长江上游和支流的水土保持与国家现代化建设和长治久安息息相关

近40年来,长江上游和支流地区,破坏得多治理得少,空话说得多认真实干得少,水土保持停的时间多搞的时间少,在点上兜圈子的多在面上铺开的少。所以滑坡、泥石流和水土流失愈演愈烈,早洪风雹灾害日益频繁,危害惨重。长江上游和支流的水土保持,与国家现代化建设和长治久安息息相关,现在已到了刻不容缓的时候了。大抓生态环境的认真保护和水土流失的综合治理,几年内即可初见成效。     

清镇市土壤侵蚀强度景观空间格局分析

以清镇市1∶10 000土壤侵蚀实地调查图件为数据基础,在ArcGIS软件和Patch Analysis for ArcGIS景观分析模块的支持下,从景观总体特征、斑块比例、斑块平均大小、斑块面积标准差、分维数、斑块密度、分离度以及Shannon均匀度指数角度进行了土壤侵蚀强度景观空间格局分析。结果表明:清镇市总体上表现出土壤侵蚀面积大、以微度侵蚀和中度侵蚀为主、土壤侵蚀程度不严重的特征;在土壤侵蚀空间分布上,以南部地区的乡镇土壤侵蚀程度最轻,其次为中部地区的乡镇,而土壤侵蚀最严重的则分布在东西部及北部地区的乡镇。清镇市的景观基质为微度侵蚀景观,该景观类型的斑块较为集中,但各斑块间差异大,斑块形状最为复杂,异质性特征明显。剧烈侵蚀与极强烈侵蚀景观均是典型的人为干扰后的景观。整体而言,各土壤侵蚀景观的斑块在面积上的分布较为均匀,且各景观类型的平均斑块面积普遍较小,斑块内土壤流动较易发生。     

Resistance in Cucumis sativus L. to Tetranychus urticae Koch. 4. The genuineness of the resistance

Summary For several generations subpopulations of the twospotted spider mite were reared on cucumber varieties previously selected as partially resistant. Subsequently resistance tests were carried out in the laboratory and the glasshouse with mites from these subpopulations and concurrently with mites from a basic population reared on a susceptible cucumber line. In these tests neither acceptance nor net reproduction or damage index on the partially resistant varieties depended on the kind of mite populations used as inoculum. Therefore it is concluded that the resistance is genuine. The stability of the resistance is discussed.     

A procedure for combining a quantitative inheritance study with the first cycle of a breeding program

Summary The number of effective factors controlling the inheritance of a quantitative character can be estimated by analysis of F₃ lines where the parental lines are homozygous. The procedure is illustrated with data from a study of pod length inheritance in common bean (Phaseolus vulgaris L.). The mean pod length of Sprite, the parent with longer pods, was compared statistically with the means of F₃ progenies derived from F₂ plants obtained from the appropriate tail of the F₂ frequency distribution for pod length. The data indicate that analysis of F₃ progenies avoids much of the underestimation of the effective factor number which is characteristic of other procedures. The number of effective factors was estimated to be a minimum of 4 and the correlation between random F₂ parents and F₃ progeny means was r=0.82.Florida Agricultural Experiment Station Journal Series No. 406.     

Inheritance of slow rusting to stem rust in wheat

Summary The inheritance of the slow rusting character was studied on F₅ progenies from seven spring wheat cultivars (Triticum aestivum) crossed in all possible combinations without reciprocals. The cultivars and their progenies were evaluated for slow rusting in 1974 and 1975 in epidemics of Puccinia graminis f. sp. tritici, races 15 and 151, and traces of other races. Slow rusting varied significantly among the parents and among the F₅ progeny of each cross. Transgressive segregation occurred in each cross, i.e. some progeny rusted more slowly than the parents and some faster. In crosses with both Idaed 59 and Kenya 58 the progeny distributions were skewed towards slow rust development but the distributions in the other crosses were normal. The genetic control of slow rusting was predominantly additive, and narrow sense heritability was approximately 80 percent. The number of segregating genes having an effect on slow rusting was estimated to be 2 to 12 pairs depending on the cross. Correlation between slow rusting and maturity was usually negative but in most crosses the relationship was small.Contribution No. 9624 from the Agricultural Experiment Station, University of Minnesota, St. Paul, Minnesota 55108.     

中草药复方添加剂对施氏鲟生长及血液生化指标的影响

实验研究了7种复方中草药作为饲料添加剂对1+龄施氏鲟(Acipenser schrenckii)生长及血液生化指标的影响.240尾鱼共分为8组.7个复方中草药组和1个对照组,对照组投喂不含中草药添加剂的饲料.结果显示:实验中所采用的几种中药复方均对施氏鲟血浆中的总蛋白、白蛋白、球蛋白含量具有升高的作用.血清中AKP酶活性,除方六外其余中草药添加组的均较对照组有所升高,其中方四及方五升高明显.反映肝功能的指标中,方五可以显著降低LHD在血清中的含量,方二对ALT有显著降低的作用,方一、方四、方五可以显著降低AST在血清中的水平.大部分所选中药方剂对血清中尿素氮(BUN)、肌酐(SCR)、钙、磷含量的影响不显著,方二和方四能显著升高血糖含量;方二、方六和方七还能提高鲟鱼血清铁的水平.研究结果表明这几种方剂具有促进机体代谢功能的作用.     

华北平原不同种植制度对粮食作物氮素利用和土壤氮库的影响

冬小麦-夏玉米一年两熟是华北平原粮食作物的主要种植制度,存在氮肥利用率低、土壤氮素过量累积问题。为探索华北平原氮素高效利用的适宜种植制度,采用15N示踪技术,基于3 a田间定位试验,对一年两熟冬小麦-夏玉米的常规水氮和优化水氮、两年三熟冬小麦-夏玉米-春玉米与冬小麦-夏大豆-春玉米及一年一熟春玉米3种种植制度的作物产量、15N利用率、氮素去向和土壤氮库表观平衡进行研究。结果表明,两年三熟的冬小麦-夏玉米-春玉米产量为32 248.52 kg/hm2,分别比一年两熟和一年一熟提高22.16%和52.88%;15N利用率为33.36%,比一年一熟提高26.12%。3种种植制度的氮肥去向最高为土壤残留,其次为作物吸收和损失,两年三熟冬小麦-夏玉米-春玉米的作物吸氮量最高为151.82 kg/hm2,土壤氮库表观盈余量为21.22 kg/hm2,显著低于其他种植制度。综合分析,冬小麦-夏玉米-春玉米两年三熟在稳产高产和提高氮素利用率上具有可持续的潜力,是华北平原未来较为理想的种植制度。     

木薯力学特性测试

木薯力学特性参数的研究,对木薯收获机械的设计、动力学仿真、数学模型建立具有重要意义。采用物理试验方法,利用中国科学院长春科新试验仪器研究所生产的WDW3100微机控制电子万能实验机,测定了华南205木薯块根、茎秆物理力学特性参数,且对数据进行了数理统计分析,结果表明,木薯块根可视为一各向同性材料,其平均轴向拉伸强度、轴向压缩强度、径向压缩强度、轴向剪切强度、径向剪切强度、抗弯强度、轴向弹性模量、径向弹性模量分别为：0.34、0.74、0.76、0.22、0.37、2.66、7.23、7.22 MPa;木薯茎秆为一各向异性材料,其平均轴向拉伸强度、轴向压缩强度、径向压缩强度、轴向剪切强度、径向剪切强度、抗弯强度、轴向弹性模量、径向弹性模量分别为：10.23、6.26、1.43、1.86、2.53、10.80、5.24、35.36 MPa。     

氮肥利用率的问题与改进

传统差减法计算氮肥利用率变异较大,影响了氮肥利用率的应用,科学的氮肥利用率计算方法对氮肥的合理施用十分重要。本文概述了氮肥利用率50多年的研究过程,并划分为3个创新研究阶段,提出差减法计算氮肥利用率各个创新研究阶段的主要创新点。采用常规计算方法和定位试验研究资料计算了氮肥利用率,阐明常规计算方法计算的氮肥利用率结果存在的问题;归纳了氮肥利用率变异较大的主要原因:1)采用土壤氮素养分系统没有达到平衡或接近平衡的试验结果;2)常规计算方法仅考虑氮肥用量和作物吸收氮量,没有考虑土壤残留氮(或消耗土壤氮)。建立了2个氮肥利用率计算的新方法:1)土壤氮素养分系统平衡状态计算公式:氮肥利用率=(施肥作物吸收氮-报酬递减系数×对照作物吸收氮)/施肥氮;2)土壤氮素养分未达到平衡状态计算公式:氮肥利用率=(施肥作物吸收氮-报酬递减系数×对照作物吸收氮)/(施肥氮+施肥处理土壤氮素消耗量-对照处理土壤氮素消耗量)。     

青海野生动植物资源分布特征与保护措施

青海省地处青藏高原,在全国具有特殊的区系分类地位和野生物种多样性,且种群、数量都十分丰富。对青海省野生动植物的区域分布特点进行概述,为加强保护管理提供了科学决策依据。实现全省生态系统的长期稳定和生物资源的合理利用。