草地退化对土壤理化性质的影响

文章以张家川县不同退化程度草地为研究对象,探讨草地退化对土壤理化性质的影响。结果显示:土壤密度和含水量均随着草地退化程度的增加而下降,有机碳和速效磷则随着草地退化程度增加呈现出先上升后下降的趋势。同时,不同退化程度的草地0~2.5 cm层土壤全氮和全磷含量基本均高于深层,土壤全钾含量在2.5~5 cm层高于其他层。总之,草地退化影响着土壤理化性质。     

草原人居环境保护与发展三元论 ——以新疆伊犁河谷为例

坚守"山水林田湖草是一个生命共同体"的理念,聚焦伊犁河谷草原人居环境背景资源、活动方式、规划建设的三元一体,将草原人居环境作为三元互动、不断成长的生命体,尝试寻找一种构建荒野、乡村、城市共存融合的草原人居环境保护与发展模式。以客观规律为依据,以主观需求为准绳,寻找及保留草原人居环境演化中相对稳定不变的基因,构建草原人居环境CVA三力评价体系,建立草原人居环境发展CVA量化模型,以求指导草原人居环境未来的保护与发展。推行这种模式不仅可为中国西部地区提供生态安全保障,也将使伊犁河谷成为多种人居环境生命共同体的典范。     

鼠类对吉林西部春季草原环境的影响研究

通过铗日法和洞道调查,得知吉林省松嫩平原北大岗草原分布有5种草原鼠：即达乌尔黄鼠、黑线仓鼠、草原鼢鼠、五趾跳鼠、缺齿鼹。鼠洞密度为29个/hm2。鼠类活动使草原平均覆盖率下降29.2%,平均高度降低4.8 cm,使丰富度指数降低16.1%,使草原鲜重生物量下降51.2 g/m2;干重生物量下降36.1g/m2,使一部分草原变成了裸地,改变了植物生存的环境。可见鼠类活动对草原环境影响很大。     

基于ZigBee无线传感器网络的草原环境监测系统设计

针对目前草原退化现象严重、载畜能力下降等问题,提出一种基于ZigBee无线传感器网络的草原环境监测系统方案。系统由草原无线监测网络和远程PC机二部分组成,实现对影响草原牧草生长状况的空气温湿度、光照强度和降雨量等环境信息的实时、远程监测。采用以CC2530无线微处理器芯片为核心,设计开发了协调器节点和传感器节点的硬件与软件流程。初步试验表明,具有构建简单、稳定可靠、准确度高等优点,能较好地满足草原环境监测的应用需求。     

基于ENVI-met模拟的不同用地类型居住小区绿地布局对PM2.5的影响

居住区绿地作为城市绿地的主要组成肌理,对改善空气质量起着重要作用。首次将ENVI-met用于居住小区绿地布局与PM2.5的模拟,选取武汉市典型的一类、二类、三类小区,定量分析不同草地、乔木布局对PM2.5的影响。研究表明,集中型的草地布局、四周型的乔木布局能更有效降低小区PM2.5浓度;分散型的草地布局、集中型的乔木布局最不利于消减PM2.5;四周型的乔木布局对阻滞道路上PM2.5的扩散效果最佳。同种绿地布局形式下,二类小区的平均PM2.5浓度最低,三类小区最高,PM2.5空间分布在3类小区中也具有一定的差异。研究揭示了居住小区绿地布局对PM2.5的影响机制,为小区绿地的规划设计实践提供一定参考。     

把我国广大的沙化草原建设成为可再生的世界级特大的清洁能源生产基地

中国有广大的约占国土面积40%的沙化退化草原,不宜亦没有用作粮食耕地。但经过大力的生态建设后每年能产出巨量的巨银草。后者是原生在中国北部,能耐干寒和恶劣环境,并是多年生高达3.5 m的巨大稠密的野草,并能利用咸水。将这些巨银草气化催化后估计每公顷可产出17.2 t的可直接替代汽油的生物丁醇,生化和基因研发专业公司孟山都和孟代尔等己开始合力提升此产能,估计到2030年左右,以沙化草原的约46%的面积种植巨量的巨银草,可使中国开始不再依赖石油和煤炭的化石能源,而转用由巨大的"巨银草油田群"供应的可再生的清洁能源,其余的面积的产量可供外销或作他用,使中国能长期成为世界能源强国,与他国合力稳定能源供应和价格,并引领世界迈向可再生的清洁能源新时代。     

Evaluation of a system of wind tunnels for field studies of ammonia loss from grassland through volatilisation

Rates of ammonia (NH₃) loss from a ryegrass sward measured using a system of small wind tunnels were compared with concurrent measurements made using a micrometeorological mass balance method. Measurements were made during two experiments within a circular plot (radius 10m) treated with urea at a rate of 200kgNha^?1. In the first experiment, air speed through the tunnels was adjusted as necessary to maintain a value of approximately 1ms^?1. This value differed on most occasions from the mean ambient wind speed which was measured at a height of 250mm and which ranged from 0.61 to 2.95ms^?1. Rates of loss measured using the wind tunnels differed by a factor of between two and five from those measured using the mass balance method; there was no consistent pattern in the differences between the rates of loss. The total losses of NH₃ measured during 15 days were equivalent to 49.1 and 30.2kg Nha^?1 for the mass balance and wind tunnel methods, respectively. In the second experiment, air speed through the tunnels was adjusted as necessary to maintain a value as close as possible to the mean ambient wind speed measured at a height of 250mm. Rates of NH₃ loss measured using the two methods did not differ significantly; total losses of NH₃ during 17 days were equivalent to 96.9 and 101kg Nha^?1 for the mass balance and wind tunnel methods, respectively. The difference between the findings of the two experiments could be attributed to the direct effect of air speed through the tunnels rather than to differences between ambient temperatures and those inside the tunnels. During and following periods of rain the rates of loss measured using the tunnels were up to six times greater than those observed with the mass balance method. Rates of loss measured by the two methods became similar again when the tunnels were moved following rain. The study demonstrates that enclosures can be designed and operated to provide reliable measurements of the rate of NH₃ loss from grassland. Potential applications of the two methods are discussed.     

海南岛热带草地的数量分类研究

本文用一些数量分类和排序的方法对海南岛鹦歌岭热带草地进行了分类和排序。所用的方法包括两种多元等级聚合分类——最近邻体法(NN)和最远邻体法(FN),极点排序(PO)和主分量分析(PCA)排序,研究结果表明:可以把19个样地分为3大类型、9个群落,其分布格局与坡度、放牧强度和土壤肥力密切相关。所用的4种方法在热带草地的研究中均有一定的适用性。     

基于微型自动驾驶飞机的航拍航摄遥感系统

飞机是一种重要的遥感平台。我们发展了一套基于微型自动驾驶飞机的航拍航摄系统。该系统具有以下特点：（1）野外作业机动灵活,对场地和气象等条件要求不高;（2）费用较低,无人身安全之虑;（3）所获得的相片和图像清晰,分辨率较高,可达到分米的量级;（4）在航拍航摄时,同时有GPS信息（即经、纬度和高度）;（5）可进行定点定高拍摄,适合对无人区的遥感普查（例如：土地利用和气象及地质灾害等）。