The effect of gypsum form and source on soil amelioration

Simple item page
dc.contributor.advisorHardie-Pieters, Ailsa G.en_ZA
dc.contributor.advisorSwanepoel, Pieter Andreasen_ZA
dc.contributor.authorDu Plessis, Men_ZA
dc.contributor.otherStellenbosch University. Faculty of Agrisciences. Dept. of Soil Science.en_ZA
dc.date.accessioned2024-02-27T07:08:20Z
dc.date.accessioned2024-04-26T08:48:18Z
dc.date.available2024-02-27T07:08:20Z
dc.date.available2024-04-26T08:48:18Z
dc.date.issued2024-03
dc.descriptionThesis (MScAgric)--Stellenbosch University, 2024. en_ZA
dc.description.abstractENGLISH ABSTRACT: Studies evaluating the effectiveness of South African gypsum sources are scarce or outdated, as new products, such as granulated and liquid gypsums, have been introduced. The efficacy of calcium (Ca) nitrate and micro-fine (MF) calcitic limes in comparison to multiple gypsum sources has also never been evaluated. Consequently, the main aim of the study was to characterise and compare the effectiveness of various South African gypsum sources for use in crop production. A controlled laboratory study was performed to compare the effectiveness of mined and by-product gypsums and other Ca sources in terms of soil sodicity remediation and saturated hydraulic conductivity (Ksat) improvement. Twelve mined and by-product gypsums sources, MF calcitic limes and calcium nitrate were surface-applied to a sodic, sandy loam soil to achieve an exchangeable sodium percentage (ESP) of 5%. The soils received 300 mm simulated rainfall. Finer by-product gypsum sources (particularly liquid and flue gas desulphurisation (FGD) gypsums) exhibited faster dissolution rates and superior performance in lowering soil ESP compared to Class A mined gypsums. Only the liquid, phospho-, FGD gypsums and calcium nitrate significantly increased soil hydraulic conductivity compared to the control. The MF calcitic limes had no effect on the sodic soil properties. In a separate controlled laboratory study, 7 gypsum sources (reagent grade gypsum, phosphogypsum, granulated phosphogypsum, mine water, FGD, mined gypsums), two calcitic lime products (granulated MF and agricultural lime), hydrated agricultural lime, and a 1:1 combination of mined agricultural gypsum and calcitic lime were surface-applied to two Western Cape acid (sandy and sandy loam) soils and compared in terms of soil acidity remediation in 50 mm increments to a depth of 400 mm. The soils received 1000 mm simulated rainfall. Gypsum could not substitute lime in terms of acidity neutralisation but did show capability in displacing acidity away from the topsoil. The 1:1 combination of mined Class A gypsum and calcitic lime proved to be a viable substitute for lime alone. In a greenhouse pot trial, 6 gypsum products (FGD gypsum, mine water gypsum, phosphogypsum, granulated phosphogypsum, mined recrystallised gypsum and mined gypsum) were surfaced applied to an acidic, sandy soil (5.1% clay) to raise soil Ca levels to 400 mg kg⁻¹. The objectives of this study were to investigate the effect of different sources and forms of gypsum on the chemical properties of an acid, sandy soil and assess their effects on canola growth and nutrient uptake. Canola (Blazer TT cultivar) plants were grown in the pots and harvested after 7 weeks. Shoot and root biomass, foliar nutrient content soil chemical properties were then determined. In the short- term, granulated phosphogypsum and mined recrystallised gypsum were superior in terms of correcting acidity and improving root growth compared to the other gypsums, but all gypsum sources adequately addressed Canola Ca and S deficiency.en_ZA
dc.description.abstractAFRIKAANSE OPSOMMING: Die beskikbare studies oor die effektiwiteit van gips bronne in Suid-Afrika is moeilik bekombaar en sluit nie nuwer produkte op die mark, soos verkorrelde gips en vloeibare gips in nie. Die effektiwiteit van kalsiumnitraat en mikro-fyn kalk in vergelyking met verskillende gips bronne is ook nog nie ondersoek nie. Daarom was die hoof doel van hierdie studie om die verskeie gips bronne in Suid- Afrika te karakteriseer en te vergelyk vir die gebruik in gewasproduksie. ʼn Beheerde laboratorium studie is uitgevoer om die effektiwiteit van gemynde en by-produk gips, sowel as ander kalsium bronne te vergelyk in terme van natrium-brak grond ameliorasie en die verbetering van versadigde hidrouliese geleiding (Ksat). Twaalf gemynde en by-produk gips bronne, mikro-fyn kalk en kalsiumnitraat is op die oppervlakte van ʼn natrium-brak, sanderige leem grond toegedien om ʼn uitruilbare natrium persentasie (UNP) van 5 % te bereik. Elke behandeling het 300 mm gesimuleerde reënval ontvang. Die fyner by-produk gips bronne (veral vloeibare gips en rookgas-ontswaveling (FGD) gips) het ʼn vinniger oplossings tempo gehad as die Klas-A gips bronne en kon meer effektief die UNP verlaag. Slegs die vloeibare gips, fosfogips, FGD gips en kalsiumnitraat kon die Ksat beduidend verhoog in vergelyking met die kontrole. Die mikro-fyn kalk bronne het geen uitwerking gehad op die natrium-brak grond se eienskappe nie. In ʼn aparte beheerde laboratorium studie, is 7 gips bronne (reagens graad gips, fosfogips, verkorrelde gips, myn water gips, FGD gips en twee gemynde gips bronne), 2 kalsitiese kalk produkte (verkorrelde mikro-fyn kalk en Klas-A kalk), geblusde kalk en ʼn 1:1 mengsel van Klas-A gips en Klas- A kalsitiese kalk op die oppervlak van ʼn sand en sanderige leem grond van die Wes-Kaap toegedien en vergelyk in terme van die vermoë om suurheid van die bogrond af te verplaas. Die 1:1 kombinasie van Klas-A gips en kalsitiese kalk het potensiaal getoon as plaasvervanger vir alleenlike kalk gebruik. In ʼn kweekhuispotproef is 6 gips produkte (FGD gips, myn water gips, fosfogips, verkorrelde gips, gemynde herkristalliseerde gips en Klas-A gips) op die oppervlak van ʼn suur, sanderige grond met 5.1 % klei toegedien, om die grond kalsium inhoud tot by 400 mg kg⁻¹ te bring. Die doel van die studie was om die effek van die verskillende gips bronne op die chemiese eienskappe van die suur, sanderige grond te ondersoek en om die effek van die gips bronne op die groei en voedingstof opname van Canola te ondersoek. Canola (Blazer TT kultivar) plante was in potte gegroei en geoes na 7 weke. Die loot en wortel biomassa, blaarvoedingstofinhoud en grond chemiese eienskappe was bepaal. Op die korttermyn was verkorrelde gips en herkristalliseerde gips verhewe in terme van grond suurheid en wortelgroei verbetering teenoor die ander gips bronne, maar alle gips bronne was voldoende kalsium en swael bronne vir die Canola.af_ZA
dc.description.versionMastersen_ZA
dc.format.extentvii, 87 pages : illustrations (some color), mapsen_ZA
dc.identifier.urihttps://scholar.sun.ac.za/handle/10019.1/130196
dc.language.isoen_ZAen_ZA
dc.language.isoen_ZAen_ZA
dc.publisherStellenbosch : Stellenbosch Universityen_ZA
dc.rights.holderStellenbosch Universityen_ZA
dc.subject.lcshGypsum -- South Africaen_ZA
dc.subject.lcshSoils -- Gypsum contenten_ZA
dc.subject.lcshPhosphogypsumen_ZA
dc.subject.lcshSoil chemistryen_ZA
dc.subject.lcshCrops -- Effect of soil acidity onen_ZA
dc.subject.lcshSoils, Salts inen_ZA
dc.subject.nameUCTDen_ZA
dc.titleThe effect of gypsum form and source on soil ameliorationen_ZA
dc.typeThesisen_ZA
Files
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
duplessis_gypsum_2024.pdf
Size:
1.87 MB
Format:
Adobe Portable Document Format
Description:
Download
Collections
Masters Degrees (Soil Science)