Submitted by Mario BC (mario@bc.ufrpe.br) on 2016-11-03T12:55:19Z No. of bitstreams: 1 Jonathas Rafael Moura de Oliveira.pdf: 1914760 bytes, checksum: 7b129e821da38e2d66a5ac9fc492da19 (MD5) / Made available in DSpace on 2016-11-03T12:55:19Z (GMT). No. of bitstreams: 1 Jonathas Rafael Moura de Oliveira.pdf: 1914760 bytes, checksum: 7b129e821da38e2d66a5ac9fc492da19 (MD5) Previous issue date: 2014-02-03 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Currently sweet sorghum (Sorghum bicolor (L.) Moench) has become very important for the energy sector and sugarcane in Brazil, which is constantly seeking alternatives to increase agricultural and industrial yields, especially in the off season of cane sugar, decreasing the idle time and production costs. It is a rustic agricultural species, with good adaptation to environmental stresses, such as those found in the Northeast, with features similar to stalks of sugarcane juice rich in fermentable sugars, and can be used to produce ethanol in the same facility used by the cane sugar. The culture is totally mechanized (by planting seeds, and harvesting), high productivity of green biomass (60-80 t ha-1), with high yields of ethanol (3000-6000 l.ha-1), bagasse usable as a source of energy (steam and electricity cogeneration industrialization). The present study was designed to indicate the most suitable for a probable launch as a variety to be grown in the Zona da Mata, Region of the State of Pernambuco, Northeast, Brazil genotypes. For this purpose, an experiment was carried out from February to June 2014 in the experimental field at the Pernambuco Agricultural Institute Enterprise - IPA, in Vitória de Santo Antão, Pernambuco. The study consisted of 65 progenies that are the result of segregation F6 a cross between two varieties (IPA467-4-2 X IPA 2502), where the first strain was used as male parent and the second as the female parent, were obtained in Vitória Santo Antão - PE in 2010, tested in Caruaru - PE in 2011 and retested in Vitória de Santo Antão - PE in 2013, more than 15 witnesses were commercial varieties in the region, including these two parental strains. The experiment was designed in randomized blocks, consisting of 80 plots and 3 replications, where each portion had dimensions of 6.0 x 0.8 m, with a total area of 4.80 m2 and is considered an area of 3.20 m² (0 , 8 x 4m), eliminating the first meter of each boundary. Variables according to the production characteristics presented in the field were analyzed: average height of plant (AMP); Days to flowering (FL); Total production of green matter (PMV); Production Shed (PCL) and Percentage of thatch to produce total green matter (% CL). Besides the agroindustrial features: Production of total dry matter (PMS); Percentage of total dry matter (% MST); Production Shed (PCL); Harvesting Brix (Brix); Extraction efficiency of broth (EEC) and theoretical Ethanol (ET). Means were compared by Scott - Knott test at 5% level of probability, genetic correlations being conducted to complement the study of these variables. / Atualmente o sorgo sacarino (Sorghum bicolor (L.) Moench) apresenta-se muito importante para o setor sucroalcooleiro e energético do Brasil, que vem buscando constantemente alternativas para aumentar rendimentos agrícolas e industriais, principalmente na entressafra da cana-de-açúcar, diminuindo o tempo ocioso e os custos de produção. É uma espécie agrícola rústica, com boa adaptação a estresses ambientais, tais como os encontrados na Região Nordeste, apresenta colmos com caldo semelhante ao da cana, rico em açúcares fermentescíveis, e pode servir para a produção de etanol na mesma instalação utilizada pela cana-de-açúcar. A cultura é totalmente mecanizável (plantio por sementes, tratos culturais e colheita), alta produtividade de biomassa verde (60 a 80 t.ha-1), com altos rendimentos de etanol (3.000 a 6.000 l.ha-1), com bagaço utilizável como fonte de energia (vapor para industrialização e cogeração de eletricidade). O presente trabalho teve como objetivo avaliar o potencial de novas progênies F6 de sorgo de duplo propósito (grão e forragem, incluindo colmo seco e sacarino), visando definição de aptidão e uso. Para tanto, foi conduzido um experimento nos meses de fevereiro a junho de 2014, no campo experimental no Instituto Agronômico de Pernambuco – IPA, no município de Vitória de Santo Antão-PE. O estudo foi composto por 65 progênies que são resultado da segregação F6 do cruzamento entre duas variedades (IPA 467-4-2 X IPA 2502), onde a primeira variedade foi utilizada como parental masculino e a segunda como parental feminino, sendo obtidas em Vitória de Santo Antão – PE em 2010, testadas em Caruaru – PE em 2011 e novamente testadas em Vitória de Santo Antão – PE em 2013, mais 15 testemunhas que foram variedades comerciais na região, incluindo nestas as duas variedades parentais. O experimento foi delineado em blocos casualizados, composto por 80 parcelas e 3 repetições, onde cada parcela teve dimensões de 6,0 x 0,8m, com 4,80m2 de área total, sendo considerada uma área útil de 3,20 m² (0,8 x 4m), eliminando o primeiro metro de cada bordadura. As variáveis foram analisadas de acordo com as características de produção apresentada em campo: Altura média de planta (AMP); Dias até o florescimento (FL); Produção de matéria verde total (PMV); produção de colmo (PCL) e Porcentagem de colmo na produção de matéria verde total (%CL). Além das características agroindustriais: Produção de matéria seca total (PMS); Porcentagem de matéria seca total (%MST); Produção de colmo (PCL); Brix na colheita (BRIX); Eficiência de extração de caldo (EEC) e Etanol teórico (ET). As médias foram comparadas pelo teste de Scott - Knott em nível de 5% de probabilidade, sendo realizada a correlação genotípica para complementar o estudo destas variáveis.

Dans l'optique de produire des agro‐carburants, le sorgho sucré est aujourd'hui proposé comme une alternative à d'autres espèces cultivées à grande échelle comme la canne à sucre et le maïs car il présente plusieurs avantages : le sorgho est résistant à la sécheresse et à la chaleur, il nécessite peu d'intrants, a en moyenne un cycle de culture relativement court (3‐4 mois) comparé à la canne à sucre. Il offre une grande diversité génétique à explorer et exploiter, tout en étant génétiquement moins complexe que la canne à sucre. Finalement, il peut être cultivé pour un double usage, le grain pouvant être utilisé comme source d'alimentation pour l'homme ou le bétail (à partir du grain) et le jus sucré contenu par les tiges comme source d'agrocarburant. Cette polyvalence en fait une culture idéale pour lutter contre la compétition entre cultures énergétiques et cultures vivrières et assurer des rendements dans des environnements de culture sujets au stress hydrique et thermique comme c'est le cas en Afrique de l'Ouest. Cependant, le caractère sucré du sorgho est complexe, car sous l'influence d'interactions Génotype X Environnement (GxE). Aussi, les mécanismes métaboliques, morphologiques ou phénologiques constituant la cinétique d'accumulation des glucides dans la tige et son éventuelle compétition avec le remplissage des grains restent mal connus ou très controversés dans la littérature. La présente thèse, réalisée dans le cadre du projet européen Sweetfuel, vise à comprendre ces mécanismes, afin de contribuer à la définition d'idéotypes de sorgho double usage, pour les environnements soudano‐sahéliens.Sur la base d'études expérimentales au champ au Mali et en serre en France, il a pu être démontré que les glucides sont accumulés dans les entrenoeuds des tiges par un jeu d'activités enzymatiques (favorisant l'accumulation d'hexoses puis de saccharose) dès le début de leur élongation, donc potentiellement avant la floraison. Au Mali, l'étude au champ de 14 génotypes adaptés aux conditions locales, plus ou moins sensibles à la photopériode et semés à trois dates différentes, a démontré le bénéfice d'un rallongement de la phase végétative sur la quantité de sucre accumulée dans les tiges de la plante à floraison, du fait d'un plus grand nombre d'entrenoeuds allongés et du temps à leur disposition pour accumuler des glucides avant ce stade. Ce bénéfice était cependant plus lié à la plus grande quantité de biomasse accumulée (taille des tiges) qu'à la concentration en sucre dans les entrenoeuds (plutôt stable entre dates de semis).Ainsi, la durée de la phase végétative et la sensibilité à la photopériode sont proposés comme des paramètres clés favorisant la quantité de glucides accumulée dans les tiges de la plante à floraison. D'autre part, il a été montré que la quantité de glucides présente à maturité dans les tiges des mêmes génotypes ne différait pas ou peu de celle à floraison, une éventuelle réduction pour quelques génotypes n'étant généralement pas significative et évitable par l'allongement du cycle. De plus, cette quantité de glucides dans les tiges à maturité n'a tiré aucun bénéfice de l'ablation de la panicule à floraison chez les mêmes génotypes. Ces résultats suggèrent que la compétition entre le remplissage du grain et la production de sucre est faible chez le sorgho, d'autant plus faible que la plante présente de grandes tiges et donc un grand compartiment de stockage des glucides, tamponnant cette éventuelle compétition. D'ailleurs, à une échelle plus fine, aucune différence n'a pu être mise en évidence en termes d'activité des principales enzymes du métabolisme carboné dans la tige d'un génotype dans sa version stérile (pas de remplissage du grain) et fertile.Ce travail a démontré le potentiel du sorgho pour une double utilisation dans un contexte soudano‐sahélien et la pertinence d'exploiter la diversité génétique de cette espèce pour cette objectif de sélection. Les résultats ob / Sweet sorghum offers many advantages as an alternative to widely cultivated crops such as corn and sugarcane to produce biofuels: it is resistant to water stress, it requires few inputs; it has a shorter growth cycle compared to sugarcane in particular. Sorghum also exhibits a great genetic diversity and is genetically less complex than sugarcane. Finally, sorghum can be cultivated for dual‐purpose uses, using grains for food or feed and sweet juice for biofuel production. Hence, sorghum is a promising option to reduce the competition for land and (water) resource use between food and fuel, in particular in cropping environments with high drought and heat stress frequency, as in West Africa. However, stem sweetness is a complex trait prone to genotype x environment interactions (GxE). The metabolic, morphological and phenological mechanisms involved in the kinetic of stem sugar accumulation and its possible competition with grain filling are largely unknown or controversial in the literature. The present work is part of the European project Sweetfuel and aims at better understanding these mechanisms and contributing to define dual‐purpose sorghum ideotypes for soudano‐sahelian conditions.Based on field and greenhouse experiments respectively in Mali and France, it was found that sugars start accumulating in stem internodes at the onset of their elongation, i.e. potentially soon before the plant flowers. The successive accumulation of hexose and then sucrose in internodes could be dynamically explained by changes in the activity of key enzymes related to sucrose metabolism. In Mali, a field experiment performed on 14 genotypes, contrasted for photoperiod sensitivity and sown at three planting dates, highlighted the interest of increasing vegetative phase duration to increase sugar yield. This was explained first of all by the higher number of internodes that could expand during a longer vegetative phase, and thus, by the higher production of stem biomass, and, to a minor extent, by the longer time for internodes to mature and accumulate sugar (sugar concentration in the stem was however fairly stable across sowing dates). Also, vegetative phase duration and photoperiod sensitivity can be considered as two key parameters promoting stem sugar content before grain filling. In the same time, it was shown that stem sugar content kept remarkably constant between anthesis and maturity in most of studied genotypes and that the reduction observed for some genotypes was overcome with an early sowing. Moreover, sugar accumulation in the stem between flowering and maturity did not benefit from panicle pruning. These results together suggest that the competition for carbohydrates between stem sugar reserves and grain filling is weak; it is even weaker for big/large stem genotypes with huge sugar reserves in the stem that would buffer a post‐flowering allocation of sugar from the stem to the grains if required. This low competition was confirmed at a finer scale, as no differences were observed in the activity of key enzymes of sucrose metabolism between the sterile and the fertile line of a same genotype.This work demonstrates the potential of sorghum for dual‐purpose in particular for soudano‐sahelian cropping conditions and the interest of using its genetic diversity for this breeding purpose. It provides further knowledge for revisiting the phenotyping strategies to be adopted to investigate the genetic basis of sugar and grain production and their combination. The results are also currently used to improve the way the source‐sink relationships underlying this dual production are formalized in crop and plant models at CIRAD. Such models will be then useful to assist sorghum ideotype exploration for dual purpose.

It is clear that renewable resources have received great interest from the international community during the last decades and play a crucial role in the current CO2-mitigation policy. In this regard, energy from biomass and waste is seen as one of the most dominant future renewable energy sources. Thus, organic waste i.e. animal wastes, wastewaters, energy crops, agricultural and agro-industrial residues are of specific importance since these sources do not compete with food crops in agricultural land usage. The various technologies that are available for power generation from biomass and waste can be subdivided into thermochemical, biochemical and physicochemical conversion processes. Anaerobic digestion (AD), classified within the biochemical conversion processes, is a robust process and is widely applied. Various types of biomass and waste, can be anaerobically co-digested to generate a homogeneous mixture increasing both process and equipment performance. This study focused on the valorization of agro-industrial wastes (such as olive mill wastewater (OMW), cheese whey (CW) and liquid cow manure (LCM)) and sweet sorghum stalks. Olive mills, cheese factories and cow farms are agro-industries that represent a considerable share of the worldwide economy with particular interest focused in the Mediterranean region. These industries generate millions of tons of wastewaters and large amounts of by-products, which are in many cases totally unexploited and thus dangerous for the environment. On the other hand, sweet sorghum as a lignocellulosic material represents an interesting substrate for biofuels production due to its structure and composition. Anaerobic co-digestion experiments using different mixtures of agro-industrial wastes were performed in a two-stage system consisting of two continuously stirred tank reactors (CSTRs) under mesophilic conditions (37°C). Subsequently, more mixtures were studied, where sweet sorghum was added, in order to simulate the operation of a centralized AD plant fed with regional agro-wastes which lacks OMW or/and CW due to seasonal unavailability. Two operational parameters were examined in a two-stage system, including pH and HRT. Batch experiments were performed in order to investigate the impact of controlled pH on the production of bio-hydrogen and volatile fatty acids, whereas continuous experiments (CSTRs) were conducted for the evaluation of HRT effect on hydrogen and methane production. Moreover, further exploitation of digestate from an anaerobic methanogenic reactor was studied using a combined ultrafiltration/nanofiltration system and further COD reduction was obtained. On the other hand, vermicomposting was conducted in order to evaluate the sludge transformation to compost and as a result, good results in terms of increased N-P-K concentration values were obtained. Furthermore, simulation of mesophilic anaerobic (co)-digestion of different substrates was applied, using the ADM1 modified model, where the results indicated that the modified ADM1 was able to predict reasonably well the steady-state experimental data. / Είναι φανερό ότι οι ανανεώσιμες πηγές ενέργειας έχουν προσελκύσει το ενδιαφέρον της διεθνούς κοινότητας τις τελευταίες δεκαετίες καθώς διαδραματίζουν καθοριστικό ρόλο στην μείωση του CO2. Η ενέργεια από βιομάζα και απόβλητα θεωρείται ως μία από τις πλέον κυρίαρχες ανανεώσιμες πηγές ενέργειας του μέλλοντος. Έτσι, τα οργανικά απόβλητα όπως κτηνοτροφικά, ενεργειακές καλλιέργειες, γεωργικά και βιομηχανικά υπολείμματα κ.ά έχουν ιδιαίτερη σημασία, δεδομένου ότι οι πηγές αυτές δεν ανταγωνίζονται με τις καλλιέργειες τροφίμων της γεωργικής γης και ωστόσο μπορούν να χρησιμοποιηθούν για την παραγωγή ηλεκτρικής ενέργειας, θερμότητας και βιοκαυσίμων. Το αυξημένο ενδιαφέρον για τις διεργασίες που αφορούν στη μετατροπή της βιομάζας σε ανανεώσιμες πηγές ενέργειας, όπως είναι η αναερόβια χώνευση, τόνωσε την έρευνα σε αυτόν τον τομέα με αποτέλεσμα την υλοποίηση ενός σημαντικού αριθμού ερευνητικών έργων για να αξιολογηθούν οι ιδανικές συνθήκες χώνευσης διαφόρων υποστρωμάτων, όπως είναι τα αγροτο-βιομηχανικά απόβλητα και οι ενεργειακές καλλιέργειες. Στη παρούσα διατριβή πραγματοποιήθηκαν πειράματα αναερόβιας συγχώνευσης χρησιμοποιώντας αγροτο-βιομηχανικά απόβλητα ή/και γλυκό σόργο. Τα αγροτο-βιομηχανικά απόβλητα, όπως είναι τα απόβλητα ελαιοτριβείου, τυροκομείου αλλά και βουστασίου, χαρακτηρίζονται από υψηλό οργανικό φορτίο και συνεπώς θεωρούνται ακατάλληλα για απευθείας διάθεση σε περιβαλλοντικούς αποδέκτες. Συγχώνευση αυτών οδήγησε σε υψηλές αποδόσεις μεθανίου κάτι το οποίο οφείλεται σε συνεργιστικές επιδράσεις όπως η συμβολή επιπλέον αλκαλικότητας, ιχνοστοιχείων, θρεπτικών κτλ. Περαιτέρω μίγματα μελετήθηκαν χρησιμοποιώντας το γλυκό σόργο με σκοπό την προσομοίωση λειτουργίας μιας κεντρικής μονάδας αναερόβιας χώνευσης, η οποία τροφοδοτείται με τοπικά απόβλητα τα οποία θα αντικατασταθούν σε περίοδο μη εποχικής διαθεσιμότητας από το γλυκό σόργο. Τα μίγματα αυτά μελετήθηκαν σε διβάθμιο σύστημα διερευνώντας την επίδραση των δύο σημαντικότερων λειτουργικών παραμέτρων (του pH και του υδραυλικού χρόνου παραμονής, HRT) στην απόδοση του συστήματος. Πιο συγκεκριμένα, πραγματοποιήθηκαν πειράματα διαλείποντος έργου προκειμένου να διερευνηθεί η επίδραση του pH στην παραγωγή υδρογόνου και μεταβολικών προϊόντων, ενώ πειράματα συνεχούς λειτουργίας διεξήχθηκαν για τη μελέτη της επίδρασης του HRT στην παραγωγή υδρογόνου και μεθανίου σε διβάθμιο σύστημα. Περαιτέρω αξιοποίηση του χωνευμένου υπολείμματος μελετήθηκε με χρήση συνδυασμένου συστήματος υπερδιήθησης/νανοδιήθησης επιτυγχάνοντας επιπρόσθετη μείωση του οργανικού φορτίου στο διήθημα. Η μετατροπή της αναερόβια χωνευμένης ιλύος σε λίπασμα αξιολογήθηκε μέσω κομποστοποίησης με γεωσκώληκες (vermi-composting) επιτυγχάνοντας ικανοποιητικά αποτελέσματα στην αύξηση των συγκεντρώσεων N-P-K. Επιπλέον, αναπτύχθηκε τροποποιημένο μοντέλο της αναερόβιας χώνευσης (ADM1) με στόχο την προσομοίωση της αναερόβιας συγχώνευσης διαφορετικών υποστρωμάτων. Τα αποτελέσματα που προέκυψαν έδειξαν ότι το μοντέλο ήταν σε θέση να προβλέψει σε ικανοποιητικό βαθμό την πορεία των πειραματικών δεδομένων.

Σκοπός της παρούσας διδακτορικής διατριβής ήταν η μελέτη της δυναμικής του αζώτου σε καλλιέργεια γλυκού σόργου. Χρησιμοποιήθηκαν φυτά γλυκού σόργου [Sorghum bicolor (L) Moench] ποικιλίας Keller και πραγματοποιήθηκαν αφ’ ενός πειράματα στο πεδίο αφ’ ετέρου πειράματα σε πλαστικά δοχεία. Τα πειράματα πεδίου πραγματοποιήθηκαν σε αγρόκτημα του Πανεπιστημίου Πατρών, τις καλλιεργητικές περιόδους του 2004 και 2005, και περιλάμβαναν δύο χειρισμούς (βιολογική και συμβατική διαχείριση της γονιμότητας του εδάφους), με τρεις επαναλήψεις ο καθένας σε πλήρη τυχαιοποιημένη διάταξη. Τα αποτελέσματα των πειραμάτων πεδίου, έδειξαν ότι η βιολογική διαχείριση της γονιμότητας του εδάφους ευνόησε τη διαθεσιμότητα του εδαφικού νιτρικού αζώτου. Το 2004, μέχρι και την ολοκλήρωση της άνθησης, τα φυτά του βιολογικού χειρισμού συσσώρευσαν περισσότερο άζωτο από ό,τι τα φυτά του συμβατικού χειρισμού, αν και οι διαφορές δεν ήταν στατιστικά σημαντικές, εκτός από τη δεύτερη δειγματοληψία, όπου τα φυτά του συμβατικού χειρισμού συσσώρευσαν 2,69 N gm-2, ενώ για τα φυτά του βιολογικού χειρισμού η αντίστοιχη τιμή ήταν 5,12 N gm-2. Το 2005, η συσσώρευση αζώτου ακολούθησε παρόμοια πορεία μέχρι τα μέσα της άνθησης και οι διαφορές δεν ήταν στατιστικά σημαντικές, εκτός από τη τρίτη δειγματοληψία, όπου τα φυτά του συμβατικού χειρισμού συσσώρευσαν 3,61 N gm-2, ενώ για τα φυτά του βιολογικού χειρισμού η αντίστοιχη τιμή ήταν 4,61 N gm-2. H επίδραση εμβολίων Azospirillum brasilense, σε παραμέτρους αύξησης φυτών γλυκού σόργου και στην πρόσληψη αζώτου από τα φυτά, υπό διαφορετικά επίπεδα αζωτούχου λίπανσης μελετήθηκε σε πειράματα σε πλαστικά δοχεία. Το κάθε πείραμα περιλάμβανε πέντε χειρισμούς με τριάντα επαναλήψεις, έκαστος. Τα φυτά που εμβολιάστηκαν με Azospirillum brasilense και έλαβαν τη μισή ποσότητα αζώτου, έδωσαν 7,69 g ξηρής βιομάζας φυτό-1 στο τέλος του πρώτου πειράματος και 4,89 g ξηρής βιομάζας φυτό-1 στο τέλος του δεύτερου πειράματος, ενώ τα φυτά που δέχθηκαν πλήρη λίπανση αζώτου χωρίς εμβόλιο έδωσαν 2,39 και 2,04 g ξηρής βιομάζας φυτό-1 στο τέλος του πρώτου και δεύτερου πειράματος αντιστοίχως. Οι διαφορές των χειρισμών ανά πείραμα ήταν στατιστικά σημαντικές. Το συνολικό προσλαμβανόμενο άζωτο από τα φυτά που εμβολιάστηκαν με Azospirillum brasilense και έλαβαν τη μισή ποσότητα αζώτου ήταν 153,23 και 99,96 mg φυτό-1 στο τέλος του πρώτου και του δεύτερου πειράματος αντιστοίχως. Οι τιμές ήταν υψηλότερες σε σχέση με τις τιμές του συνολικού προσλαμβανόμενου αζώτου των φυτών των λοιπών και οι διαφορές ήταν στατιστικά σημαντικές. Τα αποτελέσματα των πειραμάτων έδειξαν υψηλή αξιοποίηση του εφαρμοζόμενου αζώτου των φυτών που εμβολιάστηκαν με Azospirillum. Τα αποτελέσματα υποδεικνύουν την βιωσιμότητα ενός βιολογικού συστήματος καλλιέργειας, όσον αφορά την κάλυψη των αναγκών των φυτών σε άζωτο. Η υψηλή αξιοποίηση του αζώτου από τα φυτά γλυκού σόργου, οδηγεί στη μείωση εφαρμογής αζωτούχων λιπασμάτων και συμβάλλει στη μείωση του κόστους καλλιέργειας, στη μείωση εκπομπών αερίων του θερμοκηπίου και στην μείωση διήθησης νιτρικών στο υπόγειο υδροφόρο ορίζοντα. / The aim of the present thesis was to study the nitrogen dynamics in sweet sorghum crop. Sweet sorghum plants [Sorghum bicolor (L) Moench] variety Keller were used, and field and experiments were conducted. Field experiments were conducted during 2004 and 2005 growing seasons at the experimental station of the University of Patras, Greece and there were two treatments (biological and conventional soil fertility treatment), in a randomized complete block experimental design with three replications. The results showed that biological soil fertility treatment favour soil nitrate nitrogen concentration. In 2004, until completion of blooming, nitrogen uptake was higher in plants cultivated on biological fertility treated soil than in them cultivated on conventional but the differences were not statistically significant, except in second sampling, which nitrogen uptake was 2,69 N gm-2 in plants cultivated on conventional fertility treated soil and it was 5,12 N gm-2 in plants cultivated on conventional fertility treated soil. In 2005, until half of blooming, nitrogen uptake was similarly ranged for both treatments but the differences were not statistically significant, except in third sampling, which nitrogen uptake was 3,61 N gm-2 in plants cultivated on conventional fertility treated soil and it was 4,61 N gm-2 in plants cultivated on conventional fertility treated soil. Τhe effect of Azospirillum brasilense inoculation on growth parameters and nitrogen uptake in sweet sorghum plants fertilized with various nitrogen levels, was studied during pot experiments. Each experiment was including five treatments and thirty replications of each. Plants inoculated with Azospirillum brasilense and receiving half amount of nitrogen fertilizer produced 7,69 g dry biomass plant-1 at the end of the first experiment and they produced 4,89 at the end of the second one, while plants receiving full amount of nitrogen fertilizer and no inoculation produced 2,39 and 2,04 g dry biomass plant-1 at the end of the first and second experiment, respectively. Differences among treatments in each experiment, were statistically significant. Total nitrogen uptake in Plants inoculated with Azospirillum brasilense and receiving half amount of nitrogen fertilizer was 153,23 and it was 99,96 mg plant-1 at the end of first and second experiment, respectively. Those plants showed higher nitrogen uptake than plants from each other treatment and the differences were statistically significant. Results showed that treatments which inoculated with Azospirillum brasilense were the most efficient in terms of nitrogen uptake. These results indicate that biological management provides an adequate nitrogen nutrition to sweet sorghum crop. High nitrogen efficiency in sweet sorghum plants leads in reduced applying nitrogen fertilization and contribute in reduced crop cost, in reduced emission of the greenhouse gas and in reduced leaching of NO3-N to ground water.

Made available in DSpace on 2015-03-26T13:40:04Z (GMT). No. of bitstreams: 1 texto completo.pdf: 721867 bytes, checksum: 85d9a5894fb1c5c90727aacafdb3de95 (MD5) Previous issue date: 2014-07-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The sweet sorghum can become an important alternative for ethanol production in the sugar cane offseason. For this, adjustments will be necessary in the arrangement of sorghum plants in the field, to use all the available infrastructure and logistics in ethanol plants that use sugar cane as raw material. Besides adjusting the spacing of sweet sorghum cultivation machinery harvesters sugar cane, another factor to be researched refers to weed management. Sorghum is characterized by its slow initial growth which makes it very susceptible to weed competition in the early stage of growth. This fact is compounded by low efficiency of herbicides registered for weed control grasses. In the search for solutions to these problems, this research evaluated the effects of plant arrangements associated with application of herbicides on weed dynamics, sweet sorghum growth and yield. The experiment was conducted under field conditions and evaluated three plant arrangements with spacings of 0.25 m, 0.45 m 0,45 - 0,45 - 0,90 m, keeping the population of 120,000 plants per hectare in all spacings, which were either not associated with herbicide application. At 7, 14 and 28 days after herbicide application visual intoxication plants, weed control and data collection for phytosociological studies of weed community were evaluated. The fresh weight, plant height, stem diameter, mass of broth and °Brix of the sorghum stock were evaluated at harvest, 120 days after sowing. It also assessed chemical characteristics of the broth as the concentrations of sucrose, glucose and fructose, by high performance liquid chromatography efficiency. For phytosociological studies, weed populations were analyzed by calculations of density, frequency and abundance relative importance value (IVI) and similarity index (SI). We conclude that the reduction in sweet sorghum spacing increases the fresh culture weight and the application of the herbicide mixture may be an option in the management of weeds in sorghum, mainly aimed at controlling grasses. However, doses above 960 g ha-1 s-metolachlor and atrazine mixture may compromise the growth and productivity of sweet sorghum. The Cyperus esculentus and Oxalis latifolia species shown to be more tolerant to herbicides, considering that showed higher IVI values, independent of treatment assessed. / O sorgo sacarino pode se tornar importante alternativa para produção de etanol na entressafra da cana-de-açúcar. Para isso, serão necessários ajustes no arranjo das plantas de sorgo no campo, para utilização de toda a infraestrutura e logística disponíveis nas usinas de etanol que utilizam a cana-de-açúcar como matéria prima. Além do ajuste do espaçamento de cultivo do sorgo sacarino às máquinas colhedoras de cana-de-açúçar, outro fator a ser pesquisado refere-se ao manejo de plantas daninhas. O sorgo se caracteriza por possuir crescimento inicial lento o que o torna muito susceptível à interferência das plantas daninhas na fase inicial de crescimento. Este fato é agravado devido à baixa eficiência dos herbicidas registrados para controle de plantas daninhas gramíneas. Na busca de soluções para esses problemas, nessa pesquisa foram avaliados os efeitos de arranjos de plantas associado a aplicação de herbicidas sobre a dinâmica das plantas daninhas, crescimento e produtividade do sorgo sacarino. O experimento foi realizado em condições de campo, sendo avaliados três arranjos de plantas com espaçamentos de 0,25 m, 0,45 m e 0,45-0,45-0,90 m, mantendo-se a população de 120.000 plantas por hectare em todos os espaçamentos, os quais foram ou não associados a aplicação de herbicidas. Aos 7, 14 e 28 dias após a aplicação dos herbicidas foram avaliadas a intoxicação visual das plantas, o controle das plantas daninhas e coleta de dados para os estudos fitossociológicos da comunidade infestante. A matéria fresca, altura de plantas, diâmetro de colmo, massa de caldo e °Brix do caldo do sorgo foram avaliados no momento da colheita, 120 dias após semeio. Também avaliou-se as características química do caldo quanto as concentrações de sacarose, glicose e frutose, por cromatografia líquida de alta eficiência. Para os estudos fitossociológicos, as populações de plantas daninhas foram analisadas por meio de cálculos de densidade, frequência e abundância relativa, índice de valor de importância (IVI) e índice de similaridade (IS). Conclui-se que, a redução no espaçamento entre linhas do sorgo sacarino aumenta a massa fresca da cultura e a aplicação da mistura de herbicidas pode ser opção no manejo de plantas daninhas no sorgo sacarino, principalmente, objetivando o controle de gramíneas. No entanto, doses acima de 960 g ha-1 de s-metolachlor em mistura com atrazine podem comprometer o crescimento e produtividade do sorgo sacarino. As espécies Cyperus esculentus e Oxalis latifolia demonstram ser mais tolerantes aos herbicidas aplicados, tendo em vista que apresentaram maiores valores IVI, independente do tratamento avaliado.

Strategies to improve stem yield and juice quality in sweet sorghum were investigated in this study. Seed quality of sixty five accessions (landraces) from Botswana was investigated. Standard germination tests revealed that only 66% of the accessions had germination percentages in excess of 85%. The Accelerated Ageing test showed that only 50%of the 26 accessions had germination percentages above 80%. The results indicated that Botswana sweet sorghum seed quality is generally poor. Seed development and maturity observations demonstrated that maximum seed quality occurred 14 to 17 days after mass maturity (physiological maturity) and this coincided with maximum seed germination. These results suggest that harvesting sweet sorghum seed prior to mass maturity can lower seed quality. Farmers should, therefore be advised to select plants intended for seed harvesting and allow them to mature properly before the seeds are harvested. Differences in seed colour, shape and compactness of the inflorescences were observed amongst the 65 landraces collected from farmers in Botswana. Ten landraces were characterised and from the results it was evident that there was a range of genetic diversity which can be utilized in the improvement of the crop. Large panicles were characteristic of most sweet sorghum landraces, the effect of tiller, panicle and floret removal on juice quality was consequently studied. Removal of panicles and florets significantly improved juice quality whilst removal of tillers did not. Selection and breeding of genotypes with small panicles and male sterile varieties may improve juice quality and should be investigated. Effect of planting date, spacing and nitrogen were investigated. Early planting (October) resulted in increased stem yields but reduced juice quality. A 30 cm intra-row spacing resulted in high stem yields per plant and good juice quality. Nitrogen fertilisation increased stem yield and improved juice quality. On the bases of the results obtained from this study, early planting (October), application of 60 kg N ha-¹, and 30 cm intra-row spacing could be recommended for sweet sorghum production in pure stands. In pure stands yields of more than 37 000 stems (per hectare) of good quality can be attained. These could be sold at an estimated price of P2.00 (R2.25) per stem indicating the potential of sweet sorghum as a cash crop. However, its economic viability depends on the price elasticity in the supply - demand function. / Dissertation (PHD)--University of Pretoria, 2003. / Plant Production and Soil Science / unrestricted

The continuity of the menace of mercury (Hg) is due to the continuous production and use of Hg and Hg containing products. Toxicity is just an outfall of use and exposure. Anthropogenic activities such as coal combustion and artisanal and small-scale gold mining have led to increasing Hg contamination and is the major source of Hg pollution into the environment that needs to be remediated. This study aimed to assess the phytoextraction capability of sweet sorghum (Sorghum bicolor) under different fertiliser treatments in Hg-contaminated soil. The potted experiment in a controlled environment included control S. bicolor and three phytoremediation treatments, i.e., Hg only; the addition of 4:1 green compost and; the addition of 0.2% NPK fertiliser. There were conspicuous signs of Hg phytotoxicity in plants with Hg only, namely wilting, senescent, inhibition of growth, and photosynthesis. There was stunted growth, but healthy plants observed in the treatment with the addition of green compost towards the end (day 60) of exposure. However, S. bicolor grew well until the last day of exposure in the treatment with the addition of 0.2% NPK fertiliser. Thus, this treatment showed the most effective phytoextraction potential of S. bicolor in Hg-contaminated soil. The effectiveness of S. bicolor in reducing the level of mercury was best assessed in the Hg bioavailable concentration in the spiked soil in which the Hg + NPK treatment has the lowest (0.77 mg kg−1). That resulted in the highest uptake (84.31%) percentage of Hg concentration recorded in the treatment with the addition of 0.2% NPK fertiliser compared to the other two treatments. The results suggest that the proportion of phosphate in the NPK fertiliser used, plays a huge role in the phytoextraction of Hg in the contaminated soil by S. bicolor. The Translocation Factor (TF) and Bioconcentration Factor (BCF), although higher within Days 20 and 40, was greater than 1 at the end of the exposure period suggesting a high probability that Hg was significantly transferred to the aerial parts of the plants. This is regarded as typical hyperaccumulator plant species. While S. bicolor was able to reduce the level of Hg in all three treatments, Hg + NPK treatment gave overall best results in physiological growth, the uptake, and reducing the level of Hg bioavailable in the spiked soil in terms of the effectiveness of phytoremediation method. / Environmental Sciences / M. Sc. (Environmental Science)