QuEChERS-GC/MS检测氯丹的含量

介绍了一种快速低耗、简便可靠的方法测定土壤中氯丹的含量。利用QuEChERS法,以丙酮/正己烷为提取液,超声萃取后,经PSA净化后的样本上清液,用GC-MS-SIM定量检测,回收率在81%~102%之间。用该方法测得农药厂周围土壤样本中氯丹的含量在0.079mg/kg~2 927.95 mg/kg之间。     

Impacts of changing climate on the productivity of Norway spruce dominant stands with a mixture of Scots pine and birch in relation to water availability in southern and northern Finland

A process-based ecosystem model was used to assess the impacts of changing climate on net photosynthesis and total stem wood growth in relation to water availability in two unmanaged Norway spruce (Picea abies) dominant stands with a mixture of Scots pine (Pinus sylvestris) and birch (Betula sp.). The mixed stands were grown over a 100-year rotation (2000-99) in southern and northern Finland with initial species shares of 50, 25 and 25% for Norway spruce, Scots pine and birch, respectively. In addition, pure Norway spruce, Scots pine and birch stands were used as a comparison to identify whether species' response is different in mixed and pure stands. Soil type and moisture conditions (moderate drought) were expected to be the same at the beginning of the simulations irrespective of site location. Regardless of tree species, both annual net canopy photosynthesis (P(nc)) and total stem wood growth (V(s)) were, on average, lower on the southern site under the changing climate compared with the current climate (difference increasing toward the end of the rotation); the opposite was the case for the northern site. Regarding the stand water budget, evapotranspiration (E(T)) was higher under the changing climate regardless of site location. Transpiration and evaporation from the canopy affected water depletion the most. Norway spruce and birch accounted for most of the water depletion in mixed stands on both sites regardless of climatic condition. The annual soil water deficit (W(d)) was higher on the southern site under the changing climate. On the northern site, the situation was the opposite. According to our results, the growth of pure Norway spruce stands in southern Finland could be even lower than the growth of Norway spruce in mixed stands under the changing climate. The opposite was found for pure Scots pine and birch stands due to lower water depletion. This indicates that in the future the management should be properly adapted to climate change in order to sustain the productivity of mixed stands dominated by Norway spruce.     

新疆加工辣椒根腐病病原鉴定

以制干辣椒根腐病病样为分离对象,采用形态学和分子生物学方法对致病菌进行鉴定。结果表明:共采集根腐病样211个,从中分离获得161个分离物,其中镰刀菌Fusarium spp.121个,占总分离物的75.16%;其它菌40个,占24.84%,说明镰刀菌是新疆加工辣椒的主要致病菌。经致病性测定后,采用形态学观察结合18SrDNA-ITS、EF-1α和β?tubulin 3个序列分析,将80株有致病性的镰刀菌鉴定为尖孢镰刀菌(F.oxysporum)和茄病镰刀菌(F.solani),其中尖孢镰刀菌57株,占镰刀菌分离物的47.11%;茄病镰刀菌23株,占19.01%。     

Beetles (Coleoptera) caught with pheromones of Gnathotrichus retusus and G. sulcatus (Col., Scolytidae) in southern Finland

The ambrosia beetle Gnathotrichus materiarius, which originally came from North America, was discovered in southern Finland in 1996. In 1997, using Norwegian drainpipe traps baited with pheromones of Gnathotrichus retusus and G. sulcatus, we collected beetles in the region where the first specimen had been caught in order to determine whether this potential pest species had become established in the area. Samples from a total of 16 traps included 79 species of beetles and 719 individuals, but no specimens of G. materiarius. The most abundant species in the samples were the ambrosia beetles Xyleborus dispar and Trypodendron lineatum. Several predators and other associates of bark beetles were also captured. The majority of the beetles caught were saproxylic species.     

硬脂酸、月桂醇酯化反应动力学研究

本文采用非水溶液滴定法,确定了硬脂酸、月桂醇酯化反应的总级数及各种反应物的级数,建立了反应速率方程,求得了反应的活化能,并提出了可能的反应机理.     

Decision support systems in forest management: requirements from a participatory planning perspective

Participatory approaches and computerised tools such as decision support systems (DSS) represent conflicting tendencies in state-of the-art sustainable forest management. As a result, there may be considerable tension between these two developments in practice. The objective of this paper is to explore how participatory approaches and DSS could be brought together to improve planning processes and to explore how DSS could be adapted in their use or combined with other tools to enable successful participatory planning. From a review of the literature, we identified criteria related to successful participatory planning. From these criteria, we selected those a DSS can influence and created a short list of the criteria that could be used to evaluate participatory processes where DSS are applied. The evaluation criteria with particular relevance for DSS that we identified are as follows: fairness, opportunity to influence outcome, quality and selection of information, cost-effectiveness, challenging status quo and fostering creative thinking, structured decision-making process, transparency, and independence and neutrality of process. We also scrutinised existing forest DSS and identified features that may enable DSS to address these criteria. The features of DSS we identified that may support participatory processes are as follows: group decision support, possibilities to include other values than timber production, flexibility of system to include non-traditional forest data and management options, and multi-criteria decision analysis tools. We argue that the DSS to be used should be assessed to clarify, how it can be used in the specific planning situation and how it should be complemented with other available and non-computerised tools.     

硝草酮在玉米田的除草效果及安全性研究

2005年在北京市小汤山进行了田间试验,对硝草酮做茎叶处理的除草效果及对玉米的安全性进行了研究。结果表明:供试试验田反枝苋、苍耳、苘麻、苦蘵、龙葵、稗草、马唐对硝草酮敏感。铁苋菜、马齿苋对该药中度敏感。牛筋草、狗尾草、葎草、野西瓜苗、扁蓄、打碗花、刺儿菜、半夏对该药不敏感。该药对阔叶杂草防效好于对禾本科杂草的效果。供试剂量范围内,随施药量增加对敏感杂草防效提高。杂草3～4叶期施用10%硝草酮水悬浮剂70g/667m2的处理对稗草和马唐鲜重防效接近90%,对反枝苋、苍耳、苘麻鲜重防效在90%以上;100g/667m2及140g/667m2的处理对稗草和马唐鲜重防效为90%～95%,对反枝苋、苍耳、苘麻鲜重防效在95%～100%。杂草叶龄越小,硝草酮对其防效越高。禾本科杂草3～4叶期前用药防效理想,阔叶杂草反枝苋、苘麻等10叶期施药也能达到较好防效。10%硝草酮水悬浮剂施药剂量应为70～100g/667m2商品量。硝草酮100～140g/667m2的处理个别玉米植株叶片表现白化,叶片白化的植株占全小区植株数的3%～20%,但随作物生长药害症状消失。硝草酮水悬浮剂40～70g/667m2在玉米3～8叶期用药,对玉米中单44产量无影响。该剂量在玉米3～4叶期用药,对8个供试玉米品种生长及产量无影响。     

海南金煌芒果叶片营养规律研究

通过对海南省三亚市金煌芒果叶片中N、P、K、Ca、Mg、S、Fe、Mn、Cu、Zn、B十一种营养元素含量进行全年跟踪分析,结果表明：⑴金煌芒果叶片养分年平均含量大小为：N>Ca>K>Mg>P>S>Mn>Fe>B>Zn>Cu,其中N、Ca含量较高,P、Mg、S、Zn含量月变化不明显。⑵金煌芒果的生长周期可分为4个阶段:营养生长期(5～9月)、生殖生长期(9～11月)、果实膨大期(11～2月)和果实成熟期(2～4月)。各阶段叶片养分含量变化规律有所差异: 营养生长期,叶片中营养元素除K、Cu含量有所下降之外,其余营养元素均有不同程度的升高。生殖生长期,叶片中的营养元素N、B、Ca含量上升,其他元素含量有不同程度的下降。果实膨大期,叶片中的N、K、Fe、Zn、B含量下降,Ca、Cu、Mn含量上升。果实成熟期,叶片中N、Mn、Fe、B、Cu含量均有不同程度增加,K、Ca含量有所降低。     

The effects of forest structure on the risk of wind damage at a landscape level in a boreal forest ecosystem

? The aim of this work was to analyze how the forest structure affects the risk of wind damage at the landscape level in a boreal forest.

? This was done by employing: (i) Monte Carlo simulation technique for generating landscapes with different age class distributions, proportions of open areas (gaps), and tree species composition; and (ii) a mechanistic wind damage model, HWIND, for predicting the critical wind speeds at downwind stand edges of open areas (gaps) for risk consideration. The level of risk of wind damage observed at the landscape level was significantly affected by the presence of gaps and old stands. Even a slight increase in the proportion of gap areas or older stands had a significant impact on the total length of edges at risk. As a comparison, variation in species composition (Scots pine and/or Norway spruce) had much smaller impact on the risk of damage.

? In conclusion, the effects of forest structure on the risk of wind damage should especially be considered by forest managers in day-to-day forest planning in order to reduce the risk of wind damage both at the stand and landscape level.