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1.
重庆主城3条主要支流的污染状况调查   总被引:1,自引:0,他引:1       下载免费PDF全文
分析和比较了綦江、一品河和嘉陵江的水体和水体沉积物中2种重金属(铅和镉)和3种有机物(五氯酚、六六六和甲基对硫磷)的质量浓度差异,并基于重金属铅、镉及有机物五氯酚、六六六、甲基对硫磷对这3条河流的水体质量进行了评价.最后,不仅分析了污染物在河流间的差异是否具有统计学意义,而且评价了污染物的水质类别.  相似文献   
2.
不同堆置措施对园林有机废弃物堆肥有机物降解的影响   总被引:2,自引:1,他引:1  
采取不同的堆置措施,研究了调节C/N和添加复合菌剂对园林废弃物堆肥过程中有机物降解的动态变化和生物学指标的影响.结果表明:调节C/N和添加复合菌剂有利于堆肥温度的升高和腐熟的加快,降低堆肥的毒性,促进挥发性固体的降解,能加速有机质、总腐植酸和游离腐植酸的分解,提高堆肥中的胡富比,加快堆肥的腐熟和提高堆肥质量;调节C/N并添加复合菌剂的堆置措施比只进行C/N调节的措施更有利于堆肥的快速腐熟以及堆肥产品质量的提高.  相似文献   
3.
Long-term effects of continuous use of chemical fertilizers and manure on soil fertility and productivity of a maize–wheat system were investigated in the ongoing long-term fertilizer experiment, during rabi (2007–2008) and kharif (2008) seasons at the research farm of Chaudhary Sarwan Kumar Himachal Pradesh Agricultural University–Hill Agricultural Research and Extension Centre, Dhaulakuan. After 16 cropping cycles, bulk density decreased in plots where farmyard manure (FYM) was applied, whereas pH decreased in all the treatments. The organic carbon content of the soil increased in all the treatments except 100% nitrogen (N). Cation exchange capacity (CEC) increased in all the treatments over the initial status of the soil. Available N showed buildup over the initial status in most of the treatments. Available phosphorus (P) declined from initial status in treatments where only N was applied alone or with FYM. There was reduction in available potassium (K) status in all the treatments except 100% NPK. Continuous addition of FYM with balanced application of inorganic fertilizers improved content of exchangeable calcium (Ca) and magnesium (Mg) over initial status compared to imbalanced application of fertilizers. Continuous use of imbalanced inorganic fertilizers resulted in lesser crop yields and nutrient uptake compared to that with the application of balanced dose of inorganic fertilizers with FYM.  相似文献   
4.
白腐菌对难降解污染物的生物降解作用已引起世界范围内的普遍关注,它可通过其分泌的特殊的降解酶系或其他机制将各种难降解的有机污染物彻底降解为CO2和H2O。该文介绍了白腐真菌的生物学特性及其分泌的酶系,阐述了白腐菌所分泌的酶在降解各种难降解有机物中的作用机制,分析了提高白腐菌降解能力的方法,总结了白腐菌在治理环境污染方面的应用现状与研究进展,探讨了白腐菌在实际应用方面的不足以及今后的研究方向,对白腐菌在解决环境污染方面的问题具有实际意义。  相似文献   
5.
沼液微生物燃料电池的产电及有机物降解特性研究   总被引:1,自引:0,他引:1  
为了使发酵沼液得到减量化、无害化处理及能源化利用,该研究构建了以玉米秸秆发酵沼液为阳极底物的双室微生物燃料电池(microbial fuel cell,MFC)。通过对比不同浓度沼液MFC产电特性、化学需氧量(chemical oxygen demand,COD)去除率及库伦效率等探究MFC对玉米秸秆沼液的降解效果及其能量回收效率。结果表明,玉米秸秆沼液MFC能够正常启动,并且能够长时间运行产生电流。当初始COD质量浓度为(3618.6±55.6)mg/L时,其最大功率密度为203.4 mW/m2,COD去除率可达63%;并随着沼液中有机物浓度降低,MFC运行稳定性下降,最大输出功率密度成线性降低。通过对原料及阳极溶液和阳极生物膜菌群结构分析可知,以玉米秸秆发酵沼液为阳极底物的MFC菌群结构合理,MFC可以利用沼液中的水解细菌分解阳极溶液中的纤维素等大分子物质,主要以Clostridia、Flavobacteria和Bacteroidia菌纲为主;同时阳极生物膜可以富集接种物中的产电细菌,分解小分子有机物产生电能,2类微生物可以互利共生,避免了沼液MFC的高浓度抑制。该研究表明,MFC可以降解较高浓度沼液废水,并产生电能,该研究可为发酵沼液的处理与利用提供参考。  相似文献   
6.
Response of the integrated use of mycorrhiza, inorganic and organic manures on microbial variables and yield performance of colocasia (Colocasia esculenta L.) was studied in an acid Alfisol. Significantly highest mean cormel yield (14.13 t ha?1) was recorded due to application of super optimal doses of nitrogen, phosphorus, and potassium (NPK). Integrated application of lime + farmyard manure (FYM) + ½ NPK + zinc sulfate (ZnSO4) has recorded the highest dehydrogenase activity (2.048 µg TPF hr?1 g?1) and Fluorescein Diacetate Hydrolysis assay (1.855 µg g?1 hr?1). The highest acid and alkaline phosphatase activities (77.67 and 51.18 µg PNP g?1 h?1, respectively) were observed due to Vesicular Arbuscular Mycorrhiza (VAM) inoculation in combination with lime + FYM + ½ NPK. Dehydrogenase and phosphatase activities had a highly significant relationship with cormel yield and the biochemical constituents of colocasia. The study emphasized the conjunctive use of balanced inorganic fertilizers and organic manures to enhance the enzymatic activities and to realize higher crop yields of colocasia in acid Alfisols.  相似文献   
7.
The productivity of cotton is lowest in India and far below that of the world average productivity. Suitable management practices like intercropping and judicious combination of organic and inorganic manures are considered as yield improvement technologies and can avoid environmental pollution. However, which intercrop is suitable for the study area and what combination of nutrients will perform better needs to be investiaged. With this background and to test-verify the same, field experiments were conducted on cotton with split plot design to evaluate cotton based intercropping system along with nutrient management practices for enhancing the cotton productivity. Five intercropping systems viz., sole cotton, cotton + onion, cotton + blackgram, cotton + greengram and cotton + lucerne were included in the main plot. The subplot consisted of combinations of inorganic and organic manures namely, 100% recommended inorganic nitrogen (N), 75% inorganic N + 25% N through poultry manure, 75% inorganic N + 25% N through sunnhemp, 75% inorganic N + 25% N through farm wastes, 75% inorganic N + 25% N through weed compost. The results revealed that sole cotton followed by cotton + blackgram intercropping and 75% inorganic N + 25% N through poultry manure recorded better growth and yield attributes, higher cotton yield during both the years. Cotton + onion resulted in the maximum cotton equivalent yield of 2396 kg ha?1 followed by cotton + blackgram (2240 kg ha?1). Better N use efficiency and post-harvest soil available N, phosphorus (P) and potassium (K) was also associated with cotton + blackgram intercropping and 75% inorganic N + 25% N through poultry manure. Benefit: cost (BC) ratios were also higher in the same treatment. It could be concluded from these results that the cotton productivity is higher under the sole crop of cotton, however, the cotton equivalent yield is significantly higher with intercropping and these treatments proved that soil fertility status can be sustained with integrated plant nutrient management practices and intercropping systems.  相似文献   
8.
Sugars are the most abundant organic compounds in the biosphere because they are monomers of all polysaccharides. We summarize the results of the last 40 years on the sources, content, composition and fate of sugars in soil and discuss their main functions. We especially focus on sugar uptake, utilization and recycling by microorganisms as this is by far the dominating process of sugar transformation in soil compared to sorption, leaching or plant uptake. Moreover, sugars are the most important carbon (C) and energy source for soil microorganisms.Two databases have been created. The 1st database focused on the contents of cellulose, non-cellulose, hot-water and cold-water extractable sugars in soils (348 data, 32 studies). This enabled determining the primary (plant-derived) and secondary (microbially and soil organic matter (SOM) derived) sources of carbohydrates in soil based on the galactose + mannose/arabinose + xylose (GM/AX) ratio. The 2nd database focused on the fate of sugar C in soils (734 data pairs, 32 studies using 13C or 14C labeled sugars). 13C and 14C dynamics enabled calculating the: 1) initial rate of sugar mineralization, 2) mean residence time (MRT) of C of the applied sugars, and 3) MRT of sugar C incorporated into 3a) microbial biomass and 3b) SOM.The content of hexoses was 3–4 times higher than pentoses, because hexoses originate from plants and microorganisms. The GM/AX ratio of non-cellulose sugars revealed a lower contribution of hexoses in cropland and grassland (ratio 0.7–1) compare to forest (ratio 1.5) soils.13C and 14C studies showed very high initial rate of glucose mineralization (1.1% min−1) and much higher rate of sugars uptake by microorganisms from the soil solution. Considering this rate along with the glucose input from plants and its content in soil solution, we estimate that only about 20% of all sugars in soil originate from the primary source – decomposition of plant litter and rhizodeposits. The remaining 80% originates from the secondary source – microorganisms and their residues. The estimated MRT of sugar C in microbial biomass was about 230 days, showing intense and efficient internal recycling within microorganisms. The assessed MRT of sugar C in SOM was about 360 days, reflecting the considerable accumulation of sugar C in microbial residues and its comparatively slow external recycling.The very rapid uptake of sugars by microorganisms and intensive recycling clearly demonstrate the importance of sugars for microbes in soil. We speculate that the most important functions of sugars in soil are to maintain and stimulate microbial activities in the rhizosphere and detritusphere leading to mobilization of nutrients by accelerated SOM decomposition – priming effects. We conclude that the actual contribution of sugar C (not only whole sugar molecules, which are usually determined) to SOM is much higher than the 10 ± 5% commonly measured based on their content.  相似文献   
9.
多芳香烃(PAHs)、环硝胺类物质(RDX、HMX、Tetryl和CL-20)、多氯联苯(PCBs)、烷烃类化合物、氯乙烯类、硝基化合物等的有机污染物增多,对自然界和人类生活造成极大危害,自二十世纪七十年代便出现了利用微生物降解有机污染物的生物修复研究,但传统的有机污染物生物修复存在效率不高、难以维持等问题。二十世纪九十年代以来,随着分子生物学技术的迅速发展,其在污染生物修复中得到越来越多的应用,并有效地提高了生物修复效率。本文总结了近年来有机污染物污染修复中应用上述方法的研究,重点分析整理了一系列典型石油污染物降解途径中的加氧酶及其参考菌株,为今后有机污染物的生物修复提供参考。  相似文献   
10.
Effect of integrated use of mycorrhiza, lime, inorganic fertilizers, and organic manures on microbial activities and yield performance of yam bean (Pachyrhizus erosus L.) was studied for two consecutive kharif (rainy) seasons during 2013–14 and 2014–15 in an acid Alfisol. The experiment was laid out with 16 treatments consisting of graded doses of soil test–based nitrogen, phosphors, and potassium (NPK); lime; mycorrhiza; organic sources, that is, farmyard manure (FYM), vermicompost, and green manure; secondary magnesium sulfate (MgSO4) and micronutrients zinc sulfate (ZnSO4 and borax). Significantly highest mean tuber yield (29.61 t ha?1) was recorded due to integrated application of lime + FYM + NPK + ZnSO4. Graded doses of NPK showed a mean yield response of 65%, 134%, and 191% due to addition of 50%, 100%, and 150% of NPK over control, respectively. Inoculation of vesicular–arbuscular mycorrhiza (VAM) combined with NPK and FYM recorded a mean tuber yield of 25.14 t ha?1. Highest mean dry matter (18.85%) was recorded due to application of 150% NPK, whereas highest starch content on fresh weight basis was recorded due to integrated use of lime + FYM + NPK + MgSO4 (11.11%). Application of 150% NPK has recorded highest dehydrogenase activity (2.018 µg TPF h?1 g?1) and fluorescein diacetate hydrolysis assay (2.012 µg g?1 h?1). Fungal inoculation of VAM in combination with lime + FYM + NPK recorded highest acid and alkaline phosphatase activities (82.20 and 67.02 µg PNP g?1 soil h?1, respectively). Soil biological activities and phosphatase activities had highly significant relationship with tuber yield and biochemical constituents of yam bean. The study emphasized the conjunctive use of soil test–based inorganic fertilizers, lime, and organic manures to enhance the enzymatic activities and to realize higher crop yields of yam bean in acid Alfisols.  相似文献   
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