旱直播水稻的农业气象条件研究

通过１９９０年，１９９１年连续两年的分期播种试验，分析了旱直播水稻的光温特性及其与空秕率的关系，并根据当地气候特点，提出旱直播水稻的最佳及安全播种期和抽穗期。     

山西地震带历史地震序列的统计分析

在工程地震工作中需要知道某地震带或某地区未来100年内的地震活动水平,以便适当选择历史地震的统计时段,从而得到和地震活动水平相适应的不同潜在震源区的各级地震的年平均发生率。 本文利用极值理论、最大熵原理、马尔可夫模型的方法、莫尔纳方法和伯努里模型方法计算了山西地震带未来100年内中强震的年平均发生率、平均重现期大于等于某级地震的个数和发震概率,计算结果表明,山西地震带未来百年内将发生≥6.0级地震3次,发震概率为0.94左右;将发生≥6.5级地震1—2次,发震概率为0.84左右;有可能发生≥7.0级地震,发震概率为0.53左右;发生≥7.5级地震的可能性不大,发震概率为0.32左右;发生≥8.0级地震的可能性很小,发震概率为0.15左右。     

流域地貌系统的侵蚀演化与耗散结构

通过耗散结构的方法和概念,建立了流域地貌系统中熵产生和超熵产生的表达式。以此分析了流域系统的动力学机制,以黄土高原丘陵沟壑区为例,建立了流域地貌系统的侵蚀演化模型。定量描述了黄土高原丘陵沟壑区流域系统的侵蚀旋回,确定了流域的发育阶段。分析了流域系统侵蚀状况的空间不均匀性。     

湖北大别山区土地资源生产力估算

本文以湖北大别山区为例,提出了自然条件复杂,资料缺乏的山区土地资源第一性生产力的估算方法,并计算了湖北大别山区土地资源的生产力。即在土地资源带及类型(组合)区划分的基础上,以资源类型(组合)区为基本单元,通过典型地区抽样获取资料,运用多种数学模型测算,并经过综合判定,求得各类型(组合)区,资源带主要作物的第一性生产力。     

山地制度建设试验与思考

本试验针对怀化地区山地制度建设问题,通过建立山地档案制度,使山地产权制度、使用权流转制度和山地开发管理制度更趋规范化、科学化,消除由于流转不规范而影响山地开发的隐患,对促进山地的集中,规模开发和利用,提高山地生产力取得了明显的成效。     

川江流域防护林区林地的保护性利用

川江流域防护林区森林地面积仅占全区林地面积的44％,而疏林地、灌木林地、未成林造林地、宜林地等尚需抚育或营造的林地占56％,其中宜林地尚有20％。在分析区内林地利用现状的同时,指出了各类林地的主要土壤类型、主要问题及造林或抚育的难易。着重从森林营造和管理角度,提出了相应的保护林地措施。     

Changes in post world war ii distribution and status of monsoon rainforests in the Darwin area

Monsoon rainforests in the Darwin area occur as isolated patches ranging in size from 2 to 112 ha. Aerial photographic records over a 45 year period indicate a 60 per cent reduction in the cover of pre‐1945 rainforest. Urban development, cyclone damage, weed invasion and wildfire were identified as the major causes of this contraction. Urban development contributed 40 per cent of the total rainforest loss during this period. Rainforests occurring on dry substrates have been most affected by urban development. Cyclonic storm damage and indirect human affects such as weed invasion and anthropogenic fires continue to disturb the remaining rainforest patches. Although the largest expanses of rainforest presently occur within parks and reserves, providing adequate protection from further urban encroachment, smaller remnants occurring on vacant crown land are vulnerable to changes in land use. As well as the introduction of appropriate legislation, the control of fire and weeds should be given the highest priority by land managers to ensure the stability and long‐term maintenance of this remnant vegetation.     

The Location of Office Space in the Metropolitan Service Economy of the United States, 1985–1990

As the economic base of most American metropolitan areas relies increasingly on services, office industries have shifted to a more pivotal role in the new metropolitan service economy. Using primary office-space usage data of the time period 1985–1990, the changing spatial patterns of this new metropolitan service economy are investigated. It is found that the primary office activities are predominantly concentrated in a relatively small number of the largest metropolitan areas. However, an emerging spatial dispersion in primary office activities is also exhibited. Such dispersion is extremely strong at the upper end of the urban hierarchy. The Sunbelt-Snowbelt dichotomy fails to reveal any differences in the growth pattern of the new metropolitan service economy. A more diversified growth pattern of primary office activities is observed. Concentrated dispersion is the major spatial characteristic of this new metropolitan service economy.     

Influence of local geological conditions on the macroseismic effects in the town of Strazhitza

Damage caused by the earthquake of 7 December 1986 (M = 5.7) and its aftershocks in low-storey residential buildings in the town of Strazhitza, Bulgaria, situated in the epicentral zone are systematized. A scale of damages is compiled for two types of buildings which is coordinated with the MSK-64 scale. The territorial distribution of the seismic intensity is compared with the results of the detailed engineering-geological study. A correlation between the Quarternary deposit thickness and the observed seismic intensity is obtained.Paper presented at the 21st general assembly of the European Seismological Commission held in Sofia, 1988.