Based on laboratory studies with lysimeters, the concentrations of dissolved reactive phosphorus(DRP) and particulate phosphorus, which is the main part of other P (OVRP), has been studied inpercolating water. The experiment was conducted through irrigation of small soil columnscontaining clay topsoil from an experimental field in Västergötland. Three rain simulations wereconsecutively performed. DRP concentrations in the percolating water ranged between 0.2 - 0.3mg·L -1 . The amount of DRP percolating from four soils with different fertilization history wasclearly related to the phosphorus concentration in the soil, measured in a soil extract ofammonium lactate (P-AL). Concentrations of OVRP were relatively low and ranged between0.12 and 0.16 mg·L-1 in the percolating water passing through the topsoil. Any macropore flowwas not proven and the experiment may reflect how a relatively slow percolation of water mayrelease DRP. In contrast, from observed fields with drainage systems quite high concentrations ofOVRP are typically recorded. This is generally explained by fast flows through macropores in thesoil and through the drain tile systems. Solid manure was applied to the lysimeters equal to a normal agricultural load (30 tons per ha),and thereafter another three rainfall were simulated. The load of manure increased the leaching ofDRP approx. 7 times. The largest increase was observed from the soils with the highest P-AL-numbers. The relative boosts of DRP after manure application increased linearly relative to the P-AL number of the soil and with a high correlation coefficient. Thus the results from the manureaddition indicated that the soil with highest phosphorus concentrations released proportionallymore phosphorus than soils with low P-AL numbers. The studies demonstrate the importance ofadjusting the load of manure to the soil phosphorus content. Presently the spreading of manure isonly restricted by the number of cattle/cultivated land, not to the P-AL number of the soil.

No description available.

Thesis (MScAgric)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: In the humid Graskop region of Mpumalanga Province, South Africa, there is an anomalous body of highly weathered black, manganiferous oxisols derived from dolomite. With Mn contents as high as 17%, potential large-scale Mn release is an environmental concern under current, acid generating, forestry practices. This study aims at establishing the factors which may affect the stability of the manganiferous oxisols of Graskop and in the process, investigating some of the morphological, mineralogical and chemical properties of these unique soils. Typically, the soils show a reddish, nodule-rich horizon, containing 3-4% Mn, grading through a red and black mottled zone into a black (5YR 2.5/1) apedal subsoil with >7% Mn. The Mn gradient down the profile as well as the abundant nodule content of the upper subsoil horizons implies that Mn mobilization and redistribution are active pedogenic processes. The exceptional Mn content of these soils is complemented with Fe and Al concentrations of up to 10 and 8%, respectively, and anomalously high trace element levels in particular Ni and Zn (as high as 541 and 237 mg kg-1, respectively) which are at the upper limit of cited world natural maxima for soils. The Mn mineral lithiophorite [(Al,Li)MnO2(OH)2], dominates the mineralogy of the soils with accessory amounts of birnessite, gibbsite, goethite, hematite, maghemite, kaolinite, aluminous chlorite and mica - a mineral suite reflecting that of well weathered soils. With the pH of the soil being at or close to the point of zero charge (4.5-5.5) the soils show isoelectric equilibrium. The very low buffer capacity results in metal dissolution commencing with the first increment of titrated acidity. Manganese dissolution is relatively minor considering the large potential for release and is highly overshadowed by Al release. The apparent resilience of the Mn phase to added acidity may relate to the overwhelming poise of the soils which maintains robust, oxic conditions despite the usual instability of Mn oxides at low pH. Manganese release and soil redox properties are substantially affected by drying especially in the organic rich topsoils. Using various redox analyses, evidence is shown for involvement of Mn(III)-organic complexes in the drying reactions. Using this and information gained in a real time, attenuated total reflectance Fourier transform infrared(ATR-FTIR) spectroscopic study, a mechanism is suggested which may account for the observed Mn release and the loss of Cr oxidising capacity commonly observed in dried soils. The information provided by the ATR-FTIR study showed the decrease in surface pH of a clay film, from 5 to below 2, as well as the shift in coordination nature of sorbed oxalate from a more outer-sphere association to a more inner-sphere association concomitant with the removal of free water from the clay surface. This spectroscopic evidence for these chemical changes which accompany surface drying not only provides further insight into the reactions involving Mn oxides in soils but also highlights the suitability of ATR-FTIR for real time, in situ investigation into the chemistry of the drying water interface. From these results it is concluded that Mn release from the manganiferous oxisols, under acid generation of the kind known to occur in pine plantations, is less that anticipated. On the other hand, desiccation of the topsoil results in substantial Mn release with a suggested mechanism which involves a Mn(III) intermediate. / AFRIKAANSE OPSOMMING: ‘n Onreelmatige grondliggaam van hoogs verweerde, swart, mangaanhoudende oxisols wat uit dolomiet ontwikkel het, word in die humiede Graskop streek van die Mpumalanga Provinsie van Suid-Afrika aangetref. Die hoë Mn-inhoud (tot 17%) van hierdie oxisols is van groot omgewings-belang weens die potensiële grootskaalse Mn-vrystelling onder huidige, suur-genererende bosbou praktyke. Hierdie studie beoog om die faktore wat die stabiliteit van die mangaanhoudende oxisols van Graskop affekteer, vas te stel. Tesame hiermee word die morfologiese, mineralogiese en chemiese eienskappe van hierdie unieke gronde ondersoek. Kenmerkend van hierdie gronde is ‘n rooi, nodule-ryke horison met 3-4% Mn aan die oppervlakte. Bogenoemde horison verander met toename in diepte in ‘n rooi en swart gevlekte sone wat weer in ‘n swart (5YR 2.5/1) apedale ondergrond met >7% Mn oorgaan. Die Mn gradiënt in die profiel sowel as die hoë nodule-inhoud van die boonste grondhorison dui daarop dat Mn-mobilisasie en -herverspreiding huidige aktiewe pedogenetiese prosesse in die profiele is. Fe en Al, met konsentrasies van 10% en 8% onderskeidelik, word saam met die onreelmatig hoë Mn inhoud aangetref. Baie hoë vlakke van Ni en Zn (so hoog as 541 en 237 mg.kg-1 onderskeidelik) wat hoër is as aangehaalde wêreld natuurlike maksimum waardes, word ook aangetref. Die mineralogie van die gronde word deur die Mn mineraal litioforiet [(Al,Li)MnO2(OH)2] gedomineer. Bykomstige hoeveelhede van birnessiet, gibbsiet, goethiet, hematiet, maghemiet, kaoliniet, aluminiumryke chloried en mika word ook aangetref. Hierdie minerale samestelling is kenmerkend van hoogs verweerde gronde. Met die pH van die grond in die omgewing van die punt van geen lading (4.5 – 5.5), word ‘n iso-elektriese ekwilibrium by die gronde aangetref. Die baie lae bufferkapasiteit het metaal-oplossing aangehelp wat met die eerste inkrement van titreerbare suurheid ‘n aanvang geneem het. Mangaan-oplossing is baie klein indien die groot potensiaal vir vrystelling asook die groot mate van Al-vrystelling in ag geneem word. Die skynbare teenwerking van die Mn fase tot toegevoegde suurheid, mag toegeskryf word aan diesterk ewewig van die gronde om sterk, oksiese kondisies, ten spyte van die normale onstabiliteit van Mn oksiedes by lae pH, te onderhou. Mangaan vrystelling en grond redoks eienskappe word beduidend deur uitdroging beïnvloed en veral in die organies-ryke bogronde. Deur van verskeie redoks analises gebruik te maak is daar bewyse van die betrokkenheid van Mn(III)-organiese komplekse in die uitdroging-reaksies gevind. Dit. en data ingesamel in ‘n “real time, attenuated total reflectance Fourier transform infrared (ATR-FTIR)” spektroskopiese studie, is gebruik om ‘n meganisme voor te stel wat die waargenome Mn vrystelling en die verlies aan Cr oksidasie kapasiteit (algemeen waargeneem in droë gronde) te kan verklaar. Die data verkry met die ATR-FTIR studie het ‘n afname in oppervlak pH van 5 na 2 van ‘n klei film asook die verskuiwing in koördinasie toestand van die gesorbeerde oksalaat van ‘n meer buite-sfeer assosiasie tot ‘n meer binne-sfeer assosiasie, gepaardgaande met die verwydering van vry water van die klei oppervlaktes, uitgewys. Die spektroskopiese bewyse vir die chemiese veranderinge wat die oppervlak uitdroging vergesel, gee nie net meer insig in die reaksies rakende Mn oksiedes in gronde nie maar onderstreep ook die toepasbaarheid van die ATR-FTIR vir intydse (“real time”), in situ ondersoeke na die chemie van die uitdrogende water kontakvlak. Vanuit hierdie resultate kan afgelei word dat Mn vrystelling vanuit mangaanhoudende oxisols onder suur genererende denne plantasies laer is as wat verwag is. Aan die ander kant sal uitdroging van die bogrond tot aansienlike Mn vrystelling, met ‘n verwagte meganisme wat Mn (III) as intermediêre toestand insluit, lei.

Measurement of water is important in soil since this is the medium in which soil activity takes place. Pressure-saturation curves show the extent of liquid retention in the soil porous medium at different tensions during drainage and sorption (hysteresis). Measurement of soil moisture in the laboratory is time-consuming, labor-intensive and expensive. In this study, three methods for measuring pressure-saturation curves were employed, Hanging Water Column (HWC), Differential Pressure Transducer-Imbibition, and Differential Pressure Transducer-Natural. The standard HWC is compared to the other two methods which employ external manometer pressure and differential pressure transducers. Hysteresis pressure-saturation curves were determined for three liquids (water, 50% ethanol and 100% ethanol), in a homogeneous Vinton fine sand. Data was fit to the van Genuchten and Brooks Corey models and liquid capillary numbers are compared. Prediction of desorption pressure-saturation curves from water curves using relative surface tension ratios is discussed and prediction of sorption curves using relative A parameters for the drying and wetting curves. Scanning curves were scaled from the main drying and wetting curves. The capillary number-pore water velocity combination function could be another useful relationship for pressure-saturation curves. Overall, the differential pressure transducer methods were found superior to the HWC because time consumption was reduced by more than 50% yet the results obtained were of comparable accuracy. Pressure-saturation curves for other liquids may be predicted by scaling pressure and van Genuchten alpha parameter with relative surface tension ratios. Hence, hysteresis curves can be obtained faster and the main disadvantages of time-consumption, labor and cost are eliminated. In addition, handling of hazardous liquids in the laboratory is minimized which is important because understanding retention of hazardous chemicals in soil is a prerequisite to achieving remediation of residual contamination. Functional relationship between the residual nonwetting phase and the capillary number or viscosity to surface tension ratio is briefly discussed.

The occurrence and disinfectant effectiveness for pathogens which are known or thought to be important in waterborne disease was evaluated. In the first study, the occurrence of human pathogenic microsporidia, Giardia cysts and Cryptosporidium oocysts in surface waters used for the irrigation of vegetable crops was determined. Twenty-eight percent of the irrigation water samples tested positive for microsporidia, 60% positive for Giardia cysts and 36% positive for Cryptosporidium oocysts. Concentrations of Giardia cysts and Cryptosporidium oocysts detected in water samples collected in Central America compared to the United States were 559 cysts and 227 oocysts, and 25 cysts and < 19 oocysts per 100 L, respectively. The presence of human pathogenic parasites in irrigation waters used for production of crops traditionally consumed raw suggests that there may be a risk of infection to consumers who come in contact with or consume these products. In the other investigations, the effectiveness of UV light and free chlorine on the inactivation of feline calicivirus (FCV) and enteric adenovirus type 40 (AD40) was assessed and compared to model viruses, poliovirus type 1 (PV-1) and coliphage MS-2. FCV was used as a model for members of the "Norwalk like virus" (NLV) group. The UV doses required to achieve 99% inactivation of AD40, coliphage MS-2 and FCV in buffered demand free (BDF) water were 108.6, 58.5 and 16.8 mWs/cm², respectively. For chlorine reactions, higher Ct values for high pH and low temperature conditions was observed for FCV and AD40. Both viruses were more resistant to chlorine than the well-studied PV-1. FCV and AD40 were inactivated rapidly by ∼0.5 mg/L free chlorine by ≥4.00- and ≥2.54-logs at pH 6 and 5°C whereas, PV-1 was not inactivated by 4.04-logs until 10 min contact time. Experiments conducted with aggregated FCV and PV-1 and experiments conducted in treated groundwater had slower inactivation kinetics than dispersed viral suspensions in BDF water. The high disinfectant decay rate of some experiments was most likely due to the decrease in chlorine concentration throughout the experiment. However, low disinfectant decay rates of the AD40 experiments suggest that aggregation or clumping of the viruses may have occurred. The results of these studies provide information on the effectiveness of two common water treatment disinfectants in waters with different physical and chemical qualities. The results of this study may provide a basis for the establishment of guidelines for proficient application in drinking water treatment.

<p>It is estimated that 22 000 contaminated areas exist in Sweden today. In order to classify the risk of contaminant migration from these areas and to prioritize which of these contaminated areas should first be treated, the Swedish Environmental Protection Agency (EPA) has designed a method, for the investigation of contaminated areas (MIFO). One of these contaminated areas is the landfill Gräsötippen outside Köping. The landfill has been used by both Yara AB and the Köping municipality between the years 1945 and 1975, and both industrial and household waste have been deposited there. The aim of this report is to survey which contaminants that can be found in the soil and water in the landfill Gräsötippen and to evaluate the migration of these contaminants. With help of this information, the landfill will then be risk classified according to MIFO. The goal is that this report will provide a basis for future studies and remedial measures at the landfill.</p><p>To get a picture of what has been deposited at the landfill Gräsötippen, employees and former employees at Yara and others with connection to the landfill have been interviewed. Piezometers have been installed in and around the landfill so as to provide information on groundwater levels and movement, and for the collection of groundwater samples. Soils samples were collected as well. The water and soil samples were analyzed with regard to metals, organic compounds and nutrients. Furthermore, groundwater flow has been modeled using VS2DI, in order to get a picture of the groundwater’s flow direction and velocity under the landfill.</p><p>In the water samples, only lead was detected with levels over the Maximum Contaminant Level (MCL) from the EPA. Relatively high levels of nutrients were also detected. In the soil, carcinogenic PAH, PCB, aliphatic hydrocarbons, aromatic hydrocarbons, arsenic, lead, cadmium, mercury and zinc were detected over the EPA MCL. The landfill Gräsötippen has a good location in an area with deep clay, which prevents rapid spreading of contaminants. No high levels of contaminants are leaching out today. The spreading of the contaminants is minor; most of the contaminants are fixed in the soil and do not spread to the surroundings. The water flow’s primary direction from the landfill is south but there are also flows to the west and east. Today, there are a number of proposals with regard to decreasing the risk for future contaminant dispersal from the landfill and to keep control of the water that is used in the area. A few of these proposals are to finally cover the landfill, to analyze the grass and plants in the enclosed pasture on the landfill, and to continuously analyze the water in the installed piezometers and drinking water wells on and around the landfill. The landfill Gräsötippen is classified to risk class 3, moderate risk, according to MIFO.</p> / <p>Det uppskattas idag finnas 22 000 förorenade områden i Sverige. För att kunna riskklassa dessa förorenade områden och prioritera vilka som först bör efterbehandlas har Naturvårdsverket utarbetat en Metodik för Inventering av Förorenade Områden (MIFO). Gräsötippen utanför Köping är ett av dessa förorenade områden. Deponin har använts av både Yara AB och Köpings kommun mellan åren 1945-1975 och fungerat som deponi för både industri- och hushållsavfall. Syftet med denna rapport är att kartlägga vilka föroreningar som finns i mark och vatten i Gräsötippen och tolka föroreningarnas spridning. Utifrån den informationen ska deponin sedan riskklassas enligt MIFO. Målet är att rapporten ska kunna fungera som underlag för framtida åtgärdsplaner för Gräsötippen.</p><p>För att få en bild över vad som har deponerats på Gräsötippen har anställda och före detta anställda vid Yara samt andra som har haft anknytning till Gräsötippen intervjuats. Grundvattenrör har installerats i och runtom deponin för att det skulle kunna tolkas hur grundvattnet rör sig under deponin och för att det skulle kunna tas prover på grundvattnet och jorden. De vatten- och jordprover som togs, analyserades med avseende på metaller, organiska föreningar och närsalter. Dessutom har en modellering utförts i VS2DI för att få en bild över grundvattnets flödesriktning och hastighet under deponin.</p><p>I vattenproven detekterades endast bly över Naturvårdsverkets riktvärde samt relativt höga halter av närsalter. I jorden detekterades cancerogena PAHer, PCB, alifater, aromater, arsenik, bly, kadmium, kvicksilver och zink över Naturvårdsverkets riktvärden. Gräsötippen är bra placerad i ett område med tjock lera som förhindrar snabb spridning och idag lakas inga höga halter av föroreningar ut. Spridningen av föroreningar är liten, istället ligger de flesta föroreningarna fast i marken och sprids därmed inte till omgivningen. Vattenflödets huvudriktning från deponin är söderut, men det sker även flöden åt både väster och öster. Det finns i dagens läge en del förslag på åtgärder som bör utföras på Gräsötippen för att minska risken för framtida spridning och upprätthålla kontroll på det vatten som används i närområdet. Några av dessa åtgärder är att sluttäcka deponin, att analysera gräs och växter i hagen på deponin samt att kontinuerligt analysera vattnet i grundvattenrören och brunnarna på och runt Gräsötippen. Vid riskklassningen av Gräsötippen enligt MIFO, klassas den till riskklass 3, måttlig risk.</p>

Calcium carbonate, calcite, and magnesium carbonate, magnesite, form a series of solid solutions with compositions ranging 0 to 50% magnesite which is dolomite the end member of the series. The calcite magnesite solid solutions are called magnesian calcites (Mg-calcites). Mg-calcites exist in nature, in soils, in marine skeletal materials, in some marine cements, etc., and their existence has been associated with the supersaturation of calcite in sea water and the soil solution of some calcareous soils. They are clearly more soluble than calcite, but their chemical properties has not been defined. This paper examines the basic chemistry of the Mg-calcites and develops a theoretical model derived from the regular solution model and based on classical equilibrium thermodynamics. This model can be used to predict solubility and explain the behavior of the Mg-calcites.

Laser light scattering (LLS) is an alternate method for determining soil particle size. Since the majority of information on particle size analysis has traditionally been derived from sedimentation methods, it is important to be able to draw a relationship between these two methods. Twenty four soil samples from a set of 214 samples analyzed by LLS were selected and also analyzed using sedimentation techniques. Particle size percentages were obtained in five different size ranges and then these two techniques were compared. Linear regression equations were developed that convert numbers obtained from the LLS method to a pipette analysis equivalent. This data was then utilized to eliminate the variation of soil moisture due to soil texture to obtain a moisture content independent of soil moisture. This "adjusted moisture" was displayed on a geographic information system to locate areas in the soil profile where soil moisture is relatively high. The high "adjusted moisture" contents occurred predominately below 2.44 meters (8 ft.) depths suggesting that the pre-irrigation applied to this soil reached this depth.

Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1978.

The working hypothesis for this study was that small elevation differences in field depressions affect the availability of redox active nutrients because the bottom of the depression remains waterlogged and in reducing conditions longer than the edge of the depression. Mn, Fe, S and P availabilities were investigated in a field depression with a 20 meter radius and 0.5 meter depth on a flood-prone, organic vegetable farm. One depression (Depression 1) was sampled seven times during three field seasons (May 2012-June 2014). The last two dates included sampling in an additional three depressions to allow a comparison among depressions on the same date. Sampling dates were categorized by the severity of flooding into the three following kinds of events: Post-Irene, Peak, and Non-Peak. The Post-Irene category includes sampling dates in the agricultural season following prolonged snow melt and flooding from Tropical Storm Irene in 2011. Sampling dates in the Peak category occurred within 30 days after one of the the top 12 greatest rainfalls, snowfalls, or heights of Winooski River Gage in the 30 month sampling period. Sampling on Non-Peak events occurred at least one month after a preceding Peak event. Repeated waterlogging events can increase redox cycling directly affecting the interchange of Mn, Fe, and S oxides and the soil solution. Indirectly, waterlogging can increase phosphorus release into the soil solution by reduction of iron. The results of this experiment indicate that some redox-sensitive soil nutrients correlated with elevation on some dates regardless of event type. Mn was more consistently affected by waterlogging events than Fe and S. Any relationship between sulfur and elevation may have been obscured by the strong relationship of sulfur with organic matter. This data suggests that phosphorus availability depended to some extent on available iron concentration.