马尾松低效防护林多层经营技术研究

用系统整体的观点。结合乔木层郁闭度（Ｘｌ）、灌木层盖度（Ｘ２）、草本层盖度 （Ｘ３）、枯落物层盖度（Ｘ４）与林地土壤侵蚀模数建立的回归模型分析，提出了多 层经营的概念，即“同步经营林分的乔木层。灌木层、草本届和枯落物层，根 据各层目标功能确定经营措施，获取生态经济的整体效益。使林分在高效高产 水平上持续协调发展”。并通过分析马尾松低效防护林系统群落各层次的目标 功能，确立了多层经营的指导思想，据此分层阐述经营技术。     

森林生态系统中大气输入物质的数量估计

以测定输入和输出林冠的物质流为基础,针对各种化学元素呈现的确定的状态或结合,并根据植物生理学和其他学科的基础理论,经简单计算即可对大气输入物质拦截沉积速率和相关元素为林冠吸收、淋洗或缓冲速率进行数量估计。     

工程排水对低产田肥力及作物产量影响的研究——以名山县《川中项目》效益定位监测结果为例

工程排水改善了土壤生态环境,土壤理化性状得到明显改良,水、肥、气、热诸肥力因素日趋协调,肥力水平显著提高,收到了形质兼改的明显效果。生产经济效益十分显著。     

Production and decomposition of plant litter in an arid rangeland of Kenya

Data on litter production and decomposition in an arid rangeland in Kenya was collected over a two-year period. Utter sampling was carried out at monthly intervals using a rectangular 0.25m^?2 quadrat frame. Utter within the quadrats was handpicked and washed with running water to get rid of soli particles, dried, and weighed. Weights were expressed on organic matter basis. Monthly litter production ranged from 31.4g m^?2 to 130.0g m^?2. Mean monthly yield was 92.5 ± 26g m^?2, with a 28% coefficient of variation. There was no significant difference (p>0.01) in litter yield between 1992 and 1993. Rate of decomposition for aboveground material ranged from 0.005g g^?1 day^?1 to 0.084g g^?1 day^?1. The mean annual rate of decomposition was 0.026g g^?1 day^?1. Belowground plant material rates of decomposition spread from 0.009g g^?1 day^?1 to 0.062g g^?1 day^?1. with a mean annual rate of 0.041g g^?1 day^&minus1. Belowground material consistently decomposed faster than aboveground material. Peaks in both aboveground and belowground material decomposition rates coincided with rainfall peaks. Overall, in this arid environment, litter production and decomposition is pursed in nature, and trends are closely related to rainfall occurrence. Moisture is thus a limiting factor both to the production and decomposition of litter. Belowground litter plays a significant role in nutrient cycling.     

~(14)C—久效磷在稻—鱼模型生态系统中的残留

应用~(14)C示踪研究了久效磷在稻、鱼、土壤、田水中的残留。结果表明:该药在上述物体中均有残留,水稻收获时,在根、叶、茎、穗中的残留量分别为5.2248±0.4152、4.7928±0.7016、3.9895±0.6633、1.3042±0.1042微克/克干重;测得田水和土壤中的残留量为0.0012±0.0005微克/毫升,0.0241±0.0050微/克风干土。施用久效磷56天后,鱼体内的残留量为4.3964±0.9180微克/克干重。     

The ecology and management of the Miombo woodlands for sustainable livelihoods in southern Africa: the case for non-timber forest products

There is new and increasing emphasis on the contribution of non-timber forest products (NTFPs) to improving the livelihoods of rural communities and therefore the need for sustainable management of forest ecosystems of the Miombo woodlands to ensure the continued availability of these NTFPs. This paper examines and reviews some of the work that has been done in the Miombo ecoregion on the ecology, utilisation and management of the Miombo woodlands. The review points to the richness of the Miombo regions' plant species, with an estimated 8 500 species of higher plants, of which over 54% are endemic. The review also highlights the response of the Miombo ecosystem to fire and other anthropogenic processes and the lack of wide-scale adoption or implementation of the major research findings. The review shows that there is a wide range of NTFPs that significantly contribute to the total household income in forest areas and to the national economies through provision of opportunities for small-scale trade especially in the rural areas. However, there is a concern that commercialisation usually results in overexploitation of the resource by the outsiders who become the major players. It is suggested from the review that the lack of capacity by national institutions to manage Miombo woodland resources could be addressed by using participatory approaches to natural resource management. It is also proposed that for sustainable use and management of NTFPs in the Miombo region, research should focus on issues that specifically address NTFPs. In order to facilitate commercialisation and benefit the economically weak, policies that incorporate postharvesting technical assistance and access to information on markets, technology and microcredit should be developed and promoted.     

试论森林生态系统的耗散结构性质

本文运用耗散结构理论,探讨了森林生态系统的开放性、远离平衡态、非线性、突变现象、正反馈作用以及涨落的性质和特点。通过对内、外涨落的深入分类和理论分析,证明了涨落具有必然和偶然的双重性质,进而以森林季相变化为例,说明了涨落导致有序的条件。森林维护自然界生态平衡的作用是在内部自组织导致系统稳定的基础上实现的,从耗散结构看,这种稳定依赖于系统各类涨落之间的协调,无数微涨落积累而成的巨涨落可使系统发生突变而产生新的有序结构。