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。     

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.     

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。     

欧亚温带草原东缘生态样带研究探讨

为揭示全球变化与欧亚温带草原东缘生态系统的关系,提出沿着从中国长城至俄罗斯贝加尔湖设置一条经向样带,主要表征欧亚大陆东缘经向热量梯度,反映受大陆性气候控制下的草原地带的生态系列.沿样带开展生物地球化学过程、能量交换、植被结构动态、气候—植被、放牧—草地—牧草驯化、土地利用格局与管理、模型模拟等研究工作,对于加深气候变化和人为影响对草原生态系统的发生、发展、利用及演变规律的影响的认识,增强对气候变化的减缓和适应能力,具有非常重要的意义.     

古尔班通古特沙漠南缘蜱携带无形体的调查

为了解古尔班通古特沙漠南缘蜱携带无形体的状况,在该地域3个不同生境区域11个地点采集家畜寄生蜱标本,进行分类鉴定;运用套式PCR筛选无形体阳性蜱样本,并用半套式PCR扩增无形体科16SrRNA基因5′端高变区,进行克隆测序;将所获得的DNA序列与GenBank收录的序列作比对,并用Mega 5.0软件构建系统发育树,鉴定蜱携带无形体的种类。结果共采集708只蜱,鉴定为4个属8个种。在分类后的236份蜱样本中,检测出无形体阳性25份,阳性率为10.59%。序列比较发现,在亚洲璃眼蜱、血红扇头蜱、残缘璃眼蜱、长角血蜱中分别存在查菲埃立克体（Ehrlichia chaffeensis）、犬埃立克体（Ehrlichia canis）、边缘无形体（Anaplasma marginale）和绵羊无形体（Anaplasma ovis）的16SrRNA基因片段。研究结果证实在古尔班通古特沙漠南缘家畜寄生蜱中携带无形体,提示该地域可能是无形体病的自然疫源地。     

Population Studies of Limonium stocksii (Plumbaginacea) from a Salt Desert Near the Arabian Sea Coast

Abstract

A population of Limonium stocksii was studied for one year at the upper end of Manora Creek along the Arabian Sea coast, near Karachi, Pakistan. The community was divided into three zones. Soil pH varied from 8.1 to 8.5. Soil conductivity was highest (191 dS m^?1) in September and lowest (55 dS m^?1) in June. Soil water content was relatively low and varied from 1.6% in February to 9.5% in June. Limonium stocksii maintained a persistent seed bank, which peaked at 5,887 seeds m^?2 in May. Very slow growth was observed; however, plants in the intermediate zone showed better growth than the other two zones. Stem and leaf tissue water content were affected by salinity fluctuations, but root tissue water remained unaffected. Sodium (Na⁺) and chloride (Cl^?) accumulated in stems and leaves more than other ions. Leaves also accumulated a very high amount of magnesium (Mg⁺⁺) compared to roots and stems.     

Impact of organic residues and mineral fertilizer application on soil–crop system: II soil attributes

The effects of crop residues alone (Cr⁺) or combined with inorganic fertilizer (FCr⁺) sewage sludge (SS) and humentos (H) on soil properties were studied in a five-season wheat–guar rotation. Incorporation of Cr⁺ and SS significantly decreased pH by 5–9%. Highest organic carbon (OC) was observed in SS plots, whereas Cr⁺ resulted in values threefold that of the control. The added effect of Cr⁺ (46%) combined with fertilizer on total nitrogen (TN) was greater than Cr⁺ by 28%. The fraction of total residue N mineralized was 71%, whereas net N mineralized in Cr⁺, SS, H and FCr⁺ plots at 0–20 and 20–40 cm depths were 39.8, 52.3, 11.4, 66.7 mg kg^?1 and 21.2, 27.9, 8.2, 41.2 mg kg^?1, respectively. Integrated application of Cr⁺ with fertilizer had a synergistic effect on P content (3.49–3.69 units), but soil levels has never exceeded 13 mg P kg ^?1. Sole Cr⁺ significantly increased topsoil cation-exchange capacity (CEC) compared with the control treatment (9.39–21.59%). Application of SS, FCr⁺ and Cr⁺ significantly increased water-holding capacity and decreased bulk density by 9–15% and 8–9%, respectively, suggesting that such practice can restore the productivity of degraded soils and improve crop yields.     

内蒙古杭锦旗穿沙公路沿线水资源合理开发利用

内蒙古杭锦旗“穿沙公路”,穿越库布齐沙漠 ,沿线防沙治沙工程及生态工程的建设 ,均与水资源的合理开发利用有密切关系。本文根据已有资料和野外调查结果 ,对公路沿线水资源的基本特征进行了分析 ,提出了水资源合理开发利用的措施和建议 ,可为实践工作所参考。     

乌兰布和沙区的水资源条件与治理开发的节水措施

分析乌兰布和沙区的水资源现状和开发潜力，探讨沙区黄灌区和井灌区的节水措施，提出防止土壤盐渍化是沙区治理开发过程中应十分注意的问题。     

民勤连古城国家级自然保护区白刺种类及实生苗培育技术

白刺是干旱荒漠区重要的建群植物,是优良的防风固沙造林先锋树种及饲用植物,是药食两用的野生水果,其生态价值和经济价值较高。主要介绍了甘肃民勤干旱荒漠区白刺植物种类及生物学特性,探讨了其种子采集、催芽、播种、田间管理等实生苗培育技术。