LD2668 .T4 1954 T51 / Master of Science

Thesis (MScAgric)--Stellenbosch University, 2001. / ENGLISH ABSTRACT: The Eksteen method of lime requirement determination, based on the ratio of Ca+Mg:H (R-value), is widely used in the Western Cape and has proven to be extremely accurate for most soils. However, the Eksteen method is known to give erroneous predictions of lime requirement for certain soil groups. These include sandy soils (notably pale coloured sandy soils), organic-rich topsoils and strongly structured, Mg-rich subsoils. The objective of this study was to examine the nature of the Eksteen RpH relationship for these problem soils, and to develop appropriate modifications to the Eksteen method, where possible. A population of both normal and problem soils was selected and analysed, the RpH relationships of the soils were determined, and various relationships were examined. The principal findings with regard to the nature of the Eksteen RpH relationship were as follows: 1. The lime requirements of pale coloured sandy soils can be most accurately determined on an equivalent basis relative to the total extractable acidity, after the total extractable acidity has been corrected for residual lime. 2. The previously observed and acknowledged inaccuracy of the Eksteen method on organic-rich soils stems from the pH-dependant acidity component of the organic matter. The accuracy with which the lime requirement of these soils is predicted by the Eksteen method can be greatly improved by the application of an organic matter correction factor (OMCF) to the total extractable acidity, which is the parameter on which the lime requirement is then based. 3. In structured, Mg-rich subsoils the pH-neutralising capacity of Mg is considerably lower than that of Ca, a factor which is not taken into account by the Eksteen method. The Eksteen method can nevertheless be corrected to overcome this discrepancy. The high levels of Mg in the structured, Mg-rich subsoils cannot be attributed to minerals in these subsoils containing brucite interlayers. 4. Toxic levels of AI may only be expected at soil pH values below approximately 4.7 as determined in 1M KC!. Soil organic matter and CEC have marked affects on AI extractability. In accordance with the objective that appropriate modifications to the Eksteen method should be developed if possible, theoretically-based correction factors were developed which will permit the use of the Eksteen method to be confidently extended to those soil groups (pale coloured sandy soils, organicrich topsoils and strongly structured, Mg-rich subsoils) for which it was formerly considered unreliable. / AFRIKAANSE OPSOMMING: Die Eksteen metode van kalkbehoeftebepaling, gebaseer op die verhouding van Ca+Mg:H (R-waarde), word oor die algemeen wyd in die Wes-Kaap gebruik en is baie akkuraat vir meeste gronde bewys. Dit is egter bekend dat die Eksteen metode verkeerde kalkbehoeftes vir sekere grondgroepe voorspel. Hierdie sluit sanderige grande (veral lig gekleurde sandgronde), organiesryke bogrande en sterk gestruktuurde, Mg-ryke ondergronde in. Die doel van hierdie studie was om die aard van die Eksteen R:pH verwantskap vir hierdie probleemgronde te bepaal, waar moontlik. 'n Populasie van beide normaal en probleemgrande is geselekteer en geanaliseer, die R:pH verwantskap van die grande is bepaal en verskeie verwantskappe is ondersoek. Die hoof bevindinge ten opsigte van die aard van die Eksteen R:pH verwantskap was as volg: 1. Die kalkbehoefte van lig gekleurde sandgronde kan akkuraat bepaal word op 'n ekwivalente basis, relatief tot die totale ekstraheerbare suurheid, nadat die totale ekstraheerbare suurheid gekorrigeer is vir residuele kalk. 2. Die voorheen bekende onakkuraatheid van die Eksteen metode op organiesryke gronde het sy oorsprong by die pH-afhanklike suurheid komponent van organiese material. Die akkuraatheid waarmee die kalkbehoefte van hierdie grande met behulp van die Eksteen metode voorspel kan word, kan noemenswaardig verbeter word deur die totale ekstraheerbare suurheid te korrigeer met behulp van 'n organiese materiaal korreksie faktor (OMKF). Die aangepaste totale ekstraheerbare suurheid is dan die parameter waarap die kallkbehoefte gebaseer word. 3. In gestruktuurde, Mg-ryke ondergrande is die pH-neutraliseringsvermoe van Mg aansienlik laer as die van Ca, 'n faktor wat seide in berekening gebring word by die Eksteen metode. Die Eksteen metode kan tog gekorrigeer word om hierdie tekortkoming te oorkom. Die hoe vlakke van Mg in gestruktuurde, Mg-ryke ondergrande kan nie aan die teenwoordigheid van minerale in die ondergrond, wat brusiet tussenlae bevat, toegeskryf word nie. 4. Toksiese AI vlakke sal alleenlik by grond pH waardes laer as ongeveer 4.7, soos bepaal in 1M KCI, verwag word. Grand organiese materiaal en KUK het 'n noemenswaardige effek op ekstraheerbare AI. In ooreenstemming met die doelwitte om toepaslike wysigings aan die Eksteen metode aan te bring, is teoreties gebaseerde korreksiefaktore ontwikkel, wat die gebruik van die Eksteen metode verder verbreed om daardie grondgraepe (lig gekleurde sanderige grande, organies-ryke bogrande en sterk gestruktuurde, Mg-ryke ondergrande) in te sluit waarvoor dit vantevore as onbetraubaar beskou is.

Soil acidity is a major land degradation problem that limits crop production globally. The high cost of traditional liming materials (calcitic limestone, dolomite etc.) and the vast areas of land that require liming have led to the exploratory utilisation of alkaline industrial by- products such as fly ash and stainless steel slag. The liming potential and effects of liming with fly ash (from the Duvha power station) and processed stainless steel slag (Calmasil) on two acid soils were investigated in this study. The quality of fly ash and Calmasil as liming materials and their potential impacts on the soil quality and plant growth were investigated. The effects of liming with these materials on soil pH, EC, extractable Al, Mn, base cations and trace elements were investigated in an incubation experiment. A glasshouse trial was conducted to assess the effects of these materials on the growth of an acid intolerant crop, perennial rye grass. The incubation and glasshouse study were of a factorial design with two acid soils (the Avalon and Inanda soils), three materials (fly ash, Calmasil and lime); and five application rates of 0, 50, 100, 200 and 400% of the recommended optimum liming rate (OLR) for the growth of perennial rye grass. Characterization of fly ash showed that the major elements (>5%) present (Si > Al > Fe) are not comparable to lime (Ca > Si > Mg) and that it has a low liming potential (calcium carbonate equivalence (CCE) of 9.6%) in comparison to lime. The chemical composition of Calmasil is comparable to lime with Ca > Si > Mg as the major elements and it has a very high liming potential (CCE = 97%). The incubation experiment showed that adding fly ash and Calmasil increased the pH of both soils. However, at the optimum liming rate (100% OLR), only the treatment with Calmasil in the Avalon soil attained pH levels within the desired pH range. Extractable Al and Mn decreased with addition of fly ash and Calmasil to levels comparable to lime in the incubated soils. Addition of fly ash and Calmasil also increased the extractable base cations of both soils. The yield-response of perennial rye grass to treatments in both soils was in the following order: fly ash > Calmasil > lime. Application of fly ash at > 200% OLR in the Avalon soil caused injury of ryegrass. Application of fly ash and Calmasil at lower rates has great agronomic potential in ameliorating soil acidity. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.

No description available.

No description available.

Reclaimed surface mined soils in Appalachia are typically infertile and must be amended for optimum vegetative growth. Fluidized bed combustion residue (FBCR), a by-product of coal-fired power plants, has high levels of Ca, S, Zn, Fe, and Al, and 50% of the neutralizing capacity of limestone. Three treatments were applied to three replicated .81 ha reclaimed mine pastures: control (no amendment), 6760 kg FBCR/ha, and 3380 kg limestone/ha. Based on forage availability, six steers were rotationally grazed on pastures receiving each treatment. Steers were weighed and blood samples collected at 14-d intervals and all animals were sacrificed for tissue sampling at the end of the 114-d trial. Amendment with FBCR or limestone increased soil pH (P < .05) above control levels. Forage yield and steer gain were not significantly affected by treatment. Forage samples collected during the trial indicated that FBCR and limestone amendments elevated forage ash, Ca, Mg, S, Cu and Ca:P ratio (P < .05). Cellulose and NDF were depressed in forage grab samples collected from FBCR- and limestone-amended pastures. The forage sampled the following spring was lower in hemicellulose, Zn, un and Ni; and higher in ash, Ca, S, the Ca: P ratio in the FBCR- and limestone-amended pastures. Mean serum mineral levels of steers were not affected by pasture treatment. The blood packed cell volume was higher in cattle grazing FBCR-amended pastures. Liver levels of Fe, H, Hi and Na were lower in cattle on pastures amended with FBCR or limestone. Bile levels of Mn were depressed in cattle grazing FBCR~ and limestone-amended pastures. The level of Cu in the liver and serum was at deficiency levels and was not detectable in bile, regardless of treatment. Higher kidney levels of Ca, Hg and P were recorded for steers grazing FBCR- and limestone-amended pastures. Hair Zn was higher in cattle grazing the FBCR- and limestone- treated pastures. Rib Cr and long bone Cd levels were lower in animals grazing the limestone- and FBCR-treated pastures. This study suggests that FBCR amendment enhances nutrient quality of forage and mineral status of animals at least as well as limestone application to acidic reclaimed mine pastures. / Ph. D. / incomplete_metadata

The fact that when lime is added to clayey soils same very beneficial results are produced dates back into the remote past. It is not a new development, In the United States lime has been in use since l923. The objective of this study was to determine the effect of increasing soaking time of soil-lime mixtures on the strength, swell potential, and degree of saturation. In order to ascertain the exact composition of clay minerals, X-ray diffraction analysis was run on the soil sample. The analysis showed that the clayey soil contained a large amount of water with a greater percentage of halloysite minerals. The soil, it was concluded, was poorly crystalline and was found to be midway between montmorillonite and kaolinite group. / Master of Science

[Truncated abstract] Standard AOAC methods of chemical analysis have been used to characterize and evaluate the industrial byproducts; partly burnt chicken litter ash (CLA), totally burnt chicken litter ash (CLAT), wood ash (WA) and iron smelting slag for use as a combined liming agent and phosphate fertilizer. Rock phosphate has this function and was included for comparison purposes. All the byproducts had pH values above 9 and a liming capacity above 90% of pure lime, as a result, these materials will be effective as liming agents. Total P concentrations for CLA, CLAT, slag, and WA were 3.6%, 4.75%, 0.26%, and 0.44% respectively indicating that they could be used as P fertilizers when applied at the high rates required for liming soils. ... The RE values for all the materials relative to monocalcium phosphate (100%) for the first harvest are as follows, 50% for dicalcium phosphate, 31% for rock phosphate, 7% for partly burnt chicken litter ash, 7% for totally burnt chicken litter ash and 1% for wood ash and slag. The RE values for the second harvest were 100% for monocalcium phosphate, 80% for dicalcium phosphate, 40% for rock phosphate, 10% for partly burnt chicken litter ash, 8% for totally burnt chicken litter ash and 2% for wood ash and slag. Data for subsequent harvests are not reported due to the death of many plants. Clearly chicken litter ash has appreciable value as a phosphate fertilizer whereas wood ash and slag are ineffective. Explanations for these differences in effectiveness are discussed in the text. An evaluation of the liming effect of the byproducts indicates that they may be used as a soil amendment on acid soils and are nearly as effective as standard lime (CaCO3). Byproducts are also sources of other plant nutrients so they may be regarded as a form of compound fertilizer and liming agent.

No abstract available. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1986.