Effects of ditch management on caddisfly, dragonfly and amphibian larvae in intensively farmed peat areas

Conservation of natural values within farming practice is growing rapidly within the Netherlands. The focus is primarily on terrestrial flora and fauna such as the vegetation in ditch banks and meadow birds. Knowledge needed to enhance biodiversity in ditches is limited. Therefore, a field study was set up to determine the effects of dredging, ditch cleaning and nutrient supply in the adjacent fields on caddisfly, dragonfly and amphibian larvae in the ditches in a peat area.Two-hundred forty ditches spread over 84 dairy farms were selected to determine the individual effect of several management aspects. Generalised linear modelling was used as a tool to detect the most relevant aspects and to obtain quantitative relations with the chance of the larvae being present.Dredging had an impact on the presence of all larvae types. The type of dredging machine, the dredging period, the water depth and the frequency of dredging can influence the presence of the larvae. The presence of caddisfly larvae was also affected by the cleaning machine and period and by the P supply in the adjacent field. The presence of amphibian larvae was also affected by the cleaning period.Measures that will enhance the presence of the larvae are formulated. Options for water boards and other government authorities to stimulate farmers to take these measures are given.     

河套灌区九排域农田排水沟植物物种多样性

2010年8-9月对河套灌区九排域农田排水沟植物进行了综合调查.分别在干沟、支沟、斗沟/农沟的上、中、下游布设断面,断面上设置0.5m×0.5m和5m×5m样方对草本和灌木的植物种类和数量进行调查.结果表明:河套灌区九排域农田排水沟植物由17个科、38个属、39个种组成,禾本科(n=10)、菊科(n=7)和藜科(n=4)植物种类最多,芦苇、羊草和盐地碱蓬是分布面积最广的物种.干沟、支沟和斗/农沟的多样性指数、丰富度指数、均匀度指数和优势度指数值分别为0.57、1.93、0.37和0.81,0.77、3.46、0.65和0.50,0.90、3.88、0.64和0.53.物种多样性表现为边坡的高于沟底,但排沟等级间的变化趋势不明显.水的存留时间及农业管理(清沟)是影响植物物种多样性最主要的因素.     

人工沟渠的生态环境效应研究综述

人工沟渠主要指以排水和灌溉为目的人工挖掘的水道.人工沟渠作为排水和引水的廊道改善了土壤的结构、促进了作物的生长,从而提高了农作物的产量;同时人工沟渠这种景观的存在对周围的环境也产生了巨大的影响.水文效应是被大家普遍接受的生态环境效应.在整个降雨期间或之后,观察显示出沟渠对出口径流的贡献：一些沟渠收集和向河流输送水;另一些沟渠收集水但是减慢了水流的速度.本文从水文效应、对元素地球化学循环、生物及其生境的影响到对生态环境整体影响方面总结了人工沟渠的生态环境效应,并对其进一步的研究提出一些建议,旨在最大限度发挥人工沟渠的生态环境效应,改善整个生态环境.     

用于农田非点源污染控制的生态拦截型沟渠系统及其效果

针对太湖流域农田非点源污染严重的现状,结合当地实际情况提出了一种新的生态工程学解决方法——生态拦截型沟渠系统,它主要由工程部分和植物部分组成,能减缓水速,促进流水携带颗粒物质的沉淀,有利于构建植物对沟壁、水体和沟底中逸出养分的立体式吸收和拦截,从而实现对农田排出养分的控制。试验区沟渠植物具有一定的经济价值,且景观效果良好。沟渠系统对农田径流中总氮、总磷的去除效果分别达到48．36％和40．53％。此外,该生态工程的另一个显著优点就是不另外占用土地,符合平原水网地区农田沟渠的实际,具有很好的推广应用潜力。     

旱作果园深沟施肥对苹果树根系分布的影响

用干挖壕沟法研究了深沟施肥农艺措施对旱作苹果树根系的重量、结构和分布范围等的影响,结果表明,与未挖泡的对照相比,深沟施肥后,根系的总重量、总体积和分布深度都大幅度减少,总重量减少了５０％,总体积减少了６０％,分布深度减小了１．８ｍ;但吸收根的总长度增加,吸收根在总根量中所占的比例亦大幅度提高。     

Oligochaetes and eutrophication; an experiment over four years in outdoor mesocosms

Eight experimental ditch mesocosms were used to study the effect of eutrophication over four years. The experimental ditches had a sand or clay bottom. The ditches were treated with additions of phosphorus, phosphorus and nitrogen, or without additions (controls). Oligochaetes were sampled by deploying trays with substratum for colonization over twenty weeks. Both the important variables phosphorus, nitrogen and oxygen as well as the oligochaete species and numbers are presented. The effects of nutrient additions on phosphorus, nitrogen and oxygen concentrations were described together with changes in oligochaete species composition and numbers. The results were further analyzed by redundancy analysis (RDA). In the clay-lined ditches nutrient addition coincided with fluctuation in oxygen concentration. The higher the nutrient addition levels the longer the period of oxygen depletion became. During oxygen depletion the number of oligochaetes was strongly reduced or even became zero. The low nutrient status of the sandy bed in the sand-lined ditches slowed down the rate of colonization. Only a few tubificids were collected. Eutrophication effects were only observed at the highest nutrient addition level. Considerable variation is attributed to stochastic factors in the sand-lined ditches. Whether oligochaete species were present was related to the length of the colonization period. The substratum composition and food together with oxygen regime decided whether they become more or less abundant in ditches. Large-scale mesocosm experiments require time to develop. Only after the first colonization period variables of species presences and abundances can be employed to detect changes associated with eutrophication. Oligochaetes can be used to measure colonization as well as eutrophication processes.     

注射施肥对桃园土壤环境和果实产量品质的影响

以盛果期10a生品种‘阿部白’桃为试材,在大田条件下,进行连续2年定位施肥试验,设置放射沟施全量肥(R_(NPK))、放射沟施半量肥(R_(1/2NPK))、注射施全量肥(I_(NPK))和注射施半量肥(I_(1/2NPK))4个处理,分析注射施肥对桃园0~60cm土层土壤养分含量、土壤酶活性和微生物数量以及果实品质的影响,探讨注射施肥在桃树生产中的应用,为高效施肥和提高水肥利用率提供理论依据。结果表明:(1)桃幼果膨大期(5月15日),0~40cm土层中,试验各处理的总氮钾含量差异不明显,注射施肥土壤中速效养分含量显著低于放射沟施肥;果实成熟前期(7月15日),在相同施肥量下,0~40cm土层中注射施肥处理的碱解氮、速效钾含量均以I_(NPK)处理的最高,且分别比放射沟施肥处理显著提高16.61%、12.56%和10.15%、23.93%,同时注射施肥处理的0~40cm土层中有机质含量均低于放射沟施肥处理,部分处理差异达显著性水平;不同处理对土壤中磷的影响较小。(2)果实成熟前期,0~60cm土层中注射施肥土壤中蔗糖酶、过氧化氢酶和脲酶活性,以及0~20cm土层的碱性磷酸酶均显著高于放射沟施肥;同期根际土壤微生物数量变化规律与土壤酶活性变化基本一致。(3)INPK处理的桃单果重、可溶性固形物含量显著高于其他施肥处理,且分别比R_(NPK)处理显著增加了12.24%和11.21%;I_(1/2NPK)处理的单株果实产量最高(65.25kg)并显著高于放射沟施肥处理,但与INPK处理间差异不显著。研究认为,注射施肥对桃树土壤中养分含量、土壤酶活性和微生物数量以及果实品质都有积极的影响,且以NPK全量注射施肥处理效果最佳。     

Spatial dynamics and morphological plasticity of common reed (Phragmites australis) and cattails (Typha sp.) in freshwater marshes and roadside ditches

Over the last decades, the abundance of common reed has significantly increased in freshwater wetlands of eastern North America, and stands of this species are now commonly alternating with stands of cattails. Since these species share many characteristics, the contact zone between common reed and cattail stands may witness strong interspecific interactions. We surveyed stand dynamics in roadside ditches and freshwater marshes at these contact zones over three years, and we examined the morphological plasticity in response to neighbors. Results indicate that common reed is clearly gaining ground over time, while cattails stands are retreating. We also found annual variability in the spatial dynamics, suggesting that other factors, such as the effect of weather conditions on water level, may affect population processes. Interspecific interactions had a detrimental effect on both common reed and cattail biomass. However, common reed showed morphological plasticity in shoot height, number of nodes, and internodes length, while cattails did not. Our observations suggest that common reed has a net competitive advantage over cattails in roadside ditches and freshwater marshes.     

农地整理中路沟渠生态化设计研究进展

农地整理是人类对农田生态系统的强烈干扰.传统农地整理中路沟渠设计的主要技术经济指标是方便生产通行和调配水资源以及提高水的利用率,尚缺少系统化、生态化考量,已经影响了农田物种扩散,导致生物栖息地环境的退化,并对农田生态系统的生物竞争机制、缓冲和补偿能力、抵御虫害能力产生了显著的负效应.本文系统总结了路沟渠生态化的功能,着重介绍了近年来生态化路沟渠的形式与结构设计、路沟渠生态工法参数的试验以及路沟渠生态材料选择的技术和方法.未来的相关研究应根据各级道路、灌排沟渠的不同功能要求和规格,按照田间不同生物的习性和栖息要求,精确设计能够满足大多数生物需求的农田路沟渠形态、结构和控制性尺寸,切实解决农地整理带来的上述问题.     

湿地农田渠系的生态环境影响研究综述

天然湿地开垦为农田,排水渠系扩张,随之带来两个方面的生态环境影响。作为廊道,排水渠系的隔离作用割裂了景观,造成湿地景观破碎化,甚至景观性质的改变;同时,其通道作用影响了湿地的水文过程,将局部湿地排干而转变为农田,并成为农田污染物向受纳河流水体运移的快速通道。因此,根据排水渠系的功能特点,在局域和区域两个层次上,对其生态环境影响开展综合研究,可以为湿地保护和恢复提供切实可行的对策措施。在回顾相关研究的基础上,提出了排水渠系生态环境影响研究的一个思路：即基于景观生态学和生态学模型等,开展排水渠系生态环境影响的机制研究;基于环境影响评价和生态系统健康评价等,开展排水渠系生态环境影响的效应研究;以及基于恢复生态学等,开展排水渠系的生态调控对策措施研究,从而为排水渠系的生态环境影响研究提供系统性途径。