白桦与山杨叶凋落物候的差异及其生态学意义

用凋落物收集法和凋落物候模型研究了白桦(Betula platyphylla)和山杨(Populus davidiana)的叶凋落物候。结果表明:白桦叶凋落显著早于山杨,凋落开始时间和凋落高峰分别比山杨早41和20 d,但它们的叶凋落结束时间基本相同,这导致白桦的凋落期比山杨长42 d。此外,白桦叶凋落集中程度也明显小于山杨,凋落峰值仅是山杨的五分之一。白桦的叶N质量分数较高,碳氮比较低,导致了白桦叶分解较山杨叶快。这体现了处于相同的环境条件,白桦和山杨在能量利用和养分循环方面可能具有不同的生态策略。     

湿地松多效益经营模式林分采伐技术研究

在利用Richards函数对湿地松生长进行拟合和利用动态规划方法在计算机上直接模拟抚育间伐的基础上，初步确定了江西省丘陵区湿地松多效益经营模式林分的采伐技术。研究结果表明：湿地松多效益经营模式林分始伐年龄为8．10年，主伐年龄为25年，最优抚育间伐方案为间伐3次(含始伐)，时间分别为第8、12及16年，间伐强度分别为每公顷950、700、300株，最后保留株数为每公顷550株。表2参7。     

中国农地产权制度改革风险评估

研究目的:定量评估中国农地产权制度朝国有化、私有化和集体所有三种路径进行改革的风险,为农地产权制度改革路径决策提供参考.研究方法:鱼骨图法和层次分析法.研究结果:农地产权制度朝国有化改革的风险系数为0.419 5,朝私有化改革的风险系数为0.375 6,在现有集体所有的基础上改革的风险最小,为0.204 9.研究结论:(1)农地产权制度改革应特别注意规避政治风险(0.602 5);(2)改革应防范群众反对(0.267 5)引发社会动荡的风险(0.228 4);(3)改革需要调查民众的农地产权意愿,维护大多数群众的利益.     

基于灰色关联模型的河南省粮食生产驱动力分析(英文)

Henan Province is an important grain production base, whose stable production is related to the economic development and social stability significantly. To summarize the primary factors of grain producing, we used grey correlation analysis method to analyze 10 correlative factors such as grain yield, grain yield per unit area, effective irrigated area, rural employed persons, grain planting area, consumption of chemical fertilizer in 25 years. The results showed order of synthetic degree of incidence: effective irrigated area>rural electricity consumption>consumption of chemical fertilizer>disaster crop area>grain yield per unit of area>total power of agricultural machinery>afflicted crop area>grain planting area>number of the rural employed persons. Finally, according to synthetic degree of incidence between influential factors and total grain output respectively, a series of measures and the suggestions was proposed for grain production in Henan Province, which will also provide the scientific basis and help for the government correct decision-making.     

玉兰属植物特异特征的新发现（英文）

The research history and new discoveries of the specific characteristics of Yulania Spach were reported,as to the specific characteristics,such as the terminal,axillary and fascicled similar flower buds,sometimes polycymes;2-4 flower types of a plant;two spathe-like stipules of single flower;drape or overlap of tepals,deep split or shallow split on the edge of tepals.The discoveries could provide valuable information for the further studies on the taxonomic system,anthotaxical evolution,phylogenetic relationship and breeding.     

磁场对低温保存鸡精液品质的影响(英文)

[Objective] The study aimed to explore the effects of magnetic treatment on the quality of chicken semen stored at low temperature. [Method] 5 ml fresh chicken semen was divided into five groups equally, each of which was diluted at the volume ratio 1∶4. With the group without magnetic treatment as the control, the other four groups were magnetized for 6, 12, 24 and 48 min in the self-made magnetizer, respectively. Subsequently, all the five groups were stored at 2-4 ℃, and the sperm motility, survival time, survival index and deformity rate were observed regularly. [Result] Comparing with the control group, the magnetic groups showed higher sperm motilities and effective survival indices as well as lower deformity rates. The effective survival index of the group magnetized for 24 min was the highest and increased by 7.75% in contrast to the control. [Conclusion] Magnetic treatment can effectively enhance the quality of chicken semen stored at low temperature.     

面向林业资源管理和决策的GridGIS体系结构研究与应用

我国林业信息化建设现状和林业空间应用需求决定了我国林业GridGIS是资源异构、分布式协作、自适应管理的解决方案。合理的体系结构设计有助于GridGIS的实现。参照GridGIS的已有研究成果,从网络结构、层次模型、系统实现技术原则3个角度,设计了林业GridGIS的体系结构。对等式网络结构有助于解决跨网络、跨地域下分布式协作与系统自适应管理问题;4分层模型有助于降低系统设计复杂性,减少系统的耦合性;包括基于标准构建、复用中间件、SOA在内的技术原则,有助于系统的稳定、可扩展、可更新。应用实践表明,该体系结构能够满足林业空间网格的技术需求。     

Wheat Growth and Photosynthesis as Affected by Oxytetracycline as a Soil Contaminant

Extensive worldwide use of oxytetracycline (OTC),a member of the tetracyclines,has resulted in its accumulation in soils,posing a potential risk to food production and safety.A pair of OTC-sensitive (Heyou 1) and OTC-tolerant (Yannong 21) wheat (Triticum aestivum L.) cultivars was compared hydroponically at 0.01,0.02,0.04,and 0.08 mmol L-1 OTC in terms of wheat growth and photosynthesis.Biomass and shoot length decreased significantly with the addition of OTC,with the decreases in dry biomass and shoot leng...     

THE STUDY ON SITE QUALITY EVALUATION FOR DAHURIAN LARCH(LARIX GMELINII RUPR.)

Site quality of larch(Larix gmelinii Rupr.)in Da Xingan Mountain in InnerMongolia was studied systematically with about 1000 temporary plots and computersoftware.The nature of site class and site index curve was discussed in view of generalmathematical model of height growth.The height growth of dominant tree of four divisionsof forest stands were studied and site index tables were constructed respectively.In orderto unify the comparing standard and convenience for management in this region,site indextable was constucted too.Based on discussing the action and accuracy of forest type,aseries of site quality evaluation(forest type-site index class-site index)was suggested.     

改革开放以来土地承包政策的发展演变研究

土地承包政策是20世纪70年代末80年代初中国的一项划时代的政策。家庭联产承包政策暨土地承包政策，大致可以分为大突破、大磨合、大转型、大发展等几个阶段。土地承包政策所取得的巨大成就表明，以家庭联产承包为主的责任制、“统分结合”的双层经营体制，是一项符合中国农村实际情况的土地政策。