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MSCAGR ( Soil Science) / Department of Soil Science / See the attached abstract below

MSCAGR (Soil Science) / Department of Soil Science / Poultry manure (PM) is an inexpensive source of fertilizer but it decomposes quickly and releases carbon and greenhouse gases. Biochar (BC) could be an alternative source of carbon to improve soil quality and reduce greenhouse gas emission. This study investigated the effect of co-application of BC and PM on selected soil physical and chemical properties and performance of maize. A field experiment was conducted at the University of Venda experimental farm during 2015/2016 and 2016/2017 seasons. The experiment was a 4 x 3 factorial arrangement consisting of four rates of BC (0, 5, 10 and 20 t ha-1) and three rates of PM (0, 2, and 4 t ha-1) in a RCBD arrangement replicated three times. Maize was planted in both seasons. After harvest, soil bulk density was determined at four soil depths (0-5, 5-10, 10-15, and 15-20 cm), while aggregate stability and selected soil chemical properties were determined at two soil depths (0-15 cm and 15-30 cm). Data were subjected to ANOVA using Genstat 17th edition. The least significant difference was used to compare the treatment means at P < 0.05. Soil aggregate stability, organic carbon, Ca2+, Mg2+, K+, maize dry matter and maize grain yield increased with increasing rates of BC and PM application at 0 - 15 cm depth in both seasons. The combination of BC at 20 t ha-1 and PM at 4 t ha-1 significantly (P < 0.05) decreased soil bulk density at 5 - 10 cm depth but increased soil available P and total N at the two depths in both seasons. The results of this study suggested that BC and PM improved soil ability to retain and supply nutrients through improved soil aggregate stability and reduced bulk density thereby improving maize dry matter and grain yield. Combining BC with PM proved to enhance the ability of soil to function by improving selected soil physical and chemical properties thereby improving maize dry matter and grain yield. / NRF

The ever-increasing concentration of human activity in urban areas induces environmental problems beyond their boundaries on scales ranging from local to regional to global, such as resource depletion, land degradation, air and water pollution and climate change. Human-induced climate change is widely acknowledged as one of the greatest sustainability challenges of the present century and it is inextricably linked to urbanization. As a response to climate change, urban areas around the world have committed to reach climate neutrality within the next decades. In this context, the deployment of new technologies can have a key role in achieving carbon neutrality in urban areas. As new technologies emerge, it is essential to assess their environmental performance considering the broader systems context in order to ensure that they can indeed contribute to achieving climate neutrality without compromising environmental sustainability. This thesis aims is to provide insight on the environmental performance of emerging technologies that can be deployed in urban areas in order to contribute to achieving climate neutrality. The two technologies in focus are grid-connected solar microgrids and biochar-based systems for treatment of biomass waste and remediation of contaminated soil. The methods applied to conduct the environmental assessments and fulfil the aim of the thesis are: case studies, Life Cycle Assessment (LCA), Material and Energy Flow Analysis and Substance Flow Analysis. Moreover, as part of the research efforts, a spreadsheet model based on LCA data was developed. The assessment of the solar microgrid highlighted the importance of using explicit spatial and temporal boundaries when analyzing the environmental performance of energy systems, as it can increase the accuracy of the results. It also revealed that the choice of modeling approach can influence the results of the assessment, which motivates the application of different methodological approaches. Within this context, the assessment showed that in a short-term perspective the integration of a grid-connected urban solar microgrid into the Swedish electricity grid would not contribute to climate change mitigation, as solar electricity from the microgrid would displace grid electricity with lower carbon intensity. The assessment also indicated that operational and structural changes in the microgrid could reduce its climate change impact, albeit not to the extent to generate GHG emission abatements. The assessment of the biochar-based systems showed that these systems have many environmental benefits compared to incineration of waste and landfilling of contaminated soil. They have great potential to contribute to achieving climate neutrality, as they can provide net negative GHG emissions, owing mainly to carbon sequestration in the biochar. Between the two biochar-based systems, a system for on-site remediation can provide additional environmental benefits, as it can lead to more efficient use of resources. However, these systems also entail environmental trade-offs due to increased consumption of auxiliary electricity, while the extent of ecological and human health risks associated with the reuse of biochar-remediated soils is for the moment unknown. / Den ständigt ökande koncentrationen av mänsklig aktivitet i urbana områden orsakar miljöproblem utanför deras gränser på skalor som sträcker sig från lokal till regional till global, såsom utarmning av resurser, markförstöring, luft- och vattenföroreningar och klimatförändring. Mänskligt driven klimatförändring är allmänt erkänd som en av de största hållbarhetsutmaningarna under nuvarande seklet och den är nära kopplad till urbanisering. Som ett svar på klimatförändringen har urbana områden runt om i världen åtagit sig att nå klimatneutralitet inom de närmaste decennierna. I detta sammanhang kommer införandet av ny teknik ha en nyckelroll för att uppnå klimatneutralitet i stadsområden. När ny teknik dyker upp är det viktigt att bedöma dess miljöprestanda med hänsyn till den bredare systemkontexten för att säkerställa att tekniken verkligen kan bidra till att uppnå klimatneutralitet utan att kompromissa med miljömässig hållbarhet. Denna avhandling syftar till att ge insikt om miljöprestanda för framväxande teknik som kan användas i urbana områden för att bidra till att uppnå klimatneutralitet. De två teknikerna i fokus är nätanslutna solmikronät och biokolbaserade system för behandling av biomassavfall och sanering av förorenad mark. Metoderna för att genomföra miljöbedömningarna och uppfylla avhandlingens syfte är: fallstudier, livscykelanalys (LCA), material- och energiflödesanalys och substansflödesanalys. Som en del av forskningsinsatserna utvecklades dessutom en kalkylmodell baserad på LCA-data. Analysen av solmikronätet visade att det är viktigt att använda explicita rums- och tidsgränser vid analys av energisystemens miljöprestanda, eftersom det kan öka resultatens noggrannhet. Analysen visade också att valet av modelleringsmetod kan påverka resultatet, vilket motiverar en användning  av flera olika metoder. Inom detta sammanhang visade bedömningen att i ett kortsiktigt perspektiv skulle integrationen av ett nätanslutet urbant solmikronät i det svenska elnätet inte bidra till att begränsa klimatförändringen, eftersom solenergi från mikronätet skulle ersätta el med lägre klimatpåverkan. Bedömningen indikerade också att operativa och strukturella förändringar i mikronätet kunde minska mikronätets klimatförändrings påverkan, om än inte i sådan utsträckning att det skulle ge växthusgasutsläppsbesparingar. Bedömningen av de biokolbaserade systemen visade att dessa system har många miljöfördelar jämfört med förbränning av avfall och deponering av förorenad mark. De har stor potential att bidra till att uppnå klimatneutralitet, eftersom de kan ge nettonegativa utsläpp av växthusgaser, främst på grund av kolbindning i biokol. Vi jämförelse av de två biokolbaserade systemen så kan ett system för sanering på plats ge ytterligare miljöfördelar, eftersom det kan leda till en mer effektiv resursanvändning. Dessa system medför emellertid också miljöavvägningar på grund av ökad förbrukning av elektricitet, medan omfattningen av ekologiska och människors hälsorisker förknippade med återanvändning av biokolbehandlad jord ännu är okända. / <p>QC 20210419</p>

MSCAGR (Soil Sciece) / Department of Soil Science / In most parts of Limpopo Province of South Africa, crop yields are low and continue to decrease due to decline in soil fertility, which has been identified as a major constraint to crop production. Therefore, there is a pressing need for soil amendments such as the application of biochar, which has the potential to improve soil fertility due to its physical and chemical properties. Biochar is the product of incomplete combustion of biomass in the absence of oxygen. The overall objective of the study was to determine the effects of biochar and NPK fertilizer on maize performance and selected soil nutrient levels. A 3x2 factorial experiment was conducted at the School of Agriculture Experimental Farm for two consecutive seasons (2015/16 and 2016/17 seasons). Treatments consisted of biochar applied at three levels, viz. 0, 10 and 20 t/ha and NPK inorganic fertilizer applied at two rates viz. NPK0 (zero NPK fertilizer) and NPK1 {N (150 kg/ha) P (50 kg/ha) K (20 kg/ha)}. The treatments were laid out in a randomized complete block design (RCBD) and replicated three times. Maize cultivar (DKC 2147) was used as the test crop. Maize growth and yield measurements assessed included: plant height (cm), stem diameter (cm), number of leaves, leaf area, dry biomass (kg/ha), nutrient uptake, cob yield, grain yield and harvest index. Soil samples were collected from 0-10 cm and 10-20 cm soil depths at the end of each season to determine total N, P, K nutrient levels in the soil. Data collected was subjected to two-way analysis of variance using the general linear model (GLM) procedure of Genstat software version 17. Comparison of means was done using the Standard Error of Deviation (SED) method at 5% level of significance (p<0.05). Biochar and NPK fertilizer had no effect on total N and exchangeable K at all soil depths in 2015/16 and 2016/17 seasons. Biochar had no effect on phosphorus at all soil depths in 2015/16 and at 0-10 cm soil depth in 2016/17 season. The effect of biochar and NPK fertilizer was highly significant (p<0,001) on available P at 10-20 cm soil depth in 2016/17 season. Significant interactive effect of biochar and NPK fertilizer on soil total N at 10-20 cm (in 2015/16 season), available P and exchangeable K at 10-20 cm soil depth in 2016/17 season was also observed. Plant growth parameters increased with biochar addition at 20 t/ha and NPK1 (150 kg N/ha, 50 kg P/ha, 20 kg K/ha) fertilizer. The results of this study showed that biochar application at the rate of 10 and 20 t/ha has the potential to influence selected soil nutrient levels, maize growth, yield and yield components with and without NPK fertilizer application. Since this study was conducted over two seasons and biochar properties changes over a long-term period, more research is needed to evaluate the effect of biochar on soil nutrient levels and maize growth, nutrient uptake and yield over a long period of time. / NRF

Nano-scaled carbons were produced by thermal treatment of pine wood chips and bio-char. The influence of temperature, heating rate, pyrolysis time, and type and flow rate of purge gas on the production of nano-carbons was investigated. Using TEM and SEM, different carbon-based nanomaterials were observed in the prepared samples. The effect of metal ion doping on the bio-char was also investigated. Highly functionalized nano carbonaceous materials were synthesized by low temperature hydrothermal carbonization (HTC) using glucose, sucrose, xylose, and cellulose. Carbon-encapsulated iron (Fe@C) core-shell particles were also synthesized by the HTC method and used as catalyst for Fischer-Tropsch synthesis to produce liquid hydrocarbons from syngas; it showed excellent activity. Nano-structured Co-Mo carbides over several nano-sized carbon materials were prepared using the carbothermal reduction and carbothermal hydrogen reduction methods. Nano-structured Co-Mo carbides derived from Vulcan® XC-72 were used as the catalyst to produce higher alcohols.

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The growing need for climate mitigation solutions has contributed so thatbiochar has gained significant interest. Primary for its ability as a carbon sinkbut there is also a growing interest due to several other aspects within industriese.g. substitution effects, increased resource efficiency, an enabler forindustrial symbiosis, and its beneficial properties when put in soil that can increasegrowth. Previous studies of biochar have been dominant within the environmentalperspective of biochar, analyzing detailed characteristics of its propertiesand carbon sink potential. Some studies have a holistic perspective reflectingon countries specific energy mix and the different benefits of producingbiochar. However, previous studies are far too few to determine the value-chainof biochar. Hence previous studies have knowledge gaps within the holistic lifecycle approach from a provider or customer perspective of biochar, not reflectingon demand for quality requirements in different utilization areas and markets.The need for validation of the environmental and the economic performanceof biochar has to be established, and the economic perspective of biochar hasmajor knowledge gaps since previous studies are scarce. The study aims to establish the value-chain of biochar by evaluating theenvironmental, economic, and social perspectives through life cycle thinking.The core of the study is to distinguish value, which first has to reflect thebiochar quality requirements from providers and customers, captured throughinterviews and literature research. The quality requirements enable a goal forproducing biochar and determine what processes and biomass are needed fordifferent markets. This is evaluated through a case development which considersthe different quality requirements. Life cycle assessment (LCA) with acradle-to-grave perspective and life cycle costing (LCC) with a cradle-to-gatewere then used to distinguish biochar´s environmental and economic performance. The interviews and researched literature resulted in three cases being developed,biochar application in electric arc furnaces in steel production, agriculturalapplication, and commercial application through biochar-macadam. Thesteel industry has higher quality requirements due to the need to have a similarcomposition as fossil coal, resulting in biochar produced from wood being theonly option. The limitations for agricultural application are more related tothe allowed amount of phosphorus per ha and thus all the researched biocharapplies to different degrees. Biochar application in biochar-macadam is similarto agricultural application, however limited due to the EBC certification notallowing the production of biochar from sludge. The generated results from the LCA show that the climate performance isvastly different depending on what biomass was utilized and the different markets.Biochar produced from park and garden, and wood results in a higher climateperformance due to the higher carbon sequestration compared to biocharproduced from straw and sludge, however depending on how the biocharis utilized, the performance varies. During biochar application in electric arcfurnaces, the majority of the produced carbon sink is destroyed which resultsin worse climate performance, instead the majority of the reduced emissionscomes from the substituted fossil coal. Compared to biochar application inagricultural and biochar-macadam where the carbon sink stays intact, steel applicationstill has worse climate performance even when including substitution.Biochar-macadam production results in more emissions compared to agriculturalapplication due to the need to mix biochar with stones and compost,thus biochar in agriculture is the best option from a climate perspective. The economic aspects are generated through the conducted LCC which resulted inbiochar produced from park and garden, and sludge being more beneficial dueto the absence of acquisition costs. Production of biochar from wood provesto be difficult when considering a larger time frame, with the market for steelproduction not returning the investment. Biochar produced from straw hasa positive return on investment when considering the agriculture market, butnot for the production of biochar-macadam. The results show that the marketof biochar is very uncertain due to being considered immature and a futuremarket. The major uncertainty is connected with the immaturity of the market.The quality requirements are not reflected in the market pricing which isone of the major reasons for biochar utilization in the steel industry not beingeconomically beneficial. The value chain of biochar is a combination of many different economic,environmental, and social values. The conducted LCA shows that there areclimate benefits due to carbon sequestration, and a possibility to replace fossilreferences. Other than biochar there are also by-products such as heat and oilwhich can be utilized, improving the climate performance further. The multipleproducts also have economic benefits due to the potential of creating multipleproducts. The carbon sink can be sold as carbon credits, and the heat can beutilized in district heating. For providers, the creation of biochar is an enablerto reduce environmental impact, utilize products already within the system,and create value from waste. The structure of biochar generates a lot of valuefor customers. The porosity enables water storing capabilities which increasesthe efficiency of watering. This reduced the amount needed for soil applications,while also securing the harvest from drought and flooding. Even though thevalue chain of biochar shows that there is a lot of potential, it is still uncertainhow it will be integrated into society, and how the market will be shaped in theyears to come.

Diese Arbeit ist ein Beitrag zur Entwicklung einer Strategie für die eine CO2 sparende zu- künftige Landwirtschaft, in der nur geringe Emissionen von Treibhausgasen entstehen, die Stromerzeugung vor Ort aus natürlichen Ressourcen erfolgt, eine maximale Ausnutzung der Sonnenenergie genutzt wird, und der Konflikt zwischen der Nutzung der verfügbaren Ressourcen für Nahrungsmittel und Treibstoff Produktion vermieden wird. Alle Versuche in der Arbeit wurden in den Jahren 2005 -2009 auf der Öko-Farm (TOSOLY) der UTA (Fundación para la Producción Agropecuaria Tropical Sostenible Capitulo Kolumbien - UTA) unter der Leitung von Dr. TR Preston (Präsident ) und MSc Lylian Rodríguez (Director) durchgeführt. / This thesis is a contribution to the strategy that should underpin all future farming systems: namely the need to “de-carbonize” the system, by reducing emissions of greenhouse gases, generating electricity locally from natural resources, making maximum use of solar energy and ensuring there is no conflict between use of available resources for both food and fuel production. All the experiments described in the thesis were carried out in the period 2005 -2009 at the ecological farm (TOSOLY) of the UTA Foundation (Fundación para la Producción Agropecuaria Tropical Sostenible Capitulo Colombia – UTA) of which the principals are Dr T R Preston (President) and MSc Lylian Rodríguez (Director).

This thesis enters the context of smallholder agriculture communities in the developing world. It explores the potentials of biochar and what biochar systems could bring to the smallholder communities while simultaneously bringing environmental benefits. It then acknowledges the challenges of diffusion –the spreading of an unfamiliar innovation. It seeks to answer the question of what will make diffusion of biochar systems more successful in the smallholder context, fixating on the characteristic of compatibility as well as the role local community members can play in making a new biochar system more visible to the rest of the communities.