秸秆还田循环利用对土壤碳库的影响研究

为了阐明秸秆还田对土壤质量的影响机理,以冲积土和紫色土稻田为研究对象,通过4年定位试验研究了秸秆还田对稻田土壤活性碳(CA)、微生物碳(CMB)、矿化碳(CM)和碳库管理指数(CPMI)及土壤NPK养分的影响。结果表明:秸秆还田提高了土壤不同形态碳素含量和碳库管理指数及养分含量;旋耕比免耕更能改善土壤有效碳库质量,CA、CMB、CM和CPMI分别提高5.81%~31.76%、33.87%~39.33%、15.42%~21.56%和4.03%~21.13%。     

切实加强森林资源管理 提高凭证采伐率

凭证采伐率是体现一个地方森林资源管理的重要指标，文章对重点林区凭证采伐率的现状及下降原因作了分析，提出提高凭证采伐率的对策，这对森林采伐限额管理有一定的参考价值。     

我国渔业政策与渔业管理问题探讨

70年代以来 ,我国黄渤海和东海海域的主要鱼业资源 (ｆｉｓｈｅｒｙｒｅｓｏｕｒｃｅｓ)长期处于衰退状况 ,我国政府意识到海洋资源衰退的时间并不算太晚 ,为此制定和实施了一系列的保持渔业资源的文件和管理法规。建国以来 ,与渔业管理相关的法律、法规性规范性文件达 50 0多件[1] 。表 1　渔船总吨位前 5位的国家 (1 995年 )Ｔａｂ .1　Ｄｅｃｋｅｄｆｉｓｈｉｎｇｖｅｓｓｅｌｓ:ｔｏｐｆｉｖｅｃｏｕｎｔｒｉｅｓｂｙｇｒｏｓｓｔｏｎｎａｇｅ(1 995 )国　　家渔船 (百万吨 )中国 5 .5 5俄罗斯 2 .99日本 1.5 1美国 1.40印度 1.0 8　　…     

对实行林政工作量化管理的思考

通过对林政管理工作中的；定性与定量这两种管理模式，有利于林政管理目标的实现、管理责任的落９实和调动干群保护森林资源的积极性。     

灌溉对心底土积盐层的溶解作用

1.心底土积盐层是引起土壤次生盐渍化不可忽略的原因土壤次生盐渍化是干旱、半干旱地区作物正常生长和发展农业生产的一个重要限制因素,综合目前的研究资料,人们对土壤次生盐渍化的发生和防治作了大量的研究工作,但对心底土积盐层与土壤次生盐渍化研究得较少,忽略了这个问题。正如罗赞诺夫指出:“人们往往忽略了土壤以及底土的原始含盐量在灌区土壤次生盐渍化中的作用,因此,我们愿意再一次强调指出,必须重视自然条件特别是土壤的原生盐渍化在次生盐渍化中的重大意义和作     

A hundred and more years of plant protection in the Netherlands

At the occasion of the Centenary of the Netherlands Society of Plant Pathology a reflection on past, present and future of plant protection, the subject matter of the Society, was thought to be appropriate.Developments in plant protection are projected against a general stream of thought. Three turning points are distinguished which can be seen as paradigm changes. The first occurred around 1890, when the concept of pathogenitism gained its final victory over autogenitism. The second occurred around 1940, when the public outlook on human and plant health changed drastically due to the advent of chemotherapeutants. The third occurred around 1990 when a clear change in public thinking on agriculture, environment and plant protection became apparent. The background of these changes is sketched in a personal manner.Some ideas on plant protection beyond the year 2000 are given, based upon recent developments in the Netherlands to which the Society contributed in its own way.     

An advisory model for control of Puccinia recondita in winter wheat

Epidemics ofPuccinia recondita and resulting yield loss of winter wheat were studied in field experiments over three seasons in the Netherlands. Results are reported and used to construct an advisory model for control of brown rust, based on rust monitoring. If the fraction of leaves with rust (I) at a certain development stage is determined, the average number of rust sori per leaf (M) was estimated by: M=EXP(1.84+1.39ln(ln[1/(1-I)]). The final number of sori per leaf (Mf) at early dough was forecast by an exponential growth: Mf=M·EXP(RGR·t). The relative growth rate (RGR) averaged 0.163/day and the forecasting period, t, until early dough, was derived from published data. The forecast number of sori-days per leaf (S, AUDPC-value) was then obtained by: S=(Mf-M)/RGR. Yield loss (kg/ha) by brown rust was 1.15 times the number of sori-days per leaf at low rust intensities. The efficacy of the fungicides used was 85%. The forecast avoidable yield loss (L, kg/ha) was calculated by: L=0.85 (1.15 S). Economic thresholds for brown rust control at different development stages are given for Dutch wheat fields at a cost level of 270 kg/ha for one fungicide application.     

巴音郭楞蒙古自治州野生动物资源及其消长

依据新疆巴音郭楞蒙古自治州１９６５至１９９０年野生脊椎动物皮张产品的收购资料及历年实地考察研究，分析与分析了该地野生动物资源现状，利用价值，数量消长因素及有关管理措施等，该地区鸟类种数约２６４种，兽类７３种、两栖爬行类１０余种，鱼类２０多种。     

天水旱作区自然降水生产潜力的适度开发对策

通过10年的定点资料统计,分析了天水旱作地区自然降水生产潜力开发程度、适宜开发程度及可开发程度;并就资源和环境条件对水分生产潜力开发的制约问题进行了讨论,分阶段分层次提出了生产潜力适度开发对策措施。     

A viability study of Fallopia japonica stem tissue

Vegetative regeneration of intact and split nodes of Fallopia japonica (Houtt.) Ronse Decraene was the focus of this greenhouse experiment. Stem material, collected in May, July and September 1997, was cut into 40-mm-long sections and incubated on the surface of moist compost in a greenhouse. All samples showed some regrowth of buds and new shoots from both intact and split nodes in any season. A maximum number of 0.25 buds per intact node was recorded after 6 days in a spring experiment. The vegetative regrowth of shoots generally appeared after 1 week and increased over time with a maximum mean height of 77 mm after 27 days and a maximum number of 0.39 shoots per intact node after 13 days. Adventitious roots developed from both intact and split nodes during both summer and autumn experiments. From this study, a maximum of 90 stem tissue propagules per square metre of F. japonica stand has been estimated. If the plant is cut as part of a control programme, these propagules can produce shoots with growth rates of up to 2.9 mm per day with a good chance of the development of adventitious roots. This considerable potential for vegetative regeneration of stem tissue shows a clear need for guidelines on the safe management and disposal of F. japonica plant material.