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排序方式: 共有122条查询结果,搜索用时 15 毫秒
91.
Nitrogen mineralization kinetics were compared in three different soils (pH values: 5.2, 7.1 and 8.6) when treated with bovine manure (BM) and sewage sludge (SS) composts. The soil-compost mixtures were kept at a controlled moisture content of 60% of their water holding capacity (WHC) and were incubated in the dark at 25 °C for 2 years. Five mathematical models were compared (simple exponential, double exponential, special model, hyperbolic and parabolic), using as experimental data the mineralized N accumulated during 360 and 720 days of incubation. The results showed that the best fit for describing the mineralization of organic N from the compost after 1 year of experimentation was obtained with the simple exponential model. However, the special model showed the best fit for data from 2 years of incubation and thus better reflected organic N mineralization over a longer time-span. This suggested that the organic N in the two composts was made up of two organic pools of different degrees of stability. 相似文献
92.
Organic substances viz., sewage and slurry, compost, farmyard manure (FYM) and green manure used in the study under different moisture regimes had a varied effect on cyanobacterial nitrogenase activity and its distributional pattern. Green manure source was the most effective in enhancing cyanobacterial nitrogenase activity, followed by FYM, compost and sewage and slurry. A better response was observed in soils under waterlogged than under moist conditions. A gradual increase in nitrogenase activity was recorded up to one per cent organic carbon both in vitro and in vivo. The cyanobacterial diversity was maximum in sewage and slurry sites. 相似文献
93.
The organic matter (OM) of a green waste and bio waste compost was characterised over 8 months and the observed evolution was correlated with physico-chemical parameters (temperature, pH, carbon content, C/N ratio). Thermochemolysis and thermodesorption were used to monitor bacterial activity (stability) whereas diffuse reflectance infrared fourier transform spectroscopy (DRIFTS) and thermodifferential analysis (TDA) permitted to determine the degree of OM humification (maturity). DRIFT spectroscopy and TDA provide two indicators of maturity since, with these two techniques, the signals associated with the biodegradable organic matter decrease relatively to the signals associated with refractory organic matter. This increase in RTG and RIR ratios between aromatic to aliphatic signals constitutes a proof for OM complexification. It correlates with humic acids/fulvic acids ratio known to be a maturity index. 相似文献
94.
Composting of animal manures and chemical criteria for compost maturity assessment. A review 总被引:21,自引:0,他引:21
New livestock production systems, based on intensification in large farms, produce huge amount of manures and slurries without enough agricultural land for their direct application as fertilisers. Composting is increasingly considered a good way for recycling the surplus of manure as a stabilised and sanitised end-product for agriculture, and much research work has been carried out in the last decade. However, high quality compost should be produced to overcome the cost of composting. 相似文献
95.
Molecular characterization of fungal community dynamics in the initial stages of composting 总被引:4,自引:0,他引:4
Composting relies on a complex network of bacteria and fungi to process crude organic material. Although it is known that these organisms drive dynamic changes in temperature and pH, little is known about the temporal dynamics of fungal populations during the rise to thermophilic conditions. This study employed F-ARISA (fungal-automated rRNA intergenic spacer analysis) and 18S rRNA gene cloning and sequencing to examine changes in community structure during this period. Sequencing of the 18S rRNA portion of cloned F-ARISA products revealed the presence of four distinct fungal genera including Backusella sp., Mucoraceae, Geotrichum sp. and the yeast Pichia sp. Based on the presence and absence of these ARISA operational taxonomic units (A-OTUs), we observed a shift in fungal community structure between 48 and 60 h. This change in community structure preceded a rise in pH and coincided with an increase in temperature. Clone libraries constructed using fungi-specific 18S rRNA primers contained sequences similar to several other fungal genera including Penicillium sp., Aspergillus sp., Hamigera sp., Neurospora sp. and the yeast Candida sp. While the fungal species richness was relatively low at any time point, the community structure was dynamic and paralleled changes in bacterial community structure. 相似文献
96.
97.
Two challenges frequently encountered in the production of ornamental plants in organic horticulture are: (1) the rate of
mineralization of phosphorus (P) and nitrogen (N) from organic fertilizers can be too slow to meet the high nutrient demand
of young plants, and (2) the exclusive use of peat as a substrate for pot-based plant culture is discouraged in organic production
systems. In this situation, the use of beneficial soil microorganisms in combination with high quality compost substrates
can contribute to adequate plant growth and flower development. In this study, we examined possible alternatives to highly
soluble fertilizers and pure peat substrates using pelargonium (Pelargonium peltatum L’Her.) as a test plant. Plants were grown on a peat-based substrate with two rates of compost addition and with and without
arbuscular mycorrhizal (AM) fungi. Inoculation with three different commercial AM inocula resulted in colonization rates of
up to 36% of the total root length, whereas non-inoculated plants remained free of root colonization. Increasing the rate
of compost addition increased shoot dry weight and shoot nutrient concentrations, but the supply of compost did not always
completely meet plant nutrient demand. Mycorrhizal colonization increased the number of buds and flowers, as well as shoot
P and potassium (K) concentrations, but did not significantly affect shoot dry matter or shoot N concentration. We conclude
that addition of compost in combination with mycorrhizal inoculation can improve nutrient status and flower development of
plants grown on peat-based substrates. 相似文献
98.
Reductive dechlorination of tetrachloroethene by two compost samples with different maturity 总被引:1,自引:0,他引:1
This study sets up microcosms using two types of compost samples, bagasse/manure compost, and yard-trimming compost with different maturity, to evaluate their capacity for reductive dechlorination of tetrachloroethene (PCE). The experimental results show that less matured compost samples could reduce 300 μM of PCE to ethene within 180 days of incubation. Decreasing initial PCE concentration and removing dissolved oxygen from the solution could enhance reducing efficiency. The solution remains near neutral pH throughout the experiment, and ethene emerged when the redox potential dropped to below -150 mV. Different microbial inhibition agents, such as 2-bromoethanesulfonic acid and sodium molybdate 2-hydrate, exhibit different effects on the dechlorination efficiency. The potential advantages of using compost to remove PCE are discussed. Overall, due to their high carbon content, diverse microbial activity, high buffer capacity, and complex physical structure, compost samples could serve as suitable media for dechlorinating PCE. 相似文献
99.
Comparison between UV spectroscopy and Nirs to assess humification process during sewage sludge and green wastes co-composting 总被引:7,自引:0,他引:7
The humification of organic matter during composting was studied by the quantification and monitoring of the evolution of humic substances (Humic Acid-HA and Fulvic Acid-FA) by UV spectra deconvolution (UVSD) and near-infrared reflectance spectroscopy (NIRS) methods. The final aim of this work was to compare UVSD to NIRS method, already applied on the same compost samples in previous studies. Finally, UVSD predictions were good for HA and HA/FA (r2 of 0.828 and 0.531) but very bad for FA (r2 of 0.092). In contrary, all NIRS correlations were accurate and significant with r2 of 0.817, 0.806 and 0.864 for HA, FA and HA/FA ratio respectively. From these results, HA/FA ratio being a well-used index of compost maturity, UVSD and NIRS represent two invaluable tools for the monitoring of the composting process. However, we can note that NIRS predictions were more accurate than UVSD calibrations. 相似文献
100.
Shrestha K Shrestha P Walsh KB Harrower KM Midmore DJ 《Bioresource technology》2011,102(17):8027-8034
Microbially enhanced compost extracts (‘compost tea’) are being used in commercial agriculture as a source of nutrients and for their perceived benefit to soil microbiology, including plant disease suppression. Rumen content material is a waste of cattle abattoirs, which can be value-added by conversion to compost and ‘compost tea’. A system for compost extraction and microbial enhancement was characterised. Molasses amendment increased bacterial count 10-fold, while amendment based on molasses and ‘fish and kelp hydrolysate’ increased fungal count 10-fold. Compost extract incubated at 1:10 (w/v) dilution showed the highest microbial load, activity and humic/fulvic acid content compared to other dilutions. Aeration increased the extraction efficiency of soluble metabolites, and microbial growth rate, as did extraction of compost without the use of a constraining bag. A protocol of 1:10 dilution and aerated incubation with kelp and molasses amendments is recommended to optimise microbial load and fungal-to-bacterial ratio for this inoculum source. 相似文献