土壤镉处理对棉花镉吸收及分布规律的影响

用CdCl2将盆栽土壤Cd浓度处理为1mg／kg、5mg／kg、10mg／kg、20mg,／kg、30mg／kg种植棉花，研究棉花对镉的吸收及镉在棉花体内的分布规律。结果表明，当土壤镉浓度小于30mg／kg时，镉在棉花体内的分布呈现不同的规律。当土壤镉浓度小于5mg／kg时，镉主要分布在棉花的地上部；当土壤镉浓度大于20mg／kg时，镉主要分布在棉花的叶片、根、茎中，其中叶片的镉含量最高，棉絮镉含量最低。不同镉污染水平下，棉花的镉富集系数均小于1。当土壤镉污染浓度为5mg／kg时，棉花叶片的镉富集系数为0．76。在同一镉污染水平下，棉花叶片的镉转运系数最高。当土壤镉含量小于20mg／kg时，棉花茎、叶、棉絮的转运系数平均为4．63。     

骨炭＋沸石对重金属污染土壤的修复效果及评价

采用盆栽试验,研究了铜铅镉复合污染土壤添加骨炭和沸石前后对土壤pH值、土壤中重金属有效态含量、蕹菜生长、重金属吸收量的影响。结果表明,土壤污染后pH值显著降低,土壤中重金属有效态含量显著增加,蕹菜生长不良,株高、鲜重、干重显著降低,同时蕹菜重金属含量增加;添加固化剂后土壤pH值提高了2.21和2.29个单位,土壤有效态重金属含量显著降低,蕹菜株高、鲜重、干重增加,同时使轻度污染土壤上的蕹菜达到卫生安全标准。     

沼渣连续施用对土壤微生物量碳、氮剖面分布的影响

通过"棉花+小麦"轮作施用沼渣的定位试验,研究不同年限的沼渣施用对土壤剖面微生物量C、N(MBC、MBN)分布特征的影响。结果表明:在0~50cm剖面上,施用沼渣1年对0~30cm土壤的MBC、MBN影响较大,能显著提高30~40cm土层土壤MBC、MBN的含量,施用沼渣5年时对40~50cm土层MBC、MBN无明显影响。土壤MBC、MBN含量总体随施用沼渣年限的延长而增加,各土层MBC、MBN含量增幅随着施用年限的延长呈现不同趋势。施用沼渣1年,耕层土壤的MBC/MBN值较习惯耕作增加,施用沼渣3年后,其值呈降低趋势。各土层的MBC/TOC、MBN/TN和MBC的变化趋势基本一致,总体随着沼渣施用年限的延长而增加。针对"棉花+小麦"轮作模式,持续施用沼渣3年更有利于改善0~40cm土层土壤肥力。     

水基钻井废物泥浆池原位处理环境影响分析

通过对长庆油田水基钻井废物泥浆池原位处理的历史情况进行调研,分析了泥浆池对周围植被和土壤的影响。结果表明：泥浆池内玉米、牧草的平均生物量分别比泥浆池外高出15.3％和44.5％,钻井废物 提高了土壤的碱性。玉米籽粒及泥浆池内、外土壤中的重金属含量均未超标,泥浆池对牧草中的重金属含量无明显影响。分析发现钻井废物中含有大量的微量元素,可以促进植被生长,且钻井液添加物可以提高土壤肥力,使其具有土壤化利用的潜力,为钻井废物资源化利用提供了方向。     

土壤锑污染对桑树的影响初探

运用盆栽实验和实验分析方法,研究了土壤锑(Sb)污染对桑叶品质的影响,揭示了桑树对土壤锑的耐性机制。在土壤中分别添加三价锑15mg/kg、40mg/kg、80mg/kg、120mg/kg、160mg/kg和300mg/kg,以植物生长指标及生理指标为测试指标,实验周期60d。实验结果表明,低浓度Sb处理(<40mg/kg)对桑树生长有促进作用;随着土壤Sb浓度增高(40—300mg/kg),它对桑树产生抑制效应。但当土壤锑浓度不超过160mg/kg时,桑树对土壤锑污染有一定的耐性,其耐性指数>0.8。土壤锑污染对桑叶叶绿素含量、淀粉含量和可溶性糖含量影响不显著,桑叶中的锑含量随土壤锑含量的增加而增多。     

石油类对小麦生长的影响研究

为了弄清含油土壤中石油类对小麦生长情况的影响,中原油田进行了两年的盆栽小麦实验。实验中采用不同含油浓度,分别对小麦的出苗率、有效分蘖数、株高、穗长、千粒重及品质进行了观察比较。结果表明:土壤中原油含量对小麦的出苗率影响最明显,其它小麦粒中苯并芘及挥发酚残量均低于国家标准。     

石油污染土壤中石油含量对玉米的影响

为了弄清石油污染土壤中石油类对农作物的影响,吉林油田进行了一年的田间玉米种植试验。在不同浓度水平,分别对玉米出苗率、可见外观特性、百粒重、产量和品质进行了较系统的观察、监测、类比分析。结果表明,土壤中石油含量的不同,对玉米生长过程各项指标有不同的影响。并找出吉林油田土壤—玉米系统中影响玉米生长及其产量的土壤临界含油量。     

浅谈竹浆原料林基地建设对土壤环境的影响——以四川省合江县、纳溪区竹浆原料林基地为例

土壤有机质和有效养分是评价土壤质量的重要指标,也是陆地生态系统物质循环的重要组成成分。本研究以四川省合江县、纳溪区2个区县12个乡镇的竹林地土壤作为研究对象,通过对土壤剖面的取样分析,对比分析了不同年份竹浆原料林基地与邻近土地的土壤有机质及速效养分含量特征,探讨竹子生长对土质有机含量的影响。结果表明,从土壤肥力情况看,种植竹林对土壤养分有一定的影响。与旱地相比,种植竹林会降低部分区域的土壤肥力,与多年竹林地相比,竹浆原料林基地土壤全磷、速效磷、速效钾明显升高。从土壤物理性质看,种植竹林对土壤团粒结构影响不大,对土壤容重有一定正影响,可在一定程度上改良土体结构。建议在生产实际中应结合土壤肥力监测结果,科学施肥、多施有机肥,尽可能做到平衡施肥,防止土壤养分的过度消耗。     

土壤铅污染对桑树生长及桑叶品质的影响研究

运用盆栽试验和室内实验相结合的方法,研究了土壤不同浓度铅污染对桑树生长及桑叶品质的影响.结果表明,低浓度铅(≤200mg/kg干土)处理使桑树的株高呈现上升趋势,中、高浓度铅(≥300mg/kg干土)处理使桑树的株高呈现下降趋势;而桑叶中叶绿素总量、可溶性糖含量、淀粉含量均随着外加铅浓度梯度的增加呈先上升后下降的趋势,转折点为200mg/kg干土(土壤一级标准).土壤中的铅浓度超过200mg/kg干土后,桑树生长及桑叶品质开始受到明显胁迫.     

土壤湿度和机械长度对棉花秸秆分解率的影响

新疆棉花秸秆产量巨大,但是棉花秸秆的木质素和纤维素含量较高,不易被分解,很难作为饲料利用。本文研究了棉花秸秆在不同条件（土壤水分、棉花机械长度）处理下的分解速率。从土壤水分条件来看,棉花秸秆在50%土壤饱和含水量下的分解最为理想,其分解率在100 d后达到54.08%;从棉花秸秆粉碎程度来看,棉花秸秆粉碎越细越有利于其分解,但是3 cm处理100 d后分解率为54.12%,而1 cm处理100 d后分解率只有47.42%,说明棉花秸秆分解需要一定的孔隙度。另外,棉花秸秆分解之后对土壤肥力也有很大影响。此次试验结果可为推广大田试验提供科学依据。     

棉田生态系统中钾元素的施用效益研究

新疆滴灌棉花施用钾肥,灰漠土平均增产9 1%,草甸土平均增产6 6%。在适宜的氮磷肥条件下,灰漠土滴灌棉花最佳施钾量为94 5kg/hm2;草甸土滴灌棉花最佳施钾量为64 5kg/hm2。每公顷钾肥用量增加1kg,灰漠土棉株体内全钾含量提高0 006029%;草甸土棉株提高0 004457%。钾肥施用方法以基施配合滴施最佳。     

Environmental impact assessment of a proposed info-tech complex in East Calcutta wetlands

An info-tech complex is proposed for 286 acres (116 ha) of land within the East Calcutta wetlands. The proposed site is 15 km east of Kolkata city and only 8 km south of Dum Dum airport. The site is vacant, with pockets of agricultural land and a few degrading water-logged areas. In order to assess the likely impact of the proposed development on the environment, a rapid environmental impact assessment of an area of 10 km radius from the centre of the project site was carried out. The present status of the environment with respect to ambient air, surface water, groundwater, soil, landuse, noise, and socio-economics of the core and buffer zone has been documented and correlated with 24 project activities during construction, development and operational phases. The frequency of adverse impacts is greater than that of beneficial impacts. Out of the total adverse impacts 20 are short term, reversible and have a low magnitude. The total impact score for the proposed project is (–)468.75 and as per the Assessment Value Index Scale the environmental impact of the proposed project activities is no appreciable impact. But there are certain sectors where the environment will be adversely impacted. Therefore, appropriate measures have been suggested to ameliorate the adverse impacts. It is envisaged that if these measures are implemented then there will be an improvement in the quality of the environment, as well as life, by 687.5 units.     

Alteration in rhizosphere soil properties of afforested Rhamnus lycioides seedlings in short-term response to mycorrhizal inoculation with Glomus intraradices and organic amendment

The reestablishment of autochthonous plant species is an essential strategy for recovering degraded areas under semiarid conditions. A field experiment was carried out to assess the short-term effect of two reafforestation methods involving mycorrhizal inoculation and compost addition on soil quality parameters and Rhamnus lycioides seedling growth. The nutrient content (NPK) and enzymatic activities (dehydrogenase, urease, protease-BAA, acid phosphatase and beta-glucosidase) increased and bulk density decreased in the rhizosphere soil with the organic amendment. Biomass C of rhizosphere soil increased by at least 240% with respect to the control soil after mycorrhizal inoculation and the combination of compost addition + mycorrhizal inoculation. Both mycorrhizal inoculation and composted organic residue addition increased R. lycioides seedling growth in the same proportion. In the short term, we conclude that the application of both reafforestation methods not only enhances the establishment of R. lycioides seedlings, but also improves soil quality.     

油污土壤微生物生态研究

利用微生物降解土壤中的油等有机污染物的就地生物治理技术受土壤及环境的诸多条件影响,在使用该技术之前,首先要进行油污土壤微生物生态研究,弄清影响微生物处理效果的各种因素。通过对胜利油田油污土壤微生物研究得知：胜利油田油污土壤的ｐＨ值、含水量等指标利于微生物降解原油。土壤优势菌种多为原油降解菌,并且与含油量呈正相关。油污土壤中氮、磷等营养物质含量不足时,向其添加一定数量的营养物质和降解菌,能够提高微生物处理地面溢油的处理效率。     

Alteration in Rhizosphere Soil Properties of Afforested <Emphasis Type="Italic">Rhamnus lycioides</Emphasis> Seedlings in Short-Term Response to Mycorrhizal Inoculation with <Emphasis Type="Italic">Glomus intraradices</Emphasis> and Organic Amendment

The reestablisment of autochthonous plant species is an essential strategy for recovering degraded areas under semiarid conditions. A field experiment was carried out to assess the short-term effect of two reafforestation methods involving mycorrhizal inoculation and compost addition on soil quality parameters and Rhamnus lycioides seedling growth. The nutrient content (NPK) and enzymatic activities (dehydrogenase, urease, protease-BAA, acid phosphatase and β-glucosidase) increased and bulk density decreased in the rhizosphere soil with the organic amendment. Biomass C of rhizosphere soil increased by at least 240% with respect to the control soil after mycorrhizal inoculation and the combination of compost addition + mycorrhizal inoculation. Both mycorrhizal inoculation and composted organic residue addition increased R. lycioides seedling growth in the same proportion. In the short term, we conclude that the application of both reafforestation methods not only enhances the establishment of R. lycioides seedlings, but also improves soil quality.     

Sustainability of farmers' soil fertility management practices: a case study in the North China Plain

To ensure regional self-sufficiency and adequate rural livelihoods in the North China Plain (NCP), tremendous efforts were made over the last two decades by the Chinese government to raise the productivity of crops, despite increasing pressure on the land caused by a growing population. Emphasis was placed on high external input use, especially for wheat, maize and cotton, ignoring the particularities and limitations of the natural resource base. This study assesses the sustainability of current soil fertility management practices on the basis of selected location-specific indicators, such as fertilizer use, soil pH, soil organic matter content, levels of nitrogen (N), phosphorus (P) and potassium (K) in the soil, and identifies determining factors of the yield and environmental impacts of inputs use. Data used for the analysis were gathered from soil tests, groundwater and chive plant tests, household surveys, and statistical yearbooks. Stepwise multiple regression analysis is applied to determine factors affecting the yields. The study revealed unbalanced use of nutrients. Organic fertilizers (manure, crop residues) and K are insufficiently applied, whereas N and P are considerably overused in comparison with recommended doses. The intensive cropping in the area using high-input technologies -particularly fertilizer- has resulted in a remarkable general enhancement of crop productivity and improvement of soil fertility over the years. The yield of wheat and maize has increased 173 and 180 kg ha(-1) annually from 1982 to 2000, respectively and soil fertility status also improved over the years and the values of the selected indicators are within the borderline for sustainability. Irrigation water, FYM application, and total labor used during the cultivation season (with the exception of cotton and chive) for production are the main factors determining the yields of four major crops under study, while popularly and overly used N did not appear to be a significant factor affecting the yield. Its overuse, however, leads to leaching of nitrate into groundwater and nitrate enrichment of vegetables. Of 20 groundwater samples, 16 showed nitrate levels between 55 and 180 mg l(-1), which exceeds recommendations for drinking water (相似文献   

Simulating endosulfan transport in runoff from cotton fields in Australia with the GLEAMS model

Endosulfan (6,7,8,9,10,10-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9methano-2,4,3-benzodioxathiepin 3-oxide), a pesticide that is highly toxic to aquatic organisms, is widely used in the cotton (Gossypium hirsutum L.) industry in Australia and is a risk to the downstream riverine environment. We used the GLEAMS model to evaluate the effectiveness of a range of management scenarios aimed at minimizing endosulfan transport in runoff at the field scale. The field management scenarios simulated were (i) Conventional, bare soil at the beginning of the cotton season and seven irrigations per season; (ii) Improved Irrigation, irrigation amounts reduced and frequency increased to reduce runoff from excess irrigation; (iii) Dryland, no irrigation; (iv) Stubble Retained, increased soil cover created by retaining residue from the previous crop or a specially planted winter cover crop; and (v) Reduced Sprays, a fewer number of sprays. Stubble Retained was the most effective scenario for minimizing endosulfan transport because infiltration was increased and erosion reduced, and the stubble intercepted and neutralized a proportion of the applied endosulfan. Reducing excess irrigation reduced annual export rates by 80 to 90%, but transport in larger storm events was still high. Reducing the number of pesticide applications only reduced transport when three or fewer sprays were applied. We conclude that endosulfan transport from cotton farms can be minimized with a combination of field management practices that reduce excess irrigation and concentration of pesticide on the soil at any point in time; however, discharges, probably with endosulfan concentrations exceeding guideline values, will still occur in storm events.     

污泥热解残渣制备聚合氯化铝的实验研究＊

含铝污泥热解或焚烧残渣制备聚合氯化铝的研究,有利于实现污水处理过程投加的铝盐絮凝药剂的回收与高效循环利用,减少污染物排放和资源消耗。针对辽河油田欢三联稠油污水处理污泥的热解残渣具有较高铝含量的特点,开展采用盐酸进行铝溶出及制备聚合氯化铝的实验研究。结果表明:焙烧温度为700～750℃,焙烧时间控制在1h即可。将经过焙烧活化的残渣在常温下进行酸溶,酸溶时间为2～5h,选用25%～30%盐酸,氧化铝与盐酸的摩尔比为1∶1.0～1∶1.2为宜。将溶出的铝溶液制备聚合氯化铝,在常温下采用CaO粉末来调节pH值为3.5,聚合反应时间为1d,即可得聚合氯化铝溶液。