Effect of lime source, form and placement on soil pH neutralisation and permeation
| dc.contributor.advisor | Hardie-Pieters, Ailsa G. | en_ZA |
| dc.contributor.advisor | Swanepoel, Pieter Andreas | en_ZA |
| dc.contributor.author | Du Toit, Dawid Jacob Johannes | en_ZA |
| dc.contributor.other | Stellenbosch University. Faculty of AgriSciences. Dept. of Soil Science. | en_ZA |
| dc.date.accessioned | 2021-05-24T11:49:31Z | |
| dc.date.available | 2021-05-24T11:49:31Z | |
| dc.date.issued | 2021-03 | |
| dc.description | Thesis (MScAgric)--Stellenbosch University, 2021. | en_ZA |
| dc.description.abstract | ENGLISH ABSTRACT: Currently, agricultural producers in South Africa are uncertain about the relative effectiveness of locally available class A and granulated micro-fine lime sources, especially in terms of soil permeation and correction of subsoil acidity. There is also limited information regarding the effect of lime placement (surface, band-placement and incorporation) on subsoil acidity alleviation and crop growth. Therefore, the main aim of the study was to compare the effectiveness of various local lime sources (calcitic and dolomitic) and forms (class A, micro-fine and granulated micro-fine) at increasing soil pH and permeating through different textured soils. A laboratory soil-lime incubation study was conducted to compare the acid neutralisation capacity of various local dolomitic and calcitic lime sources (i.e., different quarries) and forms (class A, micro-fine and granulated micro-fine lime) at increasing soil pH over time under controlled conditions in three acid soils (sand, sandy loam, and loam). All liming materials were applied (adjusted for CCE) to reach a target pHKCl of 5.5 on the three soils, incubated at around 85% field capacity and room temperature, and then pH measured at intervals of 1, 4, 7, 14, 21, 30, 47, 60, 90, 180, 275 and 365 days. Ungranulated micro-fine limes were found to have a higher rate of dissolution than class A lime, but the difference in pH obtained attenuated over time. The granulated micro-fine lime was found to be the least effective in correcting soil acidity due to largely remaining intact. The difference in performance between commercially available class A limes was of little importance, if applied based on CCE. Chemical purity (Ca%, CCE) was found to be the main factor effecting the reaction of a liming material in soil and particle fineness only determines the short-term reaction (4-7 days) of the limes. A winter rainfall laboratory column study was carried out on two soils (sand and loam) to compare the soil permeation of different calcitic lime forms (class A, micro-fine and granulated micro-fine). Lime was surface applied to soil columns (40 cm) and irrigated in six events with a total of 350 mm water over 12 weeks. The soil chemical effects of all the surface applied limes were limited to the top 5 cm only. Lastly, a greenhouse barley (Hordeum vulgare) pot trial was conducted to assess short-term crop response to lime form and placement. Lime (class A, micro-fine and granulated micro-fine) was applied (surface, band-placed or incorporated) to an acid loamy sand soil before barley planting. The effects of liming materials on soil chemical attributes were confined to its point of placement. Thorough incorporation of lime more effectively neutralised soil acidity below 5 cm, especially Mn toxicity, resulting in larger barley shoot biomass after six weeks. The granulated lime was once again the least effective due to partial dissolution. The results of this study highlight that, if class A limes are corrected for CCE, the difference between the respective class A lime sources and micro-fine limes attenuates over time and the effects of surface applied lime is confined to its point of placement. | en_ZA |
| dc.description.abstract | AFRIKAANSE OPSOMMING: Daar heers onsekerheid onder Landbouprodusente in Suid-Afrika oor die relatiewe doeltreffendheid van plaaslik beskikbare klas-A- en gegranuleerde mikro-fynkalkbronne, veral in terme van gronddeurdringing en die regstelling van ondergrondse suurheid. Daar is ook beperkte inligting beskikbaar rakende die effek van kalkplasing (oppervlaktoediening, bandplasing en inkorporering) op die regstelling van lae pH in die ondergrond en gewasgroei. Daarom was die hoofdoel van die studie om die doeltreffendheid van verskillende plaaslike kalkbronne (kalsities en dolomities) en vorms (klas- A-, mikro-fyn- en gegranuleerde mikro-fynkalk) met mekaar te vergelyk in terme van grond pH verhoging en deurdringing deur verskillende tekstuurgronde. ‘n Laboratoriuminkubasie-studie met grond en kalk is uitgevoer om die neutraliseringsvermoë van verskillende plaaslike dolomitiese en kalsitiese kalkbronne (d.w.s. verskillende kalk myne) en vorms (klas A, mikro-fyn en gegranuleerde mikro-fyn kalk) te vergelyk onder beheerde toestande in drie suur gronde (sand, sandleem en leem). Alle kalk bronne is aangewend (aangepas vir katioon uitruil kapasiteit (KKE)) om 'n teiken pH(KCl) van 5.5 op die drie gronde te bereik, geïnkubeer by ongeveer 85% veldkapasiteit en kamertemperatuur, waarna pH gemeet was in intervalle van 1, 4, 7, 14, 21, 30, 47, 60, 90, 180, 275 en 365 dae. Mikro-fyn kalk het 'n hoër tempo van ontbinding as klas A-kalk, maar die aanvanklike verskil in pH wat verkry is, het mettertyd verklein. Daar is gevind dat die gegranuleerde mikro-fyn kalk die suurheid van gronde die swakste neutraliseer omdat dit grotendeels ongeskonde bly. Die proporsionele verskil tussen kommersiëel beskikbare klas A kalkbronne, indien gebaseer is op KKE, was van klein belang. Daar is gevind dat chemiese suiwerheid (Ca %, KKE) die belangrikste langtermyn faktor is wat die reaksie van 'n kalk bron in die grond beïnvloed, en deeltjiegrootte bepaal slegs die kalk se korttermynreaksie (4-7 dae). ‘n Laboratorium kolomstudie is op twee gronde (sand en leem) uitgevoer om die gronddeurdringing van verskillende kalsitiese kalkvorms (klas A, mikrofyn en gegranuleerde mikrofyn) te vergelyk. Kalk is op grondkolomme (40 cm) toegedien en ses keer oor 12 weke besproei. ‘n Totaal van 350 mm water is tot elke kolom toegedien. Die effekte van al die oppervlak toegediende kalke op grond chemiese eienskappe was beperk tot die boonste 5 cm. Laastens is 'n kweekhuis potproef uitgevoer om die kort termyn effek van kalkvorm en -plasing op die van oesrespons van gars (Hordeum vulgare) te beoordeel. Kalk (klas A, mikrofyn en gegranuleerde mikrofyn) is voor die plant van gars op 'n suur leem sand grond toegedien (oppervlak, bandplasing en inkorporering). Die uitwerking van die kalk vorme op grond chemiese eienskappe was beperk tot die punt van toediening. Deeglike inkorporering van kalk het die suurheid van die gronde dieper as 5 cm meer effektief geneutraliseer, veral Mn-toksisiteit, wat na ses weke tot groter garsbiomassa gelei het. Die gegranuleerde kalk het weer die swakste gevaar as gevolg van gedeeltelike ontbinding. Die resultate van hierdie studie beklemtoon dat, indien klas A kalkbronne reggestel word vir KKE, die verskil tussen die onderskeie klas A kalkbronne en mikrofynkalke mettertyd verswak en die effekte van oppervlak-toegediende kalk beperk word tot die punt van plasing. | af_ZA |
| dc.description.version | Masters | en_ZA |
| dc.format.extent | xvi, 122 pages : illustrations (some color) | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/10019.1/110492 | |
| dc.language.iso | en_ZA | en_ZA |
| dc.publisher | Stellenbosch : Stellenbosch University | en_ZA |
| dc.rights.holder | Stellenbosch University | en_ZA |
| dc.subject | Soil acidity -- South Africa | en_ZA |
| dc.subject | Liming of soils | en_ZA |
| dc.subject | Micro-fine lime | en_ZA |
| dc.subject | Conservation agriculture | en_ZA |
| dc.subject | Plants -- Effect of soil acidity on -- South Africa | en_ZA |
| dc.subject | Soils -- Effect of acid deposition on | en_ZA |
| dc.subject | UCTD | en_ZA |
| dc.title | Effect of lime source, form and placement on soil pH neutralisation and permeation | en_ZA |
| dc.type | Thesis | en_ZA |