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The ground pattems found in Pulitrouser Swamp, northern Belize, are vestiges of raised and channelized fields, types of wetland cultivation used by the ancient Maya. This form of hydraulic cultivation was apparently employed sometime between 200 B.C. and A.D. 850. The environment of the swamp, the fields and canals, and one nearby settlement, Kokeal, are described. The evidence indicates that the large number of well-defined ground patterns reported in other areas in the central Maya lowlands are probably vestiges of Maya wetland cultivation. 相似文献
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以古农书中的农业记载为主线,揭示了古农书分布的情况,并对古农书的价值进行分析,指出古农书不仅是研究我国文明史所必须利用的资料,同时也是促进今天的经济、文化发展所必须借鉴的宝贵文字载体. 相似文献
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黄河湿地孟津段生态环境状况及对策研究 总被引：1，自引：0，他引：1
通过对黄河湿地孟津段遥感影像进行土地利用类型及该区域2011-2017年鱼塘、荷塘的提取与解译,认为在湿地保护区三区中人类活动频繁。结果表明,农用地约占研究区域土地面积的41.7%,6a间鱼塘、荷塘面积增加了58.5%。此外,研究区域内农业面源污染情况不容乐观,生态环境脆弱。同时,孟津湿地中一部分处于库区,一部分位于滩区,滩区湿地的生态需水量也难以得到保证。黄河湿地在河心洲、岛及嫩滩中采用主动恢复的方式,其他区域使用被动恢复方式,以依靠恢复湿地植物群落、满足湿地生态需水量为主要恢复方法,在避免二次破坏的前提下进行湿地修复。当前情况下,可通过改变耕种方式、科普宣教、加强管理的方式保护湿地生态环境及动植物资源,未来可通过生态补偿机制等实现湿地保护区中村庄及农田的逐步退出。 相似文献
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The defeat of the Aztecs of Mexico by Hernán Cortés in 1521 was but the beginning of a long and torturous conquest of Central America that did not always result in the mastery of people and production for which the Spanish had hoped. The Maya of the resource-poor Yucatán peninsula were spared the heavy colonial hand that held fast to central Mexico and its riches. In addition, the dense forests of the peninsula served as a haven for refugees fleeing oppressive conditions in colonial towns. Despite the paucity of documentary information on Maya communities of the frontier, knowledge of Maya-Spanish relations in the 16th and 17th centuries has advanced in recent years through archeological and ethnohistorical research. Work in one region of the Maya lowlands has brought us closer to an understanding of the early interaction of the rulers and the ruled. 相似文献
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Pendergast DM 《Science (New York, N.Y.)》1982,217(4559):533-535
Discovery of mercury in an ancient Maya offering at Lamanai, Belize, has stimulated examination of possible sources of the material in the Maya area. Two zones of cinnabar and native mercury deposits can be defined in the Maya highlands, and the presence of the native metal suggests that the ancient Maya collected rather than extracted the mercury from ore. 相似文献
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Prehispanic water management in the Maya Lowlands emphasized collection and storage rather than the canalization and diversion accentuated in highland Mexico. Reexamination of site maps of the ancient Maya city of Tikal, Guatemala, has revealed an important, overlooked factor in Maya centralization and urban settlement organization. In a geographical zone affected by an extended dry season and away from permanent water sources, large, well-planned reservoirs provided resource control as well as political leverage. 相似文献
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吴塘陂是具有1 800余年的水利工程,至今依然施展着水为民利的功能价值。本文广搜文献和实地调查,对其始建时间、始建人和历代变迁,逐以钩沉与抉微。从历代诗歌对吴塘陂赞颂中,悟出这一工程灌溉、渡口、旅游的多功能价值。古人已有的这种“多功能价值”统筹的设计思维,对今天“全面协调可持续的科学发展观”理论和实践,都有着重要的启迪意义。 相似文献
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不同农业措施对土壤微生物的影响 总被引：6，自引：0，他引：6
在查阅大量科技文献的基础上,本文对不同农业措施与土壤微生物变化关系进行了概括性叙述,主要介绍了无机肥、有机肥、免耕、秸秆还田和轮作对土壤微生物生物量、多样性及活性的影响。 相似文献
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A severe incongruity has long existed between the well-known complexity of ancient Maya civilization and the relatively feeble economic base that could be reconstructed for it. Recent fieldwork has ihdicated that much more intensive cultivation patterns were used than was previously thought. Data from the use of synthetic aperture radar in aerial surveys of the southern Maya lowlands suggest that large areas were drained by ancient canals that may have been used for intensive cultivation. Ground checks in several limited areas have confirmed the existence of canals, and excavations and ground surveys have provided valuable comparative information. Taken together, the new data suggest that Late Class period Maya civilization was firmly grounded in large-scale and intensive cultivation of swampy zones. 相似文献
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Economically important trees such as ramón have been shown to have a high density in the civic-ceremonial core zone of ancient Maya ruins. The distribution of such trees is probably the result of their requirements for growth and reproduction, which are optimal on the ruins, and not because they are the descendants of trees planted by the Maya aristocracy. 相似文献
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土地革命时期,革命根据地的土地政策目标是要推翻封建地主剥削制度,保护和巩固根据地,并为完成新民主主义革命任务打下坚实基础,但早期土地政策的制定却受到了共产国际的影响和制约,混淆民主革命和社会主义革命性质和任务的界限,忽视中国农业的基本国情因素,＂破＂了＂旧＂却＂立＂不起＂新＂,从而导致土地政策经历了公有私耕、公有公耕到... 相似文献
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藏东南林芝地区典型农业土地利用方式对土壤微生物群落特征的影响 总被引：1，自引：0，他引：1
为研究藏东南林芝地区土壤微生物群落对农业土地利用方式的响应特征及其关键影响因素,可深入认识农业土地利用对该区域生态系统稳定性的影响,并为该地区农业土地资源合理利用提供科学依据。采集藏东南林芝地区2种典型农业土地利用方式(农田及放牧草地)土壤样品,以自然森林土壤样品为对照,利用磷脂脂肪酸法(PLFA)和MiSeq高通量测序分析不同土地利用方式下土壤微生物数量、多样性和群落组成的差异性,并结合土壤理化指标探讨影响土壤微生物群落组成和结构的关键因素。结果表明:与自然森林相比,农田和放牧草地土壤中微生物PLFA总量降低了38.7%~51.8%,其中革兰氏阳性细菌、革兰氏阴性细菌、放线菌和真菌的生物量分别降低了26.1%~47.6%、40.0%~61.1%、44.1%~60.6%和5.2%~31.3%。农田种植显著降低土壤真菌的多样性,其丰富度、香农多样性相比于森林土壤分别降低了53.0%和71.4%,而细菌群落的丰富度、香农多样性则显著降低了15.7%和5.1%。农田种植显著增加土壤细菌中放线菌门(A ctinobacteria)的相对丰度,但是显著降低了浮霉菌门(Planctomycetes)、绿弯菌门(Chloroflexi)和厚壁菌门(Firmicutes)的相对丰度,放牧草地则显著促进拟杆菌门(Bacteroidetes)和蓝藻门(Cyanobacteria)的生长。农业土地利用显著提高土壤真菌群落中担子菌门伞菌纲(A garicomycetes)的优势度,其在农田和放牧草地土壤中的相对丰度分别是自然森林土壤的23倍和19倍,而子囊菌门(A scomycota)和接合菌门(Zygomycota)的相对丰度则分别降低了67.7%~89.6%和58.7%~67.4%。基于距离矩阵的冗余分析表明,土壤细菌和真菌的群落结构在3种土地利用方式下有显著差异。土壤微生物的数量、多样性和群落组成受到土壤pH值、土壤有机碳、土壤C/N等理化性质的显著影响,并且土壤真菌对环境因子改变的响应比细菌敏感。研究表明,典型农业土地利用方式导致藏东南林芝地区土壤微生物群落的数量和多样性相比于自然植被显著降低,并改变细菌和真菌的群落组成和结构,而且真菌对农业土地利用方式的响应比细菌敏感。 相似文献
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黑龙江省植物园地处哈尔滨市非湿地生境地区,其中湿地专类园是由人工引种湿地植被构建而成,从中体现出具有自然特性的野性美.通过设置样方的方法调查其植物群落种类与构成,结合公众对湿地景观特征的美感度偏好的心理问卷调查研究,探讨人工湿地景观公众的认可程度.结果表明:黑龙江省植物园人工湿地园植物主要有34种,分19科31属.在调... 相似文献
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