Characterization of organic matter from animal manures after digestion by earthworms

The humification index (HI) values of three different manures and earthworm casts were calculated for three different extractant solutions (0.5M sodium hydroxide, 0.1M sodium pyrophosphate pH 7 and 0.1M sodium pyrophosphate plus 0.1M NaOH). The alkaline sodium pyrophosphate solution was found to be the most suitable because of both its extraction efficiency and the quality of the organic matter extracted which allows a good characterization of the stabilization degree attained by composting. Neutral sodium pyrophosphate extracts also show characteristic HI values for different samples but lower extraction efficiencies. The HI values for sodium hydroxide extracts show only little differences between manures and composts. The good correspondence found between HI data and isoelectric focusing (IEF) patterns confirmed on one side that humification indexes give a quantitative measure of the humification degree, on the other side that IEF is a suitable technique in order to obtain qualitative informations on organic matter stabilization in earthworm casts.     

Characterisation of organic matter from anaerobic digestion of organic waste by aerobic microbial activity

The aim of this study was to examine whether the characterisation of organic matter on the basis of an oxygen uptake rate (OUR) could be applied to organic waste from an anaerobic waste treatment process. Three anaerobic digestion experiments were carried out in a bioreactor. Volatile fatty acids (VFA) and dissolved organic carbon (DOC) were monitored. OUR-experiments were carried out with diluted samples from the process. The graphs of the OUR-experiments showed a clear lag-phase, which was due to the slow adaptation of aerobic microorganisms. Model simulations of the OUR versus time curve showed sufficient agreement, if based on one fraction of readily biodegradable and two fractions of less easily biodegradable organic matter. The shape of the simulated graphs was affected considerably by the value of the maintenance energy requirement rate qm and could be improved by reducing the standard value qm = 1 d(-1) to qm = 0.1 d(-1). Only little agreement was achieved when comparing the results of the OUR-experiments with the VFA- and DOC-concentrations. Experiments with additional trace elements and vitamins led to an increase in the OUR and proved that the oxygen consumption was not exclusively determined by the availability of organic matter.     

Modelling soil organic matter levels after long-term applications of crop residues,and farmyard and green manures

A computer simulation model for long-term soil organic matter dynamics was developed and evaluated with data from long-term field trials in Belgium, Germany and The Netherlands. The model distinguishes four pools of soil organic components (including a microbial biomass pool) with different chemical properties. Transformation rates are described by (pseudo) first order kinetics. Effects of temperature and soil moisture tension were included. Simulation results were in agreement with experimental data from arable farming practices where common input rates were applied. Model calculations overestimated soil organic matter levels when green manures or exceptionally high input rates were applied. Inadequate experimental estimations of organic matter input rates and insufficient modelling of the soil preservation capacity for organic matter and biomass are likely reasons. After changes in the soil organic matter-input management it may take more than a century to reach new equilibrium levels.     

Characterisation and reactivity continuum of dissolved organic matter in forested headwater catchments of Andean Patagonia

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Characterisation of dissolved organic matter in Parisian urban aquatic systems: predominance of hydrophilic and proteinaceous structures

Understanding the nature of organic matter is a necessary first step in assessing contaminant bioavailability and allowing water supply managers to optimise the treatment train in the aim of providing safe and inexpensive drinking water. This study provides further insight into the composition, structure and functional groups of dissolved organic matter (DOM) (both hydrophobic and hydrophilic) from urban aquatic systems by means of various analytical techniques (DAX-8/XAD-4 fractionation, elemental analysis, UV and FTIR spectroscopies, ¹³C and ¹⁵N isotopic analysis, size exclusion chromatography and Pyrolysis-GC-MS). The analytical range chosen for this study constitutes a powerful tool in the characterisation of DOM in urban water. The inclusion of information from one technique to the next might not only serve as a support to each one, but also as a complement. The DOM fraction from treated effluent and, more generally, DOM from urban water (i.e. receiving treated effluent) display a strong hydrophilic characteristic [i.e. low humic substance (HS) content, low SUVA], along with a high distribution in molecular weights observed by SEC and low average molecular weight. Due to the origin of this DOM, proteinaceous structures constitute the main compounds, as observed by FTIR and Py-GC-MS. Such characteristics (i.e. heterogeneity, low average molecular weight and diverse functional groups, which make up a total of N) could explain that DOM from treated effluent displayed a strong reactive potential metals pollutants as previously demonstrated.     

A new approach to estimating the pool of stable organic matter in soil using data from long-term field experiments

It is a necessity to have a successful method to separate, quantify and define the active and passive soil organic matter pools for appropriate verification of models. In this study, the organic carbon content of long-term bare fallow soils was used as an indicator of the size of the stable soil organic matter pool. Although soil texture and soil structure are widely accepted as having an influence on the stable pool, most soil organic models neglect the relationship between soil structure and carbon stabilization. Therefore, the aim of this presentation is to estimate the size of the stable carbon pool and to relate it to soil texture and structure properties. It was calculated that over 50 yr, under bare fallow conditions, the relative decrease in the amount of carbon (C) for the most stable pools ranged between 2 and 12%. In comparison, for the less stabilized pools the relative decrease was calculated from 50 to 100%. This indicates that the organic carbon content of long-term bare fallow soils should be very similar to the size of the most stable C pool. We also observed that the amounts of carbon associated with primary particles <20 μm for numerous soils with contrasting carbon content, soil texture, and management practices showed a lower and an upper limit. Both these limits and the carbon content of long-term bare fallow soils (which were assumed to be similar to the size of the stable pool) were related to the content of primary particles <20 μm in the soil. To calculate these relationships, an equation was used including one term to describe the influence of soil texture and another to describe that of soil structure. The calculated regression for the bare fallow soils corresponded very well to the lower limit of carbon content associated with primary particles <20 μm. The upper limit was estimated only by increasing the regression parameter which is related to the amount of C per unit primary particles <20 μm. Considering the many published results of the influence of soil texture and structure on carbon stabilization processes in soil, the stable pool may be defined as the capacity of soils to sorb C. The upper limit of carbon content associated with primary particles <20 μm may be interpreted as the capacity of soil to protect C. This revised version was published online in June 2006 with corrections to the Cover Date. This revised version was published online in June 2006 with corrections to the Cover Date. This revised version was published online in June 2006 with corrections to the Cover Date.     

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.     

Effects of four different doses of organic manures in the production of Ceriodaphnia cornuta

Mass culture of Ceriodaphnia cornuta was done by using a mixture of organic manures: cattle manure:poultry droppings:mustard oil cake (1:1:1) at four different doses: 0.263 kg/m3 (first dose), 0.526 kg/m3 (second dose), 1.052 kg/m3 (third dose) and 2.104 kg/m3 (fourth dose). The peak of C. cornuta was found on 10th day of inoculum in first two doses and on 14th and 18th day in third and fourth doses, respectively. Among these four doses, significantly (P<0.01) higher numbers of organisms (1930/l) were found in the fourth dose followed by third (1470/l), second (1017/l) and first (733/l) doses, respectively. The number of organisms decreased faster in two lower doses than higher doses. pH ranged from 7.20 to 8.09, 7.46 to 8.01, 7.55 to 7.89 and 7.61 to 8.03 in first, second, third and fourth doses, respectively. Dissolved oxygen showed inverse relationship with the dose of manures applied and direct relationship with number of organisms. This study showed that 3.28-4.63 mg/l dissolved oxygen was optimum to obtain the bloom of C. cornuta under the present manure schedule. Maximum number of organism was found when unionized ammonia and phosphate levels ranged between 0.65-0.85 mg/l and 0.42-0.98 mg/l, respectively. The fourth dose of organic manure is optimum for the culture of C. cornuta in outdoor condition and the bloom of the live food can be obtained within 18 days of inoculum.     

中国有机肥料养分资源潜力和环境风险分析

基于<中国农业年鉴2006)和其他文献的基础数据,计算了2005年中国人畜禽排泄物和秸秆数量及其产生的养分量.结果表明,2005年中国人畜禽排泄物总量为46.25亿t,秸秆总产量为6.43亿t.中国有机肥料养分资源潜力巨大,2005年人畜禽排泄物和秸秆共产生N、P2O5、K2O养分量分别为2824.52、1282.93、2947.99万t,分别为化肥N、P2O5、K2O投入量的1.08、0.86和4.56倍.但不同区域差异较大,其中河南、山东和四川省人畜禽排泄物产生N、P2O5、K2O量最多,均>400万t,西北地区和北京、天津、上海等地人畜禽排泄物产生的养分总量较少.秸秆中N、P2O5、K2O含量在河南和山东2个粮食主产省最高,均>150万t;西北地区秸秆养分产生量相对较少.单位农田面积人畜禽排泄物的N、P2O5和K2O养分负荷量以北京最高,达到787.26 kg·hm-2,其次是天津和上海,分别为515.31和505.35 kg·hm-2,环境风险较大.     

Review of organic matter in the Orgueil meteorite

The Orgueil meteorite is a carbonaceous chondrite containing about 3.1% carbon, 5.5% sulfur and 19.9% water. Virtually all of the carbon is present as organic carbon although only about 20% is soluble in common organic solvents; the remainder is in the form of a highly substituted, irregular and aromatic polymer. Detailed methods of analysis have been improved in the past ten years sufficient for the detection of individual compounds in most of the following classes of organic compounds: hydrocarbons, oxygen-, sulfur- and nitrogen-containing organic compounds, optically active species, isotopes, bacteria and organized elements. Ten series of homologous compounds have been observed in the aliphatic hydrocarbons.In the 1950's, when interest was renewed in the Orgueil meteorite, the analytical capabilities may have given a bias toward biogenic agencies for the formation of the organic matter found in the meteorites. Some of the key biochemical compounds for extraterrestrial life are present. There is doubt, however, that these particular compounds are truly indigenous. The possibility that the indigenous organic compounds in the meteorite are present as a result of abiogenic syntheses in the cosmos is becoming more generally accepted.     

Primary oxidation of organic matter in the soil

Summary The course of respiration rate during glucose decomposition in a soil sample was studied. The whole process of oxidation (mineralization) is divided into two principal parts: the primary oxidation which occurs while the substrate is still present and the secondary oxidation after the disappearance of the substrate. The primary oxidation brought about by two different components: the oxidative component represents the sum of enzyme activity present originally in the soil sample, and the assimilative component is built up during the process by synthesis of microbial enzymes. The size of the oxidative component is correlated with the biological potency of soil. Sometimes, an intermediary stage can be observed at the beginning of the secondary oxidation. A method is given for enumeration of the proportions of the two components involved in primary oxidation. The biochemical and pedological meaning of these data is discussed.     

Dynamics of organic matter in soils

Summary Dynamics of C, N, S, and to some extent P are expressed by a knowledge of the size and turnover rates of plant constituents such as soluble C and N components, cellulose and hemicellulose, and lignin. Soil organic matter constituents include: the microbial biomass as determined chemically or microscopically, non-biomass active components determined by isotopic dilution, stabilized N constituents for which good techniques are not yet available, and resistant or old C and associated N determined by carbon dating. The processes involved in the nutrient transformations and transfers are reasonably well understood. The control mechanisms require further elucidation to be able to extrapolate from the laboratory to the field, and between field sites. Major control mechanisms requiring further insight include the effects of C availability on transformations of C and N. The other control for which every little is known is that of spatial compartmentalization. Compartmentalization ranges from landscape or management sequences to pedogenic layers, rhizosphere-mycorrhizal effects, clay-sesquioxide surfaces, aggregation, localized enzymes, and microbial effects such as membrane boundaries. Control mechanisms for concurrent mineralization-immobilization, the stabilization of microbial products, and the relative role of the biomass as a catalyst rather than as a source-sink for nutrients, must be understood. There is potential for combining a knowledge of microbial production and turnover with that of the roles of the soil organic active fraction as a temporary storehouse for nutrients. This, in conjunction with management techniques such as zero tillage and crop rotation, should make it possible to better utilize soil and fertilizer N, especially in areas of the world where the cost of nutrients is high relative to the value of the crop grown.Introductory lecture     

Dynamics of seasonal bicarbonate supply in a dune slack: effects on organic matter, nitrogen pool and vegetation succession

The seasonal variation in groundwater composition was studied in an old dune slack complex on the Wadden Sea island of Schiermonnikoog that recently had lost practically all rare basiphilous plant species. In order to assess its restoration perspectives the groundwater acid neutralization capacity (ANC _aq ) of various sites was discussed in relation to the decalcification depth, amount of organic matter and amount of nitrogen in the topsoil layer. The decalcification depth reflected the (former) hydrological regime quite well; shallow in the exfiltration zone and deep in the infiltration part of the slack. The pattern of HCO₃ ^–, SO₄ ^2– and pH reflected the functioning of a flow-through lake, even when the slack was not flooded. Relics of low productivity (mesotrophic) vegetation (Samolo-Littorelletum) with rare species were related to low amounts of organic matter and nitrogen in the topsoil layer. At this site the variation in HCO₃ ^– concentration was also relatively low during the year. It was hypothesized that a regular supply of acid buffering components from calcareous soil layers buffers the pH at a high level and slows down the accumulation of organic matter thus creating opportunities for the rare basiphilous plant species. A possible biological control mechanism for these processes was discussed. A reconstruction of the former, present and future eco-hydrological situation was made of the dune slack.     

A simple model for estimating the contribution of nitrogen mineralization to the nitrogen supply of crops from a stabilized pool of soil organic matter and recent organic input

A simple model was developed to estimate the contribution of nitrogen (N) mineralization to the N supply of crops. In this model the soil organic matter is divided into active and passive pools. Annual soil mineralization of N is derived from the active pool. The active pool comprises stabilized and labile soil organic N. The stabilized N is built up from accumulated inputs of fresh organic N during a crop rotation but the labile N is a fraction of total N added, which mineralizes faster than the stabilized N. The passive pool is considered to have no participation in the mineralization process. Mineralization rates of labile and stabilized soil organic N from different crop residues decomposing in soil were derived from the literature and were described by the first-order rate equation dN/dt =-K*N, where N is the mineralizable organic N from crop residues andK is a constant. The data were groupedK ₁ by short-term (0–1 year) andK ₂ by long-term (0–10 years) incubation. Because the range of variation inK ₂ was smaller than inK ₁ we felt justified in using an average value to derive N mineralization from the stabilized pool. The use of a constant rate ofK ₁ was avoided so net N mineralization during the first year after addition is derived directly from the labile N in the crop residues. The model was applied to four Chilean agro-ecosystems, using daily averages of soil temperature and moisture. The N losses by leaching were also calculated. The N mineralization varied between 30 and 130 kg N ha^–1 yr^–1 depending on organic N inputs. Nitrogen losses by leaching in a poorly structured soil were estimated to be about 10% of total N mineralized. The model could explain the large differences in N- mineralization as measured by the potential N mineralization at the four sites studied. However, when grassland was present in the crop rotation, the model underestimated the results obtained from potential mineralization.     

Characterisation of footpad lesions in organic and conventional broilers

Recent data suggest that organic broilers often score worse on footpad lesions than conventional broilers but also that the current scoring of organic broiler feet may be misleading. In order to characterise footpad lesions in organic broilers, this study assessed and compared footpad lesions in a sample of 2987 conventional and 3578 organic broiler feet obtained from a large Danish abattoir during summer and winter. The feet were scored according to two scoring systems: the modified Danish surveillance scoring system and a histopathology-based new scoring system specifically developed to target the ability to differentiate between broiler feet with hyperkeratosis and ulcers. For both systems, all broiler feet with visible lesions were cross-sectionally incised. Significant differences between the two production systems were found for both scoring systems (χ² = 710; P < 0.001 and χ² = 247; P < 0.001 for the new and the surveillance systems, respectively), showing that a larger proportion of the organic feet compared to conventional feet – summer and winter – exhibited signs of hyperkeratosis. In addition, a smaller fraction of the organic feet than of the conventional feet were given the outermost scores, that is, normal or ulcerated; 13.4% v. 25.3% broiler feet were given score 0 for organic v. conventional production systems, respectively (χ² = 152; P < 0.001), and 18.4% v. 23.8% feet were given score 4 for organic v. conventional production systems, respectively (χ² = 308; P < 0.001). Thus, the results suggest that surveillance scoring systems such as the one used in Denmark are useful for the examination of footpad lesions in broilers from both types of production systems. However, the results have also raised attention to a typical characteristic of the feet of organic broilers, that is, profound hyperkeratosis, which may underlie potential misclassifications in surveillance scoring systems like the one used in Denmark. Among the possible solutions to this challenge to the correctness and fairness of the scoring system are improved procedures (such as mandatory incision), training of technicians and calibration of results (especially for the organic footpads).     

Growth of Nitrobacter in the presence of organic matter

1. Culture filtrates of heterotrophic bacteria were tested for their stimulatory effect on nitrification of three strains of Nitrobacter.
2. Yeast extract-peptone solution, in which Pseudomonas fluorescens had grown, after removal of the cells was added to autotrophically growing cultures of Nitrobacter agilis; it caused a stimulated nitrite oxidation and growth of Nitrobacter agilis.
3. The degree of stimulation depended on: a) the proportion of the culture filtrate to the autotrophic medium; b) the composition of the complex medium in which Pseudomonas fluorescens had been grown; c) the time the heterotrophic bacterium had been grown in the complex medium.
4. The stimulatory effect was highest with Nitrobacter agilis, less with Nitrobacter winogradskyi and negligible with Nitrobacter K ₄.
5. It was possible to adapt nitrifying cells of Nitrobacter agilis to higher concentrations of yeast extract and peptone. After the nitrite had been completely oxidized the cell-N still increased up to 30% before growth stopped.

     

Biodegradation of ferrihydrite-associated organic matter

The association of organic molecules with mineral surfaces is a major mechanism to stabilize soil organic matter against biodegradation. We performed microbial incubation experiments to quantify the mineralization of soil organic matter associated with ferrihydrite by adsorption and coprecipitation. Samples were produced using either water-extractable organic matter of a Podzol forest-floor layer (FFE) or a sulfonated lignin. Incubation was carried out with an inoculum extracted from the forest-floor layer under oxic conditions at pH 4.8 over 68 days. Our data show that the association with ferrihydrite stabilized the associated organic matter: the degradation of the polysaccharide-rich FFE was slowed down, while the degradation of lignin was inhibited. Since differences in the degradability of adsorbed and coprecipitated organic matter were small, we conclude that coprecipitation did not lead to a significant formation of microbial inaccessible organic matter domains in our experiments.