Traditional versus improved agroforestry systems in Vietnam: a comparison

Combined with the diverse biophysical and social heterogeneity encountered in the northern mountains, the socioeconomic changes in Vietnam that accompanied the decollectivisation process led to complex agrarian dynamics that today challenge traditional farming and management of natural resources. Data for this study were collected from villages in and around Ba Be National Park (BNP) in the Bac Kan Province located in the northern mountains of Vietnam. Traditional slash and burn cultivation is no longer a sustainable practice in Vietnam. The main challenges in the region are to protect biodiversity, maintain the land productivity and simultaneously support local livelihoods. The study shows that improved agroforestry cultivation could provide significantly higher productivity and income per unit of land, besides decreasing pressure on natural forests. The challenge to protect biodiversity is not met, as improved agroforestry implies less tree species. From an institutional and socio‐economic perspective, it is not easy for local communities to readily adapt to improved agroforestry. New systems must be tailored site‐specific to the diverse local conditions of resource‐poor farmers. Copyright © 2006 John Wiley & Sons, Ltd.     

Review of Nutrient Management in Freshwater Polyculture

Abstract

One of the most important issues concerning fish-pond fertilization is the determination of the optimal amount of fertilizer to be applied to the pond system. Another important concern is the suitability of fish species for polyculture in order to optimize production. The dynamics of nutrients, phytoplankton, and fish is a complex subject and practitioners are often compelled to formulate solutions without detailed scientific and practical consideration. The primary objective of pond fertilization is to maintain an optimal nutrient concentration for sustained biological production. Current fertilization practices in the Asia-Pacific region include: a fixed rate of fertilization and fertilization based on water color. Individual pond ecology determines how fertilization affects pond productivity, not the pond's physical location in relation to international borders. There is no universal recipe of “maximal” fertilization rates due to pond-specific variability. There is also no clear guide in the literature with regard to many aspects of fish-food; the type of organisms consumed, mechanisms of food consumption, and the digestibility and nutritive value of plankton. The usual practice is to divide fish according to their foraging in natural habitats; feeding on phytoplankton, zooplankton, zoo benthos, or detritus. The distinction between different feeding habits is not always absolute as many species of fish may change food preference depending on the abundance of different food items. This paper reviews the nutrient (nitrogen, N and phosphorus, P) management in regard to pond fertilization; use of organic and inorganic fertilizer and the impacts on fish production; use of organic fertilizer from different organisms (pig, cow and buffalo) and their interactions with primary production and water quality; optimum N:P concentration in pond water; and individual pond factors and their influence on fish production. A significant interaction was evident with time between water quality variables such as pH and alkalinity, and other factors, including manure type and fish species composition. This was reflected in the difference between pig and cow manure treatments. A significant interaction between species composition and fish production has been demonstrated. Fish survival and biomass production was influenced by the stocking ratio of the: rohu, Labeo rohita; mrigal, Cirrhinus mrigala; and Nile tilapia, Oreochromis niloticus. The recommended nutrient level for pond fertilization based on the South Australian Research and Development Institute (SARDI) and Research Institute for Aquaculture No. 1 (RIA#1) study is 1 ppm N:0.5 ppm P. The required quantity of fertilizer varies significantly with time. However, regional research is highly recommended to optimize fish production focusing on significant climate variability, which affects both primary and secondary production.     

Small-Scale Shrimp Grower–Collector Relationships: The Case of Thua Thien Hue Province,Central Vietnam

Small-scale shrimp-culture is an important livelihood for rural residents in Thua Thien Hue (TTH) province, central Vietnam. However, they are facing the risk of exclusion from the food system due to globalization and trade liberalization. To keep these farmers in modern supply chains, their relationships with other chain actors, foremost the collectors, need to be improved. Thus, this study explores the characteristics and constructs of the relationships between the small-scale shrimp growers and their collectors. Data was based on a survey on 83 small-scale shrimp growers, together with 16 unstructured interviews with growers (10) and collectors (6). It was revealed that the relationships between small-scale shrimp growers and collectors in TTH province are short-term and price-driven and are influenced by the power of collectors. The relationship strength was measured by five intercorrelated constructs including reliability, willingness-to-maintain, desire-fulfilment, negotiation capacity, and discussion capacity. Although some constructs were positively correlated, the strength of the relationships was weak. Both business linkages and social connections affected the grower-collector relationships. Female traders had stronger relationships with collectors than males. Therefore, interventions should be focused on business and social linkages as well as females’ involvement in shrimp trade.     

越南南定省交水县交善乡对海平面上升的家庭和社区应对经验和对策

【目的】通过收集社会经济学数据,评估居民和社区对海平面上升的适应能力,评估海平面上升的负面影响及其对策,确定应对海平面上升备用对策。【方法】在越南南定省交水县交善乡选择99户居民,分成3组,采用半问卷调查、面谈、家庭群组讨论、重要人物访谈以及当地居民非正式会谈等方法进行调查。【结果】海平面上升已对当地社区造成了极大的负面影响,如作物产量降低、土地流失、盐碱地面积增加、基础设施损坏等。当地社区和居民已经意识到海平面上升的负面影响,并采取了各种应对方法。改变经济结构、选择适宜的作物品种、把水产养殖地转给家庭、鼓励渔民成立渔业合作社并建立早期预警系统是应对海平面上升的主要对策。【结论】应根据潮汐节律和台风、暴风雨发生等所确定的水面上升规律,采取不同的应对策略和方法,以减少海平面上升造成的破坏和损失。     

越南不同龙眼品种品质分析比较(英文)

[目的]筛选出适合越南当地生产的龙眼品种。[方法]分别对引种至越南农科院北部山区农林研究所内栽培的5个龙眼品种的果实植物学性状和品种果实性状进行了比较分析。[结果]筛选出了可作为鲜食的优良龙眼品种PMP6,PHS1-1以及可用于加工的优良品种HuongChi。[结论]本研究将对越南北部山区的龙眼生产、育种提供参考。     

吡喹酮对鲤鱼感染台湾棘带吸虫后期囊幼虫的防治效果

[目的]探讨3种不同药物处理方式对台湾棘带吸虫引起的鲤鱼幼鱼急性鱼鳃传染病(开放性鳃病)的防治效果.[方法]在试验初期,将1620条鲤鱼幼鱼(70日龄)鱼鳃自然感染台湾棘带吸虫,随后分成4组,分别采用CuSO4、福尔马林和吡喹酮不同方式处理6周,与对照(自然喂食、不使用任何化学药剂)比较防治鲤鱼幼鱼急性鳃传染病的效果.[结果]感染台湾棘带吸虫的幼鱼生长缓慢,其身长和体重增长均较慢.施药后,幼鱼台湾棘带吸虫后期囊幼虫感染强度减少.在每千克饲料中分别添加50和75 mg吡喹酮喂食幼鱼5d,可以杀死鱼鳃中所有的台湾棘带吸虫后期囊幼虫,且鱼鳃恢复正常;面使用25 mg吡喹酮,仅有35%的后期囊幼虫死亡.所有不同浓度CuSO4处理(0.3、0.4和0.5mg/kg冲洗浸泡24 h及以3.0、4.0和5.0 mg/kg冲洗浸泡10m)和福尔马林处理(20、25和30 mg/kg冲洗浸泡及200、250和300 mg/kg短时间冲洗浸泡)均不能杀死台湾棘带吸虫后期囊幼虫.[结论]经普通化学药剂CuSO4或福尔马林冲洗浸泡,不能防治由台湾棘带吸虫后期囊幼虫引起的鲤鱼开放性鳃病,但50~75 mg吡喹酮/kg饲料可以在5d内治疗该病.     

越南小腹茧蜂小志

小腹茧蜂是鳞翅目害虫的重要寄生蜂,报道越南水稻、棉花等作物害虫育出的6种小腹茧蜂及其寄主和分布.     

中越边境壮族地区早期修筑水利工程的重要物证——对更贵水渠及其摩崖题刻的历史解读

本文依据调查及文献资料,认为广西龙州县上龙乡更贵山水渠是目前所知的中越边境壮族地区早期修筑的水利工程之一,立于其旁记载着该工程修筑经过的摩崖碑刻具有珍贵的史料价值。该水利工程对中越边境地区壮族民众的农业生产起到了积极的作用,体现了修筑者坚强的意志,有助于人们认识明朝时期壮族的农业生产技术水平。在自然经济条件下,官绅阶层和政府在聚合力量、稳定社会、促进经济发展中扮演着重要的角色。当前,政府在保护农业文明遗产方面同样肩负着重要使命。     

越南竹资源及竹产业发展态势

作为"一带一路"南线重要国家，越南拥有丰富的竹资源，竹产业发展前景广阔、潜力巨大。本文基于文献梳理、实地考察调研和专家互访对话，对越南竹资源和竹产业发展现状进行了较为系统而全面的阐述，为进一步促进中越"一带一路"竹产业交流互鉴与合作发展奠定基础。     

越南革新开放与社会保险制度改革

越南经济体制转型后,社会问题日益凸显,贫困、失业、医疗资源分配不均衡等问题困扰着越南社会,越南社会需要与经济体制的改革相适应、能够有效运作的社会保障体系,尤其是社会保险制度.以越南革新开放为背景,分析革新开放对经济和社会带来的一系列改变,重点论述经济转型下越南产生的社会问题,从动因的角度论证社会保险制度改革的必要性,从而进一步探索越南社会保险制度改革的目标和方向.