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Land consolidation engineering is one of the very important ways to improve the quality of farmland and the level of agricultural productivity. Studies of land consolidation and crop cultivation still mainly focus on single land functional optimization or crop breeding and yields. However, whether the improved crop varieties were sown on healthy and fertile soils is still a question. This paper introduces new ideas and engineering measures for sandy land rehabilitation and modern agricultural development in the Mu Us Sandy Land, Shaanxi Province, Western China. The important roles of particles and aggregates in soil reconstruction were confirmed following three innovative microscopic theories, including micro-structure, micro-morphology and micro-mechanism. New soil was constructed based on the physical complementarity of sandy, clay and loess particles in the Yulin area, northern Shaanxi Province. Field experiments were carried out to study the appropriate mixture ratio of different soils and their suitability for different crops. The improved crop varieties were sown on healthy and fertile soils, which were chosen by coupling according to its soil ecological suitability and crop physiological adaptability. The fertility improvement practices in the new constructed soils with different crops integrated water and fertilizer management measures, which were also provided in the experiment. Overall, an integrated land optimization configuration with improved and optimized crop variety selection was suggested for engineering sandy land-oriented consolidation from the soil particles to the agricultural system. 相似文献
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围(填)海造地是人类开发、利用海洋空间资源的一种重要方式。随着我国沿海地区各类滨海新区、工业区、旅游区等的兴起,围(填)海造地的规模与速率明显增大,逐渐暴露出一系列经济、环境、社会问题。通过对河北省黄骅市这一典型的项目驱动型的围海造地规模较大的城市进行研究,利用构建的城市土地利用效益评价指标体系与围海造地遥感影像解译,使用耦合度模型测度黄骅市城市土地利用生产、生活和城市生态效益与围海造地规模之间的相互作用、相互影响关系。结果表明:黄骅市围海造地以2005年为节点可分为起步阶段与规模化阶段,1987—2015年累计围海造地190 km~2;黄骅市城市土地利用效益整体上表现为稳中有升,不同类型略有差异;黄骅市的城市土地利用效益与围海造地规模处于效益水平较低的高耦合度阶段;城市土地利用生产效益与生活效益的提升水平与围海造地规模的扩大水平脱节,围海造地短期内规模过大,边际效益降低,没有达到最优的匹配水平。 相似文献
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世界乡村转型历程与可持续发展展望 总被引：14，自引：3，他引：11
基于对国内外文献梳理总结,根据世界银行数据,从乡村人口、就业、粮食产量、公共服务角度,系统解析了半个多世纪以来世界乡村转型发展的历程,揭示了世界发展由乡村社会逐步向城市社会转型、由农业经济向非农经济转型、发展效率与公共服务质量逐渐提升的演化特征。研究指出,全球化、工业化、城市化进程中乡村地区人口持续、快速减少,加剧了乡村发展的不稳定性和脆弱性,导致乡村衰退,严重影响到乡村经济社会发展的可持续性。为此,强调全球城市化进程中亟需高度重视乡村衰退问题,要积极推进村镇化,形成村镇化与城市化“双轮驱动”的城乡地域发展格局;要制定科学的规划来指导乡村转型与可持续发展,有序实施异地搬迁,鼓励和引导民众“自下而上”的主观能动性,构建乡村发展与农户的利益联结机制;要科学把控乡村转型发展过程,识别并培育打造乡村振兴极,不断提升乡村地域系统应对外界发展、环境变化与挑战的弹性。 相似文献
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为满足海洋上层温度数据高分辨率实时观测需求,本文设计出一种成本低、体积小、精度高的温度链观测系统,可搭载于调查船、浮标等多种海洋观测平台,具备高分辨海表温度数据实时观测功能。本文介绍了温度链系统架构的整体设计,阐述了温度传感器的高精度测量原理与方法,采用RS-485通信方式并设计出一套适用于温度链的软件通信协议,通过标定、均一性测试、稳定性测试验证了传感器的测量性能,研制出总长200 m的温度链观测设备,设备带有10个测温节点,传感器节点初始测量精度优于±0.005℃,温度链采样间隔最短可达2.7 s。本温度链在我国南海进行了拖曳功能测试,试验结果表明：温度链海上作业通信稳定可靠,数据测量准确,满足海洋现场观测对数据高时效、高精度、低误码率的传输要求。 相似文献
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