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排序方式: 共有144条查询结果,搜索用时 15 毫秒
141.
Furnes H Banerjee NR Muehlenbachs K Staudigel H de Wit M 《Science (New York, N.Y.)》2004,304(5670):578-581
Pillow lava rims from the Mesoarchean Barberton Greenstone Belt in South Africa contain micrometer-scale mineralized tubes that provide evidence of submarine microbial activity during the early history of Earth. The tubes formed during microbial etching of glass along fractures, as seen in pillow lavas from recent oceanic crust. The margins of the tubes contain organic carbon, and many of the pillow rims exhibit isotopically light bulk-rock carbonate delta13C values, supporting their biogenic origin. Overlapping metamorphic and magmatic dates from the pillow lavas suggest that microbial life colonized these subaqueous volcanic rocks soon after their eruption almost 3.5 billion years ago. 相似文献
142.
In vitro biodegradation of trifloxystrobin (TFS) under darkness could best be explained by two-compartment first + first-order rate kinetics with half-lives ranging between 1.8 and 2.3 days. Hydrolysis was found to be the major pathway of degradation resulting in the formation of the acid metabolite, TFS-acid, with an EE conformation. The adsorption rate kinetics of both TFS and TFS-acid followed linear and Freundlich isotherms. The extent of adsorption was directly correlated with organic matter and clay contents, whereas desorption had a negative correlation. The high partition coefficients (KD) indicate strong adsorption of TFS on all of the test soils without any appreciable risk of groundwater contamination. In case of the TFS-acid, however, the adsorption was weaker; hence, if its further degradation is slow, it may contaminate lower soil horizons under worst case conditions. TFS did not cause any adverse effect on the soil microbial population. TFS was susceptible to aquatic photolysis in summer with an environmental half-life of 0.7-1.3 days irrespective of the latitudes. 相似文献
143.
Arunachalam Thangasamy Kalyani Gorrepati T. P. Shabeer Ahammed R. Kavita Savalekar Kaushik Banerjee Sankar V 《Archives of Agronomy and Soil Science》2018,64(2):219-230
In an ongoing field experiment, organic and conventional farming (control) were compared for onion bulb yield, biochemical quality, soil organic carbon (SOC), and microbial activity after the sixth cropping cycle. The treatments used for organic production were farmyard manure (FYM, 20,000 kg ha?1), poultry manure (PM, 10,000 kg ha?1), vermicompost (VC, 10,000 kg ha?1), neem cake (NC, 5000 kg ha?1), and a combination of FYM (5000 kg ha?1), PM (2500 kg ha?1), VC (2500 kg ha?1), and NC (1250 kg ha?1); all treatments were compared with the control. Organic treatments produced 24.6–43.6% lower yield consistently for 6 years than the control treatment. No significant difference was observed between PM, FYM, and VC treatments for the bulb yield. Bulb analysis during the sixth year indicated that plants that received FYM, PM, or VC had higher levels of total phenol, total flavonoid, ascorbic acid, and quercetin-3-glucoside than the control plants. All the five organically treated sets had significantly higher values of SOC, microbial population, fungal-to-bacterial ratio, and dehydrogenase activity than the control and the initial values in each treated set. The results indicate that FYM, PM, or VC application enhances biochemical quality and organic farming is more sustainable than conventional farming. 相似文献
144.
Weeds pose a major challenge at the initial stages of sugarcane and when uncontrolled cause high yield losses. This study was undertaken to define a better and cost-effective weed management strategy. We compared ametryn + trifloxysulfuron-sodium (hereafter referred to as trifloxysulfuron) ready-mixes with single applications of trifloxysulfuron, atrazine and 2,4-D for efficacy, non-target and residual toxicities, yield and profitability in a sugarcane–green gram rotation. Results showed that a density of 100 weeds m?2 could reduce sugarcane yield by 18.4 t ha?1. The ready-mix ametryn + trifloxysulfuron (1097.3 + 27.8) g a.i. ha?1 applied 15 days after planting (DAP) caused reductions in weed density by 88.2%, 90.9%, and 90.3%, and weed biomass by 68.0%, 53.8%, and 56.2% compared to unweeded control at 30, 60, and 90 DAP, respectively. Consequently, the sugarcane yield, system productivity, and net returns were increased by 92.1%, 43.5%, and 1515%, respectively due to this ready-mix. It increased system productivity by 23%, 17.2%, and 22.7% compared to trifloxysulfuron, atrazine, and 2,4-D treatments, respectively. This ready-mix may be recommended in sugarcane. This would reduce weed seed bank and herbicide application cost by 50%, and prevent/delay weed shift and resistance. 相似文献