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Long-term fertilization alters soil microbiological properties and then affects the soil organic carbon (SOC) pool. However, the interrelations of SOC with biological drivers and their relative importance are rarely analyzed quantitatively at aggregate scale. We investigated the contribution of soil microbial biomass, diversity, and enzyme activity to C pool in soil aggregate fractions (&gt, 5 mm, 2–5 mm, 1–2 mm, 0.25–1 mm, and &lt, 0.25 mm) at topsoil (0–15 cm) from a 27-year long-term fertilization regime. Compared to CK (no fertilization management), NP (inorganic fertilization alone) decreased all of the microbial groups’ biomass, while NPS and NPM (inorganic fertilization plus the incorporation of maize straw or composted cow manure) significantly reduced this negative effect of NP on microbial biomass and increased the microbial contribution to C pool. The results show that microbial variables were significantly correlated with SOC content in &gt, 0.25 mm aggregates rather than in &lt, 0.25 mm aggregates. Fungal variables (fungal, AM biomass, and F/B ratio) and enzyme activities (BXYL and LAP) in &gt, 0.25 mm aggregates explained 21% and 2% of C, respectively. Overall, organic matter addition could contribute to higher C storage by boosting fungal community and enzyme activity rather than by changing microbial community diversity in macro-aggregates.

Using field slope farmland plots, this study planted the typical crop of maize (Zea mays L.) and investigated the effects of varied chemical fertilizer (organic compound fertilizer of potassium nitrate, containing 17% each of nitrogen, phosphorus, and potassium) application levels (0.5 times the common fertilizer amount (CK, 0.75 t·hm−2 to 2.5 CK) on the soil fertility in the Yuanmou dry-hot River Valley. The results showed that the soil chemical properties, microbial properties, and enzyme activities increased with the increase of fertilizer application levels from CK to 2.0 CK. However, a declining trend showed both under 0.5 CK level and the 2.5 CK level, and higher in fertilizer application level 3 (1.5 CK) and level 4 (2.0 CK) compared to level 1 (1 CK). Soil chemical properties, microbial properties, and enzyme activities in five-degree slope cropland topsoil were higher than these in 10-degree slope cropland topsoil. Five parameters (available N, nitrifying bacteria, inorganic phosphorus bacteria, organic matter, and invertase) in five-degree slope cropland and three parameters (organic matter, ammonifying bacteria, and total P) in 10-degree slope cropland, which had the greatest weight in the principal components analysis, were selected to calculate the soil quality index (SQI). The SQI calculated by integrating all critical parameters indicated that the highest SQI values were found in fertilizer levels 1.5 CK (0.71) and 2.0 CK (0.69), followed by CK (0.64), and the lowest were found in 0.5 CK (0.62) and 2.5 CK (0.61) in five-degree slope cropland soil. The highest SQI values were found in fertilizer levels 1.5 CK (0.26) and 2.0 CK (0.29), followed by CK (0.23), and the lowest were found in 0.5 CK (0.14) and 2.5 CK (0.20) in 10-degree slope cropland soil. The final SQI values implied that the fertilization treatment 2 (CK), fertilization treatment 3 (1.5 CK) and fertilization treatment 4 (2.0 CK) could improve the soil fertility, whereas the fertilization treatment 1 (0.5 CK) and fertilization treatment 5 (2.5 CK) could decrease the soil fertility. In view of the impact of slope, the soil qualities of five-degree slope cropland of five fertilization treatments were higher than in 10-degree slope cropland. The SQI values in five-degree slope cropland soil were found higher than the SQI values in 10-degree slope cropland soil by 68.65%, 64.20%, 62.22%, 57.46%, and 67.01%, respectively. For this study, the range of fertilization tolerance was 0.75–1.50 t·hm−2 (organic compound fertilizer of potassium nitrate) in 10-degree slope plot scale and 0.75–1.13 t∙hm−2 in five-degree slope cropland soil.

The objective of this study was to investigate the possibility of using microbial strains as residue decomposers and to determine the effect of these strains on chemical and microbial properties in the residue-amended soil. Greenhouse experiment consisted of eight Bacillus treatments, three Trichoderma treatments, and their combination, all applied to non-sterile chernozem soil amended with wheat straw. Incorporation of wheat straw improved soil chemical and microbial properties, while the extent of residue decom­position under microbial strains was intensified. Microbial treatments significantly affected the soil pH, the content of carbonate, total carbon, soil organic carbon, humus, and available phosphorus and potassium. Bacterial and fungal treatments also significantly influenced the total microbial number, ammonifiers, N2-fixers, fungi, actinomycetes, oligotrophs, copiotrophs, and cellulolytic microorganisms. The effect of microbial treatments varied depending on the applied strains and examined properties, with Bacillus strains being more promising residue decomposers compared to Trichoderma strains. The most effective microbial strains could be used as potential decomposers of crop residues. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR31072]

The effects of Cd, Cd + Fe, and Cd + Ni on the thermophilic anaerobic fermentation of corn stover and cow manure were studied in pilot experiments by investigating the biogas properties, process stability, substrate biodegradation, and microbial properties. The results showed that the addition of Fe and Ni into the Cd-containing fermentation system induced higher cumulative biogas yields and NH4+&ndash, N concentrations compared with the only Cd-added group. Ni together with Cd improved and brought forward the peak daily biogas yields, and increased the CH4 contents to 80.76%. Taking the whole fermentation process into consideration, the promoting impact of the Cd + Ni group was mainly attributed to better process stability, a higher average NH4+&ndash, N concentration, and increased utilization of acetate. Adding Fe into the Cd-containing fermentation system increased the absolute abundance of Methanobrevibacter on the 13th day, and Methanobrevibacter and Methanobacterium were found to be positively correlated with the daily biogas yield. This research was expected to provide a basis for the reuse of biological wastes contaminated by heavy metals and a reference for further studies on the influence of compound heavy metals on anaerobic fermentation.

Nowadays, biochar is increasingly used widely as an important soil amendment to enhance soil nutrients availability. Therefore, we investigated the effect of C.oleifera shell biochar (CSB) on C.oleifera plantation soils to provide evidence that C. oleifera shell as a raw material in biochar has great potential to be a soil amendment. For this, a short-term incubation experiment was conducted in controlled conditions to evaluate the effects of CSB application on two soil chemical properties, microbial biomass, and enzymatic activity. We compared two acidic soils, mixed with CSB of three pyrolysis temperatures (300, 500, and 700 &deg, C), and two application rates (3% and 5% (w/w)), incubated for 180 days. The results showed that the soil pH, total P (TP), and available P (AP) significantly increased under 5CSB700 in two soils, and indicated CSB application rate and pyrolysis temperature had a significant impact on soil pH, TP, and AP (p &lt, 0.05). CSB application also significantly increased the total inorganic P in two soils and presented a significantly positive correlation with soil pH, TP, and AP under redundancy analysis. The results suggested that CSB application has a variable effect on soil enzymatic activity, microbial biomass C (MBC), and microbial biomass P (MBP) on average, while it increased the soil microbial biomass N (MBN) in both soils. We concluded that CSB could be a soil amendment to increase soil nutrients of C.oleifera plantation soils. Before the application of biochar to C.oleifera plantation forest soils, long-term studies are required to assess the effects of biochar under field conditions and its promoting effect on the growth of C. oleifera.

This study investigated the effects of the mud-sinking (MS) method, agar gel-sinking (AS) method and agar gel-sinking with artificial aquatic mat (ASA) method on the growth, physiological characteristics, water purification capacity, and associated microbial community of the different organs of Vallisneria natans (V. natans). Results showed that the growth of agar-based growth (group AS and ASA) were more effective than the mud-wrapped method (group MS), exhibiting longer length, higher fresh weight and biomass of agar-based V. natans with the artificial aquatic mat (group ASA) being higher than those of other groups. MS caused a stress response in the oxidative system, which then inhibited photosynthesis. Results of water quality measurements showed that the three planting methods positively affected water purification without significant differences (p &gt, 0.05). Besides, there was no significant difference (p &gt, 0.05) between the microbial communities in terms of the roots and those found in rhizosphere soils in the MS group with high throughput sequencing. Meanwhile, the addition of agar in the AS and ASA groups increased the diversity of rhizosphere soil microbial communities and reduced the diversity of root microbial communities. Microbial community compositions in the rhizosphere soil and root differed significantly (p &lt, 0.05). High throughput sequencing and scanning electron microscopy (SEM) also revealed that the biofilm on the surfaces were different, with Proteobacteria and Cyanophyta consistently dominating. This study provides new insights on the more effective revegetation methods of V. natans, researched the environmental impact of the addition of agar, and provides some theoretical support for the revegetation of submerged macrophytes under ecological restoration.

Sodium nitrite has been always considered as one of the common additives due to its antibacterial effects on Clostridium botulinum and meat products' color, however it produces cancer creating nitrosamine. Recently, organic acids and their salts such as lactates have been employed as antimicrobial compounds. Lactates also improve organileptic properties including color, texture and taste and antioxidant properties. Sodium lactate causes to more reduction of anaerobic spore former bacteria than nitrite, inhibits botulin produced by Clostridium botulinum. Sodium lactate produces a permanent reddish pink color through reduction of deoxymygloboline and producing deoxymyoglobuline. In this study, the decrease of sodium nitrite amount from 120ppm to 15ppm by adding sodium lactate / sodium diacetate led to achieve an acceptable product. The best results revealed through adding 3.0625% of sodium lactate / sodium diacetate in combination with 30ppm sodium nitrite. Results also exhibited more reduction of pathogens' growth than nitrite, enhanced flavor slightly, but unable to produce reddish pink color as produced by nitrite. Results also exhibited that sodium lactate / diacetate cause to retard in microbial growth, reducing chemical change, enhance sensory properties, partially improvement in taste and texture. Although inappropriate color demonstrated sodium lactate / diacetate's inability in red pink color production in 4th sample (contains 15 ppm nitrite), its synergy effect in combination with sodium nitrite on nitroso myoglobuline production has been proven, led to sodium nitrite reduction in sausages.

Anaerobic fermentation is considered as a cost-effective way of biomass waste disposal. However, the compound heavy metals contained in the biomass may induce complex effects on anaerobic fermentation, which limit the utilization of metal-contaminated biowaste. In this study, the impacts of Cd and Zn addition on biogas properties, process stability, substrate biodegradation, enzyme activity, and microbial properties were studied. The results showed that the addition of Cd together with Zn (Cd+Zn) increased the maximum daily and cumulative biogas yields, and brought forward the gas production peak compared with the Cd-added group. Taking the whole fermentation process into account, the promotion effects of adding Zn into the Cd-containing fermentation system on biogas yields were mainly attributable to better process stability, higher average NH4+-N concentration in the later stage of fermentation, reduced COD (p &lt, 0.05), and increased biodegradability of lignocelluloses (p &lt, 0.01), especially cellulose (p &lt, 0.05) and lignin (p &lt, 0.01). Meanwhile, the addition of Zn promoted the coenzyme M activity (p &lt, 0.05), and increased the absolute abundance of Methanothermobacter. The bacteria communities during the fermentation process were responsible for the degradation of lignocelluloses. The results demonstrated that the addition of appropriate Zn into the Cd-containing fermentation system enhanced the efficiency of anaerobic fermentation and utilization of biowaste.

The objective of the present study was to evaluate the physicochemical and microbial properties of the Korean traditional rice wine Makgeolli, supplemented with banana during 6 day fermentation. The alcohol contents of the control and banana Makgeolli were 17.0 and 16.5%, respectively. The pH values decreased while total acidity, total soluble solids, and color values increased throughout the fermentation process. An increase in microorganism counts throughout the 6-day fermentation period was noted in all samples. The major free sugar and organic acid detected in all samples were glucose and succinic acid, respectively. There were 39 volatile compounds detected in the control and banana Makgeolli. The major ester detected was ethyl acetate (20.037 and 22.604% for the control and banana Makgeolli, respectively). The major alcohol compounds detected were 3-methylbutanol (20.933%) and 3-methyl-1-butanol (34.325%) in the control. 2-mtehyl-1-propanol (22.289%) and 3-methyl-1-butanol (39.851%) were the highest alcohol compounds detected in the banana Makgeolli.

The current trial was conducted to determine the influence of different raising systems on the meat quality properties of male Turkish Pekin ducks. Ninety male ducklings were randomly allocated to three experimental groups: an animal-fish integrated farming group (IG), a non-animal-fish integrated farming group (NIG) and a poultry house group (PHG). All ducklings were fed a starter diet from weeks 2 to 6 and a finisher diet from weeks 6 to 10. Feed and water were offered ad libitum. At the end of the trial all ducks were slaughtered and the carcasses were stored at 3 °C for 24 hours, after which L*, a* and b* values of the carcass skins were measured. After standard dissection of carcasses, pectoralis muscles were obtained on which pH, colour (L*, a*, b*, C and H), total aerobic mesophilic, total aerobic psychrotrophic, lactic acid bacteria, Micrococcus/Staphylococcus, yeast-mould and Enterobacteriaceae counts were determined. The different raising systems of the ducks had significant effects on the pH, total aerobic mesophilic, Enterobacteriaceae, and L* and b* values of the pectoralis muscle. The lowest pH, total aerobic mesophilic and Enterobacteriaceae counts were found in the PHG group. The lowest L* values for the pectoralis muscle were found in the IG group while the highest a* value was recorded in the IG group. Significant differences in skin colour were observed between the experimental groups. For all production groups, all microbial counts were found to be within acceptable ranges. However, pH, total aerobic mesophilic and Enterobacteriaceae results were found to be lower in the PHG group than in the other groups. Different raising systems were thus found to affect the meat and skin colour of ducks, which may influence the preference of consumers. Keywords : Pekin duck, integrated farming, carcass and meat colour, microbial properties South African Journal of Animal Science Vol. 38 (3) 2008: pp. 217-223

Olive mill waste water (OMW), a by-product of the olive mill industry, is produced in large amounts in Mediterranean countries. Olive mill waste water contains a high organic load, substantial amounts of plant nutrients but also several compounds with recognized toxicity towards living organisms. Moreover, OMW may represent a low cost source of water. Thus, the use of OMW for soil fertigation is a valuable option for its disposal, provided that its impact on soil chemical and biochemical properties is established. Investigations were performed on the short-term influence of OMW on several chemical and biochemical properties of a soil from a continental semi-arid Mediterranean region (Morocco). The soil was amended with 0, 18 and 36 ml 100 g −1 soil of OMW (corresponding to a field rate of 0, 40 and 80 m 3 ha −1 , respectively) and changes in various functionally related properties such as microbial biomass, basal respiration, extractable C and N, and soil hydrolases and oxido-reductases activities were measured over time. The variations of the main physical and chemical properties as well as the residual phytotoxicity of OMW amended and non-amended soils as assessed by tomato seed germination tests were also monitored. Temporary and permanent changes in several chemical and biochemical soil properties occurred following OMW application, thus being these properties varied in sensitivity to the applied disturbance. A sudden increase of total organic C, extractable N and C, available P and extractable Mn and Fe contents were measured. Simultaneously, a rapid increase of soil respiration, dehydrogenase and urease activities and microbial biomass (at 14 day incubation) of OMW amended soils occurred. In contrast, the activities of phosphatase, β-glucosidase, nitrate reductase and diphenol oxidase decreased markedly. The soil became highly phytotoxic after OMW addition (large decline of soil germination capability), mainly at 80 m 3 ha −1 OMW. After 42 days' incubation, however, a complete recovery of the soil germination capability and a residual phytotoxicity of about 30% were observed with 40 and 80 m 3 ha −1 OMW, respectively. These findings indicate that the impact of OMW on soil properties was the result of opposite effects, depending on the relative amounts of beneficial and toxic organic and inorganic compounds present. The toxic compounds contained in OMW most likely counteracted the beneficial effect of organic substrates provided, which promoted the growth and activity of indigenous microorganisms.