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1.
Biological degradation rates of six pharmaceuticals and personal care products were examined in soil from a land application site and in adjacent soil with no prior history of effluent exposure. Microbial degradation rates were compared over 2 weeks under standing water or saturated conditions and draining conditions after having been saturated for 3 days. Biological degradation of 17??-estradiol exhibited rapid rates of biological degradation under both saturated and draining conditions. Half-lives for 17??-estradiol ranged from 1.5 to 4 days; 66?C97% was lost from the soils. Estriol showed a pattern of biological degradation in both saturated and draining conditions though the half-lives were longer (8.7?C25.9 days) than those observed for 17??-estradiol. Twenty-eight percent to 73% of estriol was lost over the 14 days treatment period. Estrone and 17??-ethinylestradiol exhibited slower rates of biological transformation under saturated and draining conditions. Half-lives for estrone ranged between 27.5 and 56.8 days with loss of at most 21%. 17??-ethinylestradiol exhibited half-lives of 22.6?C207 days. Half-life data for ibuprofen ranged from 30.4 to 1,706.4 days in this experiment. Losses of up to 17% were observed in draining soils. Triclosan loss was at most 10%, and half-lives were 70.9?C398.8 days. In all cases, soils that were draining from saturated conditions exhibited faster degradation rates than soils that remained saturated. Prior exposure of the soil to effluent did not always result in higher biological degradation rates.  相似文献   

2.
为明确环氧虫啶异构体在土壤环境中的迁移转化及代谢降解规律,本试验以14C标记外消旋环氧虫啶为示踪剂,综合运用核素示踪与高效液相色谱分离技术,研究了好氧条件下环氧虫啶在3种土壤中的快速降解动态规律,并分析了其形成结合残留和母体降解可能的对映体选择特性。结果表明,好氧条件下环氧虫啶在整个培养期(120 h)内,未发现其2种对映异构体的结合残留形成和母体降解具有手性差异。环氧虫啶在3种土壤中均迅速形成结合残留,其结合残留量由高到低依次为中性黄松土、碱性滨海盐土、酸性红砂土。环氧虫啶属于易降解农药,好氧条件下环氧虫啶在3种土壤中的降解动态显著符合一级动力学方程,其降解速率由快到慢依次为酸性红砂土(半衰期为23.10 h)、中性黄松土(半衰期为53.32 h)、碱性滨海盐土(半衰期为77.02 h)。数据分析还表明,土壤p H对环氧虫啶的降解速率影响最大。本研究为环氧虫啶的登记注册奠定了基础,为环氧虫啶的正确、合理使用提供了科学依据。  相似文献   

3.
建立了黄瓜和土壤中啶氧菌酯残留量的检测分析方法,对啶氧菌酯在黄瓜和土壤中的消解动态及残留规律进行了研究。啶氧菌酯的最小检出量为3.5×10-11g;在黄瓜和土壤基质中的最低检出浓度均为0.005mg·kg-1。对黄瓜和土壤2种基质,设置了0.005、0.05、0.25 mg·kg-13个添加水平,每个添加水平设置5个重复,啶氧菌酯在黄瓜和土壤中的添加回收率为68.61%~122.4%,变异系数为1.06%~17.2%。田间试验结果表明:啶氧菌酯在天津地区黄瓜和土壤中的残留消解半衰期分别为5.71d和12.9 d,在山东地区黄瓜和土壤中的残留消解半衰期分别为2.70d和10.3 d,在江苏地区黄瓜和土壤中的残留消解半衰期分别为9.76d和14.9 d。距最后一次施药5d时,啶氧菌酯在黄瓜中的最高残留量为0.014mg·kg-1,远低于欧盟规定的黄瓜中啶氧菌酯最大残留限量0.05mg·kg-1。  相似文献   

4.
不同pH和氧气条件下土壤古菌与海洋古菌的竞争适应机制   总被引:1,自引:0,他引:1  
pH和氧气是古菌氨氧化活性的关键限制因子。然而,复杂土壤中不同古菌生态型(土壤古菌和海洋古菌)对pH和氧气的竞争适应规律尚未有相关报道。选择活性氨氧化古菌(ammonia-oxidizing archaea, AOA)为类海洋古菌Group1.1a-associated的酸性森林土( pH5.40)和活性氨氧化古菌为土壤类古菌Group 1.1b的碱性水稻土( pH8.02),调节混合土壤pH和氧气浓度;设置稳定性同位素核酸探针实验,通过微宇宙室内培养,监测土壤硝化强度;利用实时荧光定量qPCR和454高通量测序研究pH和氧气对土壤氨氧化古菌和细菌的影响规律。结果表明:pH3.8下没有硝化作用发生,而pH6.0和7.6则发生了强烈硝化作用,且高氧环境下硝化作用强于低氧环境;加底物培养后,氨氧化古菌数量明显增加;活性氨氧化古菌几乎全为土壤类古菌Group 1.1b。研究表明:尽管氧气对硝化作用也有一定影响,但pH是影响硝化作用的主要因素;与类海洋古菌相比,土壤类古菌Group?1.1b更能适应高氧和低氧的碱性土壤环境,因此具有更强的竞争力。  相似文献   

5.
To investigate a proper way to use animal manure as a fertilizer, simulated leaching experiments with soil columns (40 cm) and field experiments were both conducted. Concretely, biological organic fertilizer (BOF), ordinary organic fertilizer (OF), and swine manure (SM) were utilized, with chemical fertilizer (CF) and no phosphorus (NOP) as controls. The mobility of phosphorus and the amount of organic matter (OM) retention in soil were compared. Total phosphorus in the leachate was SM>BOF>OF (simulated) and SM>OF>BOF (field), and the content of Olsen-P in 0 to 20-cm depth of the soil was CF>SM>OF>BOF>NOP (simulated) and CF>BOF>OF>SM = NOP (field), which was caused by the absorption of vegetables in the latter. Moreover, OM retention of BOF treatment was significantly higher than other treatments in 0 to 20-cm depth of soil with vegetable planting. Consequently, it’s not advised to directly apply SM into the soil, while BOF and OF are the better way.  相似文献   

6.
随着药品和个人护理品(Pharmaceuticals and Personal Care Products,PPCPs)生产和使用量的增加,PPCPs及其代谢产物在再生水中的检出种类、检出量不断增多,再生水灌溉可影响PPCPs在土壤-作物(蔬菜)系统中的分布及累积,但其规律及驱动机制尚不明确.为探明再生水滴灌条件下滴头...  相似文献   

7.
水稻秸秆和玉米秸秆在好气和厌氧条件下的腐解规律   总被引:1,自引:0,他引:1  
采用室内模拟培养的方法,研究了水稻秸秆和玉米秸秆在好气和厌氧条件下的腐解规律。结果表明:在0~3个月的培养时间内,水稻秸秆和玉米秸秆腐解较快,腐解率达55%以上。在好气培养条件下,水稻秸秆和玉米秸秆质量减少50%所需要的时间(t_(1/2))分别为59.2 d和52.9 d,而在厌氧培养条件下的t_(1/2)分别为72.6 d和79.9 d。水稻秸秆和玉米秸秆在好气培养条件下的碳释放速率常数k(0.61~0.6月~(-1))高于其在厌氧培养条件下的碳释放速率常数k(0.55~0.57月~(-1))。水稻秸秆和玉米秸秆在好气培养条件下的氮释放速率常数k(0.25~2.36月~(-1))也高于其在厌氧培养条件下的氮释放速率常数k(0.16~2.32月~(-1))。水稻秸秆和玉米秸秆中纤维素、半纤维素和木质素含量在好气培养条件下的减少速率高于其在厌氧培养条件下的减少速率。综上所述,好气培养条件有利于作物秸秆降解和营养物质的释放。  相似文献   

8.
水稻旱作条件下土壤水分对红壤磷素的影响   总被引:14,自引:6,他引:14  
通过温室盆栽和大田试验研究旱作水稻在施用中量磷肥条件下,土壤水分对红壤中几种磷的含量和动态的影响。研究表明:土壤水分水平和采样时间对红壤全磷、有效磷、有机磷和不同形态的无机磷含量都有极显著的影响,且相互间的交互作用明显。栽种水稻后总体来说,土壤全磷、有机磷和O-P含量均有一定的提高,有效磷和Al-P、Fe-P、Ca-P含量则下降;土壤中不同形态无机磷含量为O-P>Fe-P>Al-P>Ca-P;大田和盆栽实验相比,在4种形态的无机磷、全磷和有机磷的排列顺序、演变趋势等方面基本一致,但有效磷则出现相反的结果,同时,大田试验土壤中各种磷的含量要比盆栽试验高得多,表明盆栽条件下,由于根系密度大,使土壤磷素消耗更快。  相似文献   

9.
不同气候条件下潮土微生物群落的变化   总被引:2,自引:0,他引:2  
汪峰  蒋瑀霁  李昌明  孙波 《土壤》2014,46(2):290-296
针对气候变化的背景研究农田土壤微生物对气候变化的响应机制是调控农田土壤养分循环的理论基础。本研究基于设置在3个气候带(冷温带海伦、暖温带封丘和中亚热带鹰潭)的潮土移置试验,利用磷脂脂肪酸(PLFA)分析方法研究了移置第6年土壤微生物群落的变化特征。结果表明,在3种气候条件下潮土移置6年后土壤部分理化性质显著变化,土壤有机质含量表现为冷温带最高而中亚热带最低;在种植玉米的不同施肥处理中,土壤中微生物总PLFAs、革兰氏阳性细菌(G+)、革兰氏阴性细菌(G-)、细菌和放线菌PLFAs含量均表现为海伦封丘鹰潭,真菌/细菌比值在冷温带最低;PLFA图谱的主成分分析显示气候条件显著影响了土壤微生物的群落结构,海伦和封丘位于PC1正轴,而鹰潭位于负轴,受气候影响较大的特征PLFA包括18:1ω7c、16:1ω5c、16:0、18:0和18:2ω6,9c;逐步回归分析显示温度、降雨和土壤有机质是影响微生物群落的主要因子。总体上,气候条件的变化在短期内(6年)改变了土壤微生物的群落结构,可以影响农田生态系统的生物地球化学循环。  相似文献   

10.
We examined the influence of various urea granule sizes (< 2, 7.0, 9.9 and 12.7 mm) applied into a silt loam soil (experiment 1) and soil types (sandy, silt and clay loam) treated with the largest granule (experiment 2) on gaseous N loss (except N2) at field capacity. The prilled urea (PU) was mixed into the soil whereas the urea granules were point-placed at a 5.0-cm depth. For experiment 1, N2O emission was enhanced with increasing granule size, ranging from 0.17–0.50% of the added N during the 45-day incubation period. In the case of experiment 2, the sandy loam soil (0.59%) behaved similarly with the silt loam (0.53%) but both showed remarkably lower emissions than were found for the clay loam soil (2.61%). Both nitrification and N2O emissions were delayed by several days with increasing granule size, and the latter was influenced by mineral N, soil water and pH. By contrast, the NH3 volatilization decreased with increasing granule size, implying the inhibition of urease activity by urea concentration gradients. Considering both experimental results, the NH3 loss was highest for the PU-treated (1.73%) and the larger granules regardless of soil type did not emit more than 0.27% of the added N over 22 days, possibly because the high concentrations of either mineral N or NH4 + in the soil surface layer (0–2.5 cm) and the high H+ buffering capacity might regulate the NH3 emission. Similar to the pattern of NH3 loss, NOx emission was noticeably higher for the PU-treated soil (0.97%) than for the larger granule sizes (0.09–0.29%), which were the highest for the sandy and clay loam soils. Positional differences in the concentration of mineral N and nitrification also influenced the NOx emission. As such, total NH3 loss was proportional to total NOx emission, indicating similar influence of soil and environmental conditions on both. Pooled total N2O, NH3 and NOx emission data suggest that the PU-treated soil could induce greater gaseous N loss over larger urea granules, largely in the form of NH3 and NOx emissions, whereas a similar increase with the largest granule size was mainly due to the total N2O flux.  相似文献   

11.
为了对山西省山区土壤干旱程度和水资源利用情况进行研究,通过称重法研究了山西榆次区不同植被(樱桃林地、耕地、枣树林地和杨树林地)及撂荒地土壤剖面水分变化特征、水分有效性及干燥化效应。结果表明:土壤平均含水量从小到大依次为杨树林地(8.10%)、枣树林地(9.94%)、撂荒地(10.70%)、樱桃林地(14.47%)和耕地(14.53%)。各植被下土层均有不同程度的干层发育,其中耕地和樱桃林地土壤为轻度干层,撂荒地主要为中度干层,而枣树林地与杨树林地则发育了中重度干层。杨树林地各土层均为无效水,枣树林地以无效水为主,撂荒地以无效水与难效水为主,耕地和樱桃林地受灌溉补给,以难效水与中效水为主。各植被中除杨树林地外,土壤水分含量均随土层深度增加先减后增。其中樱桃林地和枣树林地土壤水分都在0—3 m内呈递减趋势,3—5 m土壤水分迅速升高。耕地和撂荒地土壤含水量先减后增,均在2—2.5 m深度土层为含水量低值拐点。杨树林地土壤水分在0—3.5 m保持平稳,3.5—5 m水分呈下降趋势。  相似文献   

12.
Deposition rates of trace metals (Pb, Cu, Zn, Cd) were determined at the Meteorological Station in New Belgrade (H s =74 m; φ=44°49′N and λ=20°24′E) in the hydrological year 1992/93 (1 November-31 October). The dominant characteristics of the observation period were strong drought and drastically reduced pollutant emissions. Traffic and local sources operated at 0–10% of their capacities. Samples of dry and wet precipitation were taken by an automatic collector at a height of 2 m at weekly intervals. Two petri polycarbonate dishes of 93.5 mm diameter, facing upward, and one, facing downward, were used for dry precipitation sampling. Determination in a ‘clean room’ by differential pulse stripping voltammetry provided the low detection thresholds of 0.1, 1.0, 0.5 and 2.0 ng mL-1,i.e. the measurement of minimal dry deposition rates of 0.02, 0.2, 0.1 and 0.4 μg m-2d-1 for Cd, Pb, Cu and Zn, respectively. The mean annual deposition rates, expressed in μg m-2d-1, were found to be as follows: 4.5 (down), 26 (up) and 37 (wet) for Pb, 2.1 (down), 13 (up) and 36 (wet) for Cu, and 3.1 (down), 26 (up) and 95 (wet) for Zn. No values above 0.2 μg m-2d-1 were found for the Cd dry deposition rate and no Cd concentration higher than 1 ng mL-1 for precipitation with an amount >0.5 mm at the weekly interval was detected. Using the XREDS method with a scanning electron microscope, Si, Al, Fe matrix elements and Mg, Ca, S, K, P, Cu, Zn. W were identified as minor constituents of the single spherical particles and of the agglomerates present. Pb could not be categorized as a minor constituent of the coarse particles suspended in the air of New Belgrade on the basis of the previous analysis. Analysis of meteorological data showed road dust transport by outgoing SE-ESE wind from the old city of Belgrade (H s =100–250 m) as a possible Pb source at the chosen site, which was located in a park. A comparative measurement of Pb deposition on linden leaves was carried out in the vegetation period (1 April–31 October) of 1993 and 1994. The Pb distribution on leaves differed in the two growing seasons, while the sum of Pb deposition rates on the downward and upward oriented petri dishes remained practically equal. The Pb accumulation on linden leaves was higher in 1994, first because of an intensive soil supply by rain water. Besides, ‘yellow’ rain was reported during the night 15/16 April, on 16 and 17 April 1994. A Fe concentration of 2.3 μg mL-1 and a Pb concentration of 312 ng mL-1 with a total precipitation of 12.6 mm were found in the weekly wet sample of 13–20 April. Dry deposition rates of 17 and 84 μg m-2d-1 for Cd and Pb, respectively, were measured on the upward facing dishes two weeks later (27 April–4 May). The synoptic analysis confirmed the development of the Saharan cyclogenesis and its influence on the Balkan peninsula in the period of 14 to 17 April 1994. In this region the impact of dustfall originating from the Saharan storm was evident either during wet deposition or through resuspension processes.  相似文献   

13.
The effect of native palygorskite clay and that modified with dodecyltrimethylammonium chloride on the degradation of oil products in an oligotrophic peat soil under complete flooding at the application of lime and mineral fertilizers has been studied under laboratory conditions. It has been shown that the incubation of oil-contaminated soil with unmodified clay and fertilizers at the application of lime under complete flooding with water affects the dynamics of pH and Eh and slows the development of reducing conditions compared to the use of clay without fertilizers. The addition of organoclay under similar conditions favors the formation of potential-determining system with a high redox capacity, which is capable of retaining the potential on a level of 100–200 mV at pH ~ 7 for two months. It has been found that, under the experimental conditions, unmodified and modified clay, which has no toxic effect on the bacterial complex, does not increase the biodegradation efficiency of oil products in the oligotrophic peat soil compared to the experimental treatments without clay addition. Possible reasons for no positive effect of palygorskite clay on the biodegradation rate of oil products under experimental conditions have been analyzed.  相似文献   

14.
15.
以鸭粪为主要材料,添加芦苇皮、水草等不同调理剂进行高温堆肥试验,研究了不同配比条件下堆肥体系的温度、pH、C/N、种子发芽指数(GI)的动态变化及其对废弃物堆肥品质的影响。结果表明,鸭粪与芦苇皮混合堆肥效果最好,堆体升温快,4d达到50℃,高温维持时间为15d,最高温度达70℃,堆肥30d后,油菜种子发芽指数高达90.48%;鸭粪与水草混合堆肥效果较差,高温维持阶段仅8d,最高温度为57℃;纯鸭粪单独堆肥效果最差,16d达到50℃,高温维持时间为6d,最高温度仅为53℃,到堆肥结束44d,油菜种子发芽指数刚达到80.67%。4种混合配料堆肥产品全氮、全磷、全钾含量都有所增加,其中鸭粪与芦苇皮配比增加率最大,分别为15.90%、11.53%和29.94%。综合以上结果,说明添加秸秆类有机质含量较高的调理剂可加快堆肥的腐熟进程,同时减少营养元素的流失,利于养分的保存,保证了堆肥产品的品质。  相似文献   

16.
《Cereal Chemistry》2017,94(4):760-769
The interrelationships between flour quality and the variability in the dough physical properties and bread loaf characteristics were investigated under reduced salt conditions using partial least squares (PLS) regression analysis. Seventy‐two percent of the variability in dough physical properties was explained by the flour quality using a three‐factor PLS model. Damaged starch content (DS), protein content, and farinograph dough development time (DDT) explained the variability of dough creep‐recovery behavior along PLS‐1. Farinograph absorption (FAB), located along PLS‐2, was strongly related to dough adhesiveness, in which adhesiveness was highly correlated to dough stickiness (r = 0.91). Eighty‐nine percent of the variability in bread loaf characteristics was explained by the flour quality using a four‐factor PLS model; the first two PLS factors explained 66% of the variability. The loaf volume was related to a high number of loaf cells, whose expansion resulted in a greater loaf height. The relation between loaf volume and loaf height was expressed more in PLS‐3 than PLS‐1 and PLS‐2. Mean cell wall thickness and mean cell diameter were closely related negatively along PLS‐1, for which DS and farinograph dough stability explained much of the variability in these loaf characteristics. Along the third PLS factor, FAB explained the variability in loaf weight.  相似文献   

17.
Eurasian Soil Science - Managing the surface soil (0−10 mm) is important for microbes and benthic organisms that regulate various ecological services, e.g. regulation of soil or water...  相似文献   

18.
韩光中  王德彩  谢贤健 《土壤》2015,47(6):1015-1020
我国土壤退化发生广、发展快,后果严重,很多问题亟待解决,加大其研究力度势在必行。显而易见,人们对土壤特性与土壤退化过程了解得越详细,对土壤退化的评估与防治也会越好。因此迫切需要建立大量土壤退化时间序列来明确土壤退化过程中时间因素的作用并帮助人们正确理解和认识土壤退化与人为作用之间的关系。为了得到可靠的结果,土壤退化时间序列的建立需包括起始土壤相似性判定与退化土壤绝对或相对年龄的验证两个重要过程。本文详细论述了土壤退化时间序列的构建过程及应注意的问题,并探讨了土壤时间序列在我国土壤退化研究中的意义,旨在为土壤退化时间序列的正确建立与应用提供较为详尽的参考。  相似文献   

19.
冻融条件下黑土无机磷分级及有效性研究   总被引:1,自引:1,他引:1  
乔思宇  周丽丽  范昊明  贾燕锋  武敏 《土壤》2016,48(2):259-264
土壤无机磷是生态系统中磷素的重要组成部分,而冻融作用是土壤无机磷赋存形态与转化的重要影响因素。本研究以黑土为试验土壤,在室内模拟冻融环境,研究冻融前后黑土无机磷各组分含量变化及其有效性。结果表明:冻融后无机磷各组分绝对含量总体呈现增加的趋势;冻融前后相对含量没有表现出明显差异,均呈现出O-PFe-PAl-PCa-P;相关分析和通径分析结果显示,Al-P、Fe-P为有效磷源,并且直接影响有效磷含量,而O-P、Ca-P与Al-P有较大的通径链系数,即O-P、Ca-P通过Al-P间接影响有效磷含量;冻融循环条件下Olsen-P(Y)与有效磷源Al-P(X1)、Fe-P(X2)间呈线性关系。  相似文献   

20.
塔克拉玛干沙漠南缘不同植被区土壤水分状况研究   总被引:1,自引:1,他引:1       下载免费PDF全文
在新疆干旱气候条件下,2009年通过对棉花膜下滴灌进行试验研究,分析了不同灌溉定额和灌水周期对土壤水盐分布及棉花生长的影响。结果表明,灌水周期5d的处理能够达到棉花最适宜的土壤水分范围。在相同的灌水周期下,土壤剖面平均含水量随着灌溉定额的增加而增大。较高灌水频率对根区土壤盐分具有较好的淋洗作用,灌水周期10d的处理,土壤盐分波动变化较大,在生育期内土壤盐分出现累积现象。从节水增产和抑盐方面考虑,灌溉定额3 900m3/hm2,灌水周期为5~7d的灌溉制度适合北疆农业生产。  相似文献   

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