Differentiation of soil fauna in desert agriculture of the Mariut region

Summary The soil fauna of 23 sites in the Mariut region, west of Alexandria, Egypt, was sampled monthly or seasonally for periods of 1,5–2.5 years. These sites range from unutilized littoral sand dunes, to free-grazing pasture, to low- and high-intensity dry farming, to irrigated agriculture. The average population densities of the encountered taxa were compared by corresponding analysis and by ascending hierarchic classification. With intensification of the agricultural practices, true detritivores of the original system, capable of dealing with the available plant and animal litter and adapted to the harsh desert climate, are replaced by other mesic detritivores adapted to the changes in litter quality (less animal and more plant) and also adapted to the new physical and chemical soil conditions. Meanwhile, the increase in plant biomass encourages the appearance and proliferation of cryptic phytophages (agricultural pests), occupying the niche of the removed large (domestic) herbivores. Carnivores (e.g.Carabidae) also change accordingly. Sites can thus be characterized on the basis of their soil faunas, according to the stage of their evolution, and a system of exchange of missing key taxa between sites should be established.     

菊芋在民勤干旱沙区种植试验研究

2007年通过在民勤干旱沙区进行菊芋种植试验,结果表明:菊芋具有极强的抗旱抗逆能力、固沙和抗风沙能力、繁殖力强等生态适应性,在适宜的条件下,种植后不需灌水即可正常生长,而且生长量大、长势好,是优良的生态经济型防风固沙植物.因此,菊芋适宜在干旱、半干旱沙漠化地区推广种植.     

民勤荒漠草地退化原因及治理对策

介绍了民勤荒漠草地资源和草地退化现状,分析了导致荒漠草地植物组成变劣,草地生产力下降,草地生境日趋荒漠化等退化原因是由自然因素和人为因素综合引起的,有针对性地提出了民勤荒漠草地应采取加强行政措施和强化技术措施相结合的治理对策.     

库布齐沙漠不同地表类型沙粒粒径分析

通过对库布齐沙漠夜鸣沙沙物质、库布齐沙漠穿沙公路两侧沙障内沙物质、银肯响沙的沙物质、响沙湾附近新月形沙丘沙物质以及响沙湾附近固定沙丘沙物质各粒级颗粒的百分含量进行对比分析研究,得出以下结论：（1）夜鸣沙的的粒径均一,分选良好,其中细沙占95.72%,这是夜明沙在夜晚自鸣的主要原因;（2）银肯响沙的细沙占89.54%,比...     

青土湖水面形成过程对荒漠植物多样性的影响

[目的]分析青土湖输水过程对荒漠植物种多样性影响,为青土湖输水后的生态功能分析提供参考。[方法]通过4a的定位观测数据计算,分析青土湖岸植物种的多样性以及植物种的时间与空间变化及其与地下水位关系。[结果]距水面200m范围的植物种数量减少,其中距水面0m的植物种减少最多,100m处物种变化最少。Shannon-Weiner,Pielou指数和Simpson指数变化趋势相似,丰富度和多样性减小,均匀度和优势度增大;其中植物种优势度变化相对较大,且空间变化速率大于时间变化率,但Cody指数的时间变化率大于空间变化速率。[结论]青土湖输水促使植物种及其多样性以水源为中心呈带状变化,形成特征植物圈,且随地下水位上升变化程度增大。     

乌兰布和沙漠东北部不同下垫面的小气候变化特征

研究沙区不同下垫面小气候特征对充分利用气候资源及保证林业和农业的正常发展具有实践意义。该研究基于内蒙古磴口荒漠生态系统国家定位观测研究站2018年1-12月监测的荒漠区、荒漠-绿洲过渡带和绿洲内部的气温、相对湿度、风速和风向等气象资料,研究了3种下垫面的小气候特征并探讨了产生差异的原因。结果表明:1)荒漠区、荒漠-绿洲过渡带和绿洲内均为白天气温差异较小,夜间相差较大;由于近地层(0～50m)具有明显的逆温现象,使得植被在气温较高季节发挥降温增湿作用,而冬季发挥保温作用;2)绿洲使年均相对湿度增加1.31～2.57个百分点;就季节而言,夏、秋季,绿洲内的相对湿度较荒漠区和过渡带分别高4.04～6.17和0.93～1.94个百分点,春、冬季,由于近地层(0～50 m)存在明显的逆湿现象,因此绿洲内的相对湿度较荒漠区和过渡带分别低0.37～1.41和6.55～8.71个百分点;3)荒漠区、过渡带和绿洲内风向年变化特征均为以偏西风(W,WSW,SW,SSW)为主,荒漠区和过渡带的风向多变,绿洲内风向相对较为集中,绿洲能够使年均风速降低32.99%～37.05%。乌兰布和沙漠东北部过渡带植被和绿洲防护林体系对小气候具有很好的调节作用(降温、增湿、削减风速),研究区局地小气候主要体现在风速和夏秋季湿度上,而气温和冬春季湿度分别主要受逆温和逆湿的影响。     

腾格里沙漠南缘种子植物区系及其资源属性

[目的]调查植物区系,分析资源属性,为提高当地居民经济收入,改善农村产业结构提供依据。[方法]以样地调查数据为基础,通过查阅种子植物名录,对种子植物的区系属性、生活型属性和资源属性进行综合分析。[结果]腾格里沙漠南缘有种子植物31种,隶属16科,31属,大科属种为黎科、菊科和禾本科,草本植物最多,占总种数的67.7%,生态植物、饲(食)用植物和药用植物分别占总种数的83.87%,51.61%%和58.06%。[结论]大科属种为黎科、菊科和禾本科,它们在该保护区系中占有重要的地位,表现出它们在该保护区植物区系中的重要性,植物生活型中草本植物最多,生态植物、以饲(食)用植物和药用植物所占比例较大。     

治理荒漠 保持水土 加快生态农业建设步伐

<正>榆林地区位于陕西省北部,毛乌素沙漠南缘.全区12个县(市),总人口321万,农业人口283万,总土地面积4.36万km~2.榆林地区以长城为界分为两大地貌单元,北部为风沙草滩区,占42%;南部为黄土丘陵沟壑区,占58%,属干旱半干旱大陆性季风气候,年平均降水量399mm.区情特点是:经济相对落后,是国家重点扶持的贫困地区;资源极为丰富,是国家重点开发、可持续利用的能源重化工基地;生态环境脆弱,是全国水土保持、防沙治沙的重点地区.     

Responses of microbial biomass and respiration of soil to topography,burning, and nitrogen fertilization in a temperate steppe

Temporal dynamics of microbial biomass and respiration of soil and their responses to topography, burning, N fertilization, and their interactions were determined in a temperate steppe in northern China. Soil microbial indices showed strong temporal variability over the growing season. Soil microbial biomass C (MBC) and N (MBN) were 14.8 and 11.5% greater in the lower than upper slope, respectively. However, the percentage of organic C present as MBC and the percentage of total N present as MBN were 16.9 and 26.2% higher in the upper than lower slope, respectively. Neither microbial respiration (MR) nor metabolic quotient (qCO₂) was affected by topography. Both MBC and MBN were increased by burning, on average, by 29.8 and 14.2% over the growing season, and MR and qCO₂ tended to reduce depending on the sampling date, especially in August. Burning stimulated the percentage of organic C present as MBC and the percentage of total N present as MBN in the upper slope, but did not change these two parameters in the lower slope. No effects of N fertilization on soil microbial indices were observed in the first growing season after the treatment. Further research is needed to study the long-term relationships between changes in soil microbial diversity and activity and plant community in response to burning and N fertilization.     

应用NOAA/AVHRR遥感资料对阿拉善草地进行动态监测的研究

应用ＮＯＡＡ／ＡＶＨＲＲ遥感资料对阿拉善地区的６个荒漠类草地进行了生长季内的动态监测。结果表明，应用ＮＯＡＡ／ＡＶＨＲＲ遥感资料对阿拉善荒漠进行动态监测是可行的而且是必要的；提出了以“面”取样，“面”与“面”样本区配的建模方式，克服了以往建模方法中样本间“点”对“点”不能很好匹配的缺点。