引种栽培西蒙得木的适应性研究Ⅰ——生物学习性观察及枯萎病研究

概述了西蒙得木的经济价值和国内外发展状况,根据在云南发展中出现连续枯萎死亡的现象,首先研究了生物学习性和生态适应性,分离接种了来自病健根的菌类,得到的4种镰刀菌都要在根系衰弱时才能侵染根系,引起根系衰弱的原因需要进一步研究。     

固态发酵玉米秸秆的菌株组合和发酵条件研究

为了提高玉米秸秆的综合利用效率,降低对环境的污染,保护生态环境,利用正交试验法研究了固态发酵氨化玉米秸秆生产饲料蛋白工艺中菌株组合、发酵温度和发酵时间对发酵产物真蛋白含量的影响。结果表明,发酵温度对发酵产物真蛋白含量具有显著影响（P〈0.05）,发酵时间、发酵温度与发酵时间之间的交互作用对发酵产物真蛋白含量具有极显著影响（P〈0.01）。最佳菌株组合为青霉和葱色串孢,最佳发酵条件为发酵温度25℃、发酵时间5 d。在最佳菌株组合和最佳发酵条件下,玉米秸秆经氨水氨化和固态发酵后真蛋白含量由2.05%提高到29.66%,比原料本身的真蛋白含量提高了13倍多;粗蛋白含量由2.80%提高到35.41%,比原料本身的粗蛋白含量高提高了11倍多。     

环境因子对野生薇菜生长的影响

开展皖西山区野生薇菜分布和生长调研,结果表明,薇菜主要分布在坡度16～45°,其适宜生长环境因子是郁闭度0.3～0.6,海拔高度700～1 500 m,土壤pH值5.7～6.3等。     

鄂西烟叶品质垂直变化及其与气象因子的关系研究

对宣恩、兴山和利川3地不同海拔处的中部烟叶进行取样,通过检测、评吸得到其化学成分含量和感官质量得分,进而分析鄂西两大代表烟区(清江源、金神农)中部烟叶品质随海拔高度的变化,以及烟叶品质与大田期关键气象因子的相关性。结果表明,宣恩海拔900 m以下烟叶化学成分得分随海拔升高而增大,海拔900 m以上烟叶化学成分得分随海拔升高而减小;利川地区烟叶化学成分得分总体表现为随海拔升高而减小;兴山烟叶化学成分得分变化无明显规律。三地烟叶感官质量得分比较接近,与海拔没有显著相关性。大田期各阶段的降雨量和旺长期、大田期的昼夜温差是影响烟叶化学成分和感官质量的主要气象因子。     

Frog communities and wetland condition: relationships with grazing by domestic livestock along an Australian floodplain river

Frogs are in decline worldwide, and are known to be sensitive indicators of environmental change. Floodplains of the Murray-Darling Basin in southeastern Australia have been altered in many ways by livestock grazing, by the introduction of exotic fish, and by changes to flooding regimes. These changes have led to declines in wetland condition and hence to the availability of habitat for wetland frogs. This study examined relationships between frogs, wetland condition and livestock grazing intensity at 26 wetlands on the floodplain of the Murrumbidgee River. Frog communities, species richness, and some individual species of frogs declined with increased grazing intensity. Wetland condition also declined with increased grazing intensity, particularly the aquatic vegetation and water quality components. There were clear relationships between frog communities and wetland condition, with several taxa responding to aquatic and fringing vegetation components of wetland condition. Thus, grazing intensity appeared to influence frog communities through changes in wetland habitat quality, particularly the vegetation. Reduced stocking rates may result in improved wetland condition and more diverse frog communities. River management to provide natural seasonal inundation of floodplain wetlands may also enhance wetland condition, frog activity and reproductive success.     

Unreliable amphibian population metrics may obfuscate more than they reveal

Welsh et al. [Welsh, H.H., Jr. Pope, K.L., Wheeler, C.A., 2008. Using multiple metrics to assess the effects of forest succession on population status: a comparative study of two terrestrial salamanders in the US Pacific Northwest. Biological Conservation 141, pp. 1149–1160] argued for the use of four metrics to monitor population status of two terrestrial amphibians, the Siskiyou Mountains (Plethodon stormi) and Del Norte (Plethodon elongatus) salamanders. We show that inherent problems exist with Welsh et al.’s application of all four of these metrics, and that their inferences about population status are likely to be uncertain as a consequence and potentially misleading to managers. Welsh et al. (2008) used data from different populations and different years to estimate detection probabilities for both P. elongatus and P. stormi, a decision which assumes that detection probabilities do not differ across sites and populations are closed. In addition, Welsh et al. (2008) present count data for both salamanders, a metric that assumes capture probability does not vary by age, gender, size, other individual characteristics, and most importantly in their application, habitat characteristics. Welsh et al. (2008) estimated survival based upon age ratios. Age ratios are known to be biased when immigration and emigration are unequal Conn et al. [Conn, P.B., Doherty, P.F., Jr. Nichols, J.D., 2005. Comparative demography of New World populations of thrushes (Turdus spp.): comment. Ecology 86, pp. 2536–2541]. In source-sink systems, immigration and emigration are expected to be unequal. Thus, the use of this estimation technique to characterize survival in source-sink systems is invalid unless it can be shown that immigration and emigration are equal, a rare occurrence in source-sink systems. The final metric used by Welsh et al. (2008) was an index of body condition, i.e., the residuals of a least squares regression of mass on the length. Several recent articles have outlined a number of potential problems with the technique and a theoretically more robust and efficient alternative has been published. Unfortunately, Welsh et al. (2008) did not provide the details (model diagnostic statistics, tests of assumptions) needed to assess whether or not their analyses of body condition may be accurate. We think that evaluation of specific hypotheses, well-designed sampling programs, and methods such as mark–recapture and ratio sampling are more likely to provide reliable inference than re-analysis of old data sets that were collected for other purposes and obsolete methods (i.e., counting individuals on single occasions) that are known to be flawed. We agree that potential forest management impacts to sensitive taxa require evaluation and monitoring, and that changes in occupancy and abundance are useful metrics for this task (while recognizing that, when feasible to collect, information about reproductive success and survival is superior). However, reliable inference about potential impacts can only be made if reliable methods are employed and if critical assumptions receive empirical evaluation. We offer several suggestions to strengthen inference about management treatments.     

土地制度改革与中国农村现代化约束条件的演进研究

中国土地制度的形成是历史条件下的产物。新中国历史发展的不同时期面临着不同的历史任务。文章分析了中国土地制度在不同历史时期所面临问题时的选择和演进问题,对中国当前的土地制度所面临的约束问题进行了分析,指出土地流转制度是目前土地制度改革可行的路径。     

渠道运行GSM算法及其适用条件

论述渠道运行控制系统,通过建立渠道过渡过程的数学模型ＧＳＭ,讨论ＧＳＭ的求解步骤与边界条件以及对渠系建筑物的处理和ＧＳＭ的适用条件,并分析了无解或解不稳定的原因。