Temporal variation of total and DTPA-extractable heavy metal contents as influenced by sewage sludge and perlite in a calcareous soil

Continuous application of sewage sludge (SS) as a source of organic matter, may increase available heavy metals (HMs) up to their critical levels. As a consequence their uptake by plants, risks of accumulation in food chain and groundwater pollution increases. To evaluate the effects of perlite and SS on total content and available fraction of iron (Fe), manganese (Mn), lead (Pb), copper (Cu), nickel (Ni), cadmium (Cd) and zinc (Zn) over 45 and 90 days a completely randomized pot experiment was conducted. Treatments consisted of SS (0, 2 and 4%) and combined SS and perlite levels (1:1, 1.5:0.5 and 0.5:1.5% SS:perlite). Mean available Fe, Ni, Cd, Mn and Zn fractions decreased over time by 7–27%, whereas, total contents did not change. Available HMs in SS-treated soils increased by 0.5–25%; whereas, only total Zn, Cu and Pb concentrations increased with SS application (although concentrations fall in the range of critical levels). The lowest (1.6 fold) and highest (22.1 fold) increases obtained for available Cu and Zn, respectively. Perlite could mitigate the adverse effect of high rate application of SS on amplification of HMs extractability. Therefore, their concomitant applications can be suggested considering the perlite durability and its positive effects on soil physical properties.     

Stimulation in the movement and uptake of phosphorus in response to magnetic P solution and arbuscular mycorrhizal fungi in Ocimum basilicum

A greenhouse experiment was conducted to assess the effects of magnetic field, arbuscular mycorrhizal fungi (AMF), and phosphorus (P) concentration in the nutrient solution (0, 5, 10, 20, or 40 mg L^?1) on the mobility and accumulation of P in soil and plant tissues of basil (Ocimum basilicum L.). The experiment was designed as a factorial combination and treatments were arranged in a completely randomized design with four replicates. Magnetic field increased water-soluble P in the soil and P concentration in plant shoot by 30.0% and 13.0%, respectively, in comparison to the control. The application of magnetic field and inoculation of AMF at 10 mg P L^?1 increased the P translocation efficiency by 23.3% and 17.8%, respectively. Overall, our results demonstrated that the use of magnetic field and AMF could be an effective tool for enhancing of uptake and movement efficiency of P even at low concentrations.     

Integrated effects of cattle manure-derived biochar and soil moisture conditions on soil chemical characteristics and soybean yield

ABSTRACT

A greenhouse experiment was carried out to evaluate the effect of 0, 25, 50 and 100 ton ha^?1 of cattle manure-derived biochar (BC) and soil moisture conditions (SMC) of 100%, 70% and 55% of water-holding capacity (WHC) on soybean production. Most of the macro and micronutrient, soil chemical characteristics and yield production of soybean were significantly affected by BC. Under drought, BC was more effective than that of the non-stressed conditions. Interaction effect of SMC and BC on soil iron (Fe), zinc (Zn), manganese (Mn), calcium (Ca), magnesium (Mg), phosphorus (P) and nitrogen (N) concentrations was also significant indicating that different levels of water supply might show different impact under different levels of BC. Under drought, the higher BC applied, the higher grain yield obtained. Application of 0 to 75 ton BC ha^?1 under WHC caused a high grain yield but 100 ton BC ha^?1 significantly decreased it as compared with the other levels of BC. Positive impacts of BC may be more pronounced under drought. High level of BC in non-stressed conditions may reduce grain yield as occurred in this study. The statistical techniques indicated that higher content of macro and micronutrients negatively associated with yield production of soybean.     

Cattle manure biochar potential for ameliorating soil physical characteristics and spinach response under drought

Drought and low amounts of organic matter are two main constraints in arid and semiarid regions and their adverse effects on soils and plants can be alleviated by biochar (B). Therefore, the influence of 0 (0B), 1.25 (1.25B), 2.5 (2.5B) and 5% (5B) cattle-manure biochar on the growth and physiological traits of spinach and physical characteristics of postharvest soil under field capacity (FC), 0.7FC and 0.55FC conditions was evaluated. Drought decreased stomatal conductance (SC), water use efficiency (WUE), shoot dry matter yield (SDMY), soil water repellency (WR) and saturated hydraulic conductivity (K_s) by 13–45%, 3–17%, 27–51%, 48–60% and 26–36%, respectively. Whereas, all B treatments increased SC, K_s and total porosity by 11–63%, 82–221% and 2–12%, respectively. Application of 1.25B increased SDMY and WUE, whereas higher B levels were ineffective, i.e. 2.5B did not significantly affect the measured parameters and 5B reduced them. At all B levels, drought reduced SDMY. However, the lowest decrease in SDMY was observed by 1.25B. Despite their positive influence on soil’s physical quality, high B levels induced excessive salinity. Therefore, a low B level (1.25B) may be recommended since it provides positive impacts on the plant’s growth and yield while mitigating the adverse effects of drought.     

Seroepidemiological study of bovine respiratory viruses (BRSV, BoHV-1, PI-3V, BVDV, and BAV-3) in dairy cattle in central region of Iran (Esfahan province)

Respiratory diseases in calves are responsible for major economic losses in both beef and dairy production. Several viruses, such as bovine respiratory syncytial virus (BRSV), bovine herpes virus-1 (BoHV-1), bovine parainfluenza virus-3 (BPI-3V), bovine viral diarrhea virus (BVDV), and bovine adenoviruses (BAV), are detected in most clinical cases with respiratory signs. The aim of this study is to define seroprevalences of five major viral causes of bovine respiratory infections in cattle in central region of Iran (Esfahan province). The population targeted was 642 dairy cows (Holstein–Friesian) from 25 farms. Samples of blood serum from female cattle were examined. Sera were tested by commercial ELISA kits to detect antibody against BRSV, BoHV-1, BPI-3V, BVDV, and BAV-3. The results were analyzed by Chi-square test. In the present study, seroprevalences of BRSV, BoHV-1, PI3V, BVDV, and BAV-3 were 51.1%, 72%, 84.4%, 49.2%, and 55.6%, respectively. The present study shows that infections of bovine respiratory viruses are very common in cattle in Esfahan.     

Copper,zinc, and iron concentrations in blood serum and diet of dairy cattle on semi-industrial farms in central Iran

The aim of this study was to evaluate the blood serum and diet concentrations of copper, zinc, and iron in Holstein dairy cattle kept under semi-industrial farming in Isfahan province, central Iran. Moreover, the effects of season, pregnancy, and daily milk yield on serum Cu, Zn, and Fe concentrations were also evaluated. The study was carried out on 12 semi-industrial Holstein dairy cattle farms. A total of 120 blood serum samples (60 in each season) and 24 diet samples (12 in each season) were collected in the summer and winter. The Cu, Fe, and Zn contents were assessed in samples using atomic absorption spectrophotometer. In the summer, the mean concentrations of Cu and Fe in serum samples were lower and higher than the critical level, respectively (P < 0.05). In total diet samples, the mean concentrations of Zn were significantly higher than critical level (P < 0.05). In summer, winter, and total diet samples, the mean concentrations of Fe were significantly higher than critical level (P < 0.05). The serum Cu and Zn concentrations were significantly higher in the winter than those determined in the summer (P < 0.05). The serum Cu concentrations were significantly higher in nonpregnant than those in pregnant dairy cattle (P < 0.05). No significant difference was observed in serum Cu, Zn, and Fe concentrations of dairy cattle in different daily milk yield groups. It can be concluded that Holstein dairy cattle reared under semi-industrial dairy farming were deficient in serum Cu concentrations, especially in summer. Further, high level of Fe in blood serum might be due to feeding of cattle with diet containing excess quantity of Fe.     

Seroprevalence of bovine leukemia virus (BLV) infection in dairy cattle in Isfahan Province, Iran

Bovine leukemia virus (BLV), the causative agent of enzootic bovine leukosis (EBL) is an exogenous C-type oncovirus in the Retroviridae family. It causes significant economic losses associated with the costs of control and eradication programs due to carcass condemnation at slaughter and restrictions of export of cattle and semen to importing countries. The main objective of this research was to determine the seroprevalence of BLV infection in cattle herds in central region of Iran (Isfahan province) using a commercial enzyme-linked immunosorbent assay (ELISA) to detect serum antibodies against BLV. Samples of blood serum were collected from 403 female dairy cattle (Holstein-Friesian) from 21 livestock farms and 303 animals (81.9%) were BLV seropositive. A significant association was found between age as a potential risk factor and BVL seroprevalence with animals ≥ 4 years (86.6%) having a significantly (χ(2) = 35.6, p < 0.001) higher seroprevalence compared to those < 4 years (54.2%). We found no significant statistical association between seroprevalence and pregnancy, lactation status and farming systems as potential risk factors in this study (p > 0.1). It is concluded that BLV infection is a very common problem in the study area. Hence, control measures should be instituted to combat the disease and further studies are required to investigate the impact of this disease on dairy production in the country.