Submitted in fulfilment of the requirements of the Degree of Doctor of Engineering, Durban University of Technology, 2017. / Water is an essential natural resource for human existence and survival on the earth. South Africa, a water stressed country, allocates a high percentage of its available consumptive water use to irrigation. Therefore, it is necessary that we optimize water use in order to enhance food security. This study presents the development of mathematical models for irrigation scheduling of crops, optimal irrigation water release and crop yields in Vaal Harts irrigation scheme (VIS) of South Africa. For efficient irrigation water management, an accurate estimation of reference evapotranspiration (ETₒ) should be carried out. However, due to non-availability of enough historical data for the study area, mathematical models were developed to estimate ETₒ. A 20-year monthly meteorological data was collected and analysed using two data–driven modeling techniques namely principal component analysis (PCA) and adaptive neuro-fuzzy inference systems (ANFIS). Furthermore, an artificial neural network (ANN) model was developed for real time prediction of future ETₒ for the study area. The real time irrigation scheduling of potatoes was developed using a crop growth simulation model called CROPWAT. It was used to determine the crop water productivity (CWP), which is a determinant of the relationship between water applied and crop yield. Finally, a new and novel evolutionary multi-objective optimization algorithm called combined Pareto multi-objective differential evolution (CPMDE) was applied to optimize irrigation water use and crop yield on the VIS farmland. The net irrigation benefit, land area and irrigation water use of maize, potatoes and groundnut were optimized. Results obtained show that ETₒ increases with temperature and windspeed. Other variables such as rainfall and relative humidity have less significance on the value of ETₒ. Also, ANN models with one hidden layer showed better predictive performance compared with other considered configurations. A 5-day time step irrigation schedule data and graphs showing the crop water requirements and irrigation water requirements was generated. This would enable farmers know when, where, and how much water to apply to a given farmland. Finally, the employed CPMDE optimization algorithm produced a set of non-dominated Pareto optimal solutions. The best solution suggests that maize, groundnut and potatoes should be planted on 403543.44 m2, 181542.00 m2 and 352876.05 m2areas of land respectively. This solution generates a total net benefit of ZAR 767,961.49, total planting area of 937961.49 m2 and irrigation water volume of 391,061.52 m3. Among the three crops optimized, maize has the greatest land area, followed by potatoes and groundnut. This shows that maize is more profitable than potatoes and groundnut with respect to crop yield and water use in the study area. / D

L’efficience d’utilisation de l’eau (WUE), rapport entre la biomasse produite et l’eau consommée, est un trait essentiel à étudier en agronomie pour améliorer la production des cultures soumises à la sécheresse. Cependant, mesurer l’eau consommée par un couvert végétal est difficile à réaliser. L’objectif général de ce travail de thèse est de répondre à trois principales questions : (i) peut-on déterminer WUE en utilisant la discrimination isotopique du carbone (CID) facile à mesurer? (ii) comment l’analyse de la variabilité de WUE et CID peut contribuer à sélectionner des génotypes de tournesol soumis à la sécheresse? (iii) et les variations de WUE peuvent-elles être révélées par les variations de relations hydriques? Quatre expériences ont été conduites en serre pendant deux années : (i) avec deux scenario de sécheresse, l’une progressive, l’autre stable, et (ii) avec cinq niveaux de contenu en eau du sol stables. Les principaux traits mesurés sont WUE, CID et d’autres traits représentant les relations hydriques tels que le contrôle de la transpiration (FTSWt), la capacité d’extraction de l’eau (TTSW) et la tolérance à la déshydratation (OA). Une forte corrélation négative a été mise en évidence entre WUE et CID. Une large variabilité a également été observée pour FTSWt, TTSW et OA. Ces résultats permettent de connaitre le contrôle génétique de WUE et CID, ainsi que des traits associés, lesquels n’ont jamais été relatés dans la littérature. De plus, l’analyse QTL pour FTSWt n’a pas non plus été réalisée, chez aucune plante. Des QTL pour WUE et CID ont été identifiés pour différents scenario de sécheresse. Les QTL pour CID sont considérés comme ‘constitutifs’, parce qu’ils sont détectés dans les différents scenarios. Les QTL pour CID co-localisent avec ceux pour WUE, pour la biomasse et pour la transpiration cumulée. Des co-localisations de QTL ont également été observées entre FTSWt et TTSW, entre TTSW et WUE-CID-Biomasse, et entre FTSWt-TTSW et Biomasse. Cette étude met en évidence que WUE est physiologiquement et génétiquement associée à CID. De plus, CID représente un excellent substitue à la mesure de WUE et permet d’améliorer l’efficience d’utilisation de l’eau par sélection assistée par marqueurs. / Water use efficiency (WUE), measured as the ratio of plant biomass to water consumption, is an essential agronomical trait for enhancing crop production under drought. Measuring water consumption is logistically difficult, especially in field conditions. The general objective of the present Thesis is to respond to three main questions: (i) can WUE be determined by using carbon isotope discrimination (CID), easy to measure?, (ii) how WUE and CID variation analysis can contribute to the genotypic selection of sunflower subjected to drought?, and (iii) can WUE variation be revealed by the variation of plant-water relation traits. Four experiments were carried out in greenhouse across two different years: (i) on two drought scenarios, progressive soil drying and stable water-stress, and (ii) on five levels of soil water content. The main traits that have been measured include WUE, CID, as well as plant-water relation traits, i.e. control of transpiration (FTSWt), water extraction capacity (TTSW), and dehydration tolerance (OA). A highly significant negative correlation was observed between WUE and CID, and a wide phenotypic variability was observed for both WUE and CID. A wide variability was also observed for FTSWt, TTSW and OA. The results provide new insight into the genetic control of WUE and CID related-traits, which, unlike to other crops, genetic control of WUE, CID, and TTSW in sunflower have never been reported in the literature. Further, quantitative trait loci (QTL) mapping for FTSWt was never reported in any plant species. The QTL for WUE and CID were identified across different drought scenarios. The QTL for CID is considered as a ‘‘constitutive’’ QTL, because it is consistently detected across different drought scenarios. The QTL for CID co-localized with the QTL for WUE, biomass and cumulative water transpired. Co-localization was also observed between the QTL for FTSWt and TTSW, between the QTL for TTSW and WUE-CID-biomass, as well as between the QTL for FTSWt-TTSW and biomass. This study highlights that WUE is physiologically and genetically associated with CID. CID is an excellent surrogate for WUE measurement, and can be used to improve WUE by using marker-assisted selection (MAS) to achieve the ultimate goal of plant breeding at genomic level.

Quercus robur et Quercus petraea sont deux espèces de chêne sympatriques occupant des niches écologiques distinctes et présentant des différences de sensibilités à la sécheresse. La littérature disponible suggère qu’il existe des différences inter-spécifiques stables de l’efficience d’utilisation entre ces deux espèces, Q.petraea présentant des valeurs supérieures à Q.robur. L’efficience d’utilisation de l’eau peut être étudiées à différentes échelles d’intégration spatiales et temporelle. Sur la base de mesures instantanées d’échanges gazeux foliaires, l’efficience d’utilisation de l’eau intrinsèque (Wi) peut être déterminée. D’autre part, l’efficience d’utilisation de l’eau peut être caractérisée par des mesures de composition isotopique du carbone (δ13C) au sein des tissus végétaux ou par l’estimation de l’efficience de transpiration plante entière (TE), permettant ainsi une estimation de l’efficience intégrée dans le temps. La caractérisation de l’efficience à travers ces différents estimateurs a permis de mettre en évidence chez des semis croissant en conditions contrôlées une efficience de transpiration supérieure chez Q.robur bien qu’aucune différence ne soit détectable entre les deux espèces sur la base des mesures instantanées (Wi). Ces variations de TE étaient essentiellement liées aux variations de la production de biomasse par les plants tandis que les variations de Wi qui ont été observées étaient principalement associées à la conductance stomatique. Les variations intra et inter espèces de la dynamique de réponse stomatique au changement abrupte d’un facteur environnemental (lumière, CO2, VPD) n’ont pu être clairement reliées aux variations des différents estimateurs de l’efficience ou leur composantes respectives. Par ailleurs, les conditions de stress hydriques impactaient la dynamique de réponse stomatique chez les deux espèces de chênes. Cet impact se traduit par des réponses stomatiques plus rapides. Les principales différences observées entre les espèces étaient liées à la production de biomasse. Les deux espèces affichaient en effet des stratégies d’allocation du carbone divergentes notamment au niveau du compartiment racinaire. Ainsi Q.petraea produisait un système racinaire plus fin et ramifié que Q.robur. Par ailleurs, cet état de fait était plus marqué sous conditions de stress, conditions à laquelle Q.robur est plus sensible que Q.petraea en terme de production de biomasse. La complexité des relations entre efficience d’utilisation de l’eau et l’ensemble des traits physiologiques et anatomiques étudiés ainsi que leurs possibles implications dans la tolérance à la sécheresse des deux espèces de chênes sont discutées dans cette synthèse. / Quercus robur L. and Quercus petraea (Matt.) Liebl. are two sympatric oak species occupying distinctive ecological niches as well as presenting disparate drought tolerances. Available litterature reports the existence of stable inter-specific differences of water use efficiency (WUE) between the two species, Q. petraea displaying higher values than Q. robur. Water use efficiency can be studied at several integration scales both spatially and temporally. Based on instantaneous foliar gaz exchange, the intrinsic water use efficiency can be determined (Wi). On the other hand, water use can be characterised by measurements of the carbon isotopic composition of plant tissues (13C) or by estimation of the whole plant transpiration efficiency (TE), thus allowing a time-integrated estimate of water use. The characterisation of WUE through these different estimators allowed us to put in evidence in oak seedlings grown under controlled conditions a higher transpiration efficiency in Q. robur even though no differences were observed between the two species regarding instantaneous measurements (Wi). TE variations were mainly linked to the variations of the biomass production by the plants while Wi variations were essentially associated to the stomatal conductance. Both intra and inter specific variations of the dynamics of stomatal response to step changes of environmental factors (light, CO2, VPD) could not be clearly linked to the variations of the different WUE estimates nor their respective components. Nevertheless, drought conditions impacted the stomatal dynamics in both species towards faster stomatal responses, especially for stomatal closing. Furthermore, the main observed differences between species were linked to biomass production. Both species displayed different carbon allocation strategies, especially regarding the root compartment. Thus, Q. petraea produced a significantly more ramified and thinner root system than Q. robur. Such behaviour was accentuated under drought stress, under which Q. robur was more sensitive than Q. petraea in term of biomass production. The complexity of the relationships between water use efficiency and all of these morphological and physiological traits as well as the possible drought tolerance implications in both oak species are discussed in this PhD thesis.

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[ES] La escasez de agua se está convirtiendo en un problema en zonas áridas y semiáridas del mundo, donde se localiza parte de la producción de los principales cultivos hortícolas, como en el área mediterránea. La sequía es uno de los principales factores limitantes en la agricultura y está afectando gravemente a la producción de cultivos hortícolas. La mejora de la productividad del agua en la agricultura puede lograrse mediante la utilización de determinadas estrategias. El riego deficitario consiste en el aporte de agua por debajo de las necesidades de riego (NR) de los cultivos, de manera que se produce una reducción de la evapotranspiración. Puede realizarse de manera continua o sostenida (RDS) o controlada (RDC). Con el riego deficitario se puede mejorar la eficiencia del uso del agua de riego, manteniendo el rendimiento, e incluso en ocasiones, podría mejorarse la calidad de la cosecha. En este estudio, realizado en el Centro Experimental Cajamar de Paiporta (Valencia) se evalúa el efecto del riego deficitario en cuatro de los principales cultivos hortícolas cultivados al aire libre, en el área mediterránea: coliflor, cebolla, pimiento y sandía. En la evaluación se ha analizado: crecimiento y estado hídrico de las plantas, rendimiento, eficiencia del uso del agua de riego, calidad de la producción y rentabilidad de los cultivos. En la primera campaña se ensayó el RDS, lo que permitió establecer las diferentes etapas de crecimiento de cada cultivo, que se utilizaron en las siguientes campañas en el RDC. En los cuatro cultivos, las plantas control (100% NR) han mostrado un adecuado estado hídrico, tanto en el contenido relativo de agua como en el índice de estabilidad de la membrana, mientras que las sometidas a un RDS severo, han mostrado los menores valores de ambos índices. El efecto negativo del riego deficitario sobre el rendimiento ha resultado menos importante en los cultivos de otoño-invierno que en los cultivos de primavera-verano, especialmente en la coliflor. El RDS del 50% NR ha reducido drásticamente el rendimiento comercial y, consecuentemente, los ingresos brutos, aunque haya supuesto una mejora en la eficiencia del uso del agua de riego para los cultivos de otoño-invierno. Del análisis individual de los cultivos se deduce que el rendimiento en pellas de coliflor obtenidas con RDS al 75% NR o RDC al 50% NR durante la fase juvenil, se ha mantenido en niveles similares al control, mejorando la eficiencia del uso del agua de riego. En cebolla, en caso de restricción hídrica severa, sería aconsejable aplicar RDS con el 75% NR o RDC al 50% NR durante la maduración del bulbo, ya que estas estrategias han disminuido ligeramente el rendimiento, mejorando la eficiencia del uso del agua de riego. En condiciones menos restrictivas, RDC al 75% NR durante la maduración del bulbo ha dado lugar a un rendimiento satisfactorio, con un aumento de la eficiencia del uso del agua de riego. En pimiento dulce italiano, la aplicación de RDC al 75% NR durante la recolección ha dado lugar a una reducción considerable del rendimiento, y por tanto, de los ingresos brutos, aunque con importantes ahorros de agua y con un incremento en el contenido de sólidos solubles y de compuestos fenólicos de los frutos. Acortando el ciclo de cultivo hasta principios de septiembre, cuando ya se ha cosechado la mayor parte del rendimiento comercial, se conseguiría un importante ahorro de agua y permitiría utilizar la parcela en otros cultivos. El RDS al 75% y al 50% NR, o RDC al 50% NR durante la cosecha han dado lugar a una alta incidencia de frutos afectados por blossom-end rot. En sandía puede recomendarse la aplicación de RDC, tanto al 75% como al 50% NR durante la maduración del fruto, ya que ha conducido a rendimientos comerciales aceptables. De manera general se puede afirmar que la aplicación de RDS y de RDC en los cuatro cultivos, no ha afectado de manera importante a la calidad de la producción, / [CAT] Resum L'escassesa d'aigua s'està convertint en un problema en zones àrides i semiàrides del món, on es localitza part de la producció dels principals cultius hortícoles, com és el cas de l'àrea mediterrània. La sequera és un dels principals factors limitants en l'agricultura i està afectant greument a la producció de cultius hortícoles. La millora de la productivitat de l'aigua en l'agricultura en general, i en l'horticultura en particular, es pot aconseguir mitjançant la utilització de determinades estratègies. El reg deficitari consisteix en l'aportació d'aigua per sota de les necessitats de reg (NR) dels cultius, de manera que es produeix una reducció de l'evapotranspiració. Es pot fer de manera contínua o sostinguda (RDS) o controlada (RDC). Amb el reg deficitari es pot millorar l'eficiència de l'ús de l'aigua de reg, mantenint el rendiment, i fins i tot de vegades, podria conduir a una millora de la qualitat de la collita. En aquest estudi, realitzat al Centre Experimental Cajamar de Paiporta (València, Espanya) s'avalua l'efecte del reg deficitari en quatre dels principals cultius hortícoles conreats a l'aire lliure, a l'àrea mediterrània: dos de cultiu de tardor-hivern (coliflor i ceba) i dues de cultiu primaveral-estival (pimentó i meló d'Alger). En l'avaluació s'han analitzat els següents paràmetres: creixement i estat hídric de les plantes, rendiment, eficiència de l'ús de l'aigua de reg, qualitat de la producció i rendibilitat dels cultius. A la primera campanya es va assajar el RDS, el que va permetre establir les diferents etapes de creixement de cada cultiu, que es van utilitzar en les següents campanyes en el RDC. En els quatre cultius, les plantes control (100% NR) han mostrat un adequat estat hídric, tant en el contingut relatiu d'aigua com en l'índex d'estabilitat de la membrana, mentre que les sotmeses a un RDS sever, han mostrat els menors valors d'ambdós índexs. L'efecte negatiu del reg deficitari sobre el rendiment ha resultat menys important en els cultius de tardor-hivern que en els cultius de primavera-estiu, especialment en la coliflor. El RDS del 50% NR ha reduït dràsticament el rendiment comercial i, conseqüentment, els ingressos bruts, encara que hagi suposat una millora en l'eficiència de l'ús de l'aigua de reg per als cultius de tardor-hivern. De l'anàlisi individual dels cultius es dedueix que el rendiment de coliflors obtingudes amb RDS al 75% NR o RDC al 50% NR durant la fase juvenil, s'ha mantingut en nivells similars al control, millorant l'eficiència de l'ús de l'aigua de reg. En ceba, en cas de restricció hídrica severa, seria aconsellable aplicar RDS amb el 75% NR o RDC al 50% NR durant la maduració del bulb, ja que aquestes estratègies han disminuït lleugerament el rendiment, millorant l'eficiència de l'ús de l'aigua de reg . En condicions menys restrictives, RDC al 75% NR durant la maduració del bulb ha donat lloc a un rendiment satisfactori, amb un augment de l'eficiència de l'ús de l'aigua de reg. En pimentó dolç italià, l'aplicació de RDC al 75% NR durant la recol·lecció ha donat lloc a una reducció considerable del rendiment, i per tant, dels ingressos bruts, encara que amb importants estalvis d'aigua i amb un increment en el contingut de sòlids solubles i de compostos fenòlics dels fruits. Retallant el cicle de cultiu fins a principis de setembre, quan ja s'ha collit la major part del rendiment comercial, s'aconseguiria un important estalvi d'aigua i permetria utilitzar la parcel·la en altres cultius. El RDS al 75% i al 50% NR, o RDC al 50% NR durant la collita han donat lloc a una alta incidència de fruits afectats per blossom-end rot. En meló d'Alger es pot recomanar l'aplicació de RDC, tant al 75% com al 50% NR durant la maduració del fruit, ja que ha conduït a rendiments comercials acceptables. De manera general es pot afirmar que l'aplicació de RDS i de RDC en els quatre cultius, no ha afectat de maner / [EN] Water scarcity is becoming a critical problem in arid and semi-arid areas of the world, where part of the production of the main horticultural crops is located, as is the case of the Mediterranean area. Drought is one of the main limiting factors in agriculture and it is seriously affecting the production of horticultural crops. The improvement of water productivity in agriculture in general, and in horticulture in particular, can be achieved through the use of certain strategies. Deficit irrigation consists of the supply of water below the irrigation water requirements (IWR), so that there is a reduction in evapotranspiration. It can be done continuously (CDI) or regulated (RDI). With deficit irrigation, the irrigation water use efficiency can be improved, maintaining yield, and it could even lead to an improvement in the quality of the harvest. This study, carried out at the Cajamar in Paiporta Experimental Center (Valencia, Spain), analyzes the effect of deficit irrigation on four of the main cultivated horticultural crops, open field cultivated in the Mediterranean area: two of autumnal-winter crops (cauliflower and onion) and two spring-summer crops (pepper and watermelon). In the evaluation, the following parameters have been analyzed: plant growth and water status, yield, irrigation water use efficiency, quality of production and crop profitability. In the first season the CDI was tested, which allowed to establish the different growth stages for each crop, which were used in the following season for the RDI. In the four crops, the control plants (100% IWR) have shown an adequate water status, in terms of both relative water content and membrane stability index, while those subjected to a severe CDI, have shown the lowest values of both indexes. The negative effect of deficit irrigation on yield has been less important in autumn-winter crops than in spring-summer crops, especially in cauliflower. The CDI at 50% IWR has drastically reduced the marketable yield and, consequently, the gross revenue, although it has supposed an improvement in the irrigation water use efficiency for the autumn-winter crops. From the individual analysis of the crops, it can be stated that cauliflower yield obtained with CDI at 75% IWR or RDI at 50% IWR during the juvenile phase, has remained at levels similar to the control, improving the irrigation water use efficiency. In relation to onion, in case of severe water restriction, it would be advisable to apply CDI with 75% IWR or RDI at 50% IWR during bulb ripening, since these strategies have slightly decreased yield, improving the irrigation water use efficiency. In less restrictive conditions, RDI at 75% IWR during the bulb maturation has led to a satisfactory yield, with an increase in the irrigation water use efficiency. In Italian sweet pepper, the application of RDI to 75% IWR during the harvesting has resulted in a considerable reduction of the yield, and therefore, of the gross income, although with important water savings and increasing the fruit soluble solids and phenolic compounds content. By shortening the cultivation cycle until the beginning of September, when most of the marketable yield has already been harvested, significant water savings would be achieved, and the land could be used in other crops. CDI at 75% IWR and 50% IWR, or RDI at 50% IWR at harvesting have resulted in a high incidence of fruit affected by blossom-end rot. In watermelon the RDI application can be recommended, both 75% and 50% IWR, during the fruit ripening, since it has led to acceptable marketable yields. In general terms, it can be affirmed that the application of CDI and RDI in the four crops has not significantly affected the product quality, in terms of the analyzed parameters. / My grateful thanks to the Cultural Affairs and Mission Sector, Egyptian Ministry of Higher Education for supporting me with a scholarship. / Abdelkhalik, AGA. (2019). Effect of continued and regulated deficit irrigation on the productivity of four vegetable crops in open-field conditions in the Mediterranean area [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/129868 / TESIS

Bermudagrass (Cynodon spp.) is the most common turfgrass used on golf course putting greens in the southeastern United States (Lyman et al., 2007). In 2013, the National Turfgrass Evaluation Program (NTEP) started a 5-year trial of warm-season putting green cultivars. One of the bermudagrass cultivars in the study is MSB-285 (experimental cultivar). MSB-285 is a sister plant of MSB-264 (Philley and Munshaw, 2011) and is a distinct cultivar of C. dactylon × C. transvaalensis. MSB-285 has a more extensive root system and upright growth habit than traditional bermudagrass putting green cultivars (Philley and Munshaw, 2011). Due to MSB-285’s unique genetic makeup and growth habit, the objectives of this research were to determine if best management practices used to maintain ultradwarf bermudagrasses would be suitable for MSB-285 and to determine the water-use characteristics of MSB-285 compared to industry standard cultivars.

The access of water globally is becoming more strained, why the focus on industrial water use is increasing. The present study examined how industries should approach water efficiency projects, what organizational constraints that should be addressed, and what effects water saving measures have on economic costs, environmental impact and influence from water related risks. The study has been conducted at Saab Group. Primary data for water supply amount and cost has been obtained from twelve sites for the year of 2018. Data from these sites has been used to estimate the water use for the other 43 sites included in this study. Interviews with employees across Saab´s organization and with external stakeholders have functioned as important sources of information, combined with investigations of internal company documents. To facilitate for companies to structurally address water efficiency projects, the concept of the Deming Cycle is developed in this study. The steps included are necessary to address major identified organizational constraints which are lack of communication, lack of incentives for employees, and lack of economic incentives. Furthermore, with water often having energy embedded into it, a new Water Management Hierarchy is developed to include the interrelated aspects of energy supply and energy recovery. The potential for pipe leakages and the challenge to detect these are also identified. If the time from leak occurrence to repair in 2018 was eliminated, the total water supply in Arboga could have been reduced with 10100 m3 which corresponds to 35% of total supply to the site, respectively 35900 m3 and 42% in Björkborn. In Tannefors, water saving measures are identified for a surface treatment process, a facility with testing equipment, and by utilization of groundwater. Not all water saving measures result in reduced annual operating costs, due to an increased energy demand. Furthermore, if neglecting the possibility of energy recovery when aiming for water use reduction, the results show that replacing a once-through cooling system using potable municipal water as a medium with a dry-cooling unit, can increase greenhouse gas emissions. In 2018, the simultaneously implementable water saving measures in Tannefors would have reduced the water supply with 40600 m3, which corresponds to 22% of the total supply to the site. The greenhouse gas emissions would simultaneously have been reduced with 0.4 tonnes CO2eq. If also addressing energy supply reduction and energy recovery, some measures achieves a reduction of over 35 tonnes CO2eq, which results in enhanced economic viability from reduced operating costs. This study suggest that organizational constraints have to be addressed to successfully implement identified water saving measures. To allow economic motivation for all water saving measures in Tannefors, a payback period of over 7 years has to be applied, which can be lowered if the measure also reduces energy demand or increases energy recovery. In order to avoid sub-optimization of water saving measures, the current Water Management Hierarchy has to include the aspects of energy supply and energy recovery. If the aim is to reduce a corporation’s water use, the largest sites with heavy industrial processes should be addressed first. However, the potential impact from water related risks at smaller sites should not be neglected, in order to ensure safe operations and avoid increased costs in the company´s supply chain. / Tillgången av vatten blir alltmer ansträngd globalt, varför fokus på industriell vattenanvändning ökar. Den här studien undersökte hur industrier bör förhålla sig till vatteneffektivitetsprojekt, vilka organisatoriska begränsningar som bör hanteras, och vilka effekter vattenbesparande åtgärder har på ekonomiska kostnader, miljöpåverkan och påverkan från vattenrelaterade risker. Studien har genomförts på Saab Group. Primärdata för vattentillförselmängd och kostnad har erhållits från tolv platser för år 2018. Data från dessa siter har används för att uppskatta vattenanvändningen för de övriga 43 siterna som ingår i denna studie. Intervjuer med anställda inom Saabs organisation och med externa intressenter har fungerat som viktiga informationskällor, i kombination med undersökningar av interna företagsdokument. För att underlätta för företag att strukturellt ta itu med vatteneffektivitetsprojekt, så utvecklas Demingcykel-konceptet i den här studien. De inkluderade stegen är nödvändiga för att hantera viktiga identifierade organisatoriska begränsningar som är brits på kommunikation, brist på incitament för anställda och brist på ekonomiska incitament. Vidare, då vatten ofta är en energibärare, utvecklas en ny vattenminskningshierarki för att inkludera de sammanhängande aspekterna av energitillförsel och energiåtervinning. Potentialen för rörläckage och utmaningen att upptäcka dessa identifieras också. Om tiden från läckage till reparation under 2018 eliminerades, kunde den totala vattentillförseln i Arboga ha minskat med 10100 m3 vilket motsvarar 35% av total vattentillförsel till siten, respektive 35900 m3 och 42% i Björkborn. I Tannefors identifieras vattenbesparingsåtgärder för en ytbehandlingsprocess, en anläggning med testutrustning, och genom utnyttjande av grundvatten. Alla vattenbesparande åtgärder resulterar inte i minskade årliga driftkostnader, på grund av ett ökat energibehov. Vidare, om möjligheten för energiåtervinning förbises när reducering av vattenanvändning är målet, visar resultaten att ersättningen av ett kylsystem som använder kommunalt dricksvatten utan recirkulering med en luftkyld enhet, att utsläppen av växthusgaser kan öka. Under 2018, så skulle de simultant implementerbara vattenbesparande åtgärderna i Tannefors ha minskat vattentillförseln med 40600 m3, vilket motsvarar 22% av den totala tillförseln till siten. Utsläppen av växthusgaser hade samtidigt minskats med 0.4 ton CO2eq. Om även energitillförsel och energiåtervinning tas i beaktande, uppnår vissa åtgärder en minskning på över 35 ton CO2eq, vilket resulterar i förbättrad ekonomisk lönsamhet från minskade driftkostnader. Denna studie föreslår att organisatoriska begränsningar måste hanteras för att framgångsrikt genomföra identifierade vattenbesparande åtgärder. För att möjliggöra ekonomisk motivering för alla vattenbesparande åtgärder i Tannefors, måste en återbetalningstid på över sju år tillämpas, vilken kan sänkas om åtgärden också minskar energibehovet eller ökar energiåtervinningen. För att undvika suboptimering av vattenbesparande åtgärder, måste den nuvarande vattenhierarkin inkludera aspekterna av energitillförsel och energiåtervinning. Om målet är att minska ett företags vattenanvändning, bör de största anläggningarna med tunga industriprocesser först adresseras. Dock bör den potentiella påverkan från vattenrelaterade risker på mindre siter inte försummas, för att säkerställa säker drift och undvika ökade kostnader i företagets värdekedja.

Literature survey shows that with, a few exceptions, the consumer behaviour of domestic water consumers has not been a common area of research. This explains the scarcity of information in this specific field. This scarcity was noted in the region and very much so in the context of Mauritius. And yet, such information is very much relevant for the management of the water sector, for the improvement of the service, for policy makers, for personal and social development and for achieving consumer satisfaction. This research brings about information that would contribute in its own way to these areas. The object of this thesis is to study the consumer behaviour in respect of domestic water consumers in Mauritius, to develop new theories and to build a consumer behaviour model. The thesis, at its outset, gives the background of the research. It contains the description of the water supply situation in Mauritius, its production, its distribution and its management. The brief on the people of Mauritius helps to put in the right context the pluricultural nature of the Mauritian society which is important for the understanding of the consumer behaviour of Mauritians. The literature survey, inter-alia, gives the historical development of consumer behaviour, its relevance to marketing, and its study as a discipline in its own right. The very scarcity of theories and models of consumer behaviour of domestic water consumers cannot be overlooked. The literature survey, therefore, covers some of the theories and models specifically on commodities. These models along with the literature review serve as theoretical foundation for the present research The models of consumer behaviour which have been literature reviewed have further enabled to construct an integrated model of consumer behaviour which serves as a framework for the discussion and analysis of the new model which is developed during the course of this research. The research is one mainly of general interest and can be classified as an exploratory research with a substantial contribution of descriptive research. The research has necessitated the collection of primary data. For this purpose, the objective approach was adopted and a consumer survey was carried out with the use of a direct structured questionnaire. The survey has been supplemented by discussions of focus groups. The analysis of the consumer survey is followed by the testing of the hypotheses, the development of theories and discussions on results obtained. The building of a new model of consumer behaviour based on the findings of the research is then undertaken and discussed. The thesis covers a wide spectrum from the need of a domestic water connection, consumption of domestic water, post-consumption behaviour to the illegal use of water in Mauritius. The thesis winds up with conclusions and recommendations. The specific topic of this thesis is a rare one. This research is but a step in the furtherance of knowledge. It stands as an original regional contribution to the science of management and to its development. / Graduate School of Business Leadership / DBL

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.