The impact of mulch type on soil organic carbon and nitrogen pools in a sloping site

Three mulch treatments were tested for their ability to control erosion on a sloping site. Additionally, the choice of mulch can also enhance revegetation success and improve soil organic matter input. This study aimed to investigate the effects of three mulching treatments, hydro-seeding, granite mulch and forest mulch, on soil C and N pools at different positions on highly erodible slope with approximately 30 % gradient. Soil moisture, total C (TC), total N (TN), hot water-extractable organic C (HWEOC), hot water-extractable total N (HWETN), microbial biomass C and N (MBC and MBN), inorganic N and potentially mineralisable N were measured. All variables were significantly higher in soils amended with forest mulch than those with hydro-seeding and granite mulch, for the same slope positions. Soil moisture was significantly higher in the lower slope position than middle and upper slope positions in hydro-seeding and granite mulch treatments, whereas no slope effect was observed on soil moisture under the forest mulch application. In the forest mulch treatment, the upper slope position had higher soil TC, TN, HWEOC, HWETN, MBC, MBN, NO₃ ^?-N and total inorganic N than the middle and lower slope positions. Five years following mulch application, forest mulch still exerted a significant influence on soil fertility compared to the other treatments and the influence on soil moisture suggests that this treatment would be the most effective in the control of water-driven soil erosion on this steep site.     

Effect of dietary l-tryptophan on osmotic stress tolerance in common carp, Cyprinus carpio, juveniles

Common carp juveniles were fed two types of diet (control: 0.1% tryptophan and TRP: 0.6% tryptophan) over 15 days. Thereafter, both groups were directly subjected to osmotic challenge (from 0 to 10 ppt) for 168 h. Blood samples were collected at ?240, 0, 6, 24, 72 and 168 h after challenge. Survival and serum cortisol, glucose, sodium and chloride levels were measured to determine stress response and osmoregulation condition. While TRP group showed no mortality until 168 h, cumulative mortality was near 100% at 72 h after challenge in control group. Feeding tryptophan-supplemented diet led to increase in prechallenge cortisol, but not glucose, sodium and chloride values at ?240 h that stayed elevated until 0 h after challenge. After challenge, cortisol and glucose values did not significantly affected by time of sampling but type of diet and diet × time interaction. Sodium values significantly affected by diet type and time of sampling but not their interaction. Chloride values significantly affected by time of sampling but not diet type and their interaction. Control group had higher cortisol, glucose and sodium than TRP at each time of sampling. Control and TRP group showed increasing and decreasing pattern in cortisol and glucose values when experiment progressed after osmotic challenge. Both group showed increasing pattern in sodium and chloride values when experiment progressed after osmotic challenge. Results indicated that tryptophan supplementation enhanced salt water tolerance of carp that is due to increase in basal cortisol and anti-stress effect of tryptophan and possibly increase in serotonergic activity.     

Determination of antibiotic resistance pattern and virulence genes in Escherichia coli isolated from bovine with subclinical mastitis in southwest of Iran

The aims of the present study were to investigate the prevalence of some virulence genes and also determine the antimicrobial resistance pattern of E. coli isolated from bovine with subclinical mastitis. The milk of 502 cows was collected from 8 dairy herds in the southwest of Iran. Conventional biochemical tests were used for identification of E. coli at the species level. Antimicrobial susceptibility patterns of E. coli isolates were determined by disc agar diffusion method and polymerase chain reaction (PCR) was used for detection of seven virulence genes including f17A, afaE-8, afaD-8, eaeA, cnf1, cnf2, and iucD. Seventy (13.94%) isolates of E. coli were identified in 502 milk samples. The highest rate of resistance was observed against tetracycline (18.6%), while none of the isolates were resistant to streptomycin. Eight (11.5%) out of 70 E. coli isolates carried at least one of the virulence genes. The afaD-8 was the most prevalent gene detected in 5 (7.1%) isolates. The afaE-8, iucD, and eaeA were detected in 3, 3, and 2 isolates respectively. Low prevalence of virulence factors may be indicating that most of the E. coli isolates originated from the commensal flora of cows and enter to the udders via environment contamination with feces.

     

Level of dietary energy and 2,4-thiazolidinedione alter molecular and systemic biomarkers of inflammation and liver function in Holstein cows

Background: The objective of the study was to evaluate the effect of overfeeding a moderate energy diet and a2,4-thiazolidinedione(TZD) injection on blood and hepatic tissue biomarkers of lipid metabolism, oxidative stress,and inflammation as it relates to insulin sensitivity.Results: Fourteen dry non-pregnant cows were fed a control(CON) diet to meet 100% of NRC requirements for3 wk, after which half of the cows were assigned to a moderate-energy diet(OVE) and half of the cows continued on CON for 6 wk. All cows received an intravenous injection of 4 mg TZD/kg of body weight(BW) daily from 2 wk after initiation of dietary treatments and for 2 additional week. Compared with CON cows and before TZD treatment, the OVE cows had lower concentration of total protein, urea and albumin over time. The concentration of cholesterol and tocopherol was greater after 2 wk of TZD regardless of diet. Before and after TZD, the OVE cows had greater concentrations of AST/GOT, while concentrations of paraoxonase, total protein, globulin, myeloperoxidase, and haptoglobin were lower compared with CON cows. Regardless of diet, TZD administration increased the concentration of ceruloplasmin, ROMt, cholesterol, tocopherol, total protein, globulin, myeloperoxidase and beta-carotene. In contrast,the concentration of haptoglobin decreased at the end of TZD injection regardless of diet. Prior to TZD injection, the mR NA expression of PC, ANGPTL4, FGF21, INSR, ACOX1, and PPARD in liver of OVE cows was lower compared with CON cows. In contrast, the expression of HMGCS2 was greater in OVE compared with CON cows. After 1 wk of TZD administration the expression of IRS1 decreased regardless of diet; whereas, expression of INSR increased after 2 wk of TZD injection. Cows fed OVE had lower overal expression of TNF, INSR, PC, ACOX1, FGF21, and PPARD but greater HMGCS2 expression. These differences were most evident before and after 1 wk of TZD injection, and by 2 wk of TZD differences in expression for most genes disappeared.Conclusions: Based on molecular and blood data, administration of TZD enhanced some aspects of insulin sensitivity while causing contradictory results in terms of inflammation and oxidative stress. The bovine liver is TZD-responsive and level of dietary energy can modify the effects of TZD. Because insulin sensitizers have been proposed as useful tools to manage dairy cows during the transition period, further studies are required to investigate the potential hepatotoxicity effect of TZD(or similar compounds) in dairy cattle.     

Physical soil properties and slope treatments effects on hydraulic excavator productivity for forest road construction

Effects of moisture, porosity and soil bulk density properties, grubbing time and terrain side slopes on pc 220 komatsu hydraulic excavator productivity were investigated in Miana forests road construction project which located in the northern forest of Iran. Soil moisture and porosity determined by samples were taken from undisturbed soil. The elements of daily works were measured with a digital stop watch and video camera in 14 observations (days). The road length and cross section profiles after each 20 m were selected to estimate earthworks volume. Results showed that the mean production rates for the pc 220 komatsu excavators were 60.13 m3 h(-1) and earthwork 14.76 m h(-1) when the mean depth of excavation or cutting was 4.27 m3 m(-1), respectively. There was no significant effects (p = 0.5288) from the slope classes' treatments on productivity, whereas grubbing time, soil moisture, bulk density and porosity had significantly affected on excavator earthworks volume (p < 0.0001). Clear difference was showed between the earthwork length by slope classes (p = 0.0060). Grubbing time (p = 0.2180), soil moisture (p = 0.1622), bulk density (p = 0.2490) and porosity (p = 0.2159) had no significant effect on the excavator earthworks length.     

Characterization of phytoplasmas related to peanut witches’-broom and stolbur groups associated with alfalfa diseases in Iran

Journal of Plant Diseases and Protection - In the central and south eastern provinces of Iran, alfalfa plants showing phytoplasma diseases-like symptoms categorized into three major types, namely...     

Physiological traits of Acacia concurrens and Eucalyptus crebra with respect to radical site preparation practices in a revegetation trial,south east Queensland,Australia

Purpose

To successfully establish revegetation, there is a need for weed control. Herbicide application and top soil removal (scalping) may be used to suppress weeds. However, scalping alters soil water and nitrogen availability which in turn may affect plant physiology and performance during the early phase of establishment.

Materials and methods

A field trial was established in south east Queensland, Australia, to examine weed control methods, including herbicide application and scalping. Plant survival, mean periodic height gain, specific leaf area and leaf-level physiological traits were measured for Acacia concurrens Pedley and Eucalyptus crebra F. Muell. for 17 months following tree establishment.

Results and discussion

Plant survival and growth of A. concurrens were superior in the scalped area compared to the herbicide area, whereas neither survival nor growth of E. crebra was influenced by weed control methods. In general, there were no or little effect of site preparation practices on carbon and nitrogen isotope composition, specific leaf area, photosynthesis, maximum photosynthesis and instantaneous water-use efficiency. Photosynthetic capacity was not influenced by site preparation practices as reflected through the maximum rate of carboxylation and maximum rate of electron transport.

Conclusions

Despite altering soil nutrient availability in the scalped areas and high weed coverage in the herbicide areas, there was no substantial alteration in plant physiology for both species. E. crebra was less affected by either low nutrient availability in the scalped areas or high weed coverage in the herbicide areas compared to A. concurrens. Therefore, E. crebra could be considered as a valuable species to revegetate degraded lands.     

Crimp analysis of worsted fabrics in the terms of fabric extension behaviour

Inside a woven fabric structure, warp and weft yarns acquire crimp as a result of yarns interlacing according to the weave pattern. Since warp and weft yarns are oriented in two perpendicular directions, applying tensile load in one direction causes extension in the load side and fabric contraction in the opposite direction. This process was investigated in this study by using an image processing procedure and it was found that fabric’s extension is in coincidence with yarn’s de-crimping process in the same direction. After the de-crimping stage, yarns in the load direction will be extended and at the same time crimp in the other direction will be increased, until jamming phenomenon happens in the fabric structure. The crimp interchange between warp and weft yarns follows a three-order polynomial function with a turning point in which the yarns in the load direction have no crimp.     

Isolation and identification of anionic surfactant degrading bacteria from activated sludge

BACKGROUND: Linear alkylbenzene sulfonate (LABS) is an anionic surfactant widely used all over the world. They will eventually end-up and accumulate in household or industrial sewage. Due to their high foaming capabilities which can cause numerous problems in sewage treatment facilities as well as direct toxic effects on many different organisms in ecosystem; they are generally considered as serious pollutants. Many reports have indicated that common bacteria can readily degrade LABS. METHODS: In this survey, two different bacteria were isolated from Tehran municipal active sludge that showed the ability to degrade LABS rapidly and actively upon using it as their sole source of carbon. Biochemical tests as well as 16S rRNA gene sequencing performed. RESULTS: Results have indicated the two isolates to be Acinetobacter johnsoni and Pseudomonas beteli. After experiments to optimize the pH and temperature for growth of the two bacterial isolates, the extent of LABS, utilization was evaluated by HPLC method. The Pseudomonas beteli and Acinetobacter johnsoni isolates were able to degrade 96.4% and 97.2% of the original LABS levels after 10 days of growth, respectively. Mixed culture of the two isolates did not significantly increase LABS utilization (97.6%). CONCLUSION: Our study showed the ability of two isolated steains to rapidly biodegrade LABS under aerobic conditions.     

Changes of extracted bioactive compounds from brown algae (Cystoseira indica) after conversion to mill and tablet using a quantitative metabolomics approach

Aquaculture International - There is developing importance in the biomedical use of seaweeds such as brown algae, mostly due to their contents of bioactive substances. In the present study,...