“九五”我国农业科技发展基本思路与建议

 对我国改革开放以来，农业和农业科技取得的成就与问题，进行了全面总结。在充分调查分析国内外有关背景材料的基础上，提出了“九五”我国农业科技6大研究目标和14个优先发展重点项目及农业科技发展战略措施。为国家、部门的宏观决策，指导农业科技工作提供依据。     

Dropp50%WP+展着剂BioPower对棉花脱叶催熟效果田间试验分析

通过对Dropp试验结果表明：在较宽的温度范围内(13—30．2℃)对棉花脱叶催熟效果显著；Dropp混剂对棉花脱叶、催熟作用明显优于Dropp单剂，同时Dropp对中上部单铃重、衣分、籽指、发芽率、纤维品质的影响不显著。     

Late-arriving barn swallows linked to population declines

Barn swallows (Hirundo rustica) are arriving later in the spring than they did 30–40 years ago at numerous sites in Korea. In some cases their arrival times are later by more than 1 month. This result is perplexing as spring activities of plants and animals are generally getting earlier due to warming temperatures. The first arrival dates of swallows are not related to temperature, suggesting that another factor is involved. On the basis of a questionnaire, a large majority of long-term observers are confident that there has been a moderate to severe decline in swallow populations at their field site over the study period. The greatest delays in arrival times are associated with sites with more severe reported declines in population size. Simulations using trapping data of large migratory bird populations from the United States, consisting of hundreds of individuals, suggest that severe population declines of 99% can result in delays of 10–12 days in arrival times. In summary, our results suggest that the large delays in arrival time of Korean swallows are due, at least in part, to severe reductions of more than 99% in what were formerly very large populations. Significant delays in spring phenology over time during a period of climatic warming may indicate population decline, though alternative explanations, such as changes in range or migration path or changing number of broods per season, should also be investigated. Delays in first arrival data can provide a valuable new tool to conservation biologists by indicating declines in a population that would otherwise go unnoticed. This can, in turn, lead to efforts by researchers to verify the dynamics of a population and draw attention to the conservation needs of the species.     

伪满时期黑龙江省的农业政策与小麦生产和加工

根据有关资料记载,黑龙江地区在伪满洲国时期采取了低价收买和收缴土地以及粮食统制的农业政策,造成了黑龙江省的小麦种植面积大幅度下降、外国面粉大量进口、小麦加工业萎缩的局面。     

Extended flowering and high weed resistance within two layer designed perennial “prairie-meadow” vegetation

Interactions between two canopy layers in a designed perennial herbaceous plant community were investigated over a period of four and a half years to see whether it was possible to create an urban landscape vegetation that was both flower rich for an extensive time period and resistant to weed colonization at very low levels of maintenance by sowing seed in situ. The ecologically novel plant community involved a tall over-canopy layer of 18 species of North American prairie and woodland edge forbs, and a shade tolerant under-canopy of eight European and North American, mainly woodland forbs. After 5 years the community was dominated by four over-canopy and two winter green under-canopy species. Interspecific competition generated by the sown biomass restricted weed colonization to very low levels, despite the experiment being surrounded by a weedy brownfield. The winter green canopies of the two dominant under-storey forbs closed down gaps within a winter deciduous, prairie-like vegetation, improving winter appearance and providing a major flowering display in spring. This vegetation is an attractive design model for more sustainable herbaceous planting in urban landscape space.     

间伐抚育林分物候试验研究

本文对松青、浩良河落叶松人工林进行间伐抚育买验,通过不同间伐抚育强度后,各实验区保留木数量、质量、小区气候,林木物候发生有规律性的变化。随间伐强度的加大,林内积温指数在增加,生长候提前,休眠候拖后,生长期延长。从保留木数量、质量变异规律看,20％间伐强度为最佳气候和林木物候型。这对指导营林生产,防止自然灾害,病虫危害、火险预报提供理论基础。     

Genetic and Environmental Correlations Among Female Fertility Traits and Milk Production in Different Parities of Swedish Red and White Dairy Cattle

The main objective of this study was to estimate genetic correlations between fertility and production traits in first, second and third lactations as well as between fertility traits measured in the same way at different ages. The fertility traits studied were: number of inseminations per service period, number of treatments for reproductive disturbances, interval between first and last inseminations, interval between calving and first insemination, and interval between calving and last insemination. Early milk production was measured as the average of the energy-corrected milk yield at the second and third monthly testdays in a lactation. The number of records was approximately 450 000, 350 000, 180 000 and 75 000 in the heifer period, first, second, and third lactations, respectively. A linear, trivariate model that included the effects of herd-year, year, month, age and sire of the cow was applied. To reduce the effect of ongoing selection, 305-days kg protein production in first lactation was included as a variate in all of the analyses. Correlations between the herd-year effects indicated that factors of herd-year level conducive to increased production had a tendency to increase the number of inseminations as well as the number of reproductive treatments, although there was an earlier start and termination of the insemination period. Genetic correlations between fertility traits and production were in the range of 0.2-0.4, all of them unfavourable and higher at later parities. The genetic correlations between fertility traits in the heifer period and the same traits in first lactation were 0.7. Genetic correlations between the first and second lactation varied between 0.7 and 0.9, and between the second and third lactation they were all 0.9 or higher. In conclusion, fertility and production traits need to be selected for simultaneously if fertility is going to be maintained along further genetic improvement on production, and such selection should include fertility results from lactating cows.     

民国时期广西农村耕畜借贷问题探析

分析了民国时期的广西农村仍存在耕畜分配不均、耕畜借贷广泛存在的现象,全面总结了耕畜借贷的方式和利息支付方式,最后从消极、积极方面对耕畜借贷进行了客观评价。     

哈尔滨市3种灌木物候对气候变化的响应

为了揭示哈尔滨市3种灌木物候对气候变化的响应机制,根据1963-2008年哈尔滨市气象资料与黑龙江省森林植物园珍珠梅、紫丁香和东北连翘3种灌木物候观测资料,采用相关分析和一元线性回归方法,对3种灌木物候期(芽开放期、展叶始期、开花始期、脱落末期)的变化趋势及其对气候变化的响应特征进行分析.结果显示:哈尔滨市1963年以...