风沙土成土演变过程中土壤微生物生物学特性研究进展与展望

对风沙土成土演变过程中的土壤微生物分布及组成、微生物生理群、微生物活性及固沙植物的根际微生物特性等微生物学特性研究成果进行了归纳和总结,得出了在风沙土成土演变过程中,随着生境的不断变化,各类微生物的数量显著增加,其分布随着土层深度、种植年限和季节的不同而不同、微生物活性也明显增加。流沙上种植固沙植物后,根系产生的各种代谢物改变了根际的理化环境,促进了根际微生物的发展,同时微生物的旺盛繁殖,也促进了风沙土向良性方向演变。     

高分子聚合筑路剂(P.P.T)用于改善铁路路基力学特性的研究

高速、重载铁路的发展对铁路路基的稳定性、承载力提出了更高的要求,为此,笔者介绍一种运用新型高分子聚合的筑路剂——P.P.T来改善路基力学特性的方法。通过对P.P.T改良土封顶前后路基稳定性和承载力的计算和比较分析,指出其改良土在较薄封顶厚度的前提下,仍能够有效提高路基边坡的稳定性,尤其是能大幅度提高路基的容许承载力。此外,P.P.T在防治路基其他常见病害方面与传统的灰土相比也具有较大优势,实际工程应用表明,P.P.T具有较好的推广价值。     

细胞色素P450酶系作为生物标志物在毒理学上的应用

细胞色素P450酶系是一种血红素-硫铁蛋白(heme-thiolate protein)，它是由结构和功能相关的超家族(superfamily)基因编码的含铁血红素同工酶组成。对许多内源性和外源性的化学物质尤其是对环境有害化合物存在有氧氧化代谢作用以实现机体的解毒作用，但在某些情况下，外来物质可能被转化为具细胞毒性、致突变性或致癌作用更强的物质，起毒性活化作用。本文对细胞色素P450的研究简史及其作为生物标志物在毒理学上的应用作了简要的综述。提出细胞色素P450酶系在毒理学上的意义是可作为污染物潜在影响的早期预警信号系统对环境污染上物进行监测和预报，且对于制定预防性的管理措施，及时避免或减轻环境污染的损害都具有重要意义。     

INTEGRATING PHOSPHORUS AND NITROGEN DECISION MANAGEMENT AT WATERSHED SCALES1

ABSTRACT: The persistence of water quality problems has directed attention towards the reduction of agricultural nonpoint sources of phosphorus (P) and nitrogen (N). We assessed the practical impact of three management scenarios to reduce P and N losses from a mixed land use watershed in central Pennsylvania, USA. Using Scenario 1 (an agronomic soil P threshold of 100 mg Mehlich‐3 P kg^‐1, above which no crop response is expected), 81 percent of our watershed would receive no P as fertilizer or manure. Under Scenario 2 (an environmental soil P threshold of 195 mg Mehlich‐3 P kg^‐1, above which the loss of P in surface runoff and subsurface drainage increases greatly), restricts future P inputs in only 51 percent of the watershed. Finally, using scenario 3 (P and N indices that account for likely source and transport risks), 25 percent of the watershed was at high risk or greater of P loss, while 60 percent of the watershed was classified as of high risk of nitrate (NO₃) leaching. Areas at risk of P loss were near the stream channel, while areas at risk of NO₃ leaching were near the boundaries of the watershed, where freely draining soils and high manure and fertilizer N applications coincide. Remedial measures to minimize P export should focus on critical source areas, while remedial measures to reduce N losses should be source based, concentrating on more efficient use of N by crops.     

Nutrient cycling characteristics of Quercus acutissima and Pinus massoniana mixed forest in the Three-Gorge Reservoir area, China

The cycling characteristics of nitrogen(N), phosphorus(P) and potassium(K) of the Quercus acutissima and Pinus massoniana mixed forest, which is the most common forest type in the Three Gorge Reservoir areas in China, were systematically analyzed. The results showed that N, P and K accumulated in the plant pool and in the litter pool, while total N, P, and K were deficient in the soil pool and in the forest systems. Contents of N in the soil of depth 20-40 cm were the key factor limiting growth of trees. The biological outside cycling coefficients were 8.78, 72.5 and 11.7 times of inside cycling coefficients of N, P and K, respectively. 33.92, 10.26 and 15.88 kg of N, P and K return to the litter pool from branches, leaves and throughfall per year, but, 14.31, 1.32 and 10.48 kg of N, P and K return to the soil from litter pool per year respectively. It is clear that 58% of N, 87% of P, and 34% of K are lost by surface runoff per year. 5.49%, 1.30%, and 8.34% of N, P and K withdraw from leaves to branches, 4.99%, 1.99% and 7.30% of N, P and K withdraw from branches to trunks per year,respectively.     

海河流域碳、氮、硫、磷及生态环境数据库

介绍了海河流域碳、氮、硫、磷及生态环境数据库的建库目标,指导系统分解的概念模型,选择录入数据的指标体系,数据库系统构成及所含6个子库典型输出表。做为数据库的必要功效补充,还建立了地理信息系统。整个数据库系统是在DBASE-Ⅲ、汉化地理信息系统工具和FORTRAN-77统计与模式程序包支持下,在PC/AT微机上实现的。     

Treatment of turtle-breeding wastewater and domestic fecal sewage with soil cultivating system

ＩｎｔｒｏｄｕｃｔｉｏｎＬａｎｄｔｒｅａｔｍｅｎｔｓｙｓｔｅｍｆｏｒｔｒｅａｔｉｎｇｍｕｎｉｃｉｐａｌｓｅｗａｇｅｈａｓｂｅｅｎｆａｉｒｌｙｄｅｖｅｌｏｐｅｄａｔｈｏｍｅａｎｄａｂｒｏａｄ ,ｗｈｉｃｈｉｓａｌｏｗｃｏｓｔａｎｄｈｉｇｈｅｆｆｉｃｉｅｎｃｙｓｅｗａｇｅｔｒｅａｔｍｅｎｔｍｅｔｈｏｄｏｎｃｅｒｔａｉｎｃｏｎｄｉｔｉｏｎｓ.ＩｎｔｈｅｐａｓｔａｆｅｗｙｅａｒｓａｒｔｉｆｉｃｉａｌａｑｕａｔｉｃｐｒｏｄｕｃｔｓｂｒｅｅｄｉｎｇｉｎｄｕｓｔｒｙｈａｄｒａｐｉｄｄｅｖｅｌｏｐｅｄｉｎＣｈｉｎ…     

华南二叠纪末缺氧海水中的有毒气体与生物集群绝灭

对华南P/T界线地层有机碳同位素和碳酸盐岩碳氧同位素和沉积特征进行研究表明 :二叠纪末海洋中发生了大规模海水缺氧事件 ,持续时间约 6～ 10万年 ;海洋底层存在大量的CO、CO2 、H2 S和CH4等水溶性有毒气体 ,在剧烈的火山爆发事件及相伴的温室效应影响下 ,这些气水化合物由海底及陆架沉积中快速分离释放 ,导致生物集群绝灭 ,最终造成灰岩的δ13 C值发生强烈的负漂移     

畜禽粪便冻融作用后磷形态分布及其释放特征

畜禽粪便中磷(P)释放特性与其赋存的形态密切相关,冻融循环可通过改变畜禽粪便的理化性质而影响粪便中P形态的分布,进而影响其后续的释放过程.本研究通过一系列室内模拟实验,探究了冻融循环对不同含水率猪粪中P形态分布的影响,以及冻融循环后粪便中P释放特征及其影响因素.结果表明,与未经冻融猪粪相比,冻融后低含水率粪便中Ca-P、Oc-P和Res-P含量分别下降了47.38%、29.76%和55.19%,NH_4Cl-P和Al-P分别增加了36.82%和23.13%;高含水率猪粪中Ca-P、Oc-P和Res-P含量分别减少了49.59%、41.59%和76.96%,NH_4Cl-P、Al-P和Fe-P含量分别增加了37.34%、32.84%和8.96%.经冻融处理的粪便P的释放速率和累积释放量明显大于未冻融处理的粪便.伪一级动力学方程、Elovich方程、权函数方程均能较好的拟合粪便P释放动力学过程,其中Elovich方程的拟合效果最佳,表明粪便中P释放动力学过程是以扩散为主的反应过程.雨水pH值和共存阴离子会影响粪便P的释放,溶液pH越低或NO~-_3/SO■比值越小,越有利用于粪便P的释放.依据统计数据估算,我国冻融区域内畜禽粪便因冻融导致的P最大释放增量总和约为3.20万t·a~(-1),为降低其面源污染风险需要更好的粪便储存处理措施.