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371.
Modeling forest floor contribution to phosphorus supply to maritime pine seedlings in two-layered forest soils 总被引:1,自引:0,他引:1
Mathieu Jonard Laurent Augusto David L. Achat Christian Morel Sylvain Pellerin 《Ecological modelling》2010,221(6):927-935
The quantitative contribution of the forest floor to P nutrition of maritime pine seedlings was experimentally determined by Jonard et al. (2009) in a greenhouse experiment using the radio-isotopic labeling. To extend the results of the experiment on a known mineral soil, a modeling approach was developed to predict P uptake of maritime pine seedlings growing in a mineral soil covered with a forest floor layer. The classical nutrient uptake model based on the diffusion/mass-flow theory was extended to take into account mineralization of P in dead organic matter, microbial P immobilization and re-mineralization and P leaching. In addition, the buffer power characterizing the P retention properties of the mineral soil was allowed to vary with time and with the P-ion concentration in solution. To account for increasing root competition with time, a moving boundary approach was implemented. According to the model, the forest floor contributed most of the P supply to the seedlings (99.3% after 130 days). Predicted P uptake was consistent with observed P uptake and modeling efficiency was 0.97. The uptake model was then used to evaluate the impact of the P retention properties of the mineral soil on the contribution of the forest floor to P uptake. Simulations showed that the contribution of the forest floor was much lower in the quasi non-reactive soil (45.7%) but rapidly increased with soil P reactivity. 相似文献
372.
Austal 2000应用于国内“烟塔合一”类项目大气影响评价 总被引:2,自引:0,他引:2
简述了德国"烟塔合一"类大气污染扩散模式,以及相关模式Austal 2000的应用方法,修正了气象参数以适合本地化应用。以天津某电厂为实例,将Austal 2000模式"烟塔合一"和烟囱排烟方式的计算结果进行了对比分析。结果表明,在进行本地化修改后,Austal 2000模式适用于国内有关项目大气预测评价,但从环境影响角度考虑,"烟塔合一"相对于高烟囱排放方式没有明显优势,应用时需慎重。 相似文献
373.
The hilly area of Loess Plateau has some of the highest soil erosion rates in the world, and serious soil erosion causes great
losses of plant nutrients. As the most common land use in Loess Plateau, slope farmland contributed most of the erosion soils.
This study was designed to examine the effects of land use and slope angle of farmland on phosphorus (P) loss in the hilly
area of loess plateau. Farmland (FR), barrenland (BR), and four forest treantment (seabuckthorn+ poplar (SP), immature seabuckthorn
(IS), mature seabuckthorn (MS), immature Chinese pine (ICP)) were the types of land use; 10, 15, 20, 25, 30 degrees were the
slope angles of FR that were compared. The results showed a larger proportion of P loss occurred in erosion soil fraction
of FR, ICP, ICP, and the five slope treatments of FR; in SP, IS, and MS, P loss was primarily through runoff. FR produced
more P loss than SP, IS, ICP, BR, and MS. 20∼30 degrees may be the slope ranges for P loss of FR; FR in this ranges would
loss more P with soil erosion. SP, IS, and MS were reasonable land uses for their less runoff, soil loss, and P loss. Farmlands
over 15 degrees should be abandoned or reforested for it would produce more runoff, soil loss, and P loss. 相似文献
374.
Trail PW 《Environmental management》2006,38(4):532-544
Oil production operations produce waste fluids that may be stored in pits, open tanks, and other sites accessible to wildlife.
Birds visit these fluid-filled pits and tanks (“oil pits”), which often resemble water sources, and may become trapped and
die. The US Fish and Wildlife Service (USFWS) has a program to reduce these impacts by locating problem pits, documenting
mortality of protected wildlife species, and seeking cleanup or corrective action at problem pits with the help of state and
federal agencies regulating the oil industry. Species identification and verification of protected status for birds recovered
from oil pits are performed at the USFWS National Fish and Wildlife Forensics Laboratory. From 1992 to 2005, a minimum of
2060 individual birds were identified from remains recovered from oil pits, representing 172 species from 44 families. The
taxonomic and ecological diversity of these birds indicates that oil pits pose a threat to virtually all species of birds
that encounter them. Ninety-two percent of identified bird remains belonged to protected species. Most remains identified
at the Forensics Laboratory were from passerines, particularly ground-foraging species. Based on Forensics Laboratory and
USFWS field data, oil pits currently cause the deaths of 500,000–1 million birds per year. Although law enforcement and industry
efforts have produced genuine progress on this issue, oil pits remain a significant source of mortality for birds in the United
States. 相似文献
375.
Ozone risk assessment for plants: central role of metabolism-dependent changes in reducing power 总被引:2,自引:0,他引:2
Dizengremel P Le Thiec D Bagard M Jolivet Y 《Environmental pollution (Barking, Essex : 1987)》2008,156(1):11-15
The combination of stomatal-dependent ozone flux and total ascorbate level is currently presented as a correct indicator for determining the degree of sensitivity of plants to ozone. However, the large changes in carbon metabolism could play a central role in the strategy of the foliar cells in response to chronic ozone exposure, participating in the supply of reducing power and carbon skeletons for repair and detoxification, and modifying the stomatal mode of functioning. To reinforce the accuracy of the definition of the threshold for ozone risk assessment, it is proposed to also consider the redox pool (NAD(P)H), the ratio between carboxylases and the water use efficiency as indicators of the differential ozone tolerance of plants. 相似文献
376.
Britton AJ Helliwell RC Fisher JM Gibbs S 《Environmental pollution (Barking, Essex : 1987)》2008,156(2):409-416
The response of alpine heathland vegetation and soil chemistry to N additions of 0, 10, 20 and 50 kg N ha−1 year−1 in combination with simulated accidental fire (+/−) was monitored over a 5-year period. N addition caused rapid and significant increases in plant tissue N content and N:P and N:K of Calluna vulgaris, suggesting increasing phosphorus and potassium limitation of growth. Soil C:N declined significantly with N addition, indicating N saturation and increasing likelihood of N leakage. Fire further decreased soil C:N and reduced potential for sequestration of additional N. This study shows that alpine heathlands, which occupy the headwaters of many rivers, have limited potential to retain deposited N and may rapidly become N saturated, leaking N into downstream communities and surface waters. 相似文献
377.
对冬季填料床处理滇池流域污染河水进行了试验研究。结果表明:通过相关性分析可知,在2~6℃时,废砖块中微生物活性较低,温度回升后,微生物活性也随之增强;2~12℃时,废混凝土/沸石/煤渣组合生物量高,耗氧速率大且较为稳定,COD去除率保持在50%左右。降温期(5~12℃)时,废砖块对TN、NH+4-N和DTP去除率最高,平均可达64.5%、64.7%和69.7%;低温期(2~6℃)时,废混凝土/沸石/煤渣组合对NH+4-N、TN的去除率能达到56.4%~75.1%、56.5%~63.0%,大石子/小石子/煤渣组合削减DTP负荷量达到了2.1 g/(m2·d)。废砖块和大石子/小石子/煤渣组合分别适合在低负荷和高负荷下运行。综上所述,在整个试验过程中(2~12℃),废混凝土/沸石/煤渣组合表现出了对COD、N和DTP去除率相对稳定的特征,是冬季处理滇池流域污染河水的适宜填料。 相似文献
378.
379.
针对电催化还原工艺处理氯酚类有机废水受到限制等问题,制备了过渡金属O-NiCoP/Ni2P催化电极,并用于目标污染物2,4-二氯苯酚废水的电催化还原降解.同时,主要考察了2,4-二氯苯酚浓度、电流密度、电解质浓度、pH和温度等因素对O-NiCoP/Ni2P催化电极降解效能的影响.结果表明,在2,4-二氯苯酚初始浓度为10 mg·L-1,温度为25℃,溶液pH=7,Na2SO4电解质浓度为50 mmol·L-1,电流密度为10 mA·cm-2的条件下,O-NiCoP/Ni2P电极催化降解180 min,对2,4-二氯苯酚去除率可达到72.2%.同时,催化电极循环使用10次,2,4-二氯苯酚的去除效率保持在72.1%~72.7%,表明电极具有良好的稳定性和实际应用的潜在价值. 相似文献
380.
高原湖泊周边农田磷肥的大量施用和城镇村落的聚集造成了土壤剖面磷素不断累积和含磷污染物的大量排放,加剧了湖泊周边浅层地下水的磷污染,磷随湖泊周边区域浅层地下径流入湖也影响着高原湖泊的水质安全. 2019~2021年雨季和旱季,通过对云南8个湖泊周边农田和居民区水井进行监测,分析了452个浅层地下水样中磷浓度的时空差异及驱动因素.结果表明,季节变化和土地利用影响了浅层地下水中磷浓度及其组成,表现为雨季浅层地下水中磷浓度大于旱季,农田大于居民区;溶解性总磷(DTP)是总磷(TP)的主要形态,占75%~81%,溶解性无机磷(DIP)是DTP的主要形态,占74%~80%.8个湖泊周边近30%的样本TP浓度已超过地表水Ⅲ水标准(GB 3838),其中,洱海(52%)、杞麓湖(45%)、星云湖(42%)和滇池(29%)湖泊周边地下水磷的超标率远高于阳宗海(16%)、抚仙湖(13%)、程海(6%)和异龙湖(5%).影响浅层地下水磷浓度的关键因子是土壤剖面中水溶性磷(WEP)、含水率(MWC)、土壤有机质(SOM)、总氮(TN)、 pH和浅层地下水中pH、水位(P<0.05).土壤WEP、 SOM... 相似文献