Obtainment of a carbon-13-, nitrogen-15-labelled burnt soil

 The restoration of the C and N cycles in the soil-plant system is a basic step for the reclamation of burnt soils. To evaluate accurately the efficacy of restoration techniques, it is necessary to use isotopic tracers and, therefore, a ¹³C-, ¹⁵N-labelled burnt soil should be made available. The present paper describes a technique for obtaining a ¹³C-, ¹⁵N-labelled burnt soil by burning a labelled forest soil in the laboratory. Received: 8 July 1998     

沙棘对黄土高原地区露天煤矿土地复垦的作用

１９９０－１９９７年,沙棘应用于晋陕镓接壤区安太堡露天煤矿废弃地复垦和建立试验示范区。试验结果表明,（１）沙棘是所选用的植物中了优秀的植物之一,它具有良好 适应矿区生态环境的特性,生长速度快、水土保护和土壤改良效果好;（３）沙束为众多的野生岛兽了栖息觅食的良好场所,使鸟兽数量有明显增加;（３）沙束雄性植株生长势和蘖生长株能力有明显优势,水土保持效果良好。     

煤矿区土地复垦的影响因素及对策研究

煤炭开采造成了大量土地资源的破坏,作为以整治被破坏土地为目的的土地复垦,是实现矿区土地可持续利用的关键环节。根据资料分析和实地调查,认为目前我国煤矿区存在着影响土地复垦的一系列因素,包括经济、技术、理论、政策和历史因素等。对此,应加强土地复垦理论和技术经济的研究、土地复垦技术的推广相关法律制度的完善,以形成煤矿土地复垦的支撑体系,促进矿区经济社会的可持续发展。     

西安市污水再生利用系统的优化与发展趋势分析

【目的】探讨污水再生利用系统的发展趋势和投资需求。【方法】以污水再生利用系统为研究对象,建立了一个考虑技术、经济和政策因素的系统动力学(SD)与非线性优化(NLP)相结合的SD-NLP模型,对西安市污水再生利用系统的发展趋势进行了预测和优化分析。【结果】应按照城市发展的不同需求,在不同阶段对污水回用规划目标进行调整。西安市污水的回用率应达到45%左右,才能在不依靠远距离调水的情况下基本解决缺水问题。近期污水再生利用工程的投资需求较大,但也只占到同期GDP的0.035%左右,与西安市经济发展状况相比还是能够承受的。【结论】应用SD-NLP模型不仅能真实地模拟污水再生利用系统,对系统的发展势态进行分析和预测,而且可融入专家的经验,使预测结果具有较强的可行性,并提高了污水再生利用规划的科学性、合理性和经济性。     

轻便型摩托结构模态参数的识别

以ＮＦ－１２５双轮摩托为研究对象,采用频域法中的传递函数模态分析法,根据实验模态分析的实,复模态参数识别理论,成功地获取了各子结构的模态参数,建立了整车的动力学方程。     

安徽省典型区域农田地膜残留特征研究

为探究安徽省典型区域覆膜作物地膜残留特征及影响因素,于2019—2021年选择安徽省8个代表性地市13个县区共计15个监测点,利用典型样点采集的方法开展地膜残留监测,同时随机选取周边的10个农户或合作社开展问卷调查。结果表明：2019—2021年安徽省地膜平均残留量为10.80 kg·hm^-2,未超出国家标准限值(75.00 kg·hm^-2)。各监测点3 a平均残膜量在0～30kg·hm^-2之间,残膜量为5～15 kg·hm^-2的监测点占53.33%。从不同区域来看,江淮丘陵区地膜残留量较多,其农田地膜残留量为3.62～25.76 kg·hm^-2。不同作物平均残膜量为马铃薯>露地蔬菜>烟草>果树>保护地蔬菜>大豆>瓜类>花生。保护地蔬菜地膜残留系数为1.59%,在沿用当前的覆膜生产模式下,此后连续覆膜8 a,残膜量将会超过国家标准限值。影响残膜量的因素有作物类型、覆膜年限、地膜规格。覆膜<10、10～19 a和20～30 a土壤的...     

Integration of arbuscular mycorrhiza inoculation in hydroseeding technology: effects on plant growth and inter‐species competition

Hydroseeding is a technique increasingly used to establish vegetation on large degraded areas, such as large‐scale road construction sites and quarries. Native grasses and legume species are used on rehabilitation and restoration projects as a first step in the recovery of such places, prior to the establishment of native forbs and shrubs that occurs at a slower pace. The effect of mycorrhizal inoculation on the development of nine species of grasses and legumes that can be potentially used in restoration processes in the Mediterranean area was studied, in microcosm experiments under greenhouse conditions. The effect of adding arbuscular mycorrhizal (AM) inoculum to a hydroseeding mixture was also investigated in greenhouse and in field conditions. In the hydroseeding experiments the mycorrhizal inoculum was added to the seed slurry in a jet agitated hydroseeding machine and sprayed to the soil surface with a pressurised spray in a one‐step application. The study shows that Glomus intraradices Schenk & Smith BEG72 is able to establish the symbiosis when applied at sowing while Glomus mosseae (Nicol. & Gerd.) Gerdemann & Trappe BEG116 is not. It also confirms that legumes are more highly mycotrophic than grasses. The results of the hydroseeding experiments demonstrate the establishment of the symbiosis using this technology, both in the greenhouse and in the field. Mycorrhizal inoculation improved above ground plant growth and increased the legumes/grasses ratio. Copyright © 2007 John Wiley & Sons, Ltd.     

Removal of Acacia mangium overstorey increased growth of underplanted Anisoptera marginata (Dipterocarpaceae) on an Imperata cylindrica grassland site in South Kalimantan,Indonesia

Effect of removing Acacia mangium overstorey on the growth of underplanted Anisoptera marginata saplings was studied in a mixed tree plantation established on an Imperata cylindrica dominated grassland site in South-Kalimantan, Indonesia. At the time of overstorey removal the Acacia mangium trees were 80 months old (average height 21 m and DBH 20 cm) and the underplanted Anisoptera marginata saplings 68 months old (average height 4.2 m and DBH 3.1~cm), and the spacing of both species was 2 m × 4 m with such an arrangement that the saplings were located within the same lines as the nurse trees. Eight plots of 192 m² in size were randomly designated to overstorey removal (canopy gap) and no removal (closed canopy) treatments. Removal of Acacia mangium overstorey was carried out by girdling and later cutting down the dead trees. The Imperata grass did not show regrowth in canopy gaps. The mean annual increment for height and DBH of Anisoptera marginata within 22 months after the treatment were higher in canopy gaps (1.3 m a^-1 and 1.4 cm a^-1) than under closed canopy (0.7 m a^-1 and 0.7 cm a^-1). Results indicate good prospects for diversifying the composition of fast-growing forest plantations on grasslands and integrating slow-growing valuable species in plantation programs. Studies on other establishment methods, such as planting in gaps or lines, and further management practices as well as their effect on available light, moisture and nutrients are needed.     

填海工程对海洋沉积物微生物群落的影响

为了解海域微生物的群落结构和空间差异,探究其与环境的潜在联系,选择大型石化基地浙江舟山市鱼山岛海域,以期为我国海洋工程建设的环境管理提供技术支撑。在基地建设围填海时期,设置10个海域生态监测站,按《海洋监测规范》和《海洋调查规范》对海域沉积物进行取样调查。结果显示,海域环境明显受到长江、钱塘江等入海河流的影响,有机碳(TOC)、石油类(Oil)、砷(As)、镉(Cd)、铜(Cu)和铅(Pb)均在海域西北形成高值区,并逐步向东部海域递减。应用Illumina MiSeq宏基因组高通量测序技术,在海域沉积物中鉴定得到古菌和细菌共39门、260科、431属。从门水平上看,变形菌门(Proteobacteria)在各站位均表现出明显优势,其相对丰度占总数的39%;其它较为丰富的门类包括放线菌门(Actinobacteria)、酸杆菌门(Acidobacteria)、绿弯菌(Chloroflexi)、拟杆菌门(Bacteroidetes)和泉古菌(Crenarchaeota)。从属水平上看,Gamma变形菌是最主要的优势菌,其它主要种类还有Deltar变形菌、拟杆菌、放线菌、酸杆菌、浮霉菌(Planctomyces)、Beta变形菌和黏球菌(Myxococcus),Delta变形菌成为微生物群落的主要种类之一,显示海域环境一定程度地受到了沿岸人类活动的影响。微生物与环境因子的相关性分析表明,有机碳、砷和底栖生物对微生物门水平的群落分布具有显著性影响,奇古菌、黏胶球形菌和P-SR1与石油类、砷、铅、镉等重金属呈显著负相关。     

不同处理方式的秸秆对舍饲肉羊育肥增重的影响

文章旨在评估不同处理方式的秸秆对舍饲肉羊育肥增重的影响,采用秸秆综合处理技术,对肉羊进行了120?d的饲养试验.结果表明,与放牧组相比,2、3、4组平均末重增加6.48、8.45、10.75?kg,分别增加23.64％、30.84％、39.23％;在只均增重方面分别增加20.36％、31.57％、38.13％;在平均日...