first 60 days of composting, while NO₃-N concentrations did not increase until 200+ days. After 250+ days, DM and PC composts produced significantly more ryegrass biomass than either CW or HM composts. Total C, microbial respiration and water-extractable NO₃-N were good predictors of compost stability/maturity, or compost resistance to change, while dissolved organic carbon, C:N ratio and EC were not. The compost NO₃-N/CO₂-C ratio was calculated as a parameter reflecting the increase in net N mineralization and the decrease in respiration rate. At ratio values >8 mg NO₃-N/mg CO₂-C/day, ryegrass growth and N uptake were at their maximum for three of the four composts, suggesting the ratio has potential as a useful index of compost maturity.     

Mass and Nutrient Losses During the Composting Of Dairy Manure Amended with Sawdust or Straw

Composting has become an increasingly popular manure management method for dairy farmers. However, the design of composting systems for farmers has been hindered by the limited amount of information on the quantities and volumes of compost produced relative to farm size and manure generated, and the impact of amendments on water, dry matter, volume and nitrogen losses during the composting process. Amendment type can affect the free air space, decomposition rate, temperature, C:N ratio and oxygen levels during composting. Amendments also initially increase the amount of material that must be handled. A better understanding of amendment effects should help farmers optimize, and potentially reduce costs associated with composting. In this study, freestall dairy manure (83% moisture) was amended with either hardwood sawdust or straw and composted for 110-155 days in turned windrows in four replicated trials that began on different dates. Initial C:N ratios of the windrows ranged from 25:1 to 50:1 due to variations in the source and N-content of the manure. Results showed that starting windrow volume for straw amended composts was 2.1 to 2.6 times greater than for sawdust amendment. Straw amended composts had low initial bulk densities with high free air space values of 75-93%. This led to lower temperatures and near ambient interstitial oxygen concentrations during composting. While all sawdust-amended composts self-heated to temperatures >55°C within 10 days, maintained these levels for more than 60 days and met EPA and USDA pathogen reduction guidelines, only two of the four straw amended windrows reached 55°C and none met the guidelines. In addition, sawdust amendment resulted in much lower windrow oxygen concentrations (< 5%) during the first 60 days. Both types of compost were stable after 100 days as indicated by CO₂ evolution rates <0.5 mg CO₂-C/g VS/d. Both types of amendments also led to extensive manure volume and weight reductions even after the weight of the added amendments were considered. However, moisture management proved critical in attaining reductions in manure weight during composting. Straw amendment resulted in greater volume decreases than sawdust amendment due to greater changes in bulk density and free air space. Through composting, farmers can reduce the volume and weights of material to be hauled by 50 to 80% based on equivalent nitrogen values of the stabilized compost as compared to unamended, uncomposted dairy manure. The initial total manure nitrogen lost during composting ranged from 7% to 38%. P and K losses were from 14 to 39% and from 1 to 38%, respectively. There was a significant negative correlation between C:N ratio and nitrogen loss (R₂=0.78) and carbon loss (R₂=0.86) during composting. An initial C:N ratio of greater than 40 is recommended to minimize nitrogen loss during dairy manure composting with sawdust or straw amendments.     

Use of urea to correct immature Urban composts for agricultural purposes

Abstract

Municipal solid waste composts are often inadequately stabilized for agricultural purposes. In addition, compost quality may be even more reduced by loss of nitrogen (N) during the composting process. We have utilized a compost with a high content of soluble sugars (11 mg g^‐1, DM, indicating immaturity) and a low ? concentration (0.95%, DM). The compost had a low level of heavy metals. Results obtained in a germination bioassay conducted with cress, ryegrass and sunflower in a compost‐sand mixture reflected the immaturity of the compost. Such composts should be fortified with ? (in a complete fertilizer, when possible), at the same time avoiding an intimate contact with the soil (e.g., plowing down). When the compost (and raw wastes and wastes at the 4th week of composting) was mixed with a soil at a heavy rate (2.5 % w:w), ryegrass seedling emergence in pots was not affected, but the plantlets’ fresh weight in the compost treatment was significantly lower than that in the control (soil) and lower than that in the raw wastes, probably due to the lower ? concentration. As expected, plantlet fresh weight was notably increased by the combination of compost and wastes with a complete fertilizer. The application of compost in combination with a complete fertilizer or urea did not affect either dry matter production or nutrient uptake of ryegrass, despite the combination's being applied just at sowing (in pots). Results obtained in these experiments indicate that combining immature composts with urea [supplemented with phosphorus (P) and potassium (K), when possible] at a ratio of about 50:1 (about 200 kg urea per 101 compost) could be sufficient to prevent negative results in crop establishment. Such practices could contribute to overcoming the limited fertilizing capacity of the composts.     

Mineralization and N Fertilizer Equivalent Value of Composts as Assessed by Tall Fescue (Festuca arundinacea)

The capability to determine nitrogen availability of composts is necessary to ensure that such materials will provide sufficient fertilization to the growing crop and cause minimal environmental degradation. A greenhouse study using tall fescue as a bioindicator was used to evaluate nitrogen availability of two biosolids composts, two mixed yard waste-poultry manure composts, and one commercially-processed poultry litter. Five inorganic nitrogen (as NH₄NO₃-N) treatments applied at 0, 22.5, 45, 67.7, and 90 mg N/kg soil were employed to establish an N calibration curve. Yield, fescue biomass total nitrogen (as total Kjeldahl N (TKN)), and soil TKN and KCl extractable NO₃^?-N and NH₄⁺-N concentrations of the organically amended treatments were compared to the inorganically fertilized treatments to determine amendment N mineralization rates and N fertilizer equivalent values (NFEV). Nitrogen mineralization rates were greatest in the poultry litter (21%) and Panorama yard waste compost (5%) amended pots. The NFEV of these amendments were 49% and 10%, respectively. Wolf Creek biosolids compost and Huck's Hen Blend yard waste compost immobilized N (?5% and 0.18%, respectively), and had percent NFEV of ?0.66% and 0.19%, respectively. Rivanna biosolids compost immobilized N (?15%), but the NFEV was 30% due to the relatively high inorganic N content in the amendment. Nitrogen mineralization and NFEV were generally greater in amendments with greater total N concentrations and lower C:N values. The total N concentration and C:N values were less reliable variables in predicting N mineralization and percent NFEV when a significant portion of the total N was in the inorganic form. Nitrogen equivalency value and N mineralization for each amendment increased with time of sampling, indicating the potential for early season N insufficiency to plants fertilized with compost due to lack of synchrony between N mineralization and plant N needs.     

Long-term amendment of four different compost types on a loamy silt Cambisol: impact on soil organic matter,nutrients and yields

This study investigated the long-term effects of different composts (urban organic waste compost (OWC), green waste compost (GWC), cattle manure compost (MC) and sewage sludge compost (SSC)) compared to mineral fertilisation on a loamy silt Cambisol, after a 7-year start-up period. The compost application rate was 175 kg N ha^?1, with 80 kg mineral N ha^?1 and without. Soil characteristics (soil organic carbon (SOC), carbon-to-nitrogen (C/N) ratio and soil pH), nutrients (nitrogen (N), phosphorous (P) and potassium (K)) and crop yields were investigated between 1998 and 2012. SOC concentrations were increased by compost applications, being highest in the SSC treatments, as for soil pH. N contents were significantly higher with compost amendments compared to mineral fertilisation. The highest calcium-acetate-lactate (CAL)-extractable P concentrations were measured in the SSC treatments, and the highest CAL-extractable K concentrations in the MC treatments. Yields after compost amendment for winter barley and spring wheat were similar to 40 kg mineral N ha^?1 alone, whereas maize had comparable yields to 80 kg mineral N ha^?1 alone. We conclude that compost amendment improves soil quality, but that the overall carbon (C) and N cycling merits more detailed investigation.     

Schwermetallgehalte im Kultursubstrat und Erntegut des Champignons,Agaricus bisporus (Lange) Singer,beim Einsatz von Müllklärschlammkompost

Heavy metal contents in the culture substrate and in the mushroom, Agaricus bisporus, grown in composts mixed with municipal waste and sewage The addition of increasing quantities of municipal waste compost to conventional horse manure compost resulted in a proportional increase in the heavy metal content of the mixture. The increases ranged between 250% (zinc) and 900% (mercury). Ninety-four to ninety-nine percent of the heavy metals in municipal waste compost are bound in compounds from which they can not be extracted using CaCl₂ solution. The amounts extractable from horse manure compost with CaCl2₂ solution are from 1.5 (zinc)- to 33 (mercury)-times higher. The influences of the increasing quantities of heavy metals in municipal waste — horse manure composts are demonstrable in the content of these metals in harvested mushroom. This, in turn, corresponds to the availability of the metals. The relative enrichment is greatest with mercury, and least with cadmium. The quantities found in mushrooms, with the exception of mercury, fall within the normal range detected in vegetable crops.     

Agronomic effectiveness of poultry manure composts

Abstract

Two field experiments were conducted to examine the agronomic value of poultry manure composted in the presence of both phosphate rock (PR) and elemental sulphur (S°) (sulphocompost) and PR alone (phosphocompost). Winter cabbage and summer maize were used as test crops. For the first season's winter cabbage, the phosphocompost and sulphocompost were approximately 12% and 60% as effective as urea and both composts were equally effective as urea for the second season's maize crop. The greater agronomic effectiveness of sulphocompost could be attributed to the improved nitrogen (N)‐use efficiency increased PR dissolution and improved S nutrition. Distribution of nitrate‐nitrogen (NO₃‐N) in the soil profile of field plots indicated greater potential for winter leaching of N from urea than poultry manure which could be the reason for the improved residual value of the manure reflected in summer maize yields. The results from the field experiments indicated that composting poultry manure with S° and PR not only reduces environmental pollution associated with manure application, but also increases the agronomic effectiveness of manure.