黑皮冬瓜嫁接砧木的筛选与鉴定

挑选南瓜砧、蒲瓜砧和葫芦砧共10个品种,以佛山市三水黑皮冬瓜为接穗,采用斜顶插接法嫁接,露地栽培管理,比较其产量和农艺性状。试验结果表明,DZ-01冬瓜砧、京欣砧三号和强势作为三水黑皮冬瓜的嫁接砧木,可有效降低枯萎病发病率,增产10%以上,商品性状得到明显改善,商品品质差异不显著,推广应用性强。     

Two-dimensional Optimum Cutting Stock Method Based on Internet and Its Implementing Technique

Two dimensional Optimum Cutting Stock is a NP complicated problem. Each of optimum software gets the cutting results by using proximate and heuristic methods. But different optimum methods and their optimum software may not realize perfect effect according to certain data framework. Furthermore, enterprises can not buy lots of optimum software to choose the most optimized plan. Because of such problems, this paper provides a two dimensional optimum cutting stock method based on Internet and offers the real implementing technique of such method. The experiments, show that this method promotes the general optimum effect of two dimensional optimum cutting stock greatly.     

A bio-economic indicators suite for the appraisal of the demersal trawl fishery in the Southern Adriatic Sea (Central Mediterranean)

The state of demersal fishery in the Southern Adriatic Sea (GFCM-GSA 18, Central Mediterranean), years 1996–2003, from a biological, social and economic point of view was analysed using 47 indicators: 22 biological indicators obtained from fishery-independent data through yearly experimental bottom trawl surveys (“Medits” Programme), and 25 socio-economic indicators estimated from fishery-dependent data, available from the monitoring system of the Italian Institute for Economic Research on Fisheries and Aquaculture (IREPA). Biological indicators were applied for “single-species” (Eledone cirrhosa, E. moschata, Illex coindetti, Merluccius merluccius, Mullus barbatus, Nephrops norvegicus, Parapenaeus longirostris, Raja clavata, Zeus faber) and for “multi-species” analysis. Economic indicators describing economic performance, productivity, costs and prices, and the overall economic sustainability of fishery were estimated. Social indicators and a general indicator summarising social sustainability were also considered. Indicators’ values were displayed using the Traffic Light system. Both fishery-independent and fishery-dependent indicators highlighted a progressive decline of the trawl fishery system in the GSA 18. This decline was mainly related to the ongoing depletion of the traditional fishery target species (mostly long-living, late-maturing species) partially replaced by the increase of traditional accessory species (generally short-living species), as well as to the reduction of productivity and increasing costs. The whole procedure was proposed as a contribution to the identification and applicability of bio-economic indicators for fishery management purposes.     

Difference in cutting age for highest profit by methods for calculating CO<Subscript>2</Subscript> emission trading and the price of CO<Subscript>2</Subscript>

 The amounts of CO₂ that are absorbed and emitted by forest in a model stand area were determined using two calculation methods, namely the flow approach and the stock approach for emission trading, to understand the relationships between the cutting age for the highest profit rate (CAHPR; optimum tree ages to be cut so as to maximize the profit) and (1) the prices of CO₂ and (2) the balance between CO₂ emission and absorption. The resultant CAHPR differed between these two CO₂ accounting methods, which give different tree ages for maximum log volume yield. A rise in CO₂ price caused the CAHPR to approach the tree age of maximum log volume in the flow approach method, and to deviate from the tree age of maximum log volume in the stock approach method. Even at the same CO₂ price, the CAHPR differed between the CO₂ accounting methods. At low CO₂ prices, the CAHPR did not affect situations where the difference of average profit is large by cutting age. On the other hand, the CAHPR was greatly affected at low CO₂ prices when the mean log volume growth changed with tree age. These trends were found to be universal. Received: September 18, 2001 / Accepted: October 25, 2002 Acknowledgments This study is one of the fifth science study subsidy projects of the Japan Forest Technology Association. Correspondence to:K. Sakata     

天然次生白桦林凋落物的分解及其生态效应

1988～1990年间以长白山支脉张广才岭帽儿山老爷岭生态站天然次生白桦林为研究对象,对林分凋落物的积累,组成与分解进行了定位观察研究。结果表明,38年生白桦林凋落物的现存量为13.644t/ha,其中叶为10.49t/ha,枝为2.58t/ha,树皮、种实、动物尸体及粪便等仅为0.57t/ha,年凋落盈为3.38t/ha,年分解量为0.633t/ha,年分解率为18.7％。     

Assessing the green sea urchin (Strongylocentrotus drobachiensis) stock in Maine, USA

The green sea urchin (Strongylocentrotus drobachiensis) fishery is of great importance to Maine’s economy. The fishery took off in the late 1980s as a result of expanding export markets, but has experienced substantial decline in landings since 1992 because of large decreases in urchin stock abundance. Fishery-independent surveys have not been conducted, and no formal stock assessment has been done prior to this study. Using the data collected from the fishery and urchin life history parameters derived from scientific studies, we conducted a formal stock assessment for the urchin stock. A stochastic observation-error length-structured model is used to describe the dynamics of the sea urchin population. A robust Bayesian approach is used for estimating fishery parameters because of concerns of possible outliers in fisheries data and mis-specification of priors. This study shows that the current stock is only 10% of the virgin stock biomass and that the exploitation rate is close to 40% suggesting that a large reduction in exploitation rate is necessary.     

Use of formulated diets as replacements for Artemia in the rearing of juvenile American lobsters (Homarus americanus)

American lobsters, Homarus americanus, have been successfully reared in hatchery operations for over a century, yet formulated diets have never been commercially produced. In recent years, commercial Artemia replacement (CAR) diets have been developed and marketed for use in aquaculture production of marine shrimp. Three separate experiments assessed the utility of rearing American lobsters on these shrimp CAR diets. First, survival and growth of stage IV American lobsters fed one of three CAR diets (Artemac 5, CAR1; Economac 4, CAR2; and Progression 3, CAR3) were compared to those of animals fed frozen adult n-3 fatty acid enriched Artemia. Survival to 3 months was highest for animals fed CAR3 (85%), while animals fed Artemia had the greatest weight gain (> 6 % day^− 1). A cost / benefit ratio analysis showed that CAR2 was the most cost efficient for juvenile production because of its low overall purchase cost. Second, stage IV lobsters were fed either CAR2 or frozen adult n-3 fatty acid enriched Artemia exclusively, or in combination (2 : 5, and 5 : 2). Again, CAR2 was a cost effective feed to use, even as a partial replacement for Artemia. Survival was higher in diets that included CAR2, and feeding it two days per week compensated for low quality Artemia. Finally, 1.5 year old lobsters fed a gelatin-bound mix of 80% CAR2 and 20% frozen Artemia for five months survived and grew equally well compared to lobsters fed gelatin-bound frozen adult Artemia, and better than a custom formulated maintenance diet. The benefits of incorporating formulated feeds into American lobster rearing programs to increase the effectiveness of enhancement programs is discussed.     

东海区马面资源变动及其原因的初步研究

根据７０至８０年代东海外海绿鳍马面资源和产卵场调查等资料以及１９７４年以来马面渔汛生产情况，分析研究了东海区马面资源的变动趋势。结果表明，近年来东海区黄鳍马面的分布范围和主要渔场正在逐渐扩大，渔期延长，年产量在波动中增长，资源量趋于上升，但渔获物以补充群体为主，过度捕捞和产卵场生态环境受到破坏是东海区绿鳍马面资源量急剧下降的主要原因。还提出绿鳍马面资源量的变化具有长周期的变化规律。     

贵州省平坝县森林蓄积量动态变化

依据平坝县1985年、1995年、2005年的森林资源二类调查数据以及2013年平坝县林地变更调查数据,对平坝县森林蓄积量动态变化进行分析。结果表明:平坝县森林蓄积量28年来稳步增长,但森林蓄积量增长过程也存在一些问题,对此提出加强森林经营管理、改善林分质量、增加森林蓄积量、加强森林资源多样性保护、充分利用乡土树种和良种等经营建议。     

系统抽样调查在森林蓄积量测定中的应用

以江苏省农博园湿地松生态林区典型地段为调查研究对象,应用系统抽样的方法进行布点,样地测设及调查.运用CAD绘图软件对调查总体求算面积,运用一元材积表对调查结果进行汇总,并探讨了不同形状样地调查数据的抽样估计精度.结果表明：利用CAD绘图软件绘图并求算面积的方法较传统手工绘图的方法简便,准确.不同形状样地的调查数据的估计精度非常接近,考虑到方形样地测设较简单,因此,建议在森林的系统抽样调查中选用方形样地.