利用杨柳人工林处理污水

加拿大安大略树木改良和生物量研究所利用杨树蒸腾速率高,叶量大的特点来处理污水。试验林已6年生,为4×4米的杨树和柳树人工林,生长季每天用污水池中经过处理的城市污水喷灌。每日喷灌量的控制对防止污水下渗、污染地下水很重要,每日的喷灌量是按每日的大气蒸发——蒸腾量确定的,为此每日监测太阳辐射、气温、空气相对湿度、风速和降雨。由于树冠内大量树叶可以截留相当多的废水,并由叶表蒸发,所以每日的喷灌是实际上大于蒸发——蒸腾量。树木在利用渗入土壤     

北方城市污水资源化利用

指出了污水资源化利用对我国北方城市来说势在必行。污水资源化,是一个综合性问题,需要系统考虑技术难度、经济成本、社会管理、政策法规以及推广宣传等多方面共同推进。通过对我国城市污水资源化利用相关领域的分析总结,探讨了我国城市污水资源化需要解决的问题,并提出了具体的措施建议。     

内蒙古"环保世纪行"专题报道之二拯救乌梁素海在行动

乌梁素海,这个有着"塞外白洋淀"之称的我国北方黄河流域乃至地球同纬度最大的湿地,由于长期忍受传统的农业灌溉余水、工业废水、城镇生活污水等污染而不堪重负.乌梁素海的呻吟,引起了国家、自治区和巴彦淖尔市的高度重视,一场拯救乌梁素海的战斗也因此打响.     

可循环使用的抛光液

目前，我国城市污水年排放量大约在414亿立方米，城市污水集中处理率要达到45％。如果污水回用率平均达到40％，则污水回用量可达到80亿立方米，即可解决全国城市缺水问题。     

园林树木的灌溉方法及灌溉水源

园林树木灌溉方法和水源很多,如何因地制宜的选择灌水方法和灌溉水源,对节约水资源、提高灌水利用效率具有重要的意义。该文详细介绍了园林树木灌溉方法的特点及适用条件,系统总结了园林树木灌溉的可用水源,并说明了使用时的注意事项。     

敦煌石油基地防护林带污水灌溉对土壤的影响

阐述了敦煌石油基地的污水处理情况以及防护林的污水灌溉情况,重点对污水灌溉防护林带区域的土壤进行了分析,考察了污水灌溉对土壤的影响。试验分析结果证明,污水灌溉可以改良土壤,提高土壤肥力,净化环境。     

城市污水处理厂的能耗分析及节能降耗措施研究

指出了城市污水处理是能源密集的高能耗产业之一,因此,污水处理厂的能耗也越来越引起重视。分析了城市污水处理厂运行消耗的资源主要包括电能、自来水和药剂,从污水的提升系统、曝气系统、污泥的脱水系统及废弃物的综合利用等方面提出了城市污水处理厂节能降耗的主要措施,以期为污水处理厂生产管理提供参考。     

园林树木的水分利用效率研究概述

水分是树木赖以生存的必要因子之一,是保证植物正常生长发育的关键生态要素。该文回顾了城市园林树木水分利用效率的测定方法和影响因素,为确定园林绿地的灌溉量提供技术方法,使其达到树木的生理需求,同时实现节水的目的。根据园林树木的水分利用特征进行科学管理,这对于节水型园林绿地景观具有重要意义。     

高氨氮废水生物脱氮技术

当前全球面临严重的水资源危机,而水体富营养化污染正日益加速.造成水体富营养化的主要成分为氨氮,它们一部分来自于农田排灌系统的非点源排放,一部分来自于城市污水和工业废水,其中有一类污水(如养殖场废水、垃圾填埋渗滤液、制药厂废水、焦化厂废水)含有非常高的氨氮浓度,尤其是畜禽养殖场(包括部分屠宰场)及小城镇的生活污水和生活垃圾充满田间,基本上没有得到处理,严重影响地表和地下水.这类特种废水虽含有极高的氨氮浓度,但水量往往不大,不可能采用传统的生化-硝化-反硝化的模式进行,因此至今尚无很好的污染控制技术.     

地下滴灌条件下杨树速生丰产林生长与光合特性

研究了北京沿河沙地I 2 1 4杨树人工林地下滴灌和常规灌溉林地树木生长与光合特性 ,结果表明 :与常规灌溉相比 ,地下滴灌能大大增加树木的生长量 ,提高林地生产力。 2 0 0 0年 (栽植第 4年 ) ,地下滴灌区树木平均胸径、树高和单株材积分别达到 2 1 1 8cm、1 4 2 3m和 0 1 81 5m3,比常规灌溉增加了 5 4 5 %、36 9%和 2 4 7 6 % ;林地生产力达到 2 2 78～ 2 5 81m3·hm- 2 a- 1 ,比常规灌溉增加了 3 9～ 4 6倍。树木生长改善和林地生产力提高的生理机制是地下滴灌可促进树木光合作用和水分利用效率。地下滴灌区树木叶净光合速率在一天中几乎一直显著高于对照 ,幅度达 1 0 0 %～ 2 1 4 % ;从一个滴灌周期来看 ,滴灌区树木叶净光合速率显著高于对照 9 0 %～ 9 9% ;滴灌区树木水分利用效率也较对照区显著提高。通过相关分析表明 ,表层土壤 (1 5～ 2 5cm)水分含量在 5 %～ 8%时树木叶净光合速率能在长时间维持较高水平 ,而水分含量低于 4 % ,树木叶净光合速率将降低。建议在干旱半干旱和季节性干旱地区营造速生丰产用材林时应结合当地经济条件推广地下滴灌技术 ,这不仅有利于水资源的可持续利用 ,而且将大幅度提高林地生产力 ,使我国人工林生产力赶超世界先进水平。     

Die Wasser-Zugspannungs-Insuffizienz Hypothese zum Waldsterben1

A water cohesion insufficiency hypothesis to explain forest decline . A hypothesis on a possible cause of forest decline is presented. It is supposed, that small “middle ions”, which produced in industrial waste gases cause a functional disturbance in the capillary water supply system of trees.     

Biomass Production and Nutrient Removal from Municipal Wastes Using Willow Vegetation Filters

Short rotation forests, consisting of various willows (Salix spp.), are suitable vegetation filters with regard to removal of nutrients from municipal sewage sludge, wastewater, leakage water and bioash (wood ash). As long as contents of heavy metals and known organic compounds are kept below accepted limit values, such waste oducts can be regarded as valuable nutrient resources, and particularly when the vegetation is produced for energy purposes instead of for direct or indirect human consumption. The benefit is three-fold: (i) purification of municipal waste using natural circulation, (ii) production of biomass for energy purposes, (iii) reduction of air pollution when burning wood instead of fossil fuels. Most Salix plantations can be used as recipients of sludge and ash as well as be irrigated with wastewater from sewage plants or with leakage water from dumps. Regarding waste and leakage water irrigation, a combined artificial wetland for winter conditions and a willow vegetation filter during the growing season can be used for the purification The welland should be planted with a suitable vegetation cover, which can be harvested in order to remove maximal amounts of nutrients from the system. This biomass can be used as fuel or in compost. There are also indications that some willow clones are capable of taking up certain heavy metals, while others are not. This is beneficial when growing willow on contaminated soils, which either could be purified or just be used for such plantations.     

Deficit irrigation and rootstock: their effects on water relations, vegetative development, yield, fruit quality and mineral nutrition of Clemenules mandarin

Differences between rootstocks, 'Cleopatra' mandarin and 'Carrizo' citrange, in soil-plant water relations and the influence of these factors on vigor, crop yield, fruit quality and mineral nutrition were evaluated in field-grown Clemenules mandarin trees irrigated at 100% of potential seasonal evaporation (ET(c)) (control treatment), or irrigated at 100% ET(c), except during Phases I and III of fruit growth and post-harvest when no irrigation was applied (deficit irrigation (DI) treatment), for 3 years. Differences between rootstocks in plant-soil water relations were the primary cause of differences among trees in vegetative development and fruit yield. After 3 years of DI treatment, trees on 'Cleopatra' showed more efficient soil water extraction than trees on 'Carrizo', and maintained a higher plant water status, a higher gas exchange rate during periods of water stress and achieved faster recovery in gas exchange following irrigation after water stress. The DI treatment reduced vegetative development more in trees on 'Carrizo' than in trees on 'Cleopatra'. Cumulative fruit yield decreased more in DI trees on 'Carrizo' (40%) than on 'Cleopatra' (27%). The yield component most affected by DI in 'Cleopatra' was the number of fruit, whereas in 'Carrizo' it depended on the severity of water stress reached in each phase (severe water stress in Phase I affected mainly the number of fruit, whereas it affected fruit size the most in Phase III). In the third year of DI treatment, water-use efficiency decreased sharply in trees on 'Carrizo' (70%) compared to trees on 'Cleopatra' (30%). Thus, trees on 'Cleopatra' were able to tolerate moderate water stress, whereas trees on 'Carrizo' were more sensitive to changes in soil water content.     

Factors involved in alleviating water stress by partial crop removal in pear trees

We studied the relief of water stress associated with fruit thinning in pear (Pyrus communis L.) trees during drought to determine what mechanisms, other than stomatal adjustment, were involved. Combinations of control irrigation (equal to crop water use less effective rainfall) and deficit irrigation (equal to 20% of control irrigation), fruit load (unthinned and thinned to 40 fruits per tree) and root pruning (pruned and unpruned) treatments were applied to pear (cv. 'Conference') trees during Stage II of fruit development. Daily patterns of midday stem water potential (Psi(stem)) and leaf conductance to water vapor (g(l)) of deficit-irrigated trees differed after fruit thinning. In response to fruit thinning, gl progressively declined with water stress until 30 days after fruit thinning and then leveled off, whereas the effects of decreased fruit load on Psi(stem) peaked 30-40 days after fruit thinning and then tended to decline. Soil water depletion was significantly correlated with fruit load during drought. Our results indicate that stomatal adjustment and the resulting soil water conservation were the factors determining the Psi(stem) response to fruit thinning. However, these factors could not explain differences in daily patterns between g(l) and Psi(stem) after fruit thinning. In all cases, effects of root pruning treatments on Psi(stem) in deficit-irrigated trees were transitory (Psi(stem) recovered from root pruning in less than 30 days), but the recovery of Psi(stem) after root pruning was faster in trees with low fruit loads. This behavior is compatible with the concept that the water balance (reflected by Psi(stem) values) was better in trees with low fruit loads compared with unthinned trees, perhaps because more carbon was available for root growth. Thus, a root growth component is hypothesized as a mechanism to explain the bimodal Psi(stem) response to fruit thinning during drought.     

Regulated deficit irrigation and the recovery of water relations in pistachio trees

Recovery of water status in water-stressed pistachio trees (Pistacia vera L. cv. Kerman) was investigated by subjecting trees to regulated deficit irrigation (RDI) (60% of crop evapotranspiration rate, ET(c)) during stages I and II of fruit development (FD) followed by full irrigation during FD stage III (kernel-filling). Trees irrigated at 100% ET(c) throughout FD stages I, II and III served as controls. Water-stress severity was characterized by changes in soil water content and midday stem water potential (Psi(md)). Midday leaf conductance (g(1)) and trunk diameter variation (TDV) were also measured. In RDI trees, the lowest Psi(md) value, -1.8 MPa, occurred at the end of the RDI period. The corresponding value for the control trees was around -1.1 MPa. Although the RDI treatment affected gas exchange later than Psi(md), the greatest reductions in gas exchange (60% of control values) also appeared at the end of the RDI period. There were significant differences in TDV between control and RDI trees at the end of the RDI period. Although plant water status recovered within 20 days of resuming irrigation, the TDV values indicated a longer period might be necessary for complete recovery. Recovery of g(1) was faster than that of Psi(md), although differences in TDV between control and RDI trees indicated that gas exchange recovered later than Psi(md). The slow recovery of pistachio trees during FD stage III from water stress imposed during FD stages I and II suggests that irrigation should exceed 100% ET(c) during FD stage III or that more extensive irrigation should commence before the end of FD stage II.     

库尔勒地区荒山滴灌造林节水效率研究

对库尔勒地区荒山滴灌造林节水效率进行了对比试验,结果表明,滴灌较管道灌节水66.6%。由此推断,滴灌较漫灌节水73%~76%。该研究为滴灌节水技术的推广以及滴灌条件下树木合理灌溉制度的制定提供了依据。     

Root anchorage of hinoki <Emphasis Type="Italic">(Chamaecyparis obtuse</Emphasis> (Sieb. Et Zucc.) Endl.) under the combined loading of wind and rapidly supplied water on soil: analyses based on tree-pulling experiments

Wind damage in Japan is mainly caused by typhoons (i.e., tropical cyclones), which are characterized by intensive heavy rainfall and strong winds. In this study, we conducted tree-pulling experiments on two sites to find out whether rapidly supplied water on the soil would affect stability of root anchorage of hinoki (Chamaecyparis obtuse (Sieb. Et Zucc.) Endl.), as expected. For the experiments, we first supplied several quantities of water around the target trees, and then they were pulled down using a wire winch. On study site 1 (Kamiatago experimental forest), we applied general tree-pulling experiments (no water supply) in 2008 and six different irrigation treatments around the target trees in 2009. On study site 2 (Chiyoda experimental forest), we applied one irrigation treatment in 2009. As a result, five trees were uprooted and two were broken in 2008, and all nine trees were uprooted in 2009 on study site 1, regardless of irrigation treatment. On study site 2, two trees pulled down after 4 h of water supply were ruptured at the stem base, opposite to two trees pulled down immediately after supplying water. The water content below the root plate significantly affected root anchorage and more specifically, the maximum turning moment, stem angle at the maximum force, and stiffness index. Moreover, water inside the root plate increased root anchorage at the beginning of a tree failure process. However, it also reduced the root plate area of the hinge side. Conversely, high water content below the root plate decreased root anchorage.     

Effects of irrigation deprivation during the harvest period on leaf persistence and function in mature almond trees

In nut tree orchards in California, irrigation is typically withheld during the harvest period to reduce the likelihood of bark damage during mechanical shaking of the trees. The ensuing water stress, however, may result in premature defoliation and subsequent yield declines. Our objective was to establish and quantify the water stress resulting from irrigation deprivation and determine its impact on leaf function and persistence in mature almond trees (Prunus dulcis (Mill.) D.A. Webb cv. Nonpareil) during a 3-year field experiment. The severity of the water stress was characterized by measurements of predawn leaf (Psi(pd)) and midday stem (Psi(ms)) water potentials, stomatal conductance (gs), net CO2 assimilation rate (A) and leaf abscission. During 1995, Psi(ms) of fully irrigated (FI) trees was maintained above -1.0 MPa. In trees in the moderate- (MS) and severe-stress (SS) treatments, Psi(ms) was reduced to -1.4 to -2.0 MPa and -2.0 to -2.6 MPa, respectively. After 18 days of irrigation deprivation, A was reduced by 32 and 58% at midday and early afternoon, respectively, compared with morning values. A significant decrease in morning values of A only occurred after 30 days of irrigation deprivation. Water-use efficiency and A declined as evaporative demand increased from morning to afternoon. Assimilation also declined seasonally as leaves aged. Midday stem water potential was highly correlated with A, but less so with gs. The coefficient of determination between Psi(ms) and gs improved considerably when vapor pressure deficit and wind were multiply regressed with Psi(ms). Although A recovered rapidly when MS trees were irrigated, recovery in SS trees was slower and incomplete. Integrating the MS and SS effects for an extended period during 1995 resulted in 14 and 30% declines in A, and 6 and 20% declines in gs, respectively. The apparent Psi(ms) threshold for leaf abscission was -1.8 MPa. Daily canopy light interception declined with decreasing Psi(ms) as a result of premature defoliation (and perhaps altered leaf angles) from 67.9% in FI trees to 61.4 and 60.7% in MS and SS trees, respectively.     

我国暖温带经济林水分管理的实现途径及措施

我国暖温带地区是落叶经济林栽培区,水资源不足是影响该区域经济林产量和质量的主要因素之一.为了提高有限水资源的利用效率,在阐述经济林合理水分管理意义的基础上,综述了国内外有关经济林节水灌溉与旱作栽培技术的应用现状和存在的问题及有关经济林水分研究的重点领域和重要问题.     

不同水分管理措施对抽梢期油茶树体养分含量的影响

为探讨不同水分管理对抽梢期油茶树体养分状况的影响,从而为油茶水分管理提供科学依据。以‘长林4号’5年生油茶为试材,设置滴灌+花生秆+稻草、滴灌+生态膜、滴灌+油茶壳、滴灌、滴灌+黑地膜、花生秆+稻草、生态膜、油茶壳、黑地膜、不覆盖不灌水(CK)共10种水分管理措施,测定不同水分管理措施下抽梢期树体各器官氮、磷、钾养分含量,并对各养分分布特征进行了分析。结果表明:不同水分管理措施对抽梢期油茶老叶和根N、P、K含量、新叶P、K含量以及枝条P养分含量影响差异显著。不同水分管理措施对抽梢期老叶、根养分含量具有明显促进作用,对当年生新叶和枝条的影响比较小。滴灌+花生秆+稻草处理和滴灌+黑地膜处理更有利于养分的积累,滴灌+花生秆+稻草处理是最经济最环保的水分管理措施。