Dissertations / Theses on the topic 'Farming systems'

Thesis (S.B.)--Massachusetts Institute of Technology, Department of Mechanical Engineering, 2013.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 59-61).
Irrigation on small-scale farms has been noted as a key method to help lift subsistence farmers out of poverty. With water scarity growing around the globe and lack of access to electricity still prevalent in rural areas, the need to develop an energy efficient irrigation system that simultaneous limits wasted water while being low cost is essential. The possibility of using a wicking irrigation system that relies on the suction plants create for water to mitigate the pumping pressure is investigated. A theoretical model for such a system is developed for an acre sized wicking irrigation system, and the power and water efficiency is compared to a standard drip irrigation system. While the wicking irrigation system has a greater distribution of water delivery from the wicks than compared to the dripper system, a wicking system has the potential to operate at much lower power, with the possibility of even being a power source. If a direct coupling could be developed between the plant's roots and wick, eliminating the need for water to travel through the soil, the energy benefit of the wicking system would be even more dramatic.
by Lauren B. Kuntz.
S.B.

Two field studies examining direct ecological weed control practices were conducted in Lexington, Kentucky. The first evaluated weed control efficacy and influence on yields of several mulches in two organically-managed bell pepper (Capsicum annum) production systems for two years. Peppers were planted in double rows in flat, bare ground or on black polyethylene-covered raised beds with drip irrigation, and four mulches (straw, compost, wood chips, and undersown white dutch clover (Trifolium repens L.) living mulch) were applied to the two production systems. In both years, polyethylene-covered raised beds produced higher yields than the flat, bare ground system. In the second year, the polyethylene-covered bed system coupled with mulching in-between beds with compost or wood chips after cultivation provided excellent weed control and yields. The second field study evaluated the efficacy of soil solarization and shallow cultivation on the invasive and noxious weed johnsongrass over two years (Sorghum halapense). A soil solarization treatment, using clear plastic stretched over soil for eight weeks, and a cultivated bare fallow treatment, utilizing a tractor pulled cultivator implement equipped with sweep blades, were randomly applied during the summers of 2003 and 2004 to a field infested with johnsongrass. Solarized and cultivated plots in both years were lightly tilled 8 months after completion of the initial treatment period. At the conclusion of the experiment the johnsongrass population was significantly reduced in all treatments and in the control plots compared to the original infestation. These two experiments testing direct weed control practices (mulching, cultivation, solarization) were undertaken in the context of an ecological weed management plan that includes long term strategies to reduce weed infestations such as crop rotation, cover cropping, and fertility management that are essential for organic farmers.

A key challenge facing dairy farming is to meet the increasing demand for dairy products from a growing and more affluent global population in a period of unprecedented socio-economic and environmental change. In order to address this challenge, policies are currently placing emphasis on ‘sustainable intensification’ (SI), i.e. producing ‘more’ outputs and services with ‘less’ resources and environmental impacts. Determining whether or not SI can deliver greater yet sustainable dairy production requires understanding of the relationships between sustainability pillars (environmental; economic; and social) and farm aspects (e.g. on-farm management; and animal productivity) under particular farming systems and circumstances (e.g. regional bio-physical conditions). Trade-offs between pillars and aspects is inevitable within a farming system. Many widely-used assessment methods that aim to measure, scale and weight these pillars and aspects are unable to fully capture trade-offs between them. The objectives of this thesis are: 1) to identify key trade-offs in dairy farming systems to inform greater yet sustainable food production; and 2) to introduce models and methodologies aiming at a more holistic measurement and better understanding of dairy farm sustainability. This thesis assesses the sustainability of French and UK dairy farming systems via a farm efficiency benchmarking modelling framework coupled with statistical analyses. It explores the relationships between pillars, aspects and technical, economic and environmental performance; and identifies important drivers/differentials in dairy farm efficiency. Importantly, it also suggests ways in which farm inputs and outputs can be adjusted so that improvements in environmental, technical and economic performance become feasible. Efficiency benchmarking was performed with the multiple-input – multiple-output productive efficiency method Data Envelopment Analysis (DEA). DEA calculates single aggregated efficiency indices per farm by accounting for several farm inputs and outputs which the DEA model endogenously scales and weights. In this work, the notion of farm inputs and outputs was extended to also include ‘undesirable’ outputs (greenhouse gas emissions) and environmental impacts (e.g. eutrophication, acidification etc.) of dairy farming. The DEA models employed belong to the family of ‘additive’ models, which have several advantages over ‘traditional’ DEA models. These include their ability (i) to simultaneously increase outputs and reduce inputs, undesirable outputs and environmental impacts; (ii) to identify specific sources of inefficiency. These ‘sources’ represent a farm’s shortfalls in output production and its excesses in input use and/or in undesirable outputs and environmental impacts, relatively to the other farms; (iii) to position undesirable outputs in the output set rather than consider them as inputs or ‘inverse’ outputs; and (iv) to rank farms by efficiency performance. Importantly, this thesis also proposes a new additive model with a ranking property and high discriminatory power. In a second stage, DEA was coupled with partial least squares structural equation modelling (SEM) so as to develop and relate latent variables for environmental performance, animal productivity and on-farm management practices. The results suggested that the efficacy of SI may be compromised by several on-farm trade-offs between pillars, aspects and farm inputs and outputs. Moreover, trade-offs depended on particular farming systems and circumstances. Increasing animal productivity did not always improve farm environmental performance at whole farm-level. Intensifying production at animal and farm-levels, coupled with high reliance on external inputs, reduced farm environmental performance in the French case, i.e. a significant negative relationship was found between intensification and environmental performance (SEM path coefficients ranged between -0.31 and -0.57, p < 0.05). Conversely, in the UK case, systems representing animal-level intensification (via genetic selection) for increased milk fat plus protein production performed better, on average, than controls of UK average genetic merit for milk fat plus protein production in terms of technical efficiency (DEA scores between 0.91– 0.92 versus 0.78–0.79) and environmental efficiency (scores between 0.92–0.93 versus 0.80), regardless of whether on a low-forage or high-forage diet. The levels of inefficiency in (undesirable) outputs, inputs and environmental impacts varied among farming systems and depended on the regional and managerial characteristics of each system. For instance, in France, West farms had higher eutrophication inefficiencies than East farms (average normalized eutrophication inefficiencies were, respectively 0.141 and 0.107), perhaps because of their more intensive production practices. However, West farms were more DEA-efficient than East farms as the former benefited from bio-physical conditions more favourable to dairy farming (mean DEA score ranks were 97 for West and 83 for East). Such findings can guide policy incentives for SI in different regions or dairy systems. The proposed modelling framework significantly contributes to current knowledge and the search for the best pathways to SI, improves widely-used modelling approaches, and challenges earlier findings based on less holistic exercises.

The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed January 20, 2010). Thesis advisor: Dr. Georgeanne Artz. Includes bibliographical references.

Decision support systems (DSS) are usually based on computerised models of biophysical and economic systems. Despite early expectations that such models would inform and improve management, adoption rates have been low, and implementation of DSS is now “critical” The reasons for this are unclear and the aim of this study is to learn to better design, develop and apply DSS in farming systems research (FSR). Previous studies have explored the merits of quantitative tools including DSS, and suggested changes leading to greater impact. In Australia, the changes advocated have been: Simple, flexible, low cost economic tools: Emphasis on farmer learning through soft systems approaches: Understanding the socio-cultural contexts of using and developing DSS: Farmer and researcher co-learning from simulation modelling and Increasing user participation in DSS design and implementation. Twenty-four simple criteria were distilled from these studies, and their usefulness in guiding the development and application of DSS were assessed in six FSR case studies. The case studies were also used to better understand farmer learning through models of decision making and learning. To make DSS useful complements to farmers’ existing decision-making repertoires, they should be based on: (i) a decision-oriented development process, (ii) identifying a motivated and committed audience, (iii) a thorough understanding of the decision-makers context, (iv) using learning as the yardstick of success, and (v) understanding the contrasts, contradictions and conflicts between researcher and farmer decision cultures
Doctor of Philosophy (PhD)

This study investigated sustainability challenges and benefits for coffee farming with different amounts of shade management in Colombia. Data was collected from literature studies, quantitative soil analyses and interviews with farmers and other experts. The results show that shade management of coffee farms does increase ecological sustainability, but in general gives lower yields of coffee. However, shaded coffee systems have the potential of increasing economic resilience for farmers by providing diversified income possibilities. The low and fluctuating coffee price of the global market has shown to be a major challenge of sustainability for Colombian small scale coffee farms. In addition a participatory sustainability assessment of soil quality and crop health was conducted with four farmers. The results from these assessments were compared with results from quantitative analyses of soil compaction, microbiological respiration rate and organic matter content in order to evaluate the analytical reliability of the assessment. The results of the participatory assessment were shown to correlate quite well to the quantitative soil analyses. When participatory methodology was evaluated from experiences in field and literature, it was found to be an important approach in facilitating sustainability learning in local contexts.
En esta investigación se examinaron los retos y beneficios de la sostenibilidad en la producción del cultivo de café con diferentes niveles de sombra en Colombia. Los datos se colectaron de estudios de literatura, análisis de suelo y entrevistas con agricultores y expertos en el tema. Los resultados indican que el manejo con sombra incrementa la sostenibilidad ecologica de las fincas cafeteras, y esto, tiene la posibilidad de incrementar la resiliencia económica para los agricultores al ofrecer oportunidades para una producción diversificada de ingresos. El precio bajo y fluctuante del café en el mercado mundial ha demostrado ser un importante reto para la sostenibilidad de las fincas de los campesinos colombianos. Además, se realizó una evaluación de la sostenibilidad participativa de la calidad del suelo y la salud de los cultivos con cuatro agricultores. Los resultados de esta evaluación se compararon con los resultados de análisis cuantitativos: de la compactación del suelo, la tasa de respiración microbiológica y contenido de materia orgánica, con el fin de evaluar la fiabilidad analítica de la evaluación participativa. Se demostró que los resultados de la evaluación participativa tienen una estrecha relación con el análisis cuantitativo del suelo. Cuando la metodología participativa se evaluó a partir de las experiencias propias en el campo y la literatura, se encontró que puede ser un enfoque importante para facilitar el aprendizaje de sostenibilidad para los contextos locales.

For several decades, the practice of farming in mountain areas has played a key role to the proper management of the landscape, the conservation of the biodiversity as well as the soil protection. Moreover, it has significantly contributed to the protection of those areas from avalanches and fires, while at the same time it keeps reinforcing the local economy, thereby acting as a counterweight to abandonment. The mountain animal husbandry is by definition multifunctional and multidisciplinary. In fact, mountainous farming consists of a complex and dynamic system. The harmony and the balance between human activities and nature requires some of the most precious human skills, like patience, self-abnegation, endurance to handiwork and frugality, to name some, but above all, love for mother nature. These are characteristics that ensure continuity and vitality of the mountain for both humans and the surrounding nature. In Italy, almost half of the total land is classified as mountainous (47.5%). Nevertheless, farmers in mountainous regions (representing 30.9% of the national total) face several limitations. These limitations, linked to the existence of natural handicaps, cannot be easily overcome with investments. For example, in mountains the average temperatures are lower, resulting in shorter vegetative period. Moreover, the excessive fractionation, the major gradients and roughness of the lands and at the same time the lower fertility of soils, create the need for special machinery (often more expensive than those used in mainland farms) as well as increased labor and extra inputs for the farms. These factors can lead to a lower land (and consequently farm) productivity, which can be translated into a limited competitiveness of the mountain farms, compared to mainland. In addition, the difficulty of access and the distance of individual dairy farms from the lowland as well as the fewer processing facilities and their small size, create higher transportation costs and lower economies of scale. Thus, the overall objective of this thesis was to verify some parameters of sustainability that are of great importance for animal husbandry in the mountain areas. The province of Trento was selected as a model area for this type of research. More precisely, we have analyzed the relationship between dairy farms and management of the Alpine pastures, in the light of the environmental value of semi-natural grasslands. The first and second contributions are related to this goal. In the last part a survey was carried out to assess the environmental footprint of dairy farms of Trento province, focusing on innovative aspects of nutrition and management of the animals bred. More specifically, the goal of the first contribution was to analyze the role of the mountain livestock sector. At a first step, data were collected from the Veterinary Services of the province concerning the structures and the management of 395 Alpine summer pastures either with cattle (83 with only heifers and 262 including dairy cows) or sheep and goats (50 summer pastures). All the heifers and more than one third of dairy cows that kept on permanent farms of the province were brought to the temporary farms on the Alpine pastures during the summer season, with a frequency greater for cows of local and dual purpose breeds than specialized breeds (e.g. Holstein Friesian). Of the 610 permanent dairy farms associated with the Provincial Federation of Farmers, we have analyzed the differences between the dairy farms that move/do not move the lactating cows to Alpine summer pastures: i.e. the traditional dairy farms (small and medium size), with tied stall, local breeds and with low productivity, frequently using the summer pasture were compared to modern dairy farms of the same province. Results showed that the practice of transhumance to summer pasture has an important role for the dairy sector of Trento province, although the farmers changed the reasons why they choose to move the animals. In fact, the role of grazing as production support in the summer is relevant just for the traditional small and medium dairy farms, while in all cases it is important to access public subsidies that are undifferentiated between lactating cows, dry cows and replacement. The study displayed the fact that there is still the need to maintain the link between dairy farms and Alpine pastures, giving particular attention to the quality of the pasture management and the multi-functionality of services that can be provided by mountain farms. The second part aimed in evaluating the effect of pasturing of dairy cows on milk yield and quality. To this purpose, a many of traits was considered. Body Condition Score (BCS), milk production and quality, milk coagulation properties, different set of parameters and information relating to dairy processing were recorded and analyzed. In total, date regarding 799 lactating cows were collected and analyzed during 2012 from 15 temporary farms on Alpine summer pastures located in the region of Trentino. The cows were reared in 109 permanent dairy farms. Effects of the breed, parity and days in milk were taken into account. The effects of Alpine summer pasture, and in particular of the amount of compound feed given to cows, were also considered. Information was gathered not only during the period that the cows spent at the Alpine summer pasture, but also before and after the alpine season, with the objective to evaluate the changes due to the environmental changes. Results showed that the summer transhumance had an effect more or less relevant in determining a decrease in production, but also depending upon the breed. Specialized breeds, with higher production levels in permanent dairy farms, suffer a greater drop in production than the local and dual purpose breeds. This was somehow expected, since local breeds have a greater adaptability and lower nutrients requirements. Even the body condition score has been strongly influenced from the summer Alpine pasture. A decline in the first phase of the pastures and a subsequent recovery at the end of the pasture period was observed. Differences between breeds existed, with those specialized breeds showing a greater decrease in body condition. After the return from the Alpine pastures a decline in the percentage of fat content in milk (more evident in specialized breeds) was observed, while the protein content remained constant. Regarding the technological properties of milk, significant differences were found with the change of environment (after the reaching of temporary summer farms and after the return to permanent farms). The major differences for lactodynamographic properties as well as the individual cheese yields were observed between June and September. In summary, this work highlighted the better adaptation of local and dual purpose breeds in the Alpine environment and their good performance under environmental changes as well as the special conditions of the farming system in summer pasture. The last part of this thesis aimed to evaluate the environmental footprint of mountain dairy cattle farms. The study was conducted in a specific area of the Province of Trento. Data were collected from 38 dairy cattle farms of mixed breeds using different farming systems. Data on the general farm management, diet, the production performance, the agronomic management of the surfaces, the management of waste, and the energy consumption were collected. A specific questionnaire was developed and tested to this purpose. This specific questionnaire could also be used for further investigation in mountain region. The above mentioned data were used to calculate the carbon footprint of the herds using the Life Cycle Assessment (LCA) approach. The study included the entire product life, i.e. from production of raw materials and their processing till the final product (the functional unit was the kilogram of milk). All the inputs and outputs associated to the functional unit were taken into account. Three categories of environmental impact of the farms were considered: i) carbon footprint (contribution to the production of greenhouse gases), ii) acidification and iii) eutrophication. The values obtained for the three impact categories had large variability, with mean and standard deviation equal to 1.46 ± 0.58 kg for CO2 equivalent (eq), 27.18 ± 8.34 g for SO2 eq. and 7.91 ± 2.31 g for PO43- eq. per kg of milk (fat and protein corrected). The values obtained are comparable with previous studies carried out in mountain areas. The overall impact was divided between on-farm and off-farm components, and was shared according to mass allocation between milk and meat. Analysis of variance showed that the considered effects of housing (free vs fixed) and feed administration (traditional vs TMR), even if appeared statistically significant for some traits, slightly affected the high variability of the impact categories that can be observed among different dairy farms of the same group. This means that there are margins to mitigate the impact and increase the efficiency of farms with different structures and management. Overall, the results of the present thesis provided with some interesting insights on the sustainability assessment of dairy farming systems in mountainous areas, adopting innovative methodological approaches. Looking ahead, the results obtained from experimental approaches could be expanded on a large pool of dairy farms to identify the indicators of reference for the evaluation of the sustainability and multi-functionality of mountain farms.
La pratica dell’allevamento nel territorio montano ha avuto un ruolo fondamentale per la corretta gestione del paesaggio, la conservazione della biodiversità e la protezione del suolo. Inoltre svolge notevoli positività anche in termini di protezione dalle valanghe e dagli incendi, nel contrasto all'abbandono e soprattutto per lo sviluppo dell'economia locale. La zootecnia montana è per definizione multifunzionale e multidisciplinare. Infatti, spesso è artefice di uno sviluppo più complesso e dinamico, in grado di integrare altri comparti economici quali ad esempio il turismo o il sociale, assicurando continuità e vitalità alla montagna. In Italia quasi la metà del territorio è classificato come montano (47.5%) dove gli agricoltori presenti (30.9% sul totale nazionale) devono affrontare diverse limitazioni, legate all'esistenza di svantaggi naturali, che non sono facilmente affrontabili con investimenti. Le temperature medie inferiori, con conseguente periodo vegetativo più breve, l’eccessivo frazionamento, le maggiori pendenze e asperità dei suoli e allo stesso tempo la minore fertilità dei suoli stessi, la necessità di macchinari spesso più costosi come pure i tempi di lavoro più lunghi, hanno come conseguenze una minore produttività della terra, tradotto in una limitata competitività e produttività del lavoro. In aggiunta, la difficoltà di accesso e la lontananza delle singole aziende dal fondovalle, un minor numero di strutture di trasformazione e le loro ridotte dimensioni, sono la causa di maggiori costi di trasporto e minori economie di scala. L’obiettivo generale di questa tesi è di verificare alcuni parametri di sostenibilità di notevole rilievo per la zootecnia montana nella Provincia Autonoma di Trento. Nello specifico, sono state analizzate le relazioni tra bovinicoltura da latte e gestione degli alpeggi, alla luce della valenza ambientale delle praterie semi-naturali; il primo e il secondo contributo sono relativi a questo obiettivo. Nell'ultimo contributo è stata svolta un'indagine per calcolare l'impronta ambientale della bovinicoltura da latte trentina, con un innovativo focus sugli aspetti di nutrizione e gestione degli animali allevati. Nello specifico l’obiettivo del primo contributo è di analizzare il ruolo delle malghe nel comparto zootecnico montano. Sono stai raccolti dal servizio veterinario della Provincia i dati riguardanti le strutture e il management di 395 malghe dove erano presenti bovini da latte (83 solo manze e in 262 anche bovini adulti) e ovicaprini (50 strutture). Praticamente tutte le manze e più di un terzo delle vacche da latte allevate negli allevamenti di fondovalle della provincia sono portate al pascolo durante la stagione estiva, con una frequenza maggiore per le vacche di razze locali e a duplice attitudine rispetto a quelle specializzate. Delle 610 aziende di fondovalle associate alla Federazione allevatori, sono state analizzate le differenze tra le aziende che praticano/non praticano la monticazione delle vacche in lattazione: le aziende tradizionali di dimensioni medio-piccole, con stabulazione fissa, razze locali e con bassa produttività, usano più frequentemente la pratica dell’alpeggio rispetto alle aziende moderne. I risultati evidenziano come la pratica dell’alpeggio mantenga un ruolo importante per la zootecnia trentina, nonostante siano cambiate le motivazioni per cui gli allevatori scelgono di monticare gli animali. Il ruolo del pascolamento come supporto alla produzione nel periodo estivo rimane rilevante per le aziende tradizionali medio-piccole, mentre in tutti i casi riveste una particolare importanza, la possibilità di accedere a contributi indifferenziati tra bovini in lattazione, asciutta e rimonta. Si devono creare le condizioni perché il legame tra aziende e malghe possa essere mantenuto, con particolare attenzione alla qualità della gestione dei pascoli e alla multifunzionalità di servizi che possono essere forniti dalle aziende zootecniche montane. Il secondo contributo mira a valutare l'effetto della monticazione delle vacche da latte su caratteri produttivi e sulla condizione corporea, nello specifico: body condition score (BCS), produzione, qualità e proprietà di coagulazione del latte, e i parametri relativi alla trasformazione casearia. In totale sono stati raccolti e analizzati i dati di 799 vacche in lattazione, monticate nel 2012 su 15 malghe trentine che allevavano capi di diverse razze provenienti da 109 aziende permanenti. I parametri oggetto di studio sono stati messi in relazione alla razza, all’ordine di parto e ai giorni di lattazione, tenendo conto dell'effetto malga, e in particolar modo della quantità di mangime somministrato alle vacche. Il lavoro ha analizzato non solo il periodo di permanenza delle vacche in alpeggio ma anche prima e dopo la stagione di malga con l’obiettivo di valutare i cambiamenti dovuti al cambio di ambiente. I risultati evidenziano come la monticazione abbia un effetto più o meno rilevante nel determinare un calo di produzione a seconda delle razze. Le razze specializzate, con livelli produttivi più elevati nelle aziende permanenti, soffrono un maggior calo di produzione rispetto a quelle locali o a duplice attitudine, che si adattano meglio alle condizioni di alpeggio. Anche la condizione corporea degli animali è fortemente influenzata dall’alpeggio, con un calo nella prima fase della monticazione e un recupero successivo. Emergono delle differenze tra razze, con quelle specializzate che presentano un maggior calo di condizione corporea. Dopo la monticazione si è assistito ad un calo del contenuto percentuale di grasso nel latte (particolarmente evidente nelle razze specializzate), mentre il contenuto di proteine è rimasto costante. Per quanto riguarda le caratteristiche tecnologiche del latte, si sono riscontrate significative differenze sia dopo la monticazione, sia dopo il periodo estivo con il ritorno in azienda. Le maggiori differenze si sono però riscontrate tra giugno e settembre sia in termini di lattodinamografia sia in termini di rese. In conclusione, il lavoro evidenzia la migliore adattabilità delle razze locali e a duplice attitudine al cambiamento di ambiente e alle condizioni di allevamento in malga. Il terzo contributo ha l'obiettivo di valutare l’impronta ambientale di allevamenti montani di bovini da latte. È stato condotto un approfondito studio sul territorio della provincia di Trento, considerando un campione di 38 allevamenti di vacche da latte di razze miste con differenti sistemi di allevamento. Tramite visite aziendali sono stati raccolti dati relativi alla gestione e alimentazione dei bovini, alle prestazioni produttive, alla gestione agronomica delle superfici, alla gestione dei reflui e ai consumi energetici. A questo fine è stato sviluppato e testato un questionario specifico che potrà essere proposto per ulteriori indagini in ambito montano. La mole di dati raccolti è stata utilizzata per calcolare l’impronta ecologica degli allevamenti con approccio Life Cycle Assessment (LCA). Lo studio comprende l’intera vita del prodotto, dalla produzione delle materie prime, alla loro lavorazione e utilizzo finale considerando tutti gli input e gli output associati all’unità funzionale (il kg di latte). In questo studio sono state considerate tre categorie di impatto: carbon footprint (contributo alla produzione di gas serra), acidificazione ed eutrofizzazione, relative all’anno 2013. I valori ottenuti per le tre categorie di impatto presentano un’ampia variabilità, con medie e DS pari a: 1.46 ± 0.58 kg CO2 eq, 27.18 ± 8.34 g SO2 eq. e 7.91 ± 2.31 g PO43- eq. per kg FPCM. I valori ottenuti sono in linea con quanto riportato da altre ricerche condotte in ambito montano. L’impatto complessivo è stato diviso tra componenti on-farm e off-farm, e sono stati ripartiti gli impatti con allocazione di massa tra latte e carne. L’analisi della varianza ha messo in evidenza come gli effetti considerati (stabulazione, libera vs fissa, e modalità di somministrazione degli alimenti, tradizionale vs unifeed), pur significativi in alcuni casi, influiscano in maniera poco rilevante sulla variabilità delle categorie di impatto mentre esiste una rilevante variabilità dei risultati tra aziende diverse dello stesso gruppo. Ci sono quindi margini per mitigare l’impatto e aumentare l’efficienza degli allevamenti, anche con strutture e gestioni diverse. Nel complesso, i risultati della tesi offrono degli interessanti spunti sulla valutazione della sostenibilità della bovinicoltura da latte nelle aree montane, con approcci metodologici innovativi. In prospettiva, i risultati ottenuti dagli approcci sperimentali condotti potranno essere ampliati su un pool ampio di aziende al fine di identificare degli indicatori di riferimento per la valutazione della sostenibilità e multifunzionalità degli allevamenti montani.

Thesis (M.S. in soil science)--Washington State University, December 2008.
Title from PDF title page (viewed on June 15, 2009). "Department of Crop and Soil Science." Includes bibliographical references.

Increasing concern over the adverse environmental impact of intensive agriculture has led to pressure to develop more sustainable, integrated farming systems which have the potential to minimise the loss of nitrogen to the environment whilst maintaining productivity. Alternative systems include pluricompartmental systems, which combine more than one enterprise or species in a formalised design, such as a crop rotation or spatial arrangement e.g. agroforestry. Three approaches to nitrogen budgeting were developed and their ability to quantitatively describe nitrogen cycling in pluricompartmental systems tested. Budgets ranged in complexity from the EIO Budget, which accounted simply for purchases and sales of nitrogen over the farmgate, through the BIO Budget which included estimation of biological nitrogen fixation and attempted to partition losses into leaching and gaseous forms, to the TRIO Budget which also accounted for key soil processes. Unaccounted for N was attributed to leaching, however it is recognised that this is a predictor of leaching potential rather than actual loss. These approaches were tested in a range of systems; a mixed organic farm, a silvopastoral agroforestry system, organically and conventionally managed beef systems and a series of ley/arable rotations containing different proportions of ley. A simple model for predicting nitrogen fixation from yield was also developed and tested. The success of the different approaches was strongly dependent on the precise objective; whilst all the approaches were able to predict N use efficiency in economic terms, the TRIO Budget was likely to give the best estimate of potential N loss by leaching. The TRIO Budget was the only approach which quantified intercompartmental N fluxes, and it is suggested that this parameter may be a useful indicator of sustainability. Intercompartmental fluxes were particularly difficult to quantify in spatially pluricompartmental systems due to the importance of belowground processes in these systems.

Sustainable Built Environments Senior Capstone
This capstone project compares traditional agricultural methods to those of aquaponics. Qualitative research is used to study the effectiveness of aquaponic systems and its ability to solve the financial and environmental impacts of current agricultural methods. This study looks at the environmental, financial, and health impacts of agriculture. Three case studies are used to compare an aquaponic system, aquaculture operation, and an organic farm.

L'économie de la région du Moyen-Orient dépend fortement de l'agriculture comme source de nourriture et de revenus. Ces pays ont lancé des politiques agricoles qui préconisent l'intensification de leurs systèmes de production. Ces politiques encouragent une plus grande utilisation des intrants subventionnés et l'achat de la production agricole à des prix subventionnés. La méthodologie de ce travail a consisté à commencer par un sondage complet sur les exploitations agricoles suivi d'une analyse par grappes pour aider à identifier et évaluer la diversité des systèmes agricoles dans la région et leurs performances. Ensuite, proposer des scénarios de variations de la disponibilité et des prix de l'eau, des prix du marché des produits agricoles et des primes accordées aux agriculteurs afin de tester la vulnérabilité des systèmes de culture actuels aux chocs. Et enfin, construire un modèle bio-économique pour aider à capturer les indicateurs de résilience des systèmes agricoles dans la région. Baalbek-Hermel, dans la partie nord de la vallée de Bekka au Liban, a été choisi pour être représentatif en raison du fait qu'il s'agit de la zone la plus désertification dans le pays et l'une de ses zones agricoles les plus pauvres. Il a des conditions biophysiques variées / mosaïques, avec une forte fluctuation des précipitations. L'intensification de l'agriculture dans la région a commencé délibérément dans les années 1970. L'enquête au niveau de la ferme a été effectuée en choisissant d'abord les fermes représentatives: un échantillon de 97 agriculteurs sur 486 ont été sélectionnés et ont reçu un questionnaire quantitatif contenant des questions fermées couvrant le profil socioéconomique du fermier, les pratiques agricoles, la production, les coûts engagés et l'accès au marketing stratégies. Estimation de la quantité d'eau d'irrigation par culture, puisque l'eau d'irrigation est distribuée aux exploitations par heure ou par superficie, et non par le volume d'eau appliqué. Pour estimer la quantité d'eau d'irrigation appliquée par culture et, par la suite, son coût, initialement exprimé en zone ou en temps, deux étapes de calcul ont été définies: cartographier les systèmes spatiaux de distribution d'eau dans la zone d'étude et estimation du débit d'eau pour chaque source de l'eau d'irrigation.Pour classer les différentes exploitations dans la zone d'étude selon leurs modèles de culture, une analyse de composante principale (ACP), suivie de Classification ascendante hiérarchique (CAH) a été effectuée. La typologie de la ferme a ensuite été suivie d'une analyse de sensibilité pour déterminer dans quelle mesure les revenus agricoles étaient sensibles aux prix et aux variations de subvention. L'analyse effectuée visait à évaluer, pour chaque type de ferme, la perte de revenu, mais aussi la perte de productivité en réponse à la suppression des subventions pour chaque culture (blé, raisin et pomme de terre), ou à l'augmentation des prix de l'eau d'irrigation en afin de réduire sa consommation. Enfin, des scénarios de vulnérabilité ont été définis, composés principalement de quatre éléments: horizon temporel, échelle spatiale, forces d'entraînement externes, et indicateurs / variables intermédiaires. Le modèle bio-économique récursif dynamique, est développé pour évaluer les scénarios et calculer les indicateurs de résilience. Nos résultats ont montré que les voies d'intensification ont conduit à cinq types différents de systèmes agricoles. Bien que ces types de cultures suivent des trajectoires différentes, ils atteignent toujours des revenus similaires avec différents impacts environnementaux potentiels. Cette étude montre que l'intensification de l'agriculture a permis aux agriculteurs d'augmenter leurs revenus, mais souvent au détriment de la dégradation de l'environnement. Cependant, cette amélioration reste très dépendante des niveaux de soutien direct ou indirect accordés aux agriculteurs
The economy of the Middle East relies heavily on agriculture as a source of food and income. These countries have initiated agricultural policies that advocate the intensification of their production systems. These policies encourage greater use of subsidized inputs and the purchase of famers’ production at subsidized prices compared to international market prices. The methodology of this work was to start with comprehensive farms survey followed by a cluster analysis to help identify and assess the farming systems diversity in the area and their performances. Then to propose scenarios of variations in water availability and prices, market prices of agricultural produce, and premiums given to farmers for the purpose of testing the vulnerability of the current cropping systems to shocks. And finally to construct a bio-economic model to help capturing the resilience indicators of the farming systems in the area. Baalbek-Hermel, in the northern part of the Bekka Valley in Lebanon, was selected to be representative for Lebanon as well as the MENA region due to the facts that it is the most desertification prone area in country and one of its poorest agricultural areas. It has diverse /mosaic biophysical conditions, with high fluctuation in rainfall. Agricultural intensification in the area started deliberately in 1970. Survey at the farm level was conducted by first selecting representative farms: a sample of 97 farmers out of 486 were selected and given a quantitative questionnaire containing closed questions covering the farmer’s socio-economic profile, farming practices, production, costs incurred, and marketing access strategies. Estimation of amount of irrigation water per crop followed since irrigation water is distributed to farms on a per hour or per area basis, and not based on the volume of water applied. To estimate the amount of irrigation water applied per crop, and subsequently its cost, which is initially expressed as area or time, two calculation steps were defined: mapping the spatial water distribution systems in the study area, and estimation of water flow for each source of irrigation water. To classify the different farms in the study area according to their cropping patterns, a principal component analysis (PCA), followed by Hierarchical Ascendant Classification (HAC) was performed. The farm typology was then followed by a sensitivity analysis to investigate the extent to which farm incomes, in the study region, were sensitive to prices and subsidy variabilities. This includes sensitivity to allocated premiums or/and product price, and irrigation water prices, taking into consideration farming system diversity in the region. The analysis carried out was intended to assess, for each farm type, income loss, but also productivity loss in response to the suppression of subsidies for each crop (wheat tobacco, grape, and potato), or to the increase in irrigation water prices in order to reduce its consumption. Finally, scenarios for vulnerability were defined, which were composed of mainly four components: time horizon, spatial scale, external driving forces, and indicators/intermediate variables. The dynamic recursive bio-economic model was developed to assess the scenarios and calculate the resilience indicators. Our results showed that intensification pathways led to five different types of farming systems, except for conventional extensive cereal farms. Although these farming types follow different trajectories, they still achieve similar incomes with different potential environmental impacts. Beyond the results obtained at study zone level, this study shows that the intensification of agriculture has allowed farmers to increase their incomes, but often at the cost of environmental degradation. However, this improvement remains very dependent on direct or indirect support levels granted to farmers

Nitrogen (N) fixation by white clover (Trifolium repens L.) was measured in the ley phases of three experimental organic ley-arable rotations at two sites, between 1997 and 2000, using the 15N dilution technique. Soil nitrate-N, ammonium-N, and total soluble N were measured at one of the sites between 1999 and 2001. Variation of soil N was assessed in different ages of ley, year, month, rotation, site and microsite type (grass or clover). Data for soil pH, organic matter, P, K, and Mg, was also compared, as was weather data for the period. Variation of N fixation, grass and clover dry matter, proportion of nitrogen derived from the atmosphere, grass and clover N concentrations, grass and clover non symbiotic N-yield, and N transfer from clover to grass were compared in different ages of ley, years, months, rotations and sites. Flowering rates and presence of clover tap-roots were also examined. Above ground N fixation varied between 26 and 75 kg ha'1 over the course of the growing season. Estimated total N fixation ranged from 70-214 kg ha'1. N fixation was closely related to yield of clover. There were clear relationships between soil nitrate and the behaviour of the grass and clover components of the leys. Nitrate-N was slightly higher under clover patches than under grass patches in mid-late summer. White clover and perennial ryegrass were grown in circular chambers, divided radially, and their invasion into microsites with different vegetation, different management and different N treatments was observed. Ryegrass was not capable of rapidly colonising microsites by vegetative spread alone. Clover was more likely to successfully invade microsites containing grass with no added N than microsites with added N, or bare soil microsites.

Volcanic eruptions are powerful, spectacular, uncontrollable geophysical events which require management to mitigate loss of life and property. An essential part of volcanic risk management is to quantify the vulnerability of exposed elements of society to volcanic hazard. Agriculture takes advantage of the fertile soils of volcanic regions, but is vulnerable to damage and disruption from volcanic hazards, in particular ashfall. This thesis investigates the vulnerability of pastoral agriculture to volcanic ashfall by examining impacts on the resource base of pastoral farming (water supply, pasture and soil, and livestock) and explores mitigation and recovery strategies for ashfall hazards at varying levels. It provides a quantitative understanding of pastoral farming vulnerability to ashfall hazards, as part of probabilistic risk assessment. Surface farm water supplies are found to be more vulnerable to ashfall, through contamination and sedimentation, than groundwater supplies. After heavy ashfall, the physical impacts of ashfall overwhelm the more subtle chemical impacts on water supply systems, but even relatively thin ashfalls may cause potential toxic changes to water quality. Farm-scale assessment of water supplies was used to identify key areas of vulnerability to ash hazards. Modelling a large-scale evacuation of livestock following widespread, heavy ashfall found the logistical, time and cost requirements high and may make this action unrealistic. Perhaps most critically, it is doubtful that farms in surrounding regions have the capacity to accommodate the numbers of animals likely to be affected. Tunnel-house and field trials have shown pastures are relatively resilient to ashfalls of 10 mm, but this resilience rapidly reduces with increasing ashfall thickness and at .100 mm there is effectively no pasture recovery. Ashfall grain size, frequency, soluble salt volume, and different meteorological conditions also have a significant impact on pastures and soils. Pasture reestablishment will benefit from tillage of ash covered soils to mix ash and topsoil and break up the surface crust which may form on ash deposits. Targeted fertiliser treatments may also be required to buffer acidic soluble salts and remedy deficiencies of essential nutrients. Reworking of ash deposits was found to be highly disruptive to pasture re-establishment and in extreme cases may prolong and intensify the impacts following an ashfall. The majority of farmers impacted by ashfall will continue farming, albeit with varying levels of disruption. However real or perceived impacts to human health may result in farm evacuation in the short-term. Where ashfall thicknesses are too thick for a return to profitable farming, migration from impacted farms and agriculture-related industries will result in significant demographic changes to rural communities and potential social impacts. Stressed farming systems are most vulnerable to failure and psychosocial impacts.

A study of the process of technological change in contemporary Mayan agricultural systems was undertaken by an action research method that involved close collaboration with the rural development efforts of farmers in the northern highlands of Chiapas, Mexico. Firstly, the socioeconomic context of technological change in Chiapas was described, with special reference to the effects of markets on agricultural development. Secondly, theta actors affecting the productivity and sustainability of the regions principal agricultural systems: maize and beans for subsistence and coffee for cash were described and measured. The use of traditional swidden methods of maize cultivation with shorter fallow periods was found to be causing a significant decline in the fertility of soils. Alternative, non-burning methods were found to be sustainable in terms of soil fertility, but required high labour inputs and were less productive during a 2-3 year transition period. Despite government programmes to promote the development of coffee plantations most farmers had adopted only ad hoc improvements, and coffee system productivities were found to be generally low. Models integrating dynamic and linear progranuning components of the improvement problem systems in maize and coffee production were constructed using evidence from the field studies. By examining a number of hypothetical scenarios, further hypotheses about the coffee and maize systems were generated. It was inferred that the relative scarcity of farm labour, cash or land resources would affect the optimum technical decisions of farmers. In particular, it was concluded that farmers with scarce cash resources would face most difficulty (in terms of loss of effective income) in adopting non-burning maize techniques and the promoted methods of coffee plantation improvement. On the basis of the evidence from the field studies and the modelling exercises a number of technical, project and policy recommendations were advocated. These were based upon the objective of maximising the potential competitive strengths of the peasant mode of production, including: the efficient use of marginal, dispersed and inaccessible resources and the production of a wide range of specialised agricultural and forestry products.

Kyoto University (京都大学)
0048
新制・課程博士
博士(地域研究)
甲第12431号
地博第30号
新制||地||10(附属図書館)
24267
UT51-2006-J422
京都大学大学院アジア・アフリカ地域研究研究科東南アジア地域研究専攻
(主査)助教授 安藤 和雄, 教授 山田 勇, 助教授 岩田 明久
学位規則第4条第1項該当

The objectives of this study were: (a) to delineate a methodology for determining the feasibility of a water harvesting system for an arid ecosystem, (b) to develop a simulation model for the water balance of a water harvesting strip farming system, and (c) to perform a sensitivity analysis of the simulation model. The discussion focuses on the feasibility as constrained by risk. A computer program was developed for the computations. The results indicate that light textured soils cannot be used for this type of farming system since their hydrodynamic characteristics do not allow runoff from light rains (i.e. the threshold value is high). Medium textured soils require a minimum of 50% of initial soil water content and a CCAR of 2:1. Heavy soils require a minimum of 20% of initial soil water content and a CCAR greater than 5:1. As a general rule, the system is more efficient, in terms of water use efficiency (eᵤ), as the conditions become dryer. In this way, for CCAR ranging from 0 to 5 eᵤ is around 95% for all three textures. Beyond that point, as the CCAR increases eᵤ decreases being more efficient light soils and less efficient heavy soils. The shapes of the curves of profit, reflect the impact of weather conditions on the response of output to varying CCAR. Lack of rainfall prior to and during the growing season results in poor outputs. The risk (probability of loss) will depend on both the farmers own criteria and the economical situation. Thus, these criteria can be divided into two broad categories: risk-taking (those farmers who pursue a high level of investment relative to the probability of failure), and risk-adverse (those farmers with low level of investment relative to the probability of failure). Curves of minimum risk-maximum net benefit (minimax) were developed as a guide for decision making processes. According to the minimax curves, for medium soils, the minimum risk maximum net benefit is achieved with CCAR 2:1 and initial soil water content of 100%. This implies a risk of 0.2 and net benefit of $510.00. For heavy textured soils, the minimum risk maximum net benefit is achieved with CCAR 10:1 and initial soil water content of 100% with a risk of 0.55 and net benefit of $580.00. The sensitivity analysis indicate that the model is sensitive to: (1) initial soil water content, (2) soil depth and (3) soil texture in terms of reduction on yield (actual/potential yield).

ABSTRACT High-Speed Mobile Networks for Modern Farming and Agricultural Systems J.Santos Najar-Ramirez High-speed mobile networks are necessary for agriculture to inventory individual plant health, maximize yield and minimize the resources applied. More specifically, real-time information on individual plant status is critical to decisions regarding the management of resources reserved and expended. This necessity can be met by the availability of environmental sensors (such as humidity, temperature, and pH) whose data is kept on storage servers connected to static and mobile local area networks. These static and mobile local area networks are connected to cellular, core and satellite networks. For instance, agricultural experts remotely working on vast acreage farms from business offices or while traveling can easily connect their notebook computers and other portable devices to these networks in order to check farm status, send email, read industry news or arrange a visit to neighbor farms or suppliers. Today, several mobile phone companies offer broadband service with 2Mbps downlink in rural and dense urban areas, however, they do not typically exist in farm areas. Although these networks (such as 802.11ac/n, 3G, 4G, etc) are significant achievements, they do not meet the projected needs of the agricultural industry. The present use model of high-speed networks for email and multimedia content, together with agriculture’s expected intensive use of real-time plant and environmental condition monitoring, with statistics/plots and real-time high resolution video, necessitates a highly integrated and highly available networked system. For agricultural experts, attentive to market needs, seamless high-speed wireless communication ‘anywhere, anytime at any speed’ is critical to enhancing their productivity and crop yields.

Lo scopo della tesi di dottorato è comprendere gli effetti dell'adozione degli approcci agroecologici sul Sustainable Livelihood Framework dei piccoli agricoltori. Sono state adottate tre metodologie di ricerca, revisione della letteratura, meta-analisi e caso di studio, al fine di valutare i benefici derivanti dall'attuazione degli approcci agroecologici sul capitale umano, sociale, naturale, finanziario e fisico. I risultati della tesi hanno mostrato come l’adozione dei sistemi agroecologici possono migliorare i mezzi di sussistenza dei piccoli agricoltori, senza che si verifichino trade-off su una serie di indicatori socio-economici e ambientali selezionati. La tesi evidenzia come i metodi agroecologici possano essere considerati uno strumento praticabile ed efficace per promuovere l’Obiettivo di Sviluppo Sostenibile 1 "Porre fine ad ogni forma di povertà nel mondo" e l’Obiettivo di Sviluppo Sostenibile 2 "Porre fine alla fame, raggiungere la sicurezza alimentare, migliorare la nutrizione e promuovere un’agricoltura sostenibile", in particolare per i piccoli agricoltori con scarse risorse nei paesi in via di sviluppo.
The purpose of the PhD thesis is to understand the effects of the adoption of agroecological approaches, both systems and practices, on the Sustainable Livelihood Framework of smallholder farmers. Three research methodologies, literature review, meta-analysis and case study, have been adopted in order to assess the benefits derived from implementing agroecological approaches on human, social, natural, financial and physical capitals. The results of the thesis have contributed to building evidence which demonstrates that agroecological approaches can improve the livelihood of smallholders farmers, without any trade-offs occurring in a wide range of socio-economic and environmental indicators. The thesis highlights that agroecological methods can be considered as a viable and effective tool to promote SDG1 “End poverty in all its forms everywhere” and SDG2 “End hunger, achieve food security and improved nutrition and promote sustainable agriculture”, especially for poor-resource farmers in developing countries.

Lo scopo della tesi di dottorato è comprendere gli effetti dell'adozione degli approcci agroecologici sul Sustainable Livelihood Framework dei piccoli agricoltori. Sono state adottate tre metodologie di ricerca, revisione della letteratura, meta-analisi e caso di studio, al fine di valutare i benefici derivanti dall'attuazione degli approcci agroecologici sul capitale umano, sociale, naturale, finanziario e fisico. I risultati della tesi hanno mostrato come l’adozione dei sistemi agroecologici possono migliorare i mezzi di sussistenza dei piccoli agricoltori, senza che si verifichino trade-off su una serie di indicatori socio-economici e ambientali selezionati. La tesi evidenzia come i metodi agroecologici possano essere considerati uno strumento praticabile ed efficace per promuovere l’Obiettivo di Sviluppo Sostenibile 1 "Porre fine ad ogni forma di povertà nel mondo" e l’Obiettivo di Sviluppo Sostenibile 2 "Porre fine alla fame, raggiungere la sicurezza alimentare, migliorare la nutrizione e promuovere un’agricoltura sostenibile", in particolare per i piccoli agricoltori con scarse risorse nei paesi in via di sviluppo.
The purpose of the PhD thesis is to understand the effects of the adoption of agroecological approaches, both systems and practices, on the Sustainable Livelihood Framework of smallholder farmers. Three research methodologies, literature review, meta-analysis and case study, have been adopted in order to assess the benefits derived from implementing agroecological approaches on human, social, natural, financial and physical capitals. The results of the thesis have contributed to building evidence which demonstrates that agroecological approaches can improve the livelihood of smallholders farmers, without any trade-offs occurring in a wide range of socio-economic and environmental indicators. The thesis highlights that agroecological methods can be considered as a viable and effective tool to promote SDG1 “End poverty in all its forms everywhere” and SDG2 “End hunger, achieve food security and improved nutrition and promote sustainable agriculture”, especially for poor-resource farmers in developing countries.

The purpose of this study was to develop and field test an approach based upon soft systems methodology for assessing constraints and anxieties faced by farmers utilizing recession farming. The approach in this study was based on soft systems methodology with the intent of constructing root-definitions for recession farming systems. The field testing of the approach utilized three recession farming systems in northeast Thailand. The root-definitions obtained using this approach, characterized two of the recession farming systems as capitalistic using an intensive, high input mode of production with limited land and labor. The third system was characterize as subsistent agriculture with few inputs. It was concluded that the approach developed in this study accurately identified constraints and differences between recession farming systems. The rich picture developed from the farmer's information was adequate to construct the root-definitions. It is recommended that this approach be tested in another region, using indigenous personnel trained to conduct group interviews.

The study determined the influence of social patterns on the adoption of mobile phones in agricultural society. It targeted small farmers in the African society, and its population was drawn from Tanzania. The study was conducted with the knowledge that small (peasant) farmers make up a large component of the African population. Enhancing the economic performance of farmers would improve the general economy of the addressed society, and eventually be translated to the Gross Domestic Product. On this basis, the adoption of ICTs (mobile phones in particular) would enhance the farmers' ability to access the right information for their day-to- day activities. Therefore, this was the reason why this study decided to find out whether social factors contribute to the adoption of mobile phones in the farming society. There are numerous models regarding the adoption of a new innovation by users. Nevertheless, models discussed in this study had social factors as a common aspect. Conceptually the study considered farmers' spending ability, the influence of the success of others, and the adoption on demand, as the factors within social variables. Other variables included the perceived economic benefits, the perceived intention to use, and the rate of use (use behaviour). Moreover, it is necessary to acknowledge that the study was conducted objectively, and embraced hypothesis testing as the basis for decision making. Data were obtained through a survey questionnaire. Generally, the findings of the study suggested the followings: Farmers' spending ability relates to their willingness to learn new mobile tools, peer influence relates to the intention to learn, adoption on demand influences the perceived usefulness of mobile tools, and the perceived usefulness relates with the rate of mobile use. The general view of this study is that social factors influence the adoption of mobile phones in the farming community, either directly or indirectly. Therefore, these factors may be applied to enhance the adoption of mobile phones in the farming community for improved production.

This thesis covers years of field work in Malawi, Africa by the author as a Research Agronomist (Tree Nuts) for the Government of Malawi. The thesis is an action research type with core and thesis projects which are closely linked. The client group are large estate managers who control the tree nut industries in Malawi. The political, economic and historical perspectives are different from those commonly faced by Australian agronomists and the isolated location of the work make this a unique study. The thesis includes sections on plantation or estate agriculture, farming systems approaches to research and problem solving, systems concepts in agricultural settings and action research concepts. These provide a framework for the study within the constraints of the government research system and industry expectations. The body of the thesis is a review paper presented to estate managers and co-researchers after one year's work. Relevant outcomes of the study are presented. The discussion draws together the outcomes through reflection on the process and methods used. Advantages and disadvantages are considered and risks, such as the dangers to the researcher of this type of study, are highlighted.
Master of Science (Hons)

This thesis covers years of field work in Malawi, Africa by the author as a Research Agronomist (Tree Nuts) for the Government of Malawi. The thesis is an action research type with core and thesis projects which are closely linked. The client group are large estate managers who control the tree nut industries in Malawi. The political, economic and historical perspectives are different from those commonly faced by Australian agronomists and the isolated location of the work make this a unique study. The thesis includes sections on plantation or estate agriculture, farming systems approaches to research and problem solving, systems concepts in agricultural settings and action research concepts. These provide a framework for the study within the constraints of the government research system and industry expectations. The body of the thesis is a review paper presented to estate managers and co-researchers after one year's work. Relevant outcomes of the study are presented. The discussion draws together the outcomes through reflection on the process and methods used. Advantages and disadvantages are considered and risks, such as the dangers to the researcher of this type of study, are highlighted.

To be able to meet the growing demand for food and ensure food security, arable farming systems need to be made more sustainable. However, making arable farming systems more sustainable could sometimes mean reductions in the use of productivity improving inputs such as fertiliser and pesticide in order to reduce their impacts on the environment. This presents conflicting environmental and economic goals, which increase management complexities in sustainable arable farming systems. An arable farm level model, consisting of four modules, which combines mixed-integer, risk and goal-programming approaches, has been developed to capture many of the complexities in arable farming and optimise farm profit, risk and nitrate leaching. Statistical validation of the model using data from the Farm Business Survey (FBS) showed a good association between model-predicted results and observed farm data. Results of the application of the mixed-integer weighted goal-programming module to estimate aggregate cost of non-chemical (spring cropping) control of black-grass showed that in the short run the strategy could cost the UK arable farming sector, however there could be a long term benefit of reductions in black-grass infestation. On per hectare basis, cost estimates provide indication of possible farm payment to incentivise adoption of the strategy. On individual farm basis, spring cropping could be beneficial dependent on the soil type, rainfall and hectares of land available to the farm. The application of the MOTAD module and randomly generated risk-aversion parameter method showed that arable farmers in England are risk-averse and that farmers in different regions would react to change in policy differently depending on their levels of risk-aversion. The results also showed the need for regional policies and relevance of the model in policy analysis. The model, which has been developed as part of this research adds to the few arable farm level models identified in the UK and bridges model capability gaps identified in arable farm modelling. Given available data for calibration and validation, results generated by the model can be applied to better inform arable farming and policy decisions to enhance the development of robust and sustainable arable farming systems to ensure food security.