Differences In Leaching Research Articles

Impact of Populus Plantations on Water and Soil Quality

Trees of genus Populus (in our context primarily poplars) are predominantly grown in Sweden in small plantations on arable land in southern and central parts of the country to produce biomass for energy and other purposes. This study evaluated the effects (i) of poplar plantations on groundwater quality, by determining differences in leaching of nitrogen and phosphorus to groundwater, and (ii) of poplar and hybrid aspen plantations on soil quality in terms of carbon in the top- and subsoil. The study was conducted comparing Populus plantations in Sweden with adjacent fields with cereals and grasslands. The experiment concerning the groundwater leaching was conducted in eight poplar plantations along three growing seasons (2012–2015). For the soil carbon experiments, 19 poplar and two hybrid aspen plantations and the respective reference fields were sampled. NO3-N leaching from poplar plantations was significantly lower than that from reference fields with cereals, but not when compared with grasslands. Spring NO3-N leaching was significantly lower in poplars than in the reference fields, whereas leaching of NO3-N in autumn did not differ. Concentrations of PO4-P in the groundwater of poplar plantations were lower compared to the respective ones of the reference fields. There were no clear trends observed when comparing carbon concentrations in the topsoil of the poplar and hybrid aspen plantations compared to the respective adjacent reference fields. For the subsoil, the average carbon concentrations in the poplar and hybrid aspen plantations were equal to the respective ones of cereals, but were higher when compared to grassland.

Leaching of plasticizers from polyvinylchloride perfusion lines by different lipid emulsions for premature infants under clinical conditions

Plasticizers migrate from polyvinylchloride (PVC) infusion systems into lipid emulsions. The aim of this study was to investigate the leaching of different plasticizers from PVC perfusion lines by a selection of lipid emulsions under clinical conditions. Seven PVC perfusion lines with an equal length of 150cm and three internal diameters were perfused with three lipid emulsions: Intralipid® 20%, ClinOleic® 20% and SMOFlipid® 20%, mimicking clinical conditions. The concentrations of the plasticizers were measured directly in the emulsions by gas chromatography – mass spectrometry. Of the four plasticizers examined in this study, di (2-ethylhexyl) phthalate (DEHP) leached the most and was found, on average, at 46.5μg/ml in the emulsions – around one order of magnitude higher than the other plasticizers. This study demonstrates that the leaching of DEHP by lipid emulsions in conditions of total parenteral nutrition is many times higher than should be accepted and higher when compared to the other plasticizers. There was no significant difference in leaching of plasticizers in relation to the type of lipid emulsion. The influence of tube diameter on the leaching rate of plasticizers should be taken into account especially in particular exposed patients.

Environmental Impacts of Short Rotation Coppice (SRC) Grown for Biomass on Agricultural Land

This issue of BioEnergy Research highlights the activitieswithin a European Union research project funded by ERA-NET Bioenergy, “Reducing environmental impact of SRCthrough evidence-based integrated decision support tools”(RATING-SRC). The project goal was to provide scientificevidence for evaluatingthe impacts —positiveandnegative—of short rotation coppice (SRC) plantations on soil, water,biodiversity, and landscape issues and also to propose waysto mitigate the negative and increase the positive impacts.Commercial SRC plantations are currently grown at limit-edscaleinsomecountries(e.g.,Sweden),buttheareaofSRCplantationshastoincreasedramaticallyinthefutureiftheyareto contribute significantly to the replacement of fossil energysources. Thus, a rapid increase of agricultural land dedicatedto SRC with willow (Salix spp.) or poplar (Populus spp.) forproduction of biomass for heat and/or electricity is projectedin the short-term in many regions of the world. A large-scaleshift from “conventional” arable crops to SRC will haveimplications on a range of environmental issues, and large-scale implementation of those crops for bio-energy purposemakes sense only if they prove to reduce negative effects onthe environment, especially when compared with other alter-natives for reduction of fossil energy sources. As a perennialcrop,SRCdiffersfrommostarablecropsinphysicaltraitsandmanagement practices. Results so far imply many positiveenvironmental benefits due to SRC implementation, but theeffects that SRC will have on the environment depend on theexisting or previous land use, the scale of planting and themanagement practices applied. In addition, SRC is a newproduction system for most regions in which it might begrown in future, and many uncertainties exist with respect tothe environmental impacts of those plantations on soil, water,biodiversity, and landscape issues.This special issue contains sevenpaperscoveringthetopicareasofSRCeffectsonissuesofwaterandsoil(twopapersbyDimitriou et al., Schmidt-Walter and Lamersdorf), biodiver-sity (Baum et al.), and the overall impact that these planta-tions may have on the environment and sustainability(Busch, Englund et al., Langeveld et al.). The paper on soilissues by Dimitriou et al. highlights the results for pH,organic carbon (C), and trace element concentrations in thesoil of 14 long-term (10–20 years) commercial willow SRCfields in Sweden when compared with those in adjacent,conventionally managed arable soils. The paper on waterissues by Dimitriou et al. reports the effects of SRC on waterquality by determining differences in leaching of nitrogenand phosphorus to groundwater of 16 commercial SRCstands in Sweden compared to adjacent arable fields grownwith “ordinary” crops. Schmidt-Walter and Lamersdorfdescribe effects on groundwater quality, specifically the po-tential effects of SRC grown under different managementregimes on groundwater recharge. Based on flora inventoriesin eight landscapes located in two European regions(Germany and Sweden), the paper by Baum et al. focus-es on the diversity of higher plants as an indicator ofbiodiversity in willow and poplar SRC, including variousscales ranging from habitat to landscape level diversity.The contribution by Busch is an attempt to assess theimpact of SRC on various landscape functions with thehelp of GIS-based tools. Englund et al. focus on thepotential effects of sustainability requirements within theEU Renewable Energy Directive (RED) on different stake-holders along SRC bioenergy supply chains, assessing theirusefulness in ensuring that SRC bioenergy is produced with

Impact of Willow Short Rotation Coppice on Water Quality

Short rotation coppice (SRC) with willow has been grown in Sweden from the late 1980s to produce biomass for energy on agricultural land. This study evaluated the effects of SRC on water quality by determining differences in leaching of nitrogen and phosphorus to groundwater of a number of commercial “old” SRC willow stands in Sweden compared to adjacent arable fields grown with “ordinary” crops. The study was conducted in 16 locations under three vegetation seasons. NO3–N leaching from willow SRC fields was significantly lower than that from reference fields with cereals. The opposite was observed for PO4–P; concentrations in the groundwater of SRC were higher compared to reference fields. Sewage sludge applications were not responsible for the elevated PO4–P leaching under SRC compared to reference crops.

Slow diuron release formulations based on clay–phosphatidylcholine complexes

Slow release formulations of the herbicide diuron were designed to reduce the risk of water pollution resulting from conventional formulations. The new formulations were based on herbicide incorporation in phosphatidylcholine (PC) vesicles that were sorbed on the clay mineral montmorillonite. The active ingredient contents of the formulations reached up to 28% w:w. Thermal analysis revealed that the closely packed arrangement of PC on the clay enhanced diuron sorption by disrupting the interactions among PC molecules. Adsorption experiments using diuron were performed in soils with different physico-chemical properties to evaluate the relationship between the sorption and the mobility of the herbicide. In soil column experiments with sandy soil, the herbicide in PC–clay-based formulations mainly accumulated in the top soil, and there was a one-third reduction in leaching compared to the commercial formulation. The differences in leaching (compared to the commercial formulation) were lower when using loam soil due to its higher sorption of the herbicide and hysteresis effects. In the sandy soil, bioassay experiments showed a higher herbicidal activity in the top-soil layer for the PC–clay formulations than for the commercial formulation. Therefore, PC–clay formulations of this herbicide can be used at lower doses than recommended, thereby reducing the environmental risks associated with the application of diuron formulations.

English

The present study was done to check the bioleaching feasibility of brown shale for the recovery of copper (Cu), aluminum (Al), magnesium (Mg) and manganese (Mn) ions using Ganoderma lucidum. Different experimental parameters were optimized for the enhanced recovery of metals ions. Effect of different substrates like glucose, molasses, saw dust and cotton seed cake on the recovery of metals ions was investigated under shaking as well as non-shaking conditions. Significant difference in leaching of metal ions by G. lucidum was observed under shaking and non shaking conditions. Maximum leaching of Al (90.7%), Mg (96.46%), Mn (66.3%) and Cu (73.45%) was observed using glucose under shaking conditions with 5, 3, 4 and 3% pulp densities respectively. The results show that maximum solubilization up to 68.89, 77.03 and 38.37% was achieved for Cu, Al and Mg ions respectively using molasses as substrate, whereas, 57.74% recovery of Mn was achieved with saw dust. The recovery of metal ions indicated that this low grade discarded ore may be a potential source of metal ions in future.

Toxic hazard and chemical analysis of leachates from furfurylated wood

The furfurylation process is an extensively investigated wood modification process. Furfuryl alcohol molecules penetrate into the wood cell wall and polymerize in situ. This results in a permanent swelling of the wood cell walls. It is unclear whether or not chemical bonds exist between the furfuryl alcohol polymer and the wood. In the present study, five different wood species were used, both hardwoods and softwoods. They were treated with three different furfurylation procedures and leached according to three different leaching methods. The present study shows that, in general, the leachates from furfurylated wood have low toxicity. It also shows that the choice of leaching method is decisive for the outcome of the toxicity results. Earlier studies have shown that leachates from wood treated with furfuryl alcohol prepolymers have higher toxicity to Vibrio fischeri than leachates from wood treated with furfuryl alcohol monomers. This is probably attributable to differences in leaching of chemical compounds. The present study shows that this difference in the toxicity most likely cannot be attributed to maleic acid, furan, furfural, furfuryl alcohol, or 2-furoic acid. However, the difference might be caused by the two substances 5-hydroxymethylfurfural and 2,5-furandimethanol. The present study found no difference in the amount of leached furfuryl alcohol between leachates from furfurylated softwood and furfurylated hardwood species. Earlier studies have indicated differences in grafting of furfuryl alcohol to lignin. However, nothing was found in the present study that could support this. The leachates of furfurylated wood still need to be

The diagnosis and correction of potassium deficiency in New Zealand pastoral soils: a review

Field-trial data from a database comprising records of 804 potassium (K) fertiliser trials were used to define the production functions relating exchangeable soil K (quick test K (QTK) 0–75 mm) to the relative response to fertiliser K applications, for the major soil groups in New Zealand. For all soil groups for which there were sufficient data, the production functions were generally flat in the range QTK 5–10, and thus the estimated relative pasture production at QTK 5 and QTK 10 were similar. The critical QTK levels to achieve 97% maximum production were relatively well defined, being 6 (5–8) for sedimentary soils (brown and pallic) and brown soils, and 7 (5–10) for pumice soils. The data for the allophanic soils were unstable and the best estimate was 6 (5–10). For the remaining soils groups (podzols and raw soils, organic, recent and gley soils) for which there was much less data, the relationships were essentially flat over the range QTK 2–10. The probability of pasture responses to applied K increased as soil QTK decreased from 10. For the sedimentary and volcanic soils (including both allophanic and pumice) the probability was about 70–80% at soil QTK < 2. The comparable probabilities were 50–60% for the recent and gley soils, and 30–43% for the podzols and raw soils. A feature of the response functions was that some trials were not responsive to fertiliser K despite having low soil QTK. In most cases this could not be attributed to soil K reserves as measured by the soil TBK test (sodium tetra-phenol-boron extractable which measures exchangeable K plus plant-available but non-exchangeable K). Other possible reasons for this feature in the data are discussed, including uptake of K from below the soil sampling depth and the temporal effects of clover responses to applied K. Soil K buffer capacities—the amount of fertiliser K over and above maintenance required to increase soil QTK by 1 unit (ΔK)—ranged from 50 to > 150 kg K ha−1 (average 124) for sedimentary soils. For some soils (developed organic soils, gleyed soils and podzols), fertiliser K had very little effect on QTK (0–75 mm). It is not clear whether these differences are due to differences in leaching of K from the sampling depth, differences between soils in their ability to absorb and retain applied K or indeed the result of errors in the measurement of this parameter. Estimated maintenance K requirements (i.e. the amount of applied K required to maintain soil QTK levels) increased with increasing soil QTK from 4 to 10, from 0–150 kg K ha−1 yr−1 to 100–300 kg K ha−1 yr−1 in situations where losses of K were extreme due to the removal of all harvested clippings. Given the uncertainties in predicting K responses and the amount of fertiliser K required to correct K deficiency, practical suggestions are offered as to how best to diagnose and manage soil K deficiency. Areas for future research to improve the prediction of pasture responses to fertiliser K are also included.

Leaching of nutrients and emission of greenhouse gases from peatland cultivation at Bodin, Northern Norway

Peatland drainage results in several environmental impacts such as release of greenhouse gas to the atmosphere and leaching of nutrients to watercourses. These hazardous environmental effects can partly be controlled with soil management, and different drainage and remediation practices. Grading is a new method developed for soils with low conductivity suffering from poor drainage, water logging and ice. The soil surface is graded towards the ditch to increase surface runoff and drainage. The present study compares environmental effects of peatland grading compared to traditional intense pipe drainage. Detailed measurements of hydrology, climate, leaching and gas emissions were carried out at adjacent drainage areas with grass cultivation. Additional measurements were made at plots that were abandoned, cultivated with perennial crops, and remained as pristine peatlands. The results show that the leaching of nutrients is highest from pipe drainage. Climate gas emission was considerably higher at all managed sites than from the reference pristine site. Drainage, soil hydrology and soil nutrient status seemed to control gas emissions. The gas emissions were higher than assumed for Norwegian cold conditions. The results confirm observations made on peat soils in other climatic regions. The highest emissions of CO 2 were observed when the soil temperature was high and groundwater table low. The N 2O emission showed a large variation with no clear pattern. However, at some locations it peaked after a dry period when NO 3–N was leached. More CH 4 was emitted from the intensively drained site than the graded site, but more CO 2 was emitted from the graded site. The difference in leaching and emission properties is partly due to differences in near surface hydrology. At grade sites, a faster runoff response to rainfall occur probably due to shallow throughfall or overland flow which provides better drainage. The abandoned peat field no longer in cultivation continued to leach greenhouse gases in a same way as the cultivated sites.

The single heterogeneous paddock approach to modelling the effects of urine patches on production and leaching in grazed pastures

Despite the fact that urine patches within grazed paddocks are the primary source of N leaching, virtually all pastoral simulation models assume a uniform spatial return of urinary-N to the soil. This simple spatial averaging might not be appropriate if the aim of the modelling is to explore leaching losses because of the non-linearity caused by the high N concentration in urine patches. Here we describe the single heterogeneous paddock (SHP) approach to modelling the dynamics of N in pastoral systems. We also examine the potential for manipulating rate parameters in a simpler uniform-return model (URM) to compensate for the lack of explicit description of urine patches. Comparison of simulation results from the URM and SHP showed some differences in the patterns of production and a substantial difference in leaching. Depending on soil and climate simulated, there was 5–30% higher pasture production in the URM because simulated leaching in the URM was 5–85% of that simulated by the SHP. Examination of the ratio of the outputs from the two models revealed that the differences in pasture production and N fixation in the URM could probably be corrected with a change in parameter values. This was not true of leaching where there was considerable variation and skew in the ratios, so at the very least, any correction factor would be highly soil and climate specific. We suggest that models of grazed grass–legume systems can probably adequately simulate production with a simple URM but that the simulation of leaching requires an explicit representation of the heterogeneous urine return. The SHP approach is one methodology for this but this has implications for model and software complexity and for model run-time duration.

Wildfire Effects on Soil Nutrients and Leaching in a Tahoe Basin Watershed

A wildfire burned through a previously sampled research site, allowing pre- and post-burn measurements of the forest floor, soils, and soil leaching near Lake Tahoe, Nevada. Fire and post-fire erosion caused large and statistically significant (P < or = 0.05) losses of C, N, P, S, Ca, and Mg from the forest floor. There were no statistically significant effects on mineral soils aside from a decrease in total N in the surface (A11) horizon, an increase in pH in the A11 horizon, and increases in water-extractable SO4(2-) in the A11 and A12 horizons. Burning caused consistent but nonsignificant increases in exchangeable Ca2+ in most horizons, but no consistent or statistically significant effects on exchangeable K+ or Mg2+, or on Bray-, bicarbonate-, or water-extractable P concentrations. Before the burn, there were no significant differences in leaching, but during the first winter after the fire, soil solution concentrations of NH4+, NO3-, ortho-P, and (especially) SO4(2-) were elevated in the burned area, and resin lysimeters showed significant increases in the leaching of NH4+ and mineral N. The leaching losses of mineral N were much smaller than the losses from the forest floor and A11 horizons, however. We conclude that the major short-term effects of wildfire were on leaching whereas the major long-term effect was the loss of N from the forest floor and soil during the fire.

The leaching of chromium from cement-based waste form via a predominantly biological mechanism

An evaluation of the leaching of chromium from 100% cement waste forms was carried out in this study using a refined biofilm formation method. Approximately 50% of the total chromium was leached from the experimental sample (exposed to bacterial broth of pH∼2.00) within the first 24 h of evaluation. No chromium was detected in the effluent of the control sample (exposed to sterile medium chemically acidified to give pH comparable to that of bacterial broth) within the same period. An increase in the duration of the first stage of the process from 24 h to 3 days did not result in the release of chromium from the control. Comparative evaluation for the leaching of calcium gave results that contrasted sharply with those obtained for chromium. Similar levels of calcium were leached from both control and experimental samples within the first 24 h of evaluation. Evaluations carried out at elevated levels of chromium in the waste form did not result in any change in trend for both calcium and chromium. A predominant biological mechanism involving active mobilization of chromium from the matrix is suggested for the difference in leaching of chromium from control and experimental waste forms.

Soil patterns in weathering, clay translocation and podzolisation on hilly and steep land at port underwood, Marlborough Sounds, New Zealand: Classification and relation to landform and altitude

Six soil profiles ranging in altitude from 30 m to 580 m at Port Underwood in the Marlborough Sounds, New Zealand, are described, classified and discussed in terms of their morphology, chemistry and mineralogy. The soils are formed from greywacke on hilly and steep land under a climate ranging from mild and humid at lower elevations to cool and superhumid at the highest elevation. The profiles show distinct altitudinal patterns in weathering, clay translocation, leaching and podzolisation. Differences in weathering are related mainly to geomorphic history, whereas differences in leaching and podzolisation are attributed mainly to the effects of climate. Weathering has been strongest at altitudes below about 200 m where the soils are dominated by kaolinitic clay minerals. Parent materials were probably inherited from Late Pleistocene interglacial or interstadial weathering. At higher altitudes less weathered soils containing mainly vermiculite clays are formed from parent materials exposed by widespread periglacial erosion and deposition during the last glaciation, and from periodic erosion and deposition during the Holocene. Clay translocation, as evidenced by the presence of argillic horizons, has been most active at lower altitudes where the soils are older and the climate is drier than at higher elevations. Field and laboratory data show that the 2 profiles at the highest elevation are podzolised. They have substantial accumulations of illuvial amorphous minerals and mineral-organic complexes in subsoils, and one profile also has morphological eluvial features with an underlying placic horizon. Neither the New Zealand Genetic Classification nor Soil Taxonomy satisfactory classifies the podzolised soils. We think that they would be better classified as Spodosols or as spodic subgroups of Inceptisols.

Guayule seedling response to nitrogen fertilizers

Slow growth and high seedling mortality limit direct seeding establishment of guayule (Parthenium argentatum G.). This study was conducted to assess seedling growth enhancement by the addition of different rates and forms of N fertilizers and Ca salts. Experiments were conducted in a greenhouse with cultivar 593 under both surface and subirrigated conditions using water low in salts (salinity of 0.8 dSm−1, SAR of 5.0 and 10 mg Ca L−1). Under surface-irrigated conditions, seedling height and fresh plant weight increased with N application to the irrigation water to 70 mg L−1. The best seedling growth was observed when (NH4)2SO4 was added in combination with CaCl2 or CaSO4. Progressively less growth was observed by addition of (NH4)2SO4 alone, CO(NH2)2 plus CaSO4, CO(NH2)2 alone and Ca(NO3)2. When seedlings were subirrigated, however, the best growth was observed with Ca(NO3)2. Intermediate growth was obtained with (NH4)2SO4 plus CaSO4 and lowest growth rates with (NH4)2SO4 alone. These differential responses may be explained by the differences in leaching and volatile characteristics of the N forms. Growth enhancement from N and Ca additions increased with time with significant increases 45 days after seeding. Nitrogen application with Ca may be effective amendment in promoting subsequent growth of direct seeded guayule.

Solute displacement in a silt loam soil as affected by the method of water application under different evaporation rates

To study the displacement and redistribution of surface applied salts as affected by continuous and intermittent ponding, three separate experiments were conducted on a silt loam soil during periods of varying atmospheric evaporativity. The USWB class A pan values during the successive study periods averaged 1.52, 7.74 and 4.51 mm/day and a total of 15, 22.5 and 40 cm water was used for leaching, respectively. In the case of intermittent ponding, water was applied at 10-day intervals in equal splits of 7.5 or 10 cm depth. No difference in leaching of chloride was observed when the same amount of water was applied continuously or intermittently during the periods of high (7.74 mm/day) and medium (4.51 mm/day) evaporation rates. However, when evaporation at the surface was prevented or remained low (1.52 mm/day), distinctly greater amounts of chloride were removed from the soil and the salt peak was displaced deeper under intermittent as compared to continuous ponding. Preferential movement of water through macropores in relation to micropores during leaching resulted in low mobility of surface applied chloride relative to that of water.

The Influence of Embryo Condition on the Leaching of Solutes from Pea Seeds

Differences in the leaching of solutes from different seed lots of peas were found to be associated with the condition of the embryos and not the testae. Seeds with areas of dead tissue on the abaxial surfaces of their cotyledons exhibited the highest levels of leaching but the large range of levels found among seed lots resulted from differences in leaching from living tissue. When dry embryos were placed in water a rapid decline in the leaching of solutes was seen over the first 30 min for all lots tested but differences between lots were seen from the first minute in water and were related to the ability of the embryos to retain solutes rather than their solute content. Differential retention of solutes by the cytoplasm and sensitivity to the damaging effects of rapid imbibition are both discussed as possible explanations for differences in leaching.