oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 370 )

2018 ( 6223 )

2017 ( 6418 )

2016 ( 6823 )

Custom range...

Search Results: 1 - 10 of 285598 matches for " 李凤民 "
All listed articles are free for downloading (OA Articles)
Page 1 /285598
Display every page Item
论我国半干旱地区农业生产力与生态系统可持续发展

资源科学 , 1999,
Abstract: 我国半干旱地区农业生产力低下和生态环境恶化的根源在于系统内的同化作用被强烈弱化,而异化作用却异常活跃。表现为植被破坏、农业生产力低下、土壤水蚀和风蚀严重、土壤肥力持续下降,扩大开垦面积进一步导致问题的严重化。这两大系统功能的不协调变化就是所谓的“生态平衡失调”,只有同化作用得到有效提高,才能抑制异化作用的恶性发展。核心就是大幅度提高系统生产力,对以人为中心的生态系统而言,提高农业生产力是生态环境改善和生态系统可持续发展的关键环节。首先改善农田水分状况,在大幅度提高作物单产的基础上,发展以集水技术为基础的生态农业,从而实现农业生态系统的可持续发展。
宁夏盐池苜蓿人工草地地上生物量季节动态研究

生态学杂志 , 1992,
Abstract: ?
地质勘查综合统计信息网络管理系统的建立与应用
,银海
地质与勘探 , 1999,
Abstract: 主要介绍了冶金地质勘查综合统计表(TJYB)系统的总体布局、功能特点及开发运行环境;着重论述了从数据采集、数据传输、数据处理到数据查询的全过程;并指出了系统的发展远景。
清太祖外戚阿古都督家族《谱单》与《谱书》试析?李凤民?李荣发
,荣发
清史研究 , 1984,
Abstract: ?
Restoration of degraded ecosystems and development of water-harvesting ecological agriculture in the semi-arid Loess Plateau of China
半干旱黄土高原退化生态系统的修复与生态农业发展

LI Feng Min,

生态学报 , 2003,
Abstract: The natural regional vegetation and soil quality in the semi arid Loess Plateau of China have been degraded extremely due to over grazing and frequent reclamation of natural grassland. Functions of the ecosystems and regional sustainable development were seriously threatened. The analysis of the current ecological environmental situation suggests that transformation of natural vegetation to farmlands in the process of frequent reclamation of natural grassland results in water loss, soil erosion and land degradation. Repeated reclamation of wasteland due to the great pressure of food demand resulted from population growth is the key driving force to the degradation of these ecosystems. To restore natural vegetation and soil quality, we have to find a way to meet the requirement of food for the local farmers in a small portion of the land to reduce the pressure of food production for the rest of the land of a region. In semi arid areas, many studies have shown that the key step for increasing grain yield per unit area is to improve field environmental conditions, including soil moisture supply, topsoil temperature and soil nutrient level. This can be accomplished through the combination of water harvesting technology with plastic film mulching and fertilizer application, which can generally increase the unit grain yield twice or more. Based on these technologies, we propose an approach of water harvesting ecological agriculture (WHEA) and associated landscape configuration in the paper. Unit yield of cash and grain crops can be increased greatly through limited irrigation, and the irrigated cropland can be interspersed with improved pastures and restored natural vegetation in a continuous landscape (a typical hill) in WHEA. Further research and dissemination of WHEA can help supply local farmers with sufficient food and higher income. Various types of grasslands will replace cropland and cover a large proportion of the landscape; animal feeding will be mainly dependent upon pen feeding in order to decrease grazing pressure. These strategies closely follow the ecological patterns of natural vegetation and landscape, as well as the planning pattern of regional industrial arrangement. The coexistence of multiple ecological and economic systems in a landscape helps to improve both biodiversity and industrial diversity, and enhance the flexibility and stability of these systems. Therefore, WHEA, an innovative approach for regional development, can lead to significantly improvement in both the restoration of degraded ecosystems and regional sustainable development simultaneously in the semi arid Loess Plateau.
THE RAINWATER HARVESTING TECHNOLOGY APPROACH FOR DRYLAND AGRICULTURE IN SEMI ARID LOESS PLATEAU OF CHINA
半干旱黄土高原集水高效旱地农业的发展

LI Feng Min,

生态学报 , 1999,
Abstract: The traditional water soil conserving agriculture has been developed for several decades.However,its regulative roles in water,fertility and temperature,were very limited.We think that the practicable approach is to harvest and stored rainwater artificially,and to supply limited irrigation at the key stage in crop development.This paper reviewed the research progress in rainwater harvesting technology applied in crop production.It is suggested that this technology will become one of the major directions of dryland agriculture in Northwest China.
Effects of pre-sowing irrigation and P fertilization on spring wheat yield information
底墒与磷肥互作对春小麦产量形成的影响

LI Feng,|Min,

生态学报 , 2001,
Abstract: This paper investigated the effect of pre\|sowing irrigation and phosphorus fertilizer supply on grain yield formation. Four treatments were employed: CK was as a control, P was phosphorus fertilizer applied in cultivated soil layer, W was pre\|sowing irrigation with 30 mm water depth, WP was W plus P. Soil moisture, root and shoot biomass, and grain yield were measured in the given periods. The root biomass and its distribution in medium and down soil layers in WP treatment were higher than others. Compar...
宁夏盐池长芒草草原和苜蓿人工草地水分利用研究
, 张振万
植物生态学报 植物生态学报 , 1991,
Abstract: ?本文用离体快速称重法对宁夏盐池长芒草天然草地和苜蓿人工草地的水分利用状况进行了比较研究。研究发现:很干旱的苜蓿草地具有较高的生物量,而在水分条件相对较好的长芒草草地中生产力却很低。苜蓿草地的蒸腾耗水量占蒸散量的86.9%,而长芒草草地中只占40.7%。水分利用强度苜蓿草地为137.32%,而长芒草草地为88.72%,而且有迹象表明,苜蓿草地的水分利用深度超过了180cm,而长芒草草地则保持在180cm范围之内。两草地的蒸腾效率在整个生长季中基本一致,而蒸散效率苜蓿草地为0.82‰,长芒草草地为0.54‰。经过一个生长季,苜蓿草地水分亏缺达-101.8mm,而长芒草草地为-17.6mm。
黄土高原半干旱区作物水分利用研究新途径
,赵松岭
应用生态学报 , 1997,
Abstract: 以黄土高原半干旱区农业生产条件,特别是土壤水分特性为背景,结合植物根冠通讯方面的有关研究进展,讨论了根化学信号在本地区的研究与开发潜力.本地区节水农业的核心是提高作物的水分利用效率,其途径包括:1)减少土壤表面的无效蒸发量;2)增加深层根量,减少表土中的根量,优化资源分配模式,提高繁殖分配比例.根化学信号对这两方面都有重要影响.基于目前的知识积累,应在根化学信号对作物生产力的影响方面作深入研究,可揭示节水农业中某些重要的理论问题.
黄土高原半干旱地区集水型生态农业分析
,徐进章
中国生态农业学报 , 2002,
Abstract: 简介了黄土高原半干旱地区农业发展现状及面临的问题,阐述了集水型生态农业在黄土高原旱地农业中应用的重要性,指出改善土壤水分是该区农业可持续发展的关键,集水型生态农业将有广阔的发展前景。
Page 1 /285598
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.