Automated soil resources mapping based on decision tree and Bayesian predictive modeling

INTRODUCTION Land resources management and ecologicalenvironmental decision-making requires knowl-edge about the spatial distribution, and quantity andquality of soil resources. Soil maps have tradition-ally been made by interpretation of remotely sensedimagery supported by ground surveys. Thus, soilmapping becomes expensive, labor-intensive, andtime-consuming exercises. Moreover, it also issubjective, and may result in inconsistencies in theassignment of soil type boundaries or nam…     

Species-diversified plant cover enhances orchard ecosystem resistance to climatic stress and soil erosion in subtropical hillside

Naturally occurring plants in agroecosystem evidently play an important role in ecosystem stability. Field studies on the ecological effects of native plants conserved in orchard and their resistance to adverse climatic stress, and soil erosion were conducted from 1998 to 2001 in a newly developed Changshan-huyou (Citrus changshan-huyou Y.B. Chang)orchard. The experimental area covered 150 ha in typical red soil hilly region in southeastern China. The experimental design was a randomized complete block with six combinations of twelve plant species with four replications. All species used were native in the orchard. Plots were 15×8m2 and separated by 2 m buffer strips. Precipitation, soil erosion in rainstorm days and aboveground biomass of plant community when rainstorm days ended, soil temperature and moisture under various plant covers during seasonal megathermal drought period, antiscourability of soil with different root density under various simulated rainfalls were measured. Plant cover significantly decreased the daily highest and mean soil temperature and its daily variation in hot-drought season, but there was no significant difference of the alleviation among various plant covers. Plant covers significantly increased the soil moisture in seasonal megathermal drought period. Better moisture maintenance and soil erosion reduction was found when the plant species numbers in cover plant communities increased from one to eight. Higher root density in plant communities with higher species richness increased significantly the antiscourability of the soil. It was suggested that conserving plant communities with diversified native species could produce the best positiveecological effects on citrus orchard ecosystem stability.     

关于“理论力学”高等课程的探索与实践

“理论力学”高等课程曾经是一门传统的研究生课程,后因内容陈旧逐渐淡出历史舞台,现在国内鲜有高校开设。本文对该门课程的价值与意义进行了论述,指出本科阶段的“理论力学”课程并不能满足物理系研究生的需求,并对授课内容进行了探索,尝试对该课程的教学进行改革与实践。     

理论力学教学改革与学生素质能力的培养

从理论力学的自身特点出发,改革课程内容体系和教学方法,培养学生的综合素质能力。     

毕节地区水土保持建设对水文环境的良性效应

水土保持建设是毕节地区生态环境建设的主体,关系到全区社会、经济和环境的可持续发展,在减缓、拦蓄径流的同时,保护了水土资源,改变了水分的静态分布和动态循环、流动过程,必然对区域的水文环境产生影响.水土保持的各种措施都能在一定程度上控制降水耗散水文过程,明显改善水质量,提高水的利用效率.针对存在的问题,作者提出了建议.     

四川省土壤资源的特点及其合理开发利用途径

本文从四川省土壤资源特点出发,针对本省土壤资源利用中存在的问题、提出了保护土壤资源;改良中、低产水稻土;“立体种植”等合理开发利用的战略决策。     

工程力学对分课堂探索与实践

将对分课堂引入工程力学课程教学,结合课程特点制订了该教学模式的实施方案,探索了基于该模式的课堂教学实践步骤,并对实践效果进行了评价。此外,对该教学模式下的工程力学作业类型和作业批改方式也进行了探索。实践结果表明,工程力学采用对分课堂模式后,学生的课程学习参与度和学习效果都有了明显提高,学生的沟通能力、担当意识和团队协作精神也得到了很大的锻炼和提升。     

山区高速公路建设对边坡土壤侵蚀的影响初探

公路建设过程中产生的弃土、弃渣是一种主要的土壤侵蚀源。福建省山多、山高、山陡,地形复杂,修建高速公路,路基的高填深挖施工过程形成大量的裸露坡面、施工过程中产生的弃土石方、山谷间的高位挂坡等工程造成植被破坏、水土流失非常严重。如何采取合适的植物措施进行高速公路边坡的快速植被恢复值得研究探讨。调查表明：无防护措施的弃碴场的水土流失侵蚀模数是有防护措施弃碴场的2925倍;无防护措施且不集中挂坡堆放弃碴的流弃比是有防护措施且集中堆放弃碴的16.5×10⁴倍;典型挂坡的土壤侵蚀量是邻近未扰动山坡地约70倍。因此,对建设项目的水土流失防治的研究工作非常重要。     

山坡地农业开发中的水土资源保育问题探讨

该文针对南方,特别是福建山坡地开发中造成的水土流失与土壤退化等生态环境问题,在野外调查与试验研究的基础上,系统分析了近年来山地果园开发规模、现状以及开发中存在的系列水土资源保育等生态问题;揭示了山地果园水土流失发生发展的机理;明确了山地果园开发中需要注意的关键时期与关键地形部位;分析了果树早衰的原因。以生态经济学与可持续发展为理论,以山地水土资源合理开发利用为基础,提出了科学规划,坚持适地适种,提高建园质量,加强幼园管理,推行山地水土资源保育新技术,增加地面覆盖,控制水土流失,建设生态果园的可持续发展综合治理体系和对策。     

Reform and Exploration of Mechanics for Application-oriented Talents Cultivation

为了培养适应经济社会发展需要的应用型人才,必须对传统的教学模式和教学方法进行改革。介绍了比较法教学在《力学》课程教学中的应用;强调了应始终注意将相关物理概念联系起来,形成严密的、能动的物理概念体系;通过选择合适教学手段和教育技术,进行创造性教育和启发式教学,实现教学过程中师生的有效互动。