Thesis (MScAgric)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Biochar is a carbon-rich solid material produced during pyrolysis, which is the thermal degradation of biomass under oxygen limited conditions. Biochar can be used as a soil amendment to increase the agronomic productivity of low potential soils. The aim of this study was to investigate the effect of applying locally-produced biochar on the fertility of low-nutrient holding, sandy soil from the Western Cape, and to determine the optimum biochar application level. Furthermore, this study investigates the effect of biochar on the leaching of an inorganic nitrogen fertilizer and a multi-element fertilizer from the sandy soil. The biochar used in this study was produced from pinewood sawmill waste using slow pyrolysis (450 °C). The soil used was a leached, acidic, sandy soil from Brackenfell, Western Cape. In the first study, the sandy soil mixed with five different levels of biochar (0, 0.05, 0.5, 0.5 and 10.0 % w/w) was chemically characterised. Total carbon and nitrogen, pH, CEC and plant-available nutrients and toxins were determined. The application of biochar resulted in a significant increase in soil pH, exchangeable basic cations, phosphorus and water holding capacity. A wheat pot trial using the biochar-amended soil was carried out for 12 weeks and to maturity (reached at 22 weeks). The trial was conducted with and without the addition of a water-soluble broad spectrum fertilizer. Results showed that biochar improved wheat biomass production when added at low levels. The optimum biochar application level in the wheat pot trial was 0.5 % (approximately 10 t ha-1 to a depth of 15 cm) for the fertilized treatments (21 % biomass increase), and 2.5 % (approximately 50 t ha-1 to a depth of 15 cm) for unfertilized treatments (29 % biomass increase). Since most biochars are alkaline and have a high C:N ratio, caution should be taken when applying it on poorly buffered sandy soil or without the addition of sufficient nitrogen to prevent nutrient deficiencies. In the second study, leaching columns packed with sandy soil and biochar (0, 0.5, 2.5 and 10.0 % w/w) were set up to determine the effect of biochar on inorganic nitrogen fertilizer leaching over a period of 6 weeks. It was found that biochar (0.5, 2.5, and 10.0 % w/w) significantly reduced the leaching of ammonium (12, 50 and 86 % respectively) and nitrate (26, 42 and 95 % respectively) fertilizer from the sandy soil. Moreover, biochar (0.5 %) significantly reduced the leaching of basic cations, phosphorus and certain micronutrients. This study demonstrated the potential of biochar as an amendment of acidic, sandy soils. Our findings suggest that an application rate of 10 t ha-1 should not be exceeded when applying biochar on these soils. Furthermore, biochar application can significantly reduce nutrient leaching in sandy agricultural soils. / AFRIKAANSE OPSOMMING: Biochar is ʼn koolstof-ryke, soliede materiaal geproduseer gedurende pirolise, wat die termiese degradasie van biomassa onder suurstof-beperkte omstandighede behels. Biochar kan gebruik word as ʼn grondverbeterings middel om die agronomiese produktiwiteit van grond te verhoog. Die doel van hierdie studie was om die effek van plaaslike vervaardigde biochar op die vrugbaarheid van die sanderige grond van die Wes-Kaap te ondersoek, en om die optimale biochar toedieningsvlak te bepaal. Verder, het hierdie studie die effek van biochar op die loging van anorganiese stikstof kunsmis en ‘n multi-elementkunsmis op sanderige grond ondersoek. Die biochar wat in hierdie studie gebruik is, is van dennehout saagmeul afval vervaardig d.m.v. stadige pirolise (450 °C). Die grond wat in hierdie studie gebruik is, is ‘n geloogde, suur, sanderige grond van Brackenfell, Wes-Kaap. In die eerste studie, is ‘n chemiesie ondersoek van die sanderige grond wat vermeng met is met vyf verskillende vlakke van biochar (0, 0.05, 0.5 en 10.0 % w/w) uitgevoer. Totale koolstof en stikstof, pH, KUK, en plant-beskikbare voedingstowwe en toksiene is in die grondmengsels bepaal. Die toediening van biochar het ‘n veroorsaak dat die grond pH, uitruilbare basiese katione, fosfor en waterhouvermoë beduidend toegeneem het. ‘n Koringpotproef was uitgevoer vir 12 weke en ook tot volwassenheid (wat op 22 weke bereik was) om die effek van die biochar op die sanderige grond teen die vyf verskillende toedieningsvlakke te bepaal. Daar was behandelings met en sonder die bykomstige toediening van ‘n wateroplosbare breë-spektrumkunsmis. Resultate toon dat die toediening van biochar teen lae vlakke koringbiomassa produksie verbeter. Die optimale biochar toedieningsvlak in die koringpotproef is 0.5 % (omtrent 10 t ha-1 tot ‘n diepte van 15 cm) vir die bemeste behandeling (21 % biomassa toename), en 2.5 % (omtrent 50 t ha-1 na ‘n diepte van 15 cm) vir onbemeste behandelings (29 % biomassa toename). Aangesien die meeste biochars alkalies is en ‘n hoë C:N verhouding besit, moet sorg gedra word wanneer dit op swak-gebufferde of lae N-houdende sanderige gronde toegedien word. Die resultate het aangedui dat die biochar versigtig aangewend moet word om grond oorbekalking te voorkom. In die tweede studie, was kolomme gepak met 2.0 kg van die sanderige grond gemeng met biochar (0, 0.05, 0.5, 2.5 en 10.0 % w/w) om die effek van biochar op die loging die anorganiese stikstof kunsmis oor ‘n tydperk van 6 weke om vas te stel. Daar is gevind dat biochar (0.5, 2.5 en 10.0 % w/w) die loging van ammonium (12, 50 en 86 % onderskeidelik) en nitraat (26, 42 en 95 % onderskeidelik) op sanderige grond aansienliek verminder. Verder, het biochar (0.5 %) die loging van basiese katione, fosfor en mikrovoedingstowwe aansienlik verminder. Hierdie studie het die potensiaal van biochar as verbeteringmiddel van suur, sanderige grond gedemonstreer. Ons bevindinge dui daarop aan dat ‘n toepassing vlak van 10 t ha-1 moet nie oorskry word nie wanneer biochar op hierdie gronde toegedien word. Die toediening van biochar op sanderige grond kan die loging van voedingstowwe aansienlik verlaag.

Thesis (MScAgric)--Stellenbosch University, 2012 / ENGLISH ABSTRACT: Biochar has been labelled to be a key factor in the global carbon mitigation act and has been described as the modern day equivalent (terra nova) to the terra preta dark earth soils of the Brazilian Amazon. Globally biochar has been evaluated as a means to improve soil fertility and to mitigate greenhouse gases (GHGs). Little research has however been published on the effects of biochar incorporation on soil physical properties. The objective of this study was to evaluate the effect of pine sawmill waste derived biochar (locally-produced via slow pyrolysis – 450°C) on selected soil physical properties, soil-water dynamics and crop production and- performance, when amended to a Kroonstad (Kd 1000 – Morgendal) soil form. This soil form is commonly found in the Western Cape area (South Africa) and can be classified as having low agricultural suitability for perennial- and annual crop species. Two pot trials were carried out in an atmospheric controlled greenhouse, where winter wheat and green beans respectively were planted, with five different application levels of biochar (0t/ha, 1t/ha, 10t/ha, 50t/ha and 200t/ha). Soil physical properties namely, water-stable aggregates, bulk density and water-retention capacity along with physiochemical characterisation of the sandy soil and biochar was determined. The water-use was monitored throughout the trials (evapotranspiration, volumetric water content and biomass water use efficiency, BWUE). The above- and below ground (specific leaf traits for the green bean and the root structural development for the winter wheat) biomass was collected and analysed at harvest. There was significantly higher volumetric water content measured for the 50t/ha and 200t/ha biochar treatments. This effect can be ascribed due to a change in the soil’s tortuosity and porosity where more meso- and micro-pores were present as the biochar rate increased. The same results were evident when a water-retention curve was established in vitro by means of the sandbox method. The bulk densities were only significantly lower for the 200t/ha biochar treatments. The wheat root systems differed greatly among the fertilised biochar treatments: the 50t/ha and 200t/ha treatments had a more complex fibrous root system (more extensive branching and thinner roots) than 0t/ha, 1t/ha and 10t/ha application levels. This is attributed to the increased water-holding capacity along with a reduction of N- and P availability with increasing addition of biochar. Several leaf traits were measured for the green bean crops; however the leaf nitrogen- and carbon content, chlorophyll content index (CCI) and carbon isotope fractionation yielded the most interesting findings. Concerning the fertilised biochar treatments, there was established that the 10t/ha treatments had the highest leaf nitrogen- and carbon content. The leaf chlorophyll content did not differ significantly between the fertilised biochar treatments; however a very interesting observation was evident regarding the measured leaf CCI for the unfertilised treatments. A decreasing trend and lower leaf CCI was measured as the biochar application levels increased. This effect was ascribed to be due to a decrease in N uptake by the plants as the biochar application increased, the C/N ratio also increased, and this leading to N immobilisation. The lowest leaf carbon isotope fractionation was measured for the 10t/ha fertilised treatments and is inversely correlated with BWUE and therefore endorses the conclusion that the 10t/ha biochar application had a positive effect on the long term water use efficiency for the green bean plants. Biochar promoted aggregation in the sand-rhizosphere interface for winter wheat, increased water-holding capacity and enhanced crop performance for green beans. The findings reported here provide new information on the effect of biochar on the structural development of sandy soil, combined with biochar- and root growth effects for winter wheat; along with detailed interpretations of specific leaf traits associated with crop production for commercial green beans. The addition of biochar at low application levels (approximately 1-10t/ha to 15 cm depth) increased the biomass yield and water use efficiency of the crop species. Besides long term carbon storage, biochar can have immediate positive effects on the physical properties of sand and plant growth. / AFRIKAANSE OPSOMMING: Biokoolstof word beskou as ‘n sleutel komponent rakende die wet op globale koolstofvermindering en is al beskryf as die moderne ekwivalent (terra nova) van die terra preta donker-aardgronde wat aangetref word in die Brasiliaanse Amasone. Wêreldwyd word biokoolstof tans geëvalueer met die doel om grondvrugbaarheid te verbeter asook kweekhuisgasse (KHG) se nadelige gevolge te verlig. Min navorsing was tot dus ver gedoen rakende die uitwerking met toediening van biokoolstof op grondfisiese-eienskappe. Die doel van hierdie studie was om die effek van biokoolstof, wat afkomstig is van denne-saagmeul-afval (plaaslik geproduseer is en d.m.v. stadige perolise - 450°C) te evalueer aangaande die volgende faktore: geselekteerde grondfisiese-eienskappe, grond-waterdinamika interaksie en die uitwerking op gewasproduksie; met toediening aan 'n Kroonstad (Kd 1000 - Morgendal) grondvorm. Hierdie grondvorm word as algemeen in die Wes-Kaap (Suid-Afrika) bestempel en kan geklassifiseer word as ‘n lae-geskiktheid landbougrond vir meerjarige- en eenjarige gewasse. Twee potproewe is uitgevoer onder beheerde atmosfeer in ‘n kweekhuis, waar winter koring en groenbone geplant is, met vyf verskillende behandelings van biokoolstof (0t/ha, 1t/ha, 10t/ha, 50t/ha en 200t/ha). Die volgende grondfisiese-eienskappe is ondersoek, naamlik water-stabiele aggregaat formasie, bulkdigtheid en waterhouvermoë, asook die fisiochemiese karakterisering van die sanderige grond en biokoolstof wat gebuik is. Waterverbruik is gedurende die proewe gekontroleer (evapotranspirasie, volumetriese waterinhoud en die biomassa se water verbruiksdoeltreffendheid, BWVD). Die bo- en ondergrondse biomassa, spesifiek die blaareienskappe van die groenboontjie en die strukturele ontwikkeling van die winter koring se wortels, is tydens die oes ondersoek en ontleed. Die volumetriese waterinhoud was betekenisvol, asook hoër vir die 50t/ha en 200t/ha behandelings. Hierdie effek word toegeskryf as gevolg van 'n verandering in die grond se kronkeligheid en porositeit; waar meer meso- en mikroporieë teenwoordig was soos die biokoolstof inhoud toegeneem het. Dieselfde resultate was verkry met die opstelling van ‘n water-retensie kurwe in vitro d.m.v. die Sandboks metode. Bulkdigtheid was slegs betekenisvol verskilled asook aansienlik laer vir die 200t/ha biokoolstof behandelings. Die koring se wortelstelsel het drasties verskil tussen die verskillende bemeste biokoolstof behandelings: die 50t/ha en 200t/ha behandelings het 'n meer komplekse en veselagtige wortelstelsel gevorm (hoër graad van vertakking en dunner wortels was aanwesig) as die 0t/ha, 1t/ha en 10t/ha behandelings. Die effek word toegeskryf aan die toenemende waterhouvermoë, tesame met 'n tekort aan N- en P-beskikbaarheid soos die biokoolstof toedieningshoeveelhede verhoog het. Verskeie blaareienskappe is gemeet vir die groenboon gewasse, maar die blaar stikstof- en koolstof-inhoud, chlorofil inhoud indeks (CII) en koolstof-isotoop fraksionering het die mees interessante bevindinge opgelewer. Die hoogste blaar stikstof-en koolstof-inhoud is gemeet vir die 10t/ha bemeste biokoolstof behandelings. Die blaar chlorofil inhoud het nie beduidend verskil tussen die bemeste biokoolstof behandelings nie, maar daar was egter 'n baie interessante waarneming vir die onbemeste biokoolstof behandelings. ‘n Tendens was aanwesig waar die CII afgeneem het soos die biokoolstof toedieningshoeveelheid ook afgeneem het vir die onbemeste behandelings. Die effek word toegeskryf as gevolg van 'n afname in N-opname deur die plant soos die biokoolstof toedieningshoeveelheid verhoog is en tot gevolg gehad het dat die C/N-verhouding ook toegeneem het, wat gelei het tot N-immobilisasie. Die laagste blaar koolstof-isotoop fraksionering was geassioseer met die 10t/ha bemeste biokoolstof behandelings en is omgekeerd gekorreleerd met BWVD en onderskryf dus die gevolgtrekking dat die 10t/ha biokoolstof behandeling 'n positiewe uitwerking het op die langtermyn waterverbruiksdoeltreffendheid vir groenboontjie plante. Biokoolstof het aggregasie bevorder binne die wortelsone, asook deurgans die waterhouvermoë verhoog en gewasproduksie verbeter. Hierdie bevindinge lewer nuwe inligting oor die effek van biokoolstof op die strukturele ontwikkeling van sanderige grond en die gekombineerde interaksie met biokoolstof toediening en hoe dit wortegroei beïnvloed van winter koring; asook 'n gedetailleerde interpretasie van spesifieke blaareienskappe wat verband hou met die produksie van gewasse vir kommersiële verbouing soos die groenboontjie. Die toediening van biokoolstof by die lae hoeveelhede (ongeveer 1-10t/ha tot op 15 cm diepte) het die opbrengs en waterverbruiksdoeltreffendheid van die gewasse verbeter. Behalwe vir die langtermyn koolstofvaslegging, kan biokoolstof toediening onmiddellike positiewe resultate teweeg bring aangaande die fisiese eienskappe van sandgronde en plantegroei.

Doctor of Philosophy / Department of Biological and Agricultural Engineering / Ronaldo Maghirang / Emission of greenhouse gases (GHGs), including nitrous oxide (N2O), methane (CH4), and carbon dioxide (CO2), from open beef cattle feedlots is becoming an environmental concern; however, scientific information on emissions and abatement measures for feedlots is limited. This research was conducted to quantify GHG emissions from feedlots and evaluate abatement measures for mitigating emissions. Specific objectives were to: (1) measure N2O emissions from the pens in a commercial cattle feedlot; (2) evaluate the effectiveness of surface amendments in mitigating GHG emissions from feedlot manure; (3) evaluate the effects of water application on GHG emissions from feedlot manure; and (4) compare the photo-acoustic infrared multi-gas analyzer (PIMA) and gas chromatograph (GC) in measuring concentrations of N2O and CO2 emitted from feedlot manure. Field measurements on a commercial beef cattle feedlot using static flux chambers combined with GC indicated that N2O emission fluxes varied significantly with pen surface condition. The moist/muddy surface had the largest median emission flux; the dry and compacted, dry and loose, and flooded surfaces had significantly lower median emission fluxes. Pen surface amendments (i.e., organic residues, biochar, and activated carbon) were applied on feedlot manure samples in glass containers and evaluated for their effectiveness in mitigating GHG emissions. Emission fluxes were measured with the PIMA. For dry manure, all amendments showed significant reduction in N2O and CO2 emission fluxes compared with the control (i.e., no amendment). For moist manure, biochar significantly reduced GHG emissions at days 10 and 15 after application; the other amendments had limited effects on GHG emissions. The effect of water application on GHG emissions from feedlot manure was evaluated. Manure samples (with and without water application) were placed in glass containers and analyzed for GHG emission using a PIMA. For the dry manure, GHG emissions were negligible. Application of water on the manure samples resulted in short-term peaks of GHG emissions a few minutes after water application. Comparison of the GC and PIMA showed that they were significantly correlated but differed in measured concentrations of N2O and CO2. The PIMA showed generally lower N2O concentrations and higher CO2 concentrations than the GC.

Förorenade markområden utgör ett stort miljöproblem som orsakar spridning av toxiska metaller till grund- och ytvatten. Samtidigt är många metaller toxiska för djur och människor, vilket gör att markmiljön kan påverkas och risker för människors hälsa uppkommer om de vistas på platsen. I Sverige finns idag över 80 000 förorenade områden och saneringstakten anses inte vara tillräckligt snabb. Metallerna koppar (Cu), bly (Pb) och zink (Zn) hör till de allra vanligasteme tallföroreningarna i jord. Lösligheten av dessa är avgörande för hur biotillgängliga deär samt i hur stor utsträckning de kan spridas till yt- och grundvatten. Biotillgängligheten och halterna i yt- och grundvattnet har i sin tur stor betydelse för hur stor exponeringen blir för människor och djur. Biokol är ett organiskt material som genomgått kemisk omvandling i en syrefattig miljö vid höga temperaturer. Dessa framställningsbetingelser gör att biokol har stora möjligheter att fastlägga metaller genom adsorption till funktionella grupper på dess yta. Samtidigt fungerar biokol som ett jordförbättrande medel. Det anses även kunna lagra kol i upp till 1000 år och därmed fungera som en kolsänka. Biokol kan dessutom tillverkasav organiskt avfall vilket gör att avfallsströmmen minskar när detta framställs. I studien har sex olika biokol blandats in i en jord förorenad med Cu, Pb och Zn. Syftet var att undersöka hur inblandningen påverkade lösligheten av metallerna. Samtidigt testades också fastläggningen av metallerna till tre rena biokol. Det visade sig att lösligheten förändrades när biokolen blandades in i jorden. I pH-intervallet 4 - 6 minskade lösligheten av alla metaller. Det framkom att ett av biokolen var bättre på att fastläggametallerna än de andra. Detta biokol kom från anläggningen i Högdalen, Stockholm och var framställt av trädgårdsavfall. / Contaminated ground constitutes an environmental problem that causes spread of metals to groundwater and surface water. Many of the contaminating metals are toxic to animals and humans and their spreading can cause negative effects on soil environment. In Sweden there are more than 80 000 contaminated sites and the decontamination rate is considered to be too slow. The metals copper, zinc and lead are some of the most common contaminants in soils. The solubility of these metals affects how bioavailable they are and how much they can spread to groundwater and surface water. Bioavailability and concentration in water is crucial for the exposure of metals to humans and animals. Biochar is an organic material that has been chemically transformed in an environment with little or no oxygen, at high temperatures. Due to these conditions, biochar is efficient for reducing the solubility of metals through adsorption to functional groups on its surface. Biochar also improve soil fertility, and it might also remain in the soil up to 1000 years and acts as a carbon sink. Furthermore, biochar can be produced from organic wastes and thus production of biochar can contribute to a reduced waste stream. In this study, six different samples of biochar were mixed with a contaminated soil containing copper, lead and zinc. The aim was to investigate how the adding of biochar would affect the solubility of the metals, since the solubility is crucial for the spread of metals and their bioavailability. The sorption of the metals in three pure samples of biochar was also tested. It was found that the solubility changed when biochar was addedto the soil. In the pH range 4 - 6, the solubility decreased for each metal. One of thebiochar samples had better sorption capacity in the soil than the others. This biochar was produced from garden wastes in Högdalen, Stockholm.

A casca da castanha de caju (CCC), um resíduo agrícola da produção de castanha, proveniente da região nordeste do Brasil foi caracterizada e submetida ao processo de pirólise lenta. As propriedades do bio-carrvão, do bio-óleo e dos gases produzidos foram investigados e potenciais aplicações foram propostas. A CCC foi caracterizada pela seguintes técnicas: análise elementar CHNS, umidade total, conteúdo de cinzas, matérias voláteis, poder calorífico superior e por análise termogravimétrica. A análise termogravimétrica sob fluxo de nitrogênio mostrou que a decomposição é dominada pela degradação da hemicelulose e celulose na faixa de 250 a 350oC e pela decomposição da lignina na faixa de 400 a 500oC. Na presença de ar, o perfil de degradação é semelhante, porém observa-se uma maior degradação da lignina. A pirólise lenta da casca da castanha de caju foi realizada em um reator tipo batelada aquecido por chama ar-GLP sob diferentes fluxos (mL min-1) de nitrogênio ou ar. O sólido obtido (bio-carvão), líquido (fase aquosa + bio-óleo) e a fase gás foram quantificados e caracterizados por diferentes técnicas. Os experimentos realizados sob fluxo de nitrogênio apresentaram um rendimento de cerca de 30, 40 e 30% em massa paras as fases sólido, líquida e gás, respectivamente. Sob fluxo de ar ocorreu uma diminuição no rendimento da fase líquida, principalmente na produção de bio-óleo, e um aumento da fase gás. Os bio-carvões produzidos apresentaram elevados teores de carbono, na faixa de 70-75% em massa, poder calorífico na faixa de 25 a 28 MJ kg-1, características de carbono amorfo, sem morfologias definidas e ausência de poros. Os espectros FTIR de bio-óleos produzidos sob fluxo de nitrogênio apresentaram um aumento da intensidade relativa das bandas cerca de 1700 cm-1 (ν C=O) e 1230 cm-1 (ν C-O) em comparação com os produzidos sob fluxo de ar, o que sugere a presença de grandes quantidades de compostos oxigenados de carbono, como aldeídos, cetonas e ácidos carboxílicos. As análises das fases gás mostraram a predominância de CO2 e CO a temperaturas inferiores a 400ºC e a formação preferencial de H2 acima desta temperatura. / Cashew nut shell (CNS), an agricultural waste of cashew nut production, from northeast region of Brazil was characterized and slow pyrolyzed. The properties of char, bio-oil and gases products were investigated and potential applications were proposed. CNS was characterized by the following analyses: CHNS, total moisture, ash content, volatile matter, high heating value and thermogravimetric analysis. The thermogravimetric analysis under nitrogen flow showed that the decomposition is dominated by the degradation of hemicellulose and cellulose in the range from 250 to 350oC and the decomposition of lignin in the range of 400 to 500oC. In the presence of air, the degradation profile is similar; however the decomposition of lignin increases. Slow pyrolysis of cashew nut shell was carried out in batch-type reactor heated by a combustion flame (air + GLP) under different nitrogen and air flow rates. The resulting solid (char), liquid (water + bio-oil) and gas phases were characterized and quantified. The experiments performed under nitrogen showed a yield of solid, liquid and gas phases of about 30, 40 and 30wt%, respectively. Under air the yield of liquid phase was reduced, primarily the bio-oil yield; production of the gas phase was, in turn, increased. The produced biochars had high carbon contents in the range of 70-80 wt%, high heating values in the range of 25-28 MJ Kg-1 and characteristics of amorphous carbons without defined morphology and the absence of pores. The FTIR spectra of bio-oils produced under nitrogen flow showed an increase of the relative intensity of the bands around 1700 cm-1 (ν C = O) and 1230 cm-1 (ν C-O) in comparison with those produced under air flow which suggests the presence of large amounts of oxygenated carbon compounds such as aldehydes, ketones and carboxylic acids. The analysis of gas phases showed the predominance of CO2 and CO at temperatures lower than 400oC and the preferential formation of H2 above this temperature.

A diversidade microbiana é geralmente considerada por seu papel nos principais processos do ecossistema, tais como a decomposição da matéria orgânica e ciclos biogeoquímicos. No entanto, informações sobre o impacto da diversidade em funções menores, como degradação de xenobióticos são escassas. Nós estudamos a partir da abordagem da \'diluição para extinção\', o papel da diversidade sobre a capacidade da comunidade microbiana em degradar o fungicida clorotalonil (organoclorado). Também estudamos o comportamento da comunidade bacteriana após aplicação do pesticida no solo com e sem biochar. A diversidade microbiana do solo natural foi alterada artificialmente por diluição, constituindo um gradiente de diversidade (SN > 10-1 > 10-3 > 10-6), seguido pela inoculação em amostras de solo estéril e posterior reestruturação (15 dias). Após a reestruturação da comunidade, as amostras foram manejadas com biochar (1% m/m) e tratadas com a dose de campo do CHT. O comportamento da comunidade bacteriana foi estudo por PCR-DGGE e qPCR do gene 16S rDNA através de um experimento com molécula fria (não radiomarcada). Enquanto a capacidade de degradação do CHT foi estudada por radiorespirometria (14C-CHT). Inicialmente, a comunidade de bactérias foi influenciada pelo gradiente de diversidade obtido por diluição. A separação dos grupos bacterianos se mostrou bastante similar nos três primeiros períodos pré-aplicação do CHT (SN > 10-1 - 10-3 > 10-6), enquanto que no período de 15 dias, a dinâmica de grupos foi alterada (SN > 10-1 > 10-3 - 10-6). O fungicida e o biochar não exerceram efeitos na comunidade bacteriana no tempo zero (imediatamente após a aplicação), a modificação no perfil da comunidade foi atribuído à diluição. Nos períodos de 21 e 42 dias, o perfil comunidade bacteriana apresentou forte modificação. Os grupos bacterianos se mostraram mais dispersos quando considerado somente o CHT. Embora, a análise de ANOSIM indicou não haver diferença nas amostras com e sem biochar, sugerindo que o clorotalonil foi quem mais contribuiu na dispersão dos grupos bacterianos. No período de 42 d, a comunidade apresentou resposta positiva, sendo observado aumentos no número de bandas e no índice de Shannon em todos tratamentos. Isto possivelmente, devido a menor concentração do fungicida disponível na solução do solo, diminuindo assim, os efeitos deletérios sobre a comunidade. Os dados de qPCR não apresentaram alteração no número de copias do gene 16S rDNA em todos os tratamentos. A remoção da diversidade impactou fortemente a capacidade da comunidade bacteriana de degradar o clorotalonil. Apesar da capacidade de degradar não ter sido perdida, a mínima alteração na diversidade promoveu elevada redução na taxa de mineralização do CHT. A dissipação do CHT se mostrou rápida (D50 < 1 dia) em todos os tratamentos, além disso, a formação de 14C-resíduos não extraíveis foi constituiu um dos principais mecanismos de dissipação do CHT. A partir da degradação do fungicida, foram detectados três metabólitos. Conclui-se que a modificação por diluição da diversidade bacteriana promoveu impacto negativo na mineralização do clorotalonil. E que a formação de resíduos não extraíveis consistiu no principal mecanismo de dissipação do CHT em ambos solos. / Microbial diversity is generally considered for his role in key ecosystem processes, such as decomposition of organic matter and biogeochemical cycles. However, information about the impact of diversity on minor functions, such as degradation of xenobiotics is scant. We study from the approach of \'dilution to extinction\', the role of diversity on the capacity of microbial community to degrade the chlorothalonil (organochlorine). We also studied the behavior of bacterial community after applying the pesticide in the soil with and without biochar. Microbial diversity of the soil natural (control) was artificially altered by dilution, forming a gradient of diversity (SN > 10-1 > 10-3 > 10-6), followed by inoculation in sterile soil samples and subsequent restructuring (15 days). After of the community restructuring, the samples were handled with biochar (1% w/w) and treated with the chlorothalonil field dose. The behavior of the bacterial community was studied by PCR-DGGE and qPCR of the 16S rDNA gene through an experiment with cold molecule (no radiolabeled). While the CHT degradation capacity was studied by radiorespirometry (14C-CHT). Initially, the community of bacteria was influenced by the diversity gradient obtained by dilution. The separation of bacterial groups showed very similar in the first three pre-application periods of the CHT (SN > 10-1 - 10-3 > 10-6). While in the period of 15 days, the group dynamic has changed (SN > 10-1 > 10-3 e 10-6). During periods of 21 and 42 days, the profile bacterial community showed strong modification. The bacterial groups were more dispersed when only considered the CHT. Although, the ANOSIM analysis indicated no difference in samples with and without biochar, suggesting that chlorothalonil who has contributed the most in the dispersion of bacterial groups. In the period of 42 days, the community presented a positive response, being observed increases in the number of bands and Shannon-Weiner index in all treatments. This possibly due to less concentration of fungicide available in soil solution, thus reducing, the deleterious effects on the community. The qPCR dates showed no change in the number of copies of the 16S rDNA gene in all treatments. The removal of microbial strongly impacted the ability of the bacterial community to degrading chlorothalonil. Despite the ability to degrade not having been lost, the minimum change in diversity promoted high reduction in the rate of mineralization CHT. The dissipation of the CHT showed quick (D50 < 1 d) in all treatments, in addition, the formation of non-extractable 14C-residues was one of the main mechanisms of dissipation of the CHT. From the degradation of chlorothalonil, three metabolites were detected. We conclude that modification by dilution of the bacterial diversity had a negative impact on the mineralization of chlorothalonil. And the formation of non-extractable residues consisted in the main CHT dissipation mechanism in both soils.

Plants regulate responses to their environment through complex hormone signaling; these hormones can be categorized broadly into two categories: growth and defense, though many have roles in both. Much remains to be understood about the complexity of hormone signaling in relation to environmental responses, especially species- and genotype-specific differences. Unraveling this complexity of hormone signaling will lead to the development of resilient crops that are able to respond appropriately to their environment. In this dissertation, I hypothesize novel roles for growth and defense hormones in <i>Solanum </i>spp. responses to 1) biochar, a black carbon soil amendment (Chapter 2), 2) infection with<i> Ralstonia solanacearum</i>, an economically important soilborne pathogen causing bacterial wilt (Chapter 3), and 3) endophytic colonization by the soil bacterial community (Chapter 4). In Chapter 2, I showed that biochar upregulates GA signaling and affects GA-related traits in a species- and cultivar-specific manner. Biochar amendment also downregulates defense signaling. In Chapter 3, I demonstrated a novel role for auxin in resistance against <i>R. solanacearum, </i>including differential expression of auxin signaling genes in resistant genotype H7996 compared to susceptible WV in response to <i>R. solanacearum</i> infection. In addition, I observed stronger and faster upregulation of defense hormone marker genes for SA and ET in H7996 compared to WV. In Chapter 4, I showed that SA and ET are required for normal tomato root microbial community assembly, affecting the colonization of a few key taxa in order to promote alpha diversity. H7996 and WV root communities differ in alpha diversity, and a panel of H7996 x WV RILs showed quantitative variation in alpha diversity that correlated negatively with the abundance of these key taxa. In conclusion, I elucidated novel roles for hormones in responses to the soil environment, pathogen infection, and root community colonization. These findings are important for developing resilient, sustainable crops.

A casca da castanha de caju (CCC), um resíduo agrícola da produção de castanha, proveniente da região nordeste do Brasil foi caracterizada e submetida ao processo de pirólise lenta. As propriedades do bio-carrvão, do bio-óleo e dos gases produzidos foram investigados e potenciais aplicações foram propostas. A CCC foi caracterizada pela seguintes técnicas: análise elementar CHNS, umidade total, conteúdo de cinzas, matérias voláteis, poder calorífico superior e por análise termogravimétrica. A análise termogravimétrica sob fluxo de nitrogênio mostrou que a decomposição é dominada pela degradação da hemicelulose e celulose na faixa de 250 a 350oC e pela decomposição da lignina na faixa de 400 a 500oC. Na presença de ar, o perfil de degradação é semelhante, porém observa-se uma maior degradação da lignina. A pirólise lenta da casca da castanha de caju foi realizada em um reator tipo batelada aquecido por chama ar-GLP sob diferentes fluxos (mL min-1) de nitrogênio ou ar. O sólido obtido (bio-carvão), líquido (fase aquosa + bio-óleo) e a fase gás foram quantificados e caracterizados por diferentes técnicas. Os experimentos realizados sob fluxo de nitrogênio apresentaram um rendimento de cerca de 30, 40 e 30% em massa paras as fases sólido, líquida e gás, respectivamente. Sob fluxo de ar ocorreu uma diminuição no rendimento da fase líquida, principalmente na produção de bio-óleo, e um aumento da fase gás. Os bio-carvões produzidos apresentaram elevados teores de carbono, na faixa de 70-75% em massa, poder calorífico na faixa de 25 a 28 MJ kg-1, características de carbono amorfo, sem morfologias definidas e ausência de poros. Os espectros FTIR de bio-óleos produzidos sob fluxo de nitrogênio apresentaram um aumento da intensidade relativa das bandas cerca de 1700 cm-1 (&nu; C=O) e 1230 cm-1 (&nu; C-O) em comparação com os produzidos sob fluxo de ar, o que sugere a presença de grandes quantidades de compostos oxigenados de carbono, como aldeídos, cetonas e ácidos carboxílicos. As análises das fases gás mostraram a predominância de CO2 e CO a temperaturas inferiores a 400ºC e a formação preferencial de H2 acima desta temperatura. / Cashew nut shell (CNS), an agricultural waste of cashew nut production, from northeast region of Brazil was characterized and slow pyrolyzed. The properties of char, bio-oil and gases products were investigated and potential applications were proposed. CNS was characterized by the following analyses: CHNS, total moisture, ash content, volatile matter, high heating value and thermogravimetric analysis. The thermogravimetric analysis under nitrogen flow showed that the decomposition is dominated by the degradation of hemicellulose and cellulose in the range from 250 to 350oC and the decomposition of lignin in the range of 400 to 500oC. In the presence of air, the degradation profile is similar; however the decomposition of lignin increases. Slow pyrolysis of cashew nut shell was carried out in batch-type reactor heated by a combustion flame (air + GLP) under different nitrogen and air flow rates. The resulting solid (char), liquid (water + bio-oil) and gas phases were characterized and quantified. The experiments performed under nitrogen showed a yield of solid, liquid and gas phases of about 30, 40 and 30wt%, respectively. Under air the yield of liquid phase was reduced, primarily the bio-oil yield; production of the gas phase was, in turn, increased. The produced biochars had high carbon contents in the range of 70-80 wt%, high heating values in the range of 25-28 MJ Kg-1 and characteristics of amorphous carbons without defined morphology and the absence of pores. The FTIR spectra of bio-oils produced under nitrogen flow showed an increase of the relative intensity of the bands around 1700 cm-1 (&nu; C = O) and 1230 cm-1 (&nu; C-O) in comparison with those produced under air flow which suggests the presence of large amounts of oxygenated carbon compounds such as aldehydes, ketones and carboxylic acids. The analysis of gas phases showed the predominance of CO2 and CO at temperatures lower than 400oC and the preferential formation of H2 above this temperature.

Oförmåga att minska utsläppen av växthusgaser i tillräckligt takt för att undvika en alltför kraftig global uppvärmning har motiverat framtagandet av tekniker med potential att minska mängden koldioxid i atmosfären. En av dessa tekniker är bioenergi med koldioxidlagring (Bio-energy with carbon capture and storage, BECCS), där koldioxid avskiljs från punktkällor med biogena utsläpp och lagras i geologiska strukturer. Även biokol tillsatt till jordbruksmark har potential att bidra till negativa utsläpp. Både svenska och internationella strategier inkluderar negativa utsläpp för att uppfylla förpliktelserna i Parisavtalet. För att säkerhetsställa att teknikerna lever upp till potentialen krävs ett livscykelperspektiv där klimatpåverkan beräknas på systemnivå. En livscykelanalys utfördes, där klimatpåverkan vid utnyttjande av grenar och toppar (GROT) från den svenska skogsindustrin beräknades för teknikerna BECCS och biokol tillsatt till jordbruksmark. Teknikerna jämfördes med ett referensscenario där GROT förbränns i ett kraftvärmeverk för att producera el och fjärrvärme utan omhändertagande av koldioxid som bildas vid förbränning. Resultaten visar att BECCS har potentialen att bidra med negativa utsläpp på mellan -168 och -666 kg CO2-ekvivalenter/ ton GROT torrsubstans (TS). Då GROT-skörden ökar till 80% av den årliga avverkade arealen skog i Sverige och kombineras med gallring, resulterar 666 kg CO2-ekvivalenter/ ton GROT TS, i 4,4 miljoner ton CO2-ekvivalenter per år. Detta motsvarar 25,8 % av klimatpåverkan från inrikestransporter i Sverige år 2016. Nettoutsläppen från biokol tillsatt till jordbruksmarker, varierar mellan 934 och -344 kg CO2-ekvivalenter/ ton GROT TS. Då GROT-skörden ökar till 80% av den avverkade arealen skog i Sverige och kombineras med gallring, resulterar 344 kg CO2-ekvivalenter/ton GROT TS i 2,2 miljoner ton CO2-ekvivalenter. Detta motsvarar 13,3 % av klimatpåverkan från inrikes transporter i Sverige år 2016. Båda teknikerna har potential att åstadkomma nettonegativa växthusgasutsläpp, men resultaten är beroende av klimatpåverkan från ersättande el- och fjärrvärmeproduktion. / The inability to achieve sufficient reduction of greenhouse gas emissions has led to the development of techniques with potential to achieve negative greenhouse gas emissions. One of these techniques is called Bio-energy with carbon capture and storage (BECCS), where carbon dioxide is captured from biogenic point sources with biogenic emissions and stored underground. Biochar applied to farmland is another technique with potential to achieve negative greenhouse gas emissions. Both Swedish and international strategies, to meet the obligations in the Paris Agreement, include negative greenhouse gas emissions. A life cycle approach is required to ensure that the techniques deliver on the promise of negative emissions. A Life cycle assessment was conducted where the global warming potential was calculated for BECCS and biochar added to farmland in two different scenarios where tops and branches (GROT) from the Swedish forest industry were used as feedstock. The techniques were compared to a reference scenario where GROT were used in a combined heat and power plant (CHP-plant). The results show that BECCS has the potential to achieve net negative emissions of between -168 and -666 kg CO2-equivalents/ tonne GROT dry matter (DM). When GROT is harvested from 80% of the yearly final felling areas in Sweden and combined with thinning, 666 kg CO2-equivalents/ Mg GROT DM is equivalent to in 4,4 million ton CO2-equivalents per year. This corresponds to 25,8 % of Sweden's greenhouse gas emissions from domestic transportation in 2016. The results of greenhouse gas emissions from biochar applied to farmland varied between 934 to -344 CO2-equivalents/ Mg GROT DM. When GROT is harvested from 80% of final felling areas in Sweden and combined with thinning, -344 CO2-equivalents/ Mg GROT DM is equivalent to 2,2 million ton CO2- equivalents per year. This corresponds to 13,3 % of Sweden's greenhouse gas emissions from domestic transportation in 2016. Both techniques have the potential to achieve net negative greenhouse gas emissions. However, the results are greatly influenced by the climate impact from generating the electricity to replace the losses in electricity production when GROT is used for BECCS and biochar instead of in a CHP-plant.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The increasing demand for fresh water has stimulated interest in new adsorbent materials suitable for use in the remediation of contaminated waters. This work evaluates different biomasses and their biochar for use as adsorbents for the removal of polycyclic aromatic hydrocarbons from water. Biochar (BBC and BCL) were obtained by the pyrolysis of coconut bagasse (BC) and orange peel (CL). The use of infrared spectroscopy analysis revealed that some of the functional groups of the biomasses were retained after pyrolysis at 350 °C. The heat treatment resulted in greater surface area, pore size, and pore volume of the biochar, compared to the precursor biomasses, as confirmed by scanning electron microscopy. Thermogravimetric analysis showed that the biochar presented higher thermal stability than the original biomasses. X-ray diffraction analysis identified the presence of potassium chloride in BC and BBC, while elemental analysis revealed increased aromaticity of the biochar, reflected in smaller H/C ratios. Adsorption assays were performed to evaluate the effects of contact time and initial concentration for the removal of benzo(a)anthracene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, and dibenzo(a,h)anthracene, individually and in a mixed solution. Identification and quantification of the compounds employed high performance liquid chromatography with fluorescence detection. The adsorption assays showed that there were no substantial differences in the amounts of the PAHs adsorbed by BC and BBC, while a increase was found for BCL, compared to CL. It was also verified that there was no competition between the PAHs for the adsorption sites of the materials. The adsorption could be best described by pseudo-second order kinetics and the Freundlich adsorption model. The adsorption mechanism probably involved π-π interactions of similar groups of the adsorbate and adsorbent, together with hydrophobic effects. The PAH could be desorbed from the adsorbents using ultrasonic extraction, and two further reuse cycles were tested. The proposed method provided efficient adsorption using a real sample, with removal rates from 86.29 to 8.12% (BC), 90.94 to 86.99% (BBC), 76.36 to 32.18% (CL), and 85.32 to 40.12% (BCL). The findings demonstrated the potential of these adsorbents for use in the removal of PAH from water. / Em virtude do aumento na demanda por água doce, surge o interesse por novos materiais adsorventes que possam ser utilizados na remediação de águas contaminadas. Diante disso, este trabalho descreve a avaliação de biomassas e seus biocarvões, como adsorventes na remediação de hidrocarbonetos policíclicos aromáticos em água. Os biocarvões (BBC e BCL) foram obtidos a partir da pirólise das biomassas bagaço de coco (BC) e casca de laranja (CL). A partir da espectroscopia de infravermelho foi possível observar que alguns grupos funcionais das biomassas se mantêm após procedimento de pirólise a 350°C. Uma maior área superficial, tamanho e volume dos poros foram observados para os biocarvões em relação as suas biomassas precursoras, devido ao tratamento térmico sofrido, confirmados pela microscopia eletrônica de varredura. A análise termogravimétrica mostrou que os biocarvões apresentam uma maior estabilidade térmica em relação as biomassas. A difração de raios X indicou a presença de cloreto de potássio no BC e BBC. A análise elementar indicou a formação de um material mais aromático, com a diminuição na razão H/C nos biocarvões. Os ensaios de adsorção foram realizados com avaliação do tempo de contato e efeito da concentração inicial na remoção do Benzo(a)Antraceno, Benzo(b)Fluoranteno, Benzo(k)Fluoranteno, Benzo(a)Pireno e Dibenzo(ah)Antraceno individualmente, e em solução mista, onde a identificação e quantificação desses compostos foram feitas por cromatografia líquida de alta eficiência com detector de fluorescência. Os ensaios de adsorção evidenciaram que não existe grande diferença na quantidade adsorvida dos HPAs entre o BC e o BBC, mas um aumento foi observada entre o CL e o BCL. É possível observar também que não ocorreu competição dos HPAs pelos sítios dos adsorventes. O sistema melhor se adaptou ao modelo cinético de pseudo-segunda ordem e modelo de adsorção de Freundlich. O provável mecanismo de adsorção envolveu a interação π-π de grupos semelhantes entre o adsorvato e o adsorvente, onde deve ser considerado também o efeito hidrofóbico. Foi possível também a dessorção dos HPAs da superfície dos adsorventes através da extração por ultrassom e mais dois ciclos de reutilização dos mesmos foram testados. O método proposto foi eficiente também na adsorção com amostra real, removendo de 86,29 a 8,12% para o BC; 90,94 a 86,99% para o BBC; 76,36 a 32,18 % para o CL e 85,32 a 40,12% para o BCL. Com isso, o estudo demonstrou o potencial desses adsorventes na remoção de HPA em águas.