岷江上游水体中DOM光谱特征的季节变化

川西北高原湿地和高山峡谷区是岷江等河流重要集水区,地表水体中溶解性有机质(DOM)更多受环境背景影响,DOM来源与结构特征对认识流域有机碳输出通量及模式有重要意义.本文对岷江上游在4月(枯水期末)和10月(丰水期末)分别进行沿程地表水采样并测定了DOM三维荧光光谱(EEM),结合平行因子模型(PARAFAC)分析岷江上游水体DOM沿程和季节变化特征.结果表明,DOM荧光峰(类腐殖峰A、C和类蛋白峰B、T)沿程波动趋势和程度不同;枯水期末(4月)A、C峰强而丰水期末(10月)B、T峰强.PARAFAC识别出3个荧光组分,即C1(250~260/380~480 nm,类腐殖质,占比48.68%~65.02%),C2(300~330/380~480 nm,类腐殖质,占比23.17%~29.83%)和C3(270~280/300~350 nm,类蛋白质,占比11.83%~21.53%);枯水期末(4月)组分沿程波动更明显,其中C1沿程波动最显著.荧光指数(FI)均值在1.4~1.9之间,说明不同季节DOM均有内外源混合特征;枯水期末(4月)DOM腐殖化、芳香性和疏水性高,表明DOM陆源贡献更大,而丰水期末(10月)DOM自生源贡献比枯水期更高.CDOM浓度[a(355)]与类腐殖质浓度[Fn(355)]极显著正相关,这也证实岷江上游水体中DOM的陆源输入.C1、C2在枯水期末(4月)相关性极显著而丰水期末(10月)相关性未达到显著性水平,进一步表明岷江上游水体中DOM的外源性及季节性差异.     

新疆高山地区冰川阻塞湖引起的突发性洪水灾害

我国新疆地区经常发生冰川阻塞湖引起的突发性洪水灾害.通过对叶尔羌河、昆马力克河和四棵树河三条典型河流的研究,发现可预报洪水序列与阻塞湖库容量有正相关关系.结合分析阿尔泰山、祁连山和西藏地区的地理环境特点,认为塔里木盆地周边地区是冰湖洪水的突发区.     

有机酸对潮褐土和红壤吸附Cu(II)的影响及其机制

采用吸附平衡法,研究了有机酸(草酸、柠檬酸)对潮褐土和红壤吸附Cu2+的影响及机制。结果表明,潮褐土、红壤对Cu2+吸附明显有异,潮褐土对Cu2+吸附量是红壤对Cu2+吸附量的5倍多。潮褐土对Cu2+的竞争吸附率随有机酸浓度升高而降低,当草酸、柠檬酸浓度为10 mmolL-1时,Cu2+吸附率均分别比对照的降低40%和70%以上。在低浓度条件下,红壤对Cu2+的竞争吸附率随有机酸浓度的提高而增加,当草酸、柠檬酸浓度分别超过1 mmolL-1和0.05 mmolL-1时,又随有机酸浓度的升高而降低。两种土壤对Cu2+次级吸附率随有机酸浓度升高而变化的规律与竞争吸附的一致。在相同有机酸浓度下,土壤对Cu2+的次级吸附率均比竞争吸附率的高。     

黄河源区退化高寒草地土壤种子库:种子萌发的数量和动态

对青藏高原黄河源区不同退化程度高寒草地的土壤种子库土样用土壤分析筛进行浓缩,并以萌发法分析土壤种子库萌发种子数量和动态.结果表明,孔径0.25~2 mm的土壤分析筛分离土样中萌发种子可达萌发种子总量的85%~97%,而小于0.25 mm的土样中未发现种子.因此,用0.25 mm孔径大小的土壤筛对高寒草地土壤种子库土样进行大规模浓缩是一种方便、可靠的方法.4种不同退化程度高寒草地(A:未退化草甸;B:轻度退化草甸;C:中度退化草甸;D:重度退化草甸)的土壤种子库在实验室条件下萌发的种子数量分别为:A 1 194~3 744粒/m2,平均2 421.3粒/m2;B 5 376~1 0912粒/m2,平均7 786.7粒/m2;C 2 304~1 3216粒/m2,平均8 695.5粒/m2;D 4 768~12 352粒/m2,平均8 125.9粒/m2.除样地A外,其它3个样地的可萌发种子数量差异不大.单子叶植物种子在培养到d 10左右开始萌发,双子叶植物在5~7 d内开始萌发,前者3 wk后基本不再萌发,后者5 wk左右停止萌发.4个样地土壤种子库种子萌发主要集中在第2~3周,并表现出近似单峰型格局.图1表3参39     

Ecological Effectiveness of Agri-Environment Schemes in Different Agricultural Landscapes in The Netherlands

Abstract:  Agri-environment schemes are an instrument used by western European countries to counteract the negative effects of contemporary agriculture on biodiversity, but not much is known about their effectiveness. We investigated the ecological effects of Dutch agri-environment schemes aimed at promoting botanical diversity or meadow birds, and we tested whether the effectiveness of the schemes depends on landscape type or structure. In three different types of landscape, we surveyed plants, birds, bees, and hover flies on 78 paired fields that either had agri-environment schemes or were managed conventionally, and we collected data on a range of different environmental variables. Neither plant species richness nor abundance of meadow birds was higher on fields with agri-environment schemes. Landscape type had a significant effect on both species groups, but the effects of the schemes were independent of landscape type. Neither the diversity of plants nor the abundance of birds was related to any of the environmental variables. Agri-environment schemes designed to promote plant species richness or bird abundance did have positive side-effects because they enhanced the species richness of bees and hover flies, irrespective of the type of landscape. Furthermore, landscape type, groundwater level (hover flies), and area of wooded edges (bees) significantly affected both species groups. The failure of the schemes to promote the target species may be related to the high intensity of land use in The Netherlands. Simple conservation measures taken by farmers may not be sufficient to counteract the impact of factors that are often controlled at the landscape level (e.g., hydrology). Similar studies in other countries are needed to place the results of our study into a European context.     

垃圾肥在潮土上对花生的增产效果

在潮土上施用垃圾肥对花生产量和品质影响的研究结果表明，在较贫瘠的土壤上，垃圾肥单独或与Ｎ、Ｐ化肥配合施用，都有明显的增产效果：单独施用比对照增产率为９．３％～２９．１％，与化肥配合施用增产率为１０．８％～２０．５％。垃圾肥施用量在１５～３０ｔ／ｈｍ２时可获较高的增产效益。施用垃圾肥对花生仁中的粗蛋白质、粗脂肪和全磷含量有一定的提高。尽管所施用垃圾肥中含有一定量的有害元素，如Ｃｄ、Ｐｂ、Ｃｒ等，但花生仁中这些元素含量并不高，说明施垃圾肥是安全的。试验结果还表明；施用垃圾肥能提高土壤有机质、全氮以及有效Ｎ、Ｐ、Ｋ的含量。特别是有效微量元素含量提高幅度较大，Ｚｎ、Ｃｕ、Ｂ各处理平均是对照的２～１０倍，Ｆｅ、Ｍｎ、Ｍｏ比对照提高１７％～３８％。     

Human use and conservation planning in Alpine areas of Northwestern Yunnan,China

Alpine areas in northwestern Yunnan, China possess globally significant levels of biodiversity and are important locally for livelihood activities such as livestock grazing and medicinal plant collection. Because local land use has important impacts on alpine conditions and communities have significant capacity to manage alpine resources, we emphasized local collaboration during the initial stages of conservation planning. Our collaboration with local communities investigated how livelihood strategies affect the condition of alpine resources in northwestern Yunnan and how future conservation efforts can be compatible with local livelihoods. We sampled three livestock herding sites, each within a different alpine sub-region, using open-ended interviews and maximum variation sampling. According to interviewees, livestock grazing within the alpine zone currently does not appear to be negatively impacting the availability of forage. Medicinal plant collection, however, is showing unsustainable trends. Tourism is as yet a nascent industry, but is seen as having great potential by those interviewed. It is clear that with increases in population, access to regional markets, and tourism, northwestern Yunnan’s rich alpine resources will require careful management. In addition to the data collected, we found that the methodology used may be widely applicable to organizations with limited resources that wish to engage local communities during the formative stages of regional-level conservation planning.     

高寒草甸不同土地利用格局土壤CO2的释放量

分析高寒草甸不同土地利用格局下土壤CO₂的释放量大小表明,在植物生长季的5～9月,土壤CO₂释放量大小排序为:金露梅灌丛草甸(1871.40g/m²)＞矮嵩草草甸(1769.63g/m²)＞退化金露梅灌丛草甸(1495.60g/m²)＞退化矮嵩草草甸(1191.26g/m²);而在植物非生长季的10月到翌年4月,其土壤CO₂释放量大小与植物生长季略有差异,表现出矮嵩草草甸(661.46g/m²)＞金露梅灌丛草甸(550.90g/m²)＞退化矮嵩草草甸(502.50g/m²)＞退化金露梅灌丛草甸(384.50g/m²)的特点;全年内表现为矮嵩草草甸(2431.09g/m²)＞金露梅灌丛草甸(2422.30g/m²)＞退化金露梅灌丛草甸(1880.10g/m²)＞退化矮嵩草草甸(1694.06g/m²).高寒草甸地区不同土地利用格局土壤CO₂释放数量的差异及季节变化,不仅与各利用格局的土壤生物活性及土壤物理化学性状有关,而且与气象条件(特别是温度)及其土壤冬季冻结期长短关系极为密切.     

铜污染草地对放牧乌蒙半细毛羊矿物质元素代谢的影响

为了评价草地铜污染对放牧乌蒙半细毛羊的影响,探讨铜污染的治理方法,在乌蒙山区的妈姑镇和凉水沟开展草地放牧试验和矿物质元素补充研究。应用原子发射光谱分析土壤、牧草和动物组织的重金属含量,应用全自动血液分析仪分析血液指标。放牧试验的结果显示:铜污染草地放牧明显增加了动物组织铜和锌的含量(P 0.01),降低了动物组织钼和铁的含量(P 0.01),试验结束时,试验组动物的血红蛋白(Hb)、红细胞压积(PCV)、红细胞数(RBC)和平均红细胞体积(MCV)显著低于对照组(P 0.01),羊毛产量和长度显著低于对照组(P 0.01)。矿物质元素补充试验的结果显示:补充硫酸钠明显降低了铜污染草地放牧动物血液和肝脏铜元素含量,补充试验结束时,处理Ⅰ组动物血液的Hb、PCV、RBC和MCV显著高于处理Ⅱ组(P 0.01),血液指标达到正常范围。处理Ⅱ组动物血液和肝脏铜元素的含量继续升高,动物组织钼的含量继续降低(P 0.01),Hb、PCV和RBC继续下降,试验结束时出现溶血性贫血,但补充硫对羊毛品质的相关指标没有显著的影响。研究表明,铜污染草地严重影响了乌蒙半细毛羊的矿物质代谢,补充硫酸钠可以部分拮抗铜的毒性。     

藏北高寒草原样带土壤有机碳分布及其影响因素

沿藏北高寒草原冈底斯山-申扎-双湖样带（30°25′N至33°6′N）,在37个样点采集土壤和植物样品,分析藏北高寒草原土壤有机碳含量及其影响因素。结果表明：藏北高寒草原土壤0~15、15~30和0~30 cm有机碳含量分别为2.27、2.17和4.44 kg.m-2。土壤有机碳含量沿样带呈随着纬度的增加而减少的趋势。藏北高寒草原土壤质地总体偏粗,不同质地土壤之间有机碳含量大小关系为砂土〈壤质砂土〈粉壤土〈砂质壤土〈壤土。不同深度土壤有机碳含量与土壤颗粒含量相关性存在显著差异,0~15 cm土壤有机碳与粉粒、黏粒含量呈显著性正相关,与砂粒含量呈显著性负相关,而15~30 cm土壤有机碳含量与土壤颗粒组成相关性不显著。0~15 cm土壤有机碳含量与草地盖度、地下生物量和总生物量呈显著或极显著正相关,与优势种高度呈极显著负相关;15~30 cm土壤有机碳含量与优势种高度呈显著负相关。