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1.
平原地区河道堤防滩地的水土流失,直接淤积河床,影响行洪安全。堤防滩地的水土流失是自然因素和人为因素共同作用的结果,以新修堤防的水土流失最为严重,对其防治须实行工程措施、植物措施和人为预防相结合。  相似文献   

2.
论水土、水土生态与水土生态保持   总被引:4,自引:7,他引:4  
在论述水土在陆地生态系统中的地位和作用的基础上,提出了水土生态的概念,认为植被与水土不可分割的整体观念是水土生态的重要特征。同时,对水土生态保持的含义作了新的定义,并将水土生态保持划分为四大类型,即生态型、自然型、生产型、建设型。从水土生态的高度,从源头上、要素的联系中去认识和防治水土流失,是一种主动的、有机的、整体的水土保持观念,是水土保持认识观的深化和发展,将使水土生态保持事业进入一个崭新的时代。  相似文献   

3.
重庆地处长江上游、三峡库区,由于三峡库区水土流失严重、生态环境脆弱、自然灾害频繁,且三峡库区的水土保持和生态建设事关全市经济社会发展全局、事关三峡工程建成后的安全运行和库区的长治久安,因此是我市水土保持生态建设的重点。虽然,“长治”工程的有效实施,使我市的水土保持生态建设取得了较大的成绩,但离全面建设小康社会的要求尚有不少的差距,因此,我们要紧紧抓住国家实施可持续发展战略和西部大开发战略的历史机遇,进一步增强紧迫感、责任感和使命感,调动全社会各界力量,防治水土流失,改善生态环境,建设巴渝秀美山川。  相似文献   

4.
The charge characteristics of A1 or Ap and B2 horizon samples of total 23 Ultisols, Alfisols and Oxisols in Korea and Thailand were studied by measuring the retention of NH4+ and NO3? at different pH values (4–8) and NH4NO3 concentrations (0.1–0.005 m ). The magnitude of their negative charge (σ?; meq/100g) was dependent on pH and NH4NO3 concentration (C; m ) as represented by a regression equation: log σ?=apH +blogC +c. The values of the coefficient a (0.04–0.226), b (0.03–0.264) and c (–0.676–1.262) were correlated with the kinds of the soil and horizon and with the region where the soil exists. The retention of NO3? was less than 1 and 2–3 meq/100 g for the A1 or Ap and B2 horizon samples, respectively. The sum of exchangeable base and Al (‘effective’ CEC) was close to and higher than the magnitude of permanent charge (=σ? measured at pH = 4.3 and at C = 0.005 m ) for one-third and two-thirds of samples, respectively. A σ? value of 16 meq/100 g clay at pH = 7 and C = 0.01 m was found appropriate to separate the B2 horizons of Thai Ultisols and Oxisols from those of Korean Ultisols and Alfisols. Korean Alfisols and Ultisols and Thai Ultisols were distinguished from each other on the status of exchangeable base and Al  相似文献   

5.
水土保持法律规范和相关行政法律规范,共同构成了水土保持监督管理法律体系,其内容庞杂,相互交叉、融合,程序复杂。通过一组网络图及其简要注释,直观地表述了水土保持监督管理工作的相关程序、时效、逻辑关系和法律依据;通过对网络图呈现的逻辑问题所反映出的法律缺陷进行分析,提出应当按照立法法的有关规定,对现行法律特别是水土保持法律法规进行必要的修改,以适应不断发展的水土保持监督管理工作需要的建议。  相似文献   

6.
简析了婺源县城镇开发区建设过程中造成水土流失的状况、危害、原因后,提出了其防治措施,并阐明开展城市(镇)水土保持的紧迫性。  相似文献   

7.
我国滑坡、崩塌的区域特征、成因分析及其防御   总被引:2,自引:0,他引:2  
论述了我国滑坡、崩塌的区域分布特征,滑坡和崩塌的危害程度,滑坡和崩塌类型和成因分析,并且提出了灾害的防御措施,以期达到环境保护成为社会发展过程中的一个重要组成部分。  相似文献   

8.
9.
Soils were collected from 2-year (2-y) and 3-year (3-y) old red-pine seedling plots in two tree nurseries, Hayward in the north and Wilson in the southwestern part of Wisconsin State respectively, and equilibrated with 0.01 M Ca(NO3)2 for soil solution Zn and Mn (solu-Zn and Mn), and with 0.01 M Ca(NO3)2+0.005 M EDTA for soil adsorbed Zn and Mn (ad-Zn and Mn). Buffering capacity of soil Zn and Mn (b-Zn and Mn) was obtained from the ratio of ad-Zn and Mn to the solu-Zn and Mn. The concerned traces in pine seedling needles (ndls), stems(sts) and roots (rts) were simultaneously measured.  相似文献   

10.
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