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1.
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   

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.
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   

4.
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   

5.
20世纪末,开发建设项目水土保持方案的编报工作已经实现了规范化和制度化,但有不少的编制者在编制建设类和建设生产类项目的水土保持方案时往往出现失误.建设类和建设生产类项目的水土保持方案在很多方面都存在很大区别.根据多年编制两类水土保持方案的实践经验,总结出了这两类项目水土保持方案的编报工作在水土保持要求、服务年限、预测时段划分、防治目标等方面的异同,以防止在编报过程中出现水土流失量预测、水土保持措施体系以及水土保持监测等方面产生较大的偏差.  相似文献   

6.
Abstract

Lucerne (Medicago sativa L.) and phalaris (Phalaris aquatica L.) were grown separately and together in a pot trial on a yellow‐brown pumice soil with three rates of sodium (Na) and two rates of potassium (K) in factorial combination. Lucerne alone had a low Na concentration but growing phalaris as a companion grass produced herbage with a Na concentration adequate for stock. Na application increased the Na concentration in phalaris and the mixture of phalaris and lucerne much more than in lucerne alone; had little effect on K concentration; slightly reduced Mg concentration; and greatly reduced Ca concentration but not as much in lucerne as in phalaris or the mixture with lucerne. K application increased K concentration and reduced Na, Ca and Mg concentrations throughout. Yield of phalaris grown alone and in combination with lucerne was increased significantly by Na application when K concentration in the plants was low. Yield of lucerne was not affected by Na application and it is concluded that Na did not substitute for K in this species. It is concluded that field trials are warranted to investigate the possibility of growing a special purpose mixture of lucerne and phalaris on New Zealand yellow‐brown pumice soils to provide feed that has adequate Na for grazing animals.  相似文献   

7.
反疏浚理论、反疏浚工程与抗旱   总被引:1,自引:0,他引:1  
分析了防洪与抗旱之间的关系 ,认为用反疏浚理论与反疏浚工程增大地下水蓄积量是根治正在年年升级的旱情的重要举措 ,传统工程与反疏浚工程相结合 ,安全、科学地调控地下水在陆地空间场的时间分布可解除旱情对海河等流域工农业的瓶颈制约  相似文献   

8.
分布式移动农业病虫害图像采集与诊断系统设计与试验   总被引:3,自引:2,他引:1  
姚青  张超  王正  杨保军  唐健 《农业工程学报》2017,33(Z1):184-191
为了便捷地采集和实时诊断农业病虫害图像,设计了一个分布式移动农业病虫害图像采集与诊断系统。该系统由多个便携式图像采集终端和一个图像处理服务器组成;其中,图像采集终端包括嵌入式相机、可伸缩的手持杆和装载控制App的手机;图像处理服务器包括农业病虫害诊断、信息记录和反馈模块等。手持杆可将安装在其前端的嵌入式相机送到人手或视觉难以企及的病虫害区域,手机可实时预览前端相机的拍摄画面和实现控制相机完成农业病虫害图像采集等功能;系统通过HTTP协议实现多个采集终端与图像处理服务器的数据交互,协同进行分布式计算,可以减少网络移动资费和服务器的负载。利用该系统对水稻纹枯病图像采集与诊断测试结果表明,该系统的图像采集终端可以便捷地采集到水稻纹枯病图像,手机端视频预览画面延时低,对相机控制命令无误,图像采集终端与服务器通信稳定,服务器端对水稻纹枯病图像处理和诊断实时,基于图像的水稻纹枯病为害等级诊断准确率为83.5%。如果服务器端加载不同的农业病虫害图像处理和诊断算法,该系统可广泛应用于各种农业病虫害图像的采集与诊断。  相似文献   

9.
Commercial fertilizers containing synthetic manganese (Mn) chelates and complexes are currently used to alleviate Mn deficiency in crops. However, studies conducted on Mn sources in order to evaluate their behavior maintaining Mn soluble in nutrient solution and soil have not been done. In this work, representative commercial Mn fertilizers based on chelates and complexes were characterized and their chemical stability in solution and interaction with soils has been evaluated. Fertilizers studied were two ethylene diamine tetraacetic acid (EDTA) Mn chelates, one N‐(1,2‐dicarboxyethyl)‐D,L‐aspartic acid (IDHA) Mn chelate, two lignosulfonates, one carboxylate, one fulvate, one gluconate, and one heptagluconate‐based Mn complex. Characterization consisted of the determination of the soluble and chelated or complexed Mn, and the ligand identification by nuclear‐magnetic resonance (NMR). Stability study included batch experiments in Ca solution at different pH and three batch experiments with soil comparing with MnSO4. Results indicate that most of the Mn fertilizers comply with the declared “soluble and chelated or complexed” metal content. At a usual pH range of calcareous soils (7.5–8.5), both chelates and complexes maintain more Mn in solution than MnSO4 in the presence of Ca. Several factors affect the Mn remaining in solution after the interaction with the soil, especially, the soil‐to‐solution ratio. All chelates and complexes are better alternatives to the use of MnSO4 in agronomical practices such as fertigation and soil application. Mn‐IDHA as chelate and Mn‐HGl or Mn‐Carb as complexes can be efficient, economical, and environmental friendly fertilizers for foliar application and hydroponic cultures. In soil application, Mn‐EDTA or Mn‐LS would be the best options. In this case, lignosulfonic acid represents a sustainable and low‐cost solution.  相似文献   

10.
采用液质联用仪比较分析了3个不同种植区域(江苏南京、广西南宁和湖南长沙)露地和大棚两种种植条件下黄瓜和土壤中甲基硫菌灵及其代谢物多菌灵的残留动态,同时对黄瓜中的最终残留量进行了比较分析。施药后,甲基硫菌灵在黄瓜和土壤中均能很快转化为多菌灵[施药后1 d甲基硫菌灵未检出(〈0.01 mg·kg-1)],多菌灵在露地黄瓜和土壤中的原始沉积量均低于大棚。3个试验点露地黄瓜中的半衰期分别为2.3、1.4 d和1.4 d,在大棚黄瓜中的半衰期分别为2.6、1.7 d和2.0 d。在3个试验点露地土壤中的半衰期分别为1.6、1.7 d和2.3 d,在大棚土壤中的半衰期分别为2.3、2.0 d和2.3 d。最终残留试验在最后一次施药后1 d采样时,大棚、露地黄瓜中的甲基硫菌灵均未检出(〈0.01 mg·kg-1),多菌灵在3个试验点露地黄瓜中的最终残留量为0.014~0.162 mg·kg-1,而在3个试验点大棚黄瓜中的最终残留量为0.121~0.561 mg·kg-1。参照我国所制定的黄瓜中多菌灵的MRL(0.5 mg·kg-1),露地种植方式下所有处理黄瓜中甲基硫菌灵代谢物多菌灵的最终残留量均符合国家标准的规定,但大棚种植方式下其残留量有超标的风险。  相似文献   

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