Co-composting of PAH-contaminated soil with poultry manure

AIMS: To investigate the effects of co-composting poultry manure with soil contaminated with different concentrations of polycyclic aromatic hydrocarbons (PAHs), on the degradation of selected PAHs in a static-pile compost system. METHODS: Mispah form (Food & Agricultural Organisation, FAO : lithosol) soil contaminated with PAHs was co-composted with poultry manure for 19 months. The soil was mixed with wood chips in a ratio of 1:1 to improve aeration and then mixed with poultry manure in a ratio of 4:1. A data logger measured temperature monthly. Residual concentrations of selected PAHs in the compost were determined monthly by gas chromatography/flame ionisation detection (GC/FID). Moisture, pH, ash content and C:N ratios were also monitored monthly. Microbial activity was measured by measuring CO(2) evolution. CONCLUSIONS: The results obtained in this experiment have shown that co-composting poultry manure with PAH-contaminated soil is capable of removing large concentrations of high molecular weight PAH from contaminated soil to levels below 1 mg kg(-1) in 19 months. SIGNIFICANCE AND IMPACT OF THE STUDY: The paper adds to the body of knowledge necessary for the development of a cost effective technology for the remediation of soil contaminated with high molecular weight PAHs by providing information on the behaviour of selected PAHs and factors such as nutrient ratio, temperature and pH during composting.     

Dissolution and effectiveness of phosphate rock in acidic soil amended with cattle manure

Plant and Soil - Phosphate rock (PR) and organic manure (OM) are promising amendments to acidic soils to correct P deficiency and Al/Mn toxicities. The interaction between PR and OM and consequent...     

Microbial biomass and activity of an agricultural soil amended with the solid phase of pig slurries

Information about the mineralisation rates and effects on soil microorganisms must be obtained prior to the rational use of organic wastes in agriculture or forestry. The objective of this work was to study the mineralisation of two manures derived from the solid phase of pig slurries and the effects on the soil microbial biomass of an agricultural soil. Samples of this soil were mixed at two different rates with two manures derived from the solid phase of pig slurry (composted, CSP, and non-composted, NSP), and then were incubated during 163 days. Carbon mineralised from manures was fitted to first-order kinetic model, and small differences were found between manures despite the composting of one of them. Approximately 45% of the C added was mineralised in the experimental period. The soil microbial biomass C (C(mic)) was increased by the amendments according to the application rate. The sudden increases of the qCO(2) in the treated samples were ephemeral. The most appreciable differences between these manures were those related with net N mineralisation, being greater in the NSP-treated samples. The application of the solid phase of pig slurries, composted or not, could be a feasible practice to enhance in a short-term the microbial biomass of agricultural soils. In order to avoid an excessive release of inorganic N, the use of composted materials is preferred.     

Natural 15N abundances of maize and soil amended with urea and composted pig manure

To investigate the effect of inorganic fertilizer and composted manure amendments on the N isotope composition (delta ¹⁵N) of crop and soil, maize (Zea mays L.) was cultivated under greenhouse conditions for 30, 40, 50, 60, and 70 days. Composted pig manure (delta ¹⁵N= +13.9) and urea (-2.3) were applied at 0 and 0 kg N ha^–1 (C0U0), 0 and 150 kg N ha^–1 (C0U2), 150 and 0 kg N ha^–1 (C2U0), and 75 and 75 kg N ha^–1 (C1U1), respectively. The delta ¹⁵N of total soil-N was not affected by both amendments, but delta ¹⁵N of NH⁺ ₄ and NO^– ₃ provided some information on the N isotope fractionation in soil. During the early growth stage, significant differences (P < 0.05) in delta ¹⁵N among maize subjected to different treatments were observed. After 30 days of growth, the delta ¹⁵N values of maize were +6.6 for C0U0, +1.1 for C0U2, +7.7 for C2U0, and +4.5 for C1U1. However, effects of urea and composted manure application on maize delta ¹⁵N progressively decreased with increasing growth period, probably due to isotope fractionation accompanying N losses and increased uptake of soil-derived N by maize. After 70 days of growth, delta ¹⁵N of leaves and grains of maize amended with composted pig manure were significantly (P < 0.05) higher than those with urea. The temporal variations in delta ¹⁵N of maize amended with urea and composted manure indicate that plant delta ¹⁵N is generally not a good tracer for N sources applied to field. Our data can be used in validation of delta ¹⁵N fractionation models in relation to N source inputs.     

土壤硝化作用的抑制剂调控及其机理

既要保证氮肥在优质高效农业生产中的促进作用,又要保证农业和环境的可持续发展,如何提高氮肥利用率、减轻氮肥污染成了解决问题的关键.从氮素在土壤中的生物化学转化过程入手,通过抑制剂的施用来调控氮素的转化,减缓硝化过程的进行,是解决该问题的一种有效措施.本文从硝化抑制剂的定义、筛选硝化抑制剂的条件、国内外较受关注的硝化抑制剂品种以及硝化抑制机理等几个方面对目前的研究进展进行综述,并提出目前研究中存在的问题及今后的研究方向.     

Bioremediation of gasoline contaminated soil by a bacterial consortium amended with poultry litter, coir pith and rhamnolipid biosurfactant.

The aim of the present study was to find methods for enhancing rates of hydrocarbon biodegradation in gasoline contaminated soil by ex situ bioremediation. Red soil (RS) was treated with gasoline-spilled soil (GS) from a gasoline station and different combinations of amendments were prepared using (i) mixed bacterial consortium (MC), (ii) poultry litter (PL), (iii) coir pith (CP) and (iv) rhamnolipid biosurfactant (BS) produced by Pseudomonas sp. DS10-129. The study was conducted for a period of 90 days during which bacterial growth, hydrocarbon degradation and growth parameters of Phaseolus aureus RoxB including seed germination, chlorophyll content, shoot and root length were measured. Approximately 67% and 78% of the hydrocarbons were effectively degraded within 60 days in soil samples amended with RS + GS + MC + PL + CP + BS at 0.1% and 1%. Maximum percentage of seed germination, shoot length, root length and chlorophyll content in P. aureus were recorded after 60 days in the above amendments. Further incubation to 90 days did not exhibit significant improvements. Statistical analysis using analysis of variance (ANOVA) and Duncan's multiple range test (DMRT) revealed that the level of amendments, incubation time and combination of amendments significantly influenced bacterial growth, hydrocarbon degradation, seed germination and chlorophyll content at a 1% probability level. All tested additives MC, PL, CP and rhamnolipid BS had significant positive effects on the bioremediation of GS.     

Operating a full-scale poultry manure anaerobic digester

A full-scale, completely-mixed digester, with a liquid capacity of 587 m³, was constructed to process the manure from 70 000 caged layers. Biogas from the digester was used as fuel for an engine/generator set. The operating temperature was maintained at 35°C using waste heat from the engine. The digester was operated on a 22–24 day HRT. Digester influent averaged 5·90% TS, 5250 ppm TKN, and 3790 ppm NH₃N. Digester effluent averaged 3·11% TS, 5090 ppm TKN, and 4060 ppm NH₃N.Sustained operation of the digester was achieved during the period of study (8/83−4/85). During this period biogas production averaged 0·38 m³ kg⁻¹ VS added (0·58 m³ kg⁻¹ VS destroyed). The CH₄ content averaged 58·0%. The major operational problem encountered was grit accumulation in the digester. This problem was reduced by settling most of the grit from the manure prior to the digester. Biogas production was reduced when concentrated lagoon-liquid was used as make-up water. Approximately 22% of the electricity produced was required for operating the system.     

畜禽粪便施用对稻麦轮作土壤质量的影响

通过采集试验区长期施用鸡粪 (PL)、猪粪 (LM) 和化肥 (CF) 的稻麦轮作耕层和犁底层土壤,分析了不同施肥处理土壤有机碳和养分含量、土壤物理结构特征、土壤生物学性质的差异,探讨了长期施用畜禽粪便对土壤质量的影响。研究结果显示,长期施用畜禽粪便耕层和犁底层土壤有机碳含量显著高于施用化肥处理(P<0.05);与CF处理比较,PL和LM处理土壤氮、磷、钾全量和有效养分含量均明显增加,其中耕层土壤Olsen-P 含量为施用化肥处理的7-8倍,速效钾含量比施用化肥土壤高89.2%-102.9%。施用畜禽粪便明显改善了土壤物理结构,其耕层土壤大孔隙体积、中孔隙体积和总孔隙度分别为CF处理土壤的1.48-1.70倍,1.35-1.75倍和1.07-1.11倍;土壤团聚体水稳定性显著增强,而土壤抗张强度显著降低。施用畜禽粪便土壤微生物和生化性质也明显高于施用化肥土壤,其中LM处理耕层土壤MBC和MBN最大,分别是CF处理土壤的2.1倍和1.5倍;施用畜禽粪便土壤脲酶和转化酶活性也分别为施用化肥土壤的3.5-6.7倍和1.6-2.1倍。相关分析显示,土壤有机碳含量与各肥力指标间均表现出极显著相关(P<0.01)。研究结果说明,长期施用畜禽粪便土壤质量显著高于仅施化肥土壤。     

Co-composting of chestnut burr and leaf litter with solid poultry manure

A co-composting of chestnut burr and leaf litter mixed with solid poultry manure was assessed by comparison of several chemical, physicochemical and biological parameters. The final pH of the co-compost was 8.89 and the C/N ratio was 13. The germination index (GI) obtained using the co-compost varied with the seeds used. It was 155.35% for ryegrass seeds, 56.56% for wheat seeds and 100% for barley seeds. The co-compost was mature in 103 days from a biological point of view.     

Suppression of adult lesser mealworm (Coleoptera: Tenebrionidae) using soil incorporation of poultry manure

The effectiveness of manure incorporation in reducing the numbers of adult lesser mealworms emerging from caged-layer poultry manure applied to agricultural fields was examined in summer 2002 and 2004. Incorporation treatments included control (no incorporation), disk (7-cm depth), harrow (15-cm depth), chisel plow (30-cm depth), and moldboard plow (33-cm depth) on silt loam soils in New York state. An estimated 55,192 and 183,500 live adult lesser mealworms were applied to the field in 2002 and 2004, respectively. Mortality due to the action of the manure spreader was 32.4% in 2002 and 6.5% in 2004. No significant differences were observed between treatments in 2002. However, moldboard plowing significantly reduced beetle emergence compared with no tillage in 2004. Peak beetle flight was observed 10 and 17 d after manure application in 2002 and 2004, respectively.     

Assessment of two techniques for measuring nitrification rates in aerated slurries of seagrass-bed sediments

Two methods were assessed to measure rates of nitrification in aerated slurries of seagras-bed sediments; (1) monitoring ammonium concentrations in samples with and without nitrapyrin ((2-chloro-6-(trichloromethyl) pyridine) treatment and (2) monitoring the accumulation of nitrate plus nitrite. Nitrifying bacteria were inhibited completely after 14 days exposure to nitrapyrin at 5 mg⁻¹, but the effect was poor over shorter periods, probably owing to limited diffusion of the inhibitor. Hence, nitrapyrin was not a satisfactory inhibitor to use in these sediments. Nitrification rates could not be measured by monitoring the concentrations of nitrate plus nitrite, because nitrate reduction occurred simultaneously with nitrification, even though the slurries contained from 3.5 to 8.9 mg O₂ l⁻¹.     

Comparison of Karanjin with other nitrification inhibitors for retardation of nitrification of urea N in soil

Summary Comparative evaluation of Kranjin and three patented nitrification inhibitors for retardation of nitrification of urea in a sandy clay loam showed that the effectiveness of the compounds tested decreased in the order: Nitrapyrin>Karanjin>A.M.>dicyandiamide.     

Investigation of nitrification in forest soils with soil percolation columns

Soil percolation columns in which a pF of 2 could be maintained were developed to study nitrification in soils and litter of an acid and a calcareous forest soil location. High nitrification rates were observed in the calcareous soil. In the acid soil nitrification was much slower. A column filled with leaf litter gave a low nitrification rate at the start of the experiment, but a high rate was found after 60 days of percolation with an ammonium-containing medium of pH 4. In this leaf litter high numbers of autotrophic bacteria were just present at the beginning of the experiment, whereas at the end only low numbers were detected. Results indicate that autotrophic bacteria from acid soils are sensitive to a pH increase.     

Enzyme activities in a clay-loam soil amended with various crop residues

Summary Amylase, dehydrogenase, arylsulphatase and phosphatases activities were measured in a clay-loam soil amended with seven different crop residues. All enzyme activities, except phosphomonoesterase, were generally higher in the derived soil samples than in the original soil. Addition of tobacco and sunflower residues caused an increase on most of the enzyme activities while tomato residues increased only the amylase and phosphodiesterase activities. As the enzyme activities were positively correlated to each other, a common source of the enzymes is suggested even though the coefficients of correlation demonstrate that only a low percentage of the variability can be ascribed to the interactions among enzyme activities.     

Fungicidal control of Rhizoctonia solani in soil amended with organic manures

Amendments of nutrient-deficient soil with three organic manures and one non-edible oil-cake reduced the disease controlling potential of methoxyethyl mercury chloride (MEMC), quintozene and carbendazim used as seed treatments on cowpea and cotton against seedling rot caused by Rhizoctonia solani. Biogas sludge (BGS) and farm yard manure (FYM) nullified the activity of MEMC and quintozene and reduced markedly the efficacy of carbendazim. Humic acid extracted from BGS inactivated MEMC and carbendazim but had little effect on quintozene. Green manure (Sesbania aculeata) slightly reduced the efficacy of MEMC only. Soil amendment with mahua (Madhuca indica) cake and soil drench with its aqueous extract greatly reduced the efficacy of the three fungicides.     

The development of phenanthrene catabolism in soil amended with transformer oil

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants frequently associated with light non-aqueous-phase liquids (LNAPLs) in soil. Microbial degradation comprises a major loss process for PAHs in the environment. Various laboratory studies, using known degraders, have shown reduced or enhanced mineralisation of PAHs when dissolved in different LNAPLs. Effects due to the presence of LNAPLs on indigenous micro-organisms, however, are not fully understood. A pristine pasture soil was spiked with [14C]phenanthrene and transformer oil to 0, 0.01 and 0.1%, and incubated for 180 days. The catabolic potential of the soil towards phenanthrene was assessed periodically during ageing. The extent of the lag phase (prior to >5% mineralisation), maximum rates and overall extents of mineralisation observed during the course of a 14-day bioassay appeared to be dependent upon phenanthrene concentration, the presence of transformer oil, and soil-contaminant contact time. Putatively, transformer oil enhanced acclimation and facilitated the development of measurable catabolic activity towards phenanthrene in a previously uncontaminated pasture soil. Exact mechanisms for the observed enhancement, longer-term fate/degradation of the oil and residual phenanthrene, and effects of the presence of the oil on the indigenous microbes over extended time frames warrant further investigation.     

Co-composting of oil exhausted olive-cake, poultry manure and industrial residues of agro-food activity for soil amendment

The co-composting of exhausted olive-cake with poultry manure and sesame shells was investigated. These organic solid wastes were watered by the confectionary wastewater which is characterized by its high content of residual sugars raising its COD. Four aerated windrows were performed to establish the effects of confectionary by-products on the compost process. Different mixtures of the agro-industrial wastes were used. During the composting process, physico-chemical parameters (temperature, moisture, pH, electrical conductivity, total carbon and total nitrogen) were studied. The stability of the biological system was noticed after 70 days. The final products were characterized by their relatively high organic matter content, and low C/N ratio of 14-17. The humidification of the windrows with the wastewater seemed to have accelerated the composting process in comparison to a windrow humidified with water. In addition, the organic matter degradation was enhanced to reach 55-70%. The application of the obtained composts to soil appeared to significantly improve the soil fertility. Indeed, field experiments showed an increase in potato yield; the production was 30.5-37.5 tons ha(-1), compared to 30.5 tons ha(-1) with farm manure.