石灰对土壤吸附镉行为及有效性的影响

酸性红壤上添加石灰显著增加土壤对镉的吸附量并降低吸附态镉的解吸量。但石灰用量较低时,镉的解吸率反而比未施石灰时增加。盆栽试验亦表明,在石灰用量较低时,土壤pH虽有所升高,但小麦和黑麦草植株镉含量降低不明显甚至有所升高;只有较高的石灰用量使土壤pH得以明显升高,植株吸镉量才能明显降低。对这一现象的原因进行了讨论。      

Effect of liming on the distribution of heavy metals in untreated industrial sewage sludge produced in Pakistan for the cultivation of <Emphasis Type="Italic">Sorghum bicolor</Emphasis> (L.)

The recycling of sewage sludge on agriculture land represents an alternative, advantageous, disposal of this waste material. The aim of the present study was to evaluate the feasibility of using industrial sewage sludge, produced in Pakistan, as a fertiliser. Agricultural soil amended with 25% (w/w) sewage sludge with or without lime treatment was used for growing a variety of sorghum (PARC-SS-1). The mobility of the heavy metals (HMs) (Cd, Cu, Cr, Ni, Pb and Zn) and metalloid (As) in the untreated industrial waste water sewage sludge (UIWS) samples were assessed by applying a modified BCR (Community Bureau of Reference) sequential extraction procedure. The single extraction procedure comprised of the application of mild extractant (CaCl₂) and water for the estimation of the proportion of easily soluble metal fractions. The precision and accuracy of BCR was evaluated by using a certified reference material of soil amended with sewage sludge BCR 483. The plant available metal contents, as extracted by the deionised water and 0.01 M CaCl₂ solution and exchangeable fraction of BCR sequential, decreased with lime application in the range of 10–44% for As, Cr, Ni, Pb and Zn, except in the cases of Cd and Cu, where their mobility was increased by 10% and 24%, respectively. Sludge amendment enhanced the dry weight yield of sorghum and the increase was more obvious after liming up to 25%. The uptake of HMs were lower in test samples (3.2–21.8%), except for Cu and Cd, which was higher (4%), while they were below the permissible limit of these metals. The present experiment demonstrates that liming was important in factors facilitating the growth of sorghum in sludge-amended soil.     

镇江市老城区生活污水水质特征及排放规律研究

镇江市老城区排水系统落后,主要以合流管网为主,区域内居民生活污水已成为镇江市水环境污染的重要来源之一,对该区域内居民生活污水水质特征和污染排放规律进行研究,不但有助于正确认识、科学把握城市面源污染特征,还有利于污染控制对策的制定和治理工程的开展。选择镇江市老城区典型合流制管网系统——黎明河溢流口,采用定点动态采样的方法,进行该区域生活污水水质特征和污染排放规律研究。研究结果表明,研究区域内各月的COD、TN、TP和SS的逐时变化规律具有各自的相似性。     

Environmental history: A piece in the puzzle for establishing plans for environmental management

Establishment of plans for environmental planning and management requires that a number of natural and societal factors must be taken into consideration. Insights into the inherent dynamics of nature as well as the role that past human activities have played for establishing the current condition of the landscape and the natural environment in general are essential. Many natural and man-made changes occur over time scales of decades or centuries, and these are difficult to comprehend without a historical perspective. Such a perspective can be obtained using palaeoecological studies, i.e. by geochemical and biological analyses of lake sediment and peat deposits. To illustrate the long-term dynamics of nature and particularly the role of man, we present here five case studies from Sweden concerning pollution, lake acidification, lake eutrophication, biodiversity, and landscape dynamics and conservation – topics of broad interests – and discuss benefits of including a longer time perspective in environmental management.     

Evidence for Ph Insensitivity in Some Insects Inhabiting Peat Pools in the Loch Fleet Catchment

The impact of liming on the insects associated with peat pools was studied in the Loch Fleet catchment in 1991 and 1992. Fifty-six taxa were identified from 121 timed samples. Despite the raised pH associated with liming in 1986, the population densities of Odonata, Hemiptera and Coleoptera appeared to be unaffected when compared with those of untreated peat pools in the same area. the study demonstrated the existence of two main types of community, that of the steep-sided edges of pools, dominated by odonate nymphs and large species of beetles, and that of the shallower pools, dominated by Hydroporus species (Col., Dytiscidae).     

Potential Use of Olive-Waste Ash from Cogeneration Plants as a Soil Amendment

A greenhouse study was conducted to evaluate the potential use of olive-cake ash as a soil amendment, using pepper (Capsicum annuum, L. cv Italian sweet). Three soils of different pH (acidic, neutral and calcareous) were used. Treatments included a control (no fertilizer application), NPK fertilizer, and two ash-application rates that provided a complete dose (equivalent to the K₂O amount in the fertilizer) and a half dose (equivalent to half the K₂O amount in the fertilizer), respectively. The ash was effective in raising soil pH. Ash treatments increased the pepper (stems and leaves) dry matter yield over control; although these increases were lower than treatment including NPK. Application of ash significantly increased leaf P concentration and AB-DTPA extractable P in soil, especially in the acidic and neutral soils. Leaf K concentrations and readily and slowly available K forms in soils were affected positively by the addition of the ash. These results demonstrate that ash from the combustion of wet olive cake can be used as a beneficial organic soil amendment.     

Cs uptake by four plant species and Cs-K relations in the soil-plant system as affected by Ca(OH)2 application to an acid soil

Three rates of Ca(OH)₂ were applied to an acid soil and the ¹³⁴Cs uptake by radish, cucumber, soybean and sunflower plants was studied. The ¹³⁴Cs concentration in all plant species was reduced from 1.6-fold in the sunflower seeds to 6-fold in the soybean vegetative parts at the higher Ca(OH)₂ rate. Potassium (K) concentration in plants was also reduced, but less effectively. The significantly decreased ¹³⁴Cs-K soil to plant distribution factors (D.F.) clearly suggest a stronger effect of soil liming on ¹³⁴Cs than on K plant uptake. This observation was discussed in terms of ionic interactions in the soil matrix and within the plants. The results also indicated that the increased Ca²⁺ concentration in the exchange phase and in the soil solution along with the improved root activity, due to the soil liming, enhanced the immobilization of ¹³⁴Cs in the soil matrix and consequently lowered the ¹³⁴Cs availability for plant uptake.     

Evidence for Ph Insensitivity in Some Insects Inhabiting Peat Pools in the Loch Fleet Catchment

The impact of liming on the insects associated with peat pools was studied in the Loch Fleet catchment in 1991 and 1992. Fifty-six taxa were identified from 121 timed samples. Despite the raised pH associated with liming in 1986, the population densities of Odonata, Hemiptera and Coleoptera appeared to be unaffected when compared with those of untreated peat pools in the same area. the study demonstrated the existence of two main types of community, that of the steep-sided edges of pools, dominated by odonate nymphs and large species of beetles, and that of the shallower pools, dominated by Hydroporus species (Col., Dytiscidae).     

Amelioration of Streamwater Acidity by Catchment Liming-Response of Podzolic Soils to Pasture Improvement

The effects of agricultural improvement by cultivation, re-seeding, lime and fertiliser additions on the soil solution chemistry of acid podzolic soils have been investigated in a field experiment in a mid-Wales catchment. the treatment resulted in an increase in the pH, alkalinity and calcium content of soil waters from the surface, organic-rich horizon. in the year following treatment, soil waters in the mineral horizons became more acid and had higher aluminium concentrations than observed at the control site. This response is ascribed to soil water acidification resulting from increased nitrification rates following liming and cultivation. in subsequent years, soil water acidity in these lower horizons was neutralised by lime-rich water percolating from the surface. No changes in stream water acidity and calcium content were observed in the catchment containing the area of agriculturally improved soils. This suggests that the selective treatment of moorland catchments to improve agricultural productivity may not always be accompanied by amelioration of acid stream water.     

施石灰对新垦赤红壤化学性质和作物生长的影响

本文采用pH4.8、交换性酸2.8cmol kg~(-1),交换性Ca0.8cmol kg~(-1)的花岗岩赤红壤(荒丘),进行盆栽试验和田间试验,研究施生石灰对土壤化学性质及花生、甘薯生长的影响。结果表明,大田施用相当于交换酸60％的生石灰,可使土壤pH值在9个月内保持在5.8以上,但就提高花生产量来说,石灰用量以中和交换性酸30％为宜。土壤中Fe、Al的固P能力远比Ca大,即使施用高量的石灰,新形成的Fe-P、Al-P各为新形成Ca-P的2倍以上,同时亦有大量的O-P形成。各水平的石灰处理均显著改善花生的经济性状和品质,但产量的提高却以低水平石灰处理为显著。