半干旱的

Make rain seeps through loess to be utilized by agronomic crop. The develop of the ditcher has become a new approach to solve agricultural drought in northwest area.

该机具的开发研制将成为干旱半干旱地区特别是我国西北地区解决农业干旱问题的新途径。

Supported by the ESCAP pilot project on integrated land and water resources management in arid areas using remote sensing and GIS (ESCAP 5-4-401), the land and water resources optimization model was developed and an integrated land and water resources management system based on remote sensing and GIS was designed and developed in this paper.

本文结合联合国亚太经社理事会示范项目"利用遥感与GIS技术进行干旱区水土资源综合管理"（Pilot project on integrated land and water resources management in arid areas using remote sensing and GIS，ESCAP 5-4-401），针对我国广大的干旱半干旱区水土资源综合管理的实际需要，详细讨论了基于遥感与GIS的干旱半干旱地区水土资源综合管理系统的设计思想、目标、结构与功能及系统开发中的关键技术。

Loess Plateau is locate in areas transited from semi-arid and semi-humid areas to arid hungriness area, Because of the influence of war and long-term\'s unreasonable utilization, the ecological environment in this region is poor and serious soil and water loss is heavy. The water and soil conservation ecosystem project of emphasis tributary is implemented by Yellow River Committee from 2000, during several years centralized treatment,Project Construction have got remarkable effect.

黄土高原地处我国从半湿润半干旱带向干旱荒漠带过渡的地区，由于受历史上战乱和人为不合理开发利用的影响，生态环境比较脆弱，经济发展滞后，水土流失严重。2000年以来，黄委会启动实施了以黄河多沙粗沙区为治理重点的黄河水土保持坡面生态工程的重点支流治理项目，经过几年投资集中治理，项目建设成效显著。

The 250 mm isohyet is used as the climatic boundary line between arid and semiarid region and it shifts at a maximum distance of 110-130 km during the extreme dry and wet year.

干旱半干旱过渡带是生态环境变化的敏感和脆弱地带，气候的波动性和人口压力是生态脆弱的根本原因，干旱和半干旱区交界线在丰枯年份的空间摆动幅度最大达110-130km。

Desertification is land degradation occurs in arid, semi-arid and subhumid regions, which is one of the he environmental problems human society generally concerned in the context of global change, has a direct relationship with the survival and development of their own humanity.

沙漠化即发生在干旱、半干旱及半湿润干旱地区的沙质荒漠化，是全球变化背景下，人类社会普遍关注的环境问题之一，与人类自身的生存和发展有着直接的关系。

First of all,we tested the germination and water uptake rate of 47 species typical xerophil seeds grow up in north China from 20 families,38 genuses under sufficient water and different Grads water stress by high-molecular-weight polyethylene glycol(PEG6000).The results show that Xerophil seeds from the same habitat exhibited similar patterns in response to water stress.Xerophil seeds from arid community were stronger in germination and imbibition than that from other two communities under serious water stress,whereas Xerophil seeds from humid community were sensitive to any degree of water stress.Namely,the seeds live in arid habitat possessed high germination and quickly water uptake in sufficient water or any degree of water stress,but the others grow up in humid habitat shown significant difference which germination and water uptake well under sufficient water but inhibited even if slight water stress.

首先，我们通过对20个科，38属，47种旱生植物种子在水分充足和不同梯度的干旱处理(聚乙二醇PEG6000)条件下的萌发率及吸水率实验发现，当水分胁迫强烈时，分布于干旱沙漠地区的植物种子其吸水率和萌发率都高于半干旱和湿润地区的植物群落，相反，湿润地区植物种子的吸水率和萌发率对任何的水分胁迫都表现出敏感的响应趋势，也就是说，生境恶劣的植物种子在较强的干旱胁迫下，仍然保持了较高较快的萌发率及吸水率，水分充足与水分缺乏时无显著差异，而生境相对较好的植物种子在水分充足情况下萌发与吸水良好，但在干旱胁迫时则受到明显抑制，水分充足与水分缺乏时差异显著。

It also suggested that the climate and environment in the area are characterized by changeability, sensitivity, instability, its general changes are the positive process of desertification correspondingly to the dry-cold steppe or desert steppe and desert, while the reverse process correspondingly to warm semi-humid forest steppe and temperate-humid shrub steppe.

进一步证实了古土壤S〓发育和河湖相沉积的萨拉乌苏组堆积时为温暖半湿润的森林或森林草原环境，全新世的砂质古土壤或湖沼相沉积时为温湿灌丛草原或疏林草原环境，黄土沉积时为半干旱干草原环境，风成砂沉积时为干旱荒漠草原甚至荒漠环境。

Analysis of sedimentary facies and the multiple proxy indexes indicate that climate have many times dry-cold and warm-wet changes in the desert-loess transition belt since the last interglacial, and environment undergone alternations from warm semi-humid forest steppe, temperate-humid shrub steppe, semi-arid steppe and dry-cold steppe, desert steppe to desert.

地层沉积相及粒度、磁化率、化学元素、孢粉和古脊椎动物化石等气候代用指标的测试分析，揭示了研究区末次间冰期以来气候有过多次干冷、暖湿波动，曾经历了干冷的干旱荒漠、干旱荒漠草原、半干旱干草原、温湿灌丛草原或疏林草原、温暖半湿润森林草原气候环境的交替变化。

This highly drought-resistant spe-cies is adapted to arid and semi-arid conditions.

这个高度抵抗干旱的种类适应干旱和半干旱情况。

Reference crop evapotranspiration (ET0) and new wetness index were both calculated and analyzed according to Penman-Monteith scheme recommended by FAO with routine meteorological data from 616 weather stations in China from 1975 to 2004. In terms of grades of wetness index from Chinese Climate Classification Criterion, China is classified into severe arid, arid, semi-arid, semi-humid and humid zones, respectively, which are compared with the demarcations from rainfall-based indices in order to reveal the similarity and difference in association with the two schemes under current global climate warming. Besides, the spatio-temporal analysis of climate wetness over the country in the past thirty years was performed.

依据中国616个地面气象台站1975年至2004年的日气象资料，利用联合国粮农组织推荐的参考蒸散计算方法，计算参考作物蒸散（ET0）和湿润指数，按照中国气候区划中的干湿指标把中国分为极干旱、干旱、半干旱、半湿润和湿润气候区，并与传统的降水量干湿指标进行对比，揭示在全球气候变化下两种干湿指标的异同，最后对中国近30 a干湿状况进行时空分析。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。