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11.
Mohammad Reza Ghosi Mobaraki Abdolmohammad Abedian Kenari Sara Bahrami Gorji Mohammad Esmaeili 《Aquaculture Nutrition》2020,26(3):894-907
This study investigated the effect of two lipid sources on reproduction performance and growth in pearl gourami. For this purpose, 180 fish (3.32 ± 0.25 g) were fed with three isoenergetic (19.80) and isonitrogenous diets (480 g/kg protein) including FO (80 g/kg fish oil), FS (40 g/kg fish oil and 40 g/kg soybean oil) and SO (80 g/kg soybean oil) for 10 weeks before maturation. At the end of the trial, there was no significant difference in weight gain, feed conversation ratio and body composition between fish fed FO and FS diets. Individuals fed dietary FO had significantly higher levels of n‐3 long‐chain polyunsaturated fatty acids in the muscle (130.5 g/kg lipid) and ovary (140.4 g/kg lipid) as compared with those fed SO diet (64.5, 103.6 g/kg, respectively) (p < .05). Feeding pearl gourami with FO and FS diets enhanced regarding absolute fecundity, relative fecundity, the fertilization rate, larvae total length and survival at 3 day posthatch (p < .05). Also, 17 beta‐estradiol in plasma of fish fed dietary FO (6.2 ng/L) was higher than those fed SO diet (1.7 ng/L) (p < .05). In conclusion, we suggest FS diet for broodstock nutrition of pearl gourami as a model for asynchronous multi‐batch spawning fish. 相似文献
12.
Changes in land use can significantly affect soil properties. This study was conducted in the Taleghan watershed of Tehran Province, Iran, to determine the effects of land use changes on soil organic matter (SOM) and soil physical properties including soil aggregate stability, saturated hydraulic conductivity, infiltration rate, available water content, total porosity and bulk density (BD). In the present study, two sites contained adjacent land uses of natural pasture and dryland farming were selected. Soil samples were taken from depths of 0–15 and 15–30 cm for each land use. The results indicated that the conversion of natural pasture to dryland farming led to a significant decrease in SOM at 0–30 cm in the first and second sites (24.7 and 44.2%, respectively). In addition, a significant increase in BD was observed at a depth of 0–30 cm in dryland farm soils (1.39 g cm–3) compared to pastureland (1.20 g cm–3) at the first site. An increase in BD was also observed at the same depth of dryland farm soils (1.46 g cm–3) and pastureland soils (1.42 g cm–3) at the second site. In addition, total porosity, mean‐weight diameter of aggregates, saturated hydraulic conductivity, available water content and estimated final infiltration rate showed significant differences between land uses. The results showed that the conversion of natural pasture to dryland farming alters soil properties that negatively affect soil productivity and erodibility. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
13.
Salman Mirzaee Ali Asghar Zolfaghari Manoochehr Gorji Miles Dyck Shoja Ghorbani Dashtaki 《Archives of Agronomy and Soil Science》2013,59(5):681-693
In this study, the ability of eight different infiltration models (i.e. Green and Ampt, Philip, SCS (US-Soil Conservation Service), Kostiakov, Horton, Swartzendruber, Modified Kostiakov (MK) and Revised Modified Kostiakov (RMK) models) were evaluated by least-squares fitting to measured infiltration data. Six comparison criteria including coefficient of determination (R2), mean root mean square error (MRMSE), root mean square error (RMSE), the F-statistic (F), Cp statistic of Mallows (Cp) and Akaike information criterion (AIC) were used to determine the best performing model with the least number of fitting parameters. Results indicated that R2 and MRMSE were not suitable for model selection. A more valid comparison was achieved by F, Cp, AIC and RMSE statistics. The RMK model including four parameters had the best performance with the majority of soils studied. RMK was better than the MK model in approximately 51.6, 57, 68.5 and 70.6% of soils, when using F, Cp, AIC and RMSE statistics, respectively, and for the other models, a higher per cent of soils was obtained. The RMK model was the best for loam, clay loam and silty clay loam soils, but the MK model was the best for silty loam soils. 相似文献
14.
Hossein Asadi Mohammad Ghorbani Mehran Rezaei-Rashti Sepideh Abrishamkesh Elnaz Amirahmadi Chen Chengrong Manouchehr Gorji 《水稻科学》2021,28(4):325-343
This paper critically reviewed the current knowledge and challenges of rice husk biochar(RHB) production and its effects on soil properties, plant growth, immobilization of heavy metals, reduction of nutrient leaching and mitigation of greenhouse gas emissions. The characteristics of RHBs produced at various pyrolysis temperatures were discussed and compared to biochars derived from other agroindustrial wastes. RHBs produced at higher pyrolysis temperatures show lower hydrogen/carbon ratio, which suggests the presence of higher aromatic carbon compounds. The increase of pyrolysis temperature also results in production of RHBs with higher ash content, lower yield and higher surface area. RHB usually has higher silicon and ash contents and lower carbon content compared to biochars derived from other feedstocks at the same pyrolysis conditions. Although it depends on soil type, RHB application can improve soil organic carbon content, cation exchange capacity, available K concentration, bulk density and microbial activity. The effect of RHB on soil aggregation mainly depends on soil texture. The growth of different crops is also enhanced by application of RHB. RHB addition to soil can immobilize heavy metals and herbicides and reduce their bioavailability. RHB application shows a significant capacity in reduction of nitrate leaching, although its magnitude depends on the biochar application rate and soil biogeochemical characteristics. Use of RHB, especially in paddy fields, shows a promising mitigation effect on greenhouse gas(CH_4, CO_2 and N_2 O) emissions. Although RHB characteristics are also related to other factors such as pyrolysis heating rate and residence time, its performance for specific applications(e.g. carbon sequestration, p H amendment) can be manipulated by adjusting the pyrolysis temperature. More research is needed on long-term field applications of RHB to fully understand the advantages and disadvantages of RHB as a soil amendment. 相似文献
15.
Amongst all forest utilization phases, harvesting plays a key role as the beginning phase of the utilization cycle and has a significant effect on the following phases.In this research, in order to examine the reduction of costs with respect to present and planned operations, the starting time of the harvesting or cutting phase and work flow were recorded. The starting time of each phase of the entire operation was recorded as well. Before harvesting the marked tree, the appropriate felling direction was determined and the azimuth of the correct direction was taken.The results indicate that there was not a meaningful relationship between the differences in direction of a leaning tree compared with the felling direction. However, there was a significant relationship between the difference of the defined and felling direction and the difference in tree leaning and defined direction. The same trend was observed between tree leaning and felling directions and tree leaning and defined directions. On the other hand,there was no significant relationship between tree leaning and felling directions and the defined and tree felling directions. In addition, this research shows that with an increase in tree volume, the time for tree cutting rose.Furthermore, when the difference of tree leaning and felling direction decreased, the time to cut the tree declined.The regression equation is Y = 168.9–0.14(the difference between tree leaning and felling direction) + 0.7(volume). 相似文献
16.
The aim of this study was to investigate the development of the pupillary light reflex in neonatal calves and the effect on the development of the menace response of keeping them in individual stalls. Seventy-three Holstein calves were divided into test (n = 44) and control (n = 29) groups and the animals were kept in individual stalls for the first 32 ± 4 and 73 ± 5 days post partum, respectively. They were then moved to group pens. All calves in both groups were observed daily from the first day after birth until the pupillary light reflex and menace response had become well established.All 73 calves had a positive pupillary light reflex on the first day post partum. None of the animals developed a menace response during the time they were housed in individual stalls. Over 14 days (test group) and 12 days (control group) after the calves had been moved to the group pens they became positive to the menace response at ages 41 ± 4 and 81 ± 5 days, respectively. The Mann–Whitney test revealed a significant difference (P < 0.001) in the ages of the calves with positive menace responses between groups. Group rearing may produce more visual threats to the eyes and the calves learn the menace response by closing the lids in response to sudden alarming movements. 相似文献