粮田土壤磷、钾养分的垂直分布特征

本文研究了粮田土壤磷、钾养分垂直分布特征。结果表明 ,0～ 2 0 cm土层 N( NH4 - N)、P、K、Mn、Zn、Fe、Cu等主要养分速效含量明显高于 2 0～ 4 0和 4 0～ 60 cm土层 ,其中 0～ 2 0 cm土层 P含量数倍高于 2 0～ 4 0和 4 0～ 60 cm土层 ,显示磷肥应尽可能深施 ,以提高下部土层 P素肥力 ,2 0～ 4 0和 4 0～ 60 cm土层养分含量差异不大。不同施肥措施对上部土层 ( 0～ 2 0 cm) P、K等养分含量有较明显影响 ,而对下部土层 ( 2 0～ 4 0和 4 0～ 60 cm) P、K等养分含量影响较小     

Molecular genetic and chemical assessment of Rhizoma Curcumae in China

Rhizoma Curcumae (Ezhu) is a traditional Chinese medicine that has been used in removing blood stasis and alleviating pain for over a thousand years. Three species of Curcuma rhizomes are being used, which include Curcuma wenyujin, Curcuma phaeocaulis, and Curcuma kwangsiensis. In China, the production of Rhizoma Curcumae largely depends on agricultural farming. The essential oils are considered as active constituents in Rhizoma Curcumae, which include curdione, curcumol, and germacrone. On the basis of the yield of curdione, curcumol, and germacrone in an orthogonal array design, the optimized extraction condition was developed. The amounts of these compounds within essential oils in Rhizoma Curcumae varied according to different species and their regions of cultivation. Chemical fingerprints were generated from different species of Curcuma, which therefore could serve as identification markers. In molecular genetic identification of Rhizoma Curcumae, the 5S-rRNA spacer domains of 5 Curcuma species, including the common adulterants of this herb, were amplified, and their nucleotide sequences were determined. Diversity in DNA sequences among various species was found in their 5S-rRNA spacer domains. Thus, the chemical fingerprint together with the genetic distinction could serve as markers for quality control of Curcuma species.     

磁化水对黄瓜叶片氮磷钾钙镁含量的影响

以当地冬春茬保护地品种寒秀、鲁圣顶峰1号为试材，研究了磁化水对黄瓜叶片氮、磷、钾、钙、镁含量的影响。结果表明：叶片生长发育期间，黄瓜叶片氮、磷含量呈单峰曲线变化；钾、钙、镁含量呈双峰曲线变化。磁化水处理后，寒秀叶片内磷、镁含量极显著高于对照，钙含量显著高于对照，氮、钾含量差异不显著；鲁圣顶峰1号磷、镁含量极显著高于对照，氮、钾、钙含量差异不显著。     

非饱水冻融作用下的古砖动弹性模量

在对我国北方销售的冻梨品种、产地来源、制作方式及存在问题进行实地调查的基础上,对冻梨的生产历史、文化、品种特性及研究现状进行综述与分析,并提出我国冻梨产业需要解决的问题及今后的研究方向。     

Preprocessor of Reinforced Concrete FEM Analysis

Reinforcing element and concrete element have effects on the order of the stiff-matrix of the reinforce-concrete FEM. The program divided the elements is programmed by FORTRAN language in current analysis, and the data of the elements are stored by the array. The stiff-matrix of the reinforce-concrete FEM is extended by the large residual between the serial numbers of the nodes of cohering element. This paper establishes the graph class, path class and point class via objectoriented programming. The storage of the points and the paths by the chain structure realization of copying graph, moving graph, adding graph, continuously numbering the cohering elements are built. This paper presents the example of the dividing domain with the crack.     

高产优质西瓜对氮,磷,钾的吸收及分配规律

研究表明，西瓜苗期对氮、磷、钾的吸收很少。随着植株的生长逐渐增多，抽蔓到一棚瓜成熟期间对氮的吸收有明显的线性关系，回归方程为ｙ＝０．１４１９ｘ－５．３８７８，ｒ＝０．９９７１＊＊。座果后对磷的吸收逐渐增多；开花结果后对钾的吸收逐渐增多。西瓜植株对、氮、磷、钾的分配在结果前主要用于叶的发育和建成，其次是茎、根的生长；座果后，逐渐转向果实的发育     

光敏核不育水稻存在BT型等位不育基因及其遗传关系的研究

农垦58s及其转育于不同遗传背景的光敏核不育水稻与BT型不育水稻六千辛A和寒丰A杂交,得到的F_1植株完全不育,证明农垦58s不育的2对隐性基因中有1对来源于农垦58,即为与BT型水稻等位的不育基因.由此推论农垦58s源于农垦581个基因位点的突变,而它的光敏不育性则为此突变基因和原有不育基因重叠作用的结果.当用作光敏不育的恢复亲本原已存在或不存在BT型水稻不育基因,决定了它们杂种F_2代的可育株和不育株呈3:1或15:1不同的比率分离.     

Movement of mud snails affects population dynamics,primary production and landscape heterogeneity in tidal flat ecosystems

Landscape Ecology - Animal movements influence the spatial heterogeneity of variously ecosystem processes. However, our understand of how movement in heterogeneous landscapes shapes ecological...     

活牛、牛肉与生产原料比价关系分析

【目的】为掌握肉牛生产及其产品市场价格波动规律,了解牛产业各环节收益和波动情况,及时为生产指导提供科学依据。 【方法】选择在张掖市辖区内设置10个畜产品价格监测点,按日汇总,以最近一个监测周期（410天）数据为总体,选择近3个月和去年同期3个月数据为样本,按统计学原理分析其均值、标准差、误差区间、变异系数、波动趋势概率（P）和增幅等,进行总比、同比分析。【结果】本监测期玉米价格2.890.03、活牛32.772.26、牛肉72.271.97、M 11.410.65 、R 2.210.11;确定以活牛/玉米（M值）为参数,将原料与产品结合起来作活牛成本分析;用牛肉/活牛比价（R值）分析养殖与屠宰消费环节营销利益分配关系。根据M、DP（屠宰率）均值11.41、55.81%确定3个盈亏平衡点为：活牛成本32.97元,牛肉成本59.08元,活牛屠宰到消费端营销成本R值为1.8;根据 R均值2.21确定活牛屠宰到消费端营销临界利润率为 22.7%,当R≧2.21时营销利润率≧22.7%,效益增加,R≦2.21时营销利润率≦22.7%效益降低。【结论】与肉牛生产息息相关的4个临界点分别为M值为11.41,基于M值的活牛成本32.97元、牛肉成本59.08元、活牛屠宰到消费端营销成本R值2.21利润率22.7%。近期M值连续下降溢出正常区间下限值10.65达66天,R值上升溢出正常区间上限2.32达52天,养殖环节收益缩减呈现亏损状态,屠宰消费环节营销利率高达30%。 M、R值变化呈不同步状态, R滞后。     

上海精养鱼塘高产饲草的选择和应用

本研究根据上海精养鱼塘的生产现状，经３年（１９９２～１９９５年）大面积试验实施，指出种植高产饲草代替部分精料，以草换鱼是解决饲料不足和我国粮食短缺的有效途径。实践中，按照鱼的摄食规律，科学选择草种，合理组合草种、重视科学种草栽培技术是稳定发展本市节粮型淡水养殖业的重要环节。