Disponibilidade de n e k no solo e sua absorção pela videira de vinho fertirrigada no semiárido

Pós-graduação em Agronomia (Irrigação e Drenagem) - FCA

Silício e amônio na nutrição e no crescimento de brássicas

Pós-graduação em Agronomia (Produção Vegetal) - FCAV

Subacute toxicity assessment of diflubenzuron, an insect growth regulator, in adult male rats

Difubenzuron (DFB), an insecticide and acaricide insect growth regulator, can be used in agriculture against insect predators and in public health programs, to control insects and vectors, mainly Aedes aegypti larvae. Due to the lack of toxicological assessments of this compound, the objective of the present study was to evaluate the toxicological effects of subacute exposure to the DFB insecticide in adult male rats. Adult male rats were exposed (gavage) to 0, 2, 4, or 8 mg/kg of DFB for 28 days. No clinical signs of toxicity were observed in the DFB-treated animals of the experimental groups. However, there was an increase in serum levels of alanine aminotransferase in the group that received 8 mg/Kg/DFB/day and urea at doses of 4 and 8 mg/Kg/DFB/day, without altering other biochemical or hematological parameters. The subacute exposure to the lowest dose of DFB caused significant decrease in testis weight, daily sperm production, and in number of sperm in the epididymis in relation to the control group. However, no alterations were observed in the sperm morphology, testicular, epididymis, liver and kindney histology, or testosterone levels. These findings unveiled the hazardous effects of DFB on male reproduction after the subacute exposure and special attention should be addressed to the effects of low doses of this pesticide.

SOME VERTEBRATE PEST PROBLEMS IN JAPAN

The wildlife in Japan does more damage in outbreaks in forestry than in agriculture. Hares annually damage in excess of 250 thousand acres. Voles annually damage 50 to 100 thousand acres; in some areas great damage may occur suddenly. The giant flying squirrel damages areas of replanted trees in southern areas of Japan. The Himalayan black bear strips the bark on tree trunks. In agriculture, the sparrow and the duck do an excessive amount of damage in rice fields, and the boar does conspicuous harm in the plowed fields of mountain villages. In Okinawa, sugar cane is attacked by Rattus rattus, and in some years the loss is severe. Of even greater concern is the damage done by introduced vertebrates. The gem-faced civet was imported from Taiwan. Similarly introduced from Taiwan, the tree squirrel increased on Izu-Oshima. The nutria was introduced in 1940; they escaped from cages in Southern Honshu and have increased.

Use of levoglucosan, potassium, and water-soluble organic carbon to characterize the origins of biomass-burning aerosols

Three chemical species related to biomass burning, levoglucosan, potassium and water-soluble organic carbon (WSOC), were measured in aerosol samples collected in a rural area on the outskirts of the municipality of Ourinhos (Sao Paulo State, Brazil). This region is representative of the rural interior of the State, where the economy is based on agro-industrial production, and the most important crop is sugar cane. The manual harvesting process requires that the cane be first burned to remove excess foliage, leading to large emissions of particulate materials to the atmosphere. Most of the levoglucosan (68-89%) was present in small particles (<1.5 mu m), and its concentration in total aerosol ranged from 25 to 1186 ng m(-3). The highest values were found at night, when most of the biomass burning occurs. In contrast, WSOC showed no diurnal pattern, with an average concentration of 5.38 +/- 2.97 mu g m(-3) (n = 27). A significant linear correlation between levoglucosan and WSOC (r = 0.54; n = 26; p < 0.0001) confirmed that biomass burning was in fact an important source of WSOC in the study region. A moderate (but significant) linear correlation between levoglucosan and potassium concentrations (r = 0.62; n = 40; p < 0.0001) was indicative of the influence of other sources of potassium in the study region, such as soil resuspension and fertilizers. When only the fine particles (<1.5 pm; typical of biomass burning) were considered, the linear coefficient increased to 0.91 (n = 9). In this case, the average levoglucosan/K+ ratio was 0.24, which may be typical of biomass burning in the study region. This ratio is about 5 times lower than that previously found for Amazon aerosol collected during the day, when flaming combustion prevails. This suggests that the levoglucosan/K+ ratio may be especially helpful for characterization of the type of vegetation burned (such as crops or forest), when biomass-burning is the dominant source of potassium. The relatively high concentrations of WSOC (and inorganic ions) suggest an important influence on the formation of cloud condensation nuclei, which is likely to affect cloud formation and precipitation patterns. (C) 2012 Elsevier Ltd. All rights reserved.

Influence of caffeine on the survival of leaf-cutting ants Atta sexdens rubropilosa and in vitro growth of their mutualistic fungus

BACKGROUND: Leaf-cutting ants collect plant fresh material for the cultivation of their mutualistic fungus. Atta sexdens rubropilosa Forel (Hymenoptera: Formicidae) cause great economic losses through their foraging activity, mainly in agriculture. The main control method is the application of granulated toxic baits incorporated with an active ingredient (AI). The present goal is to evaluate the effect of caffeine on in vitro growth of the mutualistic fungus and on the survival of the leaf-cutting ants, aiming to verify the potential toxicity of this secondary metabolite over these organisms. RESULTS: Three distinct patterns of fungal growth correlated with caffeine concentration were observed: (1) no effect (0.01% caffeine); (2) intermediate growth reduction (0.05% caffeine); (3) drastic growth reduction (0.10 and 0.50% caffeine). The highest caffeine concentration causes fungus death in the first week. As for insect survival, caffeine does not seem to exert any effect. The treatments with diet containing caffeine showed similar values of M50, irrespective of caffeine concentration. CONCLUSION: As caffeine was shown to reduce growth of the mutualistic fungus of Atta sexdens rubropilosa, but with no conclusive effect on insect survival, a hypothetical explanation for the selection of different Coffea species by this leaf-cutting ant species might be associated with caffeine toxicity to the fungus. Copyright (C) 2011 Society of Chemical Industry

Characteristics of WWTP sludge after drying in greenhouse for agricultural purposes

The sludge generated by sewage treatment which meets regulatory standards can be used in agriculture. With this understanding, the focus of this study is the evaluation of the agricultural characteristics and inorganic substances in excess activated sludge, which was subjected to drying in a greenhouse. The variables (factor) evaluated during the drying process were: type of sludge (digested or not digested), addition of lime to the sludge, and the physical layout and rotation of sludge in the greenhouse. The parameters monitored for this assessment were moisture, volatile solids and pH. The greenhouse cover and sides were made of translucent plastic to allow the penetration of solar radiation and prevent water from entering. A impermeable floor was used. The sludge was generated in sewage treatment plants located in the metropolitan region of Grande Vitoria, Espirito Santo, Brazil. The solar drying of wastewater sludge in a greenhouse presented satisfactory results.

The role of collective action in the provision of agri-environmental public goods: theoretical development through case studies in Italy

The thesis aims at analysing the role of collective action as a viable alternative to the traditional forms of intervention in agriculture in order to encourage the provision of agri-environmental public goods. Which are the main benefits of collective action, in terms of effectiveness and efficiency, compared to traditional market or public intervention policies? What are the drivers that encourage farmers to participate into collective action? To what extent it is possible to incorporate collective aspects into policies aimed at providing agri-environmental public goods? With the objective of addressing these research questions, the thesis is articulated in two levels: a theoretical analysis on the role of collective action in the provision of public goods and a specific investigation of two local initiative,s were an approach collective management of agro-environmental resources was successfully implemented. The first case study concerns a project named “Custodians of the Territory”, developed by the local agency in Tuscany “Comunità Montana Media Valle del Serchio”, which settled for an agreement with local farmers for a collective provision of environmental services related to the hydro-geological management of the district. The second case study is related to the territorial agri-environmental agreement experimented in Valdaso (Marche), where local farmers have adopted integrated pest management practices collectively with the aim of reducing the environmental impact of their farming practices. The analysis of these initiatives, carried out through participatory methods (Rapid Rural Appraisal), allowed developing a theoretical discussion on the role of innovative tools (such as co-production and co-management) in the provision of agri-environmental public goods. The case studies also provided some recommendations on the government intervention and policies needed to promote successful collective action for the provision of agri-environmental public goods.

On land management: landowners' attitudes to land and farming in Valdera, Tuscany

This thesis aims at explaining the intersecting dynamics of structural changes in agriculture and urbanisation, which involves changes in urban-rural relationships. The research questions are: how and why do landowners differ in their attitudes to land and farming? what are the main implications on rural landscapes and the policy implications? Relationships between urbanisation and agriculture are firstly analysed through a critical literature review; the analysis focuses on the 'landowner' as the key actor who actively takes decisions on the rural landscape From the empirical study – which is based on a Tuscan area (Valdera), and addressed through qualitative methods – a great diversity of landowners' attitudes to land and farming emerge, thus contributing to the agricultural restructuring, such as: 1) the emphasis on recreational function of the countryside for urban people 2) contracting out of land management, especially when landowners live or/and have 'urban' employment 3) the active role of hobby farmers in land management 4) agricultural operations simplification and lack of investments (especially in case of property rights expropriation). The thesis is framed in three papers, with the same methods and research questions. It seems evident that rural landscapes is subjected to functional changes (e.g. residential) and structural changes (landscape polarisation), which requires the need 1) to consider that rural landscape management is increasingly less connected to agricultural production as economic activity; 2) to give a coherence to the range of policy interventions (physical planning, landscape, sectoral).

Aspetti di sostenibilità in agricoltura a diverse scale spaziali e temporali. Valutazioni ambientali, economiche ed energetiche.

La Tesi analizza le relazioni tra i processi di sviluppo agricolo e l’uso delle risorse naturali, in particolare di quelle energetiche, a livello internazionale (paesi in via di sviluppo e sviluppati), nazionale (Italia), regionale (Emilia Romagna) e aziendale, con lo scopo di valutare l’eco-efficienza dei processi di sviluppo agricolo, la sua evoluzione nel tempo e le principali dinamiche in relazione anche ai problemi di dipendenza dalle risorse fossili, della sicurezza alimentare, della sostituzione tra superfici agricole dedicate all’alimentazione umana ed animale. Per i due casi studio a livello macroeconomico è stata adottata la metodologia denominata “SUMMA” SUstainability Multi-method, multi-scale Assessment (Ulgiati et al., 2006), che integra una serie di categorie d’impatto dell’analisi del ciclo di vita, LCA, valutazioni costi-benefici e la prospettiva di analisi globale della contabilità emergetica. L’analisi su larga scala è stata ulteriormente arricchita da un caso studio sulla scala locale, di una fattoria produttrice di latte e di energia elettrica rinnovabile (fotovoltaico e biogas). Lo studio condotto mediante LCA e valutazione contingente ha valutato gli effetti ambientali, economici e sociali di scenari di riduzione della dipendenza dalle fonti fossili. I casi studio a livello macroeconomico dimostrano che, nonostante le politiche di supporto all’aumento di efficienza e a forme di produzione “verdi”, l’agricoltura a livello globale continua ad evolvere con un aumento della sua dipendenza dalle fonti energetiche fossili. I primi effetti delle politiche agricole comunitarie verso una maggiore sostenibilità sembrano tuttavia intravedersi per i Paesi Europei. Nel complesso la energy footprint si mantiene alta poiché la meccanizzazione continua dei processi agricoli deve necessariamente attingere da fonti energetiche sostitutive al lavoro umano. Le terre agricole diminuiscono nei paesi europei analizzati e in Italia aumentando i rischi d’insicurezza alimentare giacché la popolazione nazionale sta invece aumentando.

An Innovation System Perspective on Adaptation Strategies to Climate Variability and Water Management in India

Government policies play a critical role in influencing market conditions, institutions and overall agricultural productivity. The thesis therefore looks into the history of agriculture development in India. Taking a political economy perspective, the historical account looks at significant institutional and technological innovations carried out in pre- independent and post independent India. It further focuses on the Green Revolution in Asia, as forty years after; the agricultural community still faces the task of addressing recurrent issue of food security amidst emerging challenges, such as climate change. It examines the Green Revolution that took place in India during the late 1960s and 70s in a historical perspective, identifying two factors of institutional change and political leadership. Climate change in agriculture development has become a major concern to farmers, researchers and policy makers alike. However, there is little knowledge on the farmers’ perception to climate change and to the extent they coincide with actual climatic data. Using a qualitative approach,it looks into the perceptions of the farmers in four villages in the states of Maharashtra and Andhra Pradesh. While exploring the adaptation strategies, the chapter looks into the dynamics of who can afford a particular technology and who cannot and what leads to a particular adaptation decision thus determining the adaptive capacity in water management. The final section looks into the devolution of authority for natural resource management to local user groups through the Water Users’ Associations as an important approach to overcome the long-standing challenges of centralized state bureaucracies in India. It addresses the knowledge gap of why some local user groups are able to overcome governance challenges such as elite capture, while others-that work under the design principles developed by Elinor Ostrom. It draws conclusions on how local leadership, can be promoted to facilitate participatory irrigation management.

Technology Development and Consumer Acceptance of Innovation in Fruit Production

Precision Agriculture (PA) and the more specific branch of Precision Horticulture are two very promising sectors. They focus on the use of technologies in agriculture to optimize the use of inputs, so to reach a better efficiency, and minimize waste of resources. This important objective motivated many researchers and companies to search new technology solutions. Sometimes the effort proved to be a good seed, but sometimes an unfeasible idea. So that PA, from its birth more or less 25 years ago, is still a “new” management, interesting for the future, but an actual low adoption rate is still reported by experts and researchers. This work aims to give a contribution in finding the causes of this low adoption rate and proposing a methodological solution to this problem. The first step was to examine prior research about Precision Agriculture adoption, by ex ante and ex post approach. It was supposed as important to find connections between these two phases of a purchase experience. In fact, the ex ante studies dealt with potential consumer’s perceptions before a usage experience occurred, therefore before purchasing a technology, while the ex post studies described the drivers which made a farmer become an end-user of PA technology. Then, an example of consumer research is presented. This was an ex ante research focused on pre-prototype technology for fruit production. This kind of research could give precious information about consumer acceptance before reaching an advanced development phase of the technology, and so to have the possibility to change something with the least financial impact. The final step was to develop the pre-prototype technology that was the subject of the consumer acceptance research and test its technical characteristics.

Risk analysis of tractor rollover in the normal operation in field

Tractor rollover represent a primary cause of death or serious injury in agriculture and despite the mandatory Roll-Over Protective Structures (ROPS), that reduced the number of injuries, tractor accidents are still of great concern. Because of their versatility and wide use many studies on safety are concerned with the stability of tractors, but they often prefer controlled tests or laboratory tests. The evaluation of tractors working in field, instead, is a very complex issue because the rollover could be influenced by the interaction among operator, tractor and environment. Recent studies are oriented towards the evaluation of the actual working conditions developing prototypes for driver assistance and data acquisition. Currently these devices are produced and sold by manufacturers. A warning device was assessed in this study with the aim to evaluate its performance and to collect data on different variables influencing the dynamics of tractors in field by monitoring continuously the working conditions of tractors operating at the experimental farm of the Bologna University. The device consists of accelerometers, gyroscope, GSM/GPRS, GPS for geo-referencing and a transceiver for the automatic recognition of tractor-connected equipment. A microprocessor processes data and provides information, through a dedicated algorithm requiring data on the geometry of the tested tractor, on the level of risk for the operator in terms of probable loss of stability and suggests corrective measures to reduce the potential instability of the tractor.

Rural governance and livelihoods systems diversification in the Western Balkans: comparative case studies of Bosnia and Herzegovina, Montenegro and Serbia

Agriculture is still important for socio-economic development in rural areas of Bosnia, Montenegro and Serbia (BMS). However, for sustainable rural development rural economies should be diversified so attention should be paid also to off-farm and non-farm income-generating activities. Agricultural and rural development (ARD) processes and farm activity diversification initiatives should be well governed. The ultimate objective of this work is to explore linkages between ARD governance and rural livelihoods diversification in BMS. The thesis is based on an extended secondary data analysis and surveys. Questionnaires for ARD governance and coordination were sent via email to public, civil society and international organizations. Concerning rural livelihood diversification, the field questionnaire surveys were carried out in three rural regions of BMS. Results show that local rural livelihoods are increasingly diversified but a significant share of households are still engaged in agriculture. Diversification strategies have a chance to succeed taking into consideration the three rural regions’ assets. However, rural households have to tackle many problems for developing new income-generating activities such as the lack of financial resources. Weak business skills are also a limiting factor. Fully exploiting rural economy diversification potential in BMS requires many interventions including improving rural governance, enhancing service delivery in rural areas, upgrading rural people’s human capital, strengthening rural social capital and improving physical capital, access of the rural population to finance as well as creating a favourable and enabling legal and legislative environment fostering diversification. Governance and coordination of ARD policy design, implementation and evaluation is still challenging in the three Balkan countries and this has repercussions also on the pace of rural livelihoods diversification. Therefore, there is a strong and urgent need for mobilization of all rural stakeholders and actors through appropriate governance arrangements in order to foster rural livelihoods diversification and quality of life improvement.

Signalling mechanisms affecting regulated neurotrophin secretion in hippocampal neurons

Die Neurotrophine aus Säugetiere BDNF und NT-3 sind von Neuronen sekretierte Wachstumsfaktoren. Ferner sind Neurotrophine in verschiedene Formen der aktivitätsabhängigen synaptische Plastizität involviert. Obwohl die Ausschüttung von Neurotrophine aus Synapsen beschrieben worden ist, sind die intrazellulären Signalkaskaden, die die synaptische Ausschüttung von Neurotrophine regulieren, bei weitem nicht verstanden. Deswegen ist die Analyse der Sekretion von Neurotrophine auf subzellulärer Ebene erforderlich, um die genaue Rolle von präsynaptische und postsynaptische NT-Sekretion in der synaptischen Plastizität aufzudecken. In der vorliegenden Arbeit wurden die Kulturen von dissoziierten hippocampalen Neuronen aus Ratten mit grün fluoreszierenden Protein-markierten Konstrukten von BDNF und NT-3 transfiziert und Neurotrophine-enthaltenden Vesikeln durch die Colokalisierung mit dem cotransfizierten postsynaptischen Marker PSD-95-DsRed an glutamatergen Synapsen identifiziert. Depolarisationsinduzierte Sekretion von BDNF und NT-3 wurde per Direktaufnahme am Fluoreszenzmikroskop beobachtet. Die unvermittelte postsynaptische Depolarisation mit erhöhtem Kalium, in Gegenwart von Inhibitoren der synaptischen Transmission, erlaubte die Untersuchung der Signalwege, die am postsynaptischen Sekretionsprozess der Neurotrophinvesikel beteiligt sind. Es konnte gezeigt werden, dass die depolarisationsinduzierte postsynaptische Ausschüttung der Neurotrophine durch Calcium-Einstrom ausgelöst wird, entweder über L-Typ-spannungsabhängige Calcium-Kanäle oder über NMDA-Rezeptoren. Eine anschließende Freisetzung von Calcium aus intrazellulären Speichern über Ryanodin-Rezeptoren ist für den Sekretionsprozess erforderlich. Die postsynaptische Neurotrophinausschüttung wird durch KN-62 und KN-93 gehemmt, was auf eine unmittelbare Abhängigkeit von aktiver alpha-Calcium-Calmodulin-abhängige Proteinkinase II (CaMKII) hinweist. Der Inhibitor der cAMP/Proteinkinase A (PKA), Rp-cAMP-S, sowie der NO-Donor, SNP, minderten die Neurotrophinausschüttung. Hingegen blieben die Erhöhung des intrazellulären cAMP und der NO-Synthase-Inhibitor L-NMMA ohne Wirkung. Mit dem Trk-Inhibitor K252a konnte gezeigt werden, dass autokrine Neurotrophin-induzierte Neurotrophinausschüttung nicht an der synaptischen Freisetzung der Neurotrophine beiträgt und, dass BDNF seine eigene postsynaptische Sekretion nicht auslöst. Freisetzungsexperimente mit dem Fluoreszenz-Quencher Bromphenolblau konnten den Nachweis erbringen, dass asynchrone und anhaltende Fusionsporenöffnung von Neurotrophinvesikeln während der Sekretion stattfindet. Wegen der im Vergleich zum komplexen Sekretionsprozess schnellen Fusionsporenöffnung, scheint die Freisetzungsgeschwindigkeit von Neurotrophine durch ihre Diffusion aus dem Vesikel begrenzt. Zusammenfassend zeigen diese Ergebnisse eine starke Abhängigkeit der aktivitätsabhängigen postsynaptischen Neurotrophinausschüttung vom Calcium-Einstrom, von der Freisetzung von Calcium aus internen Speichern, von der Aktivierung der CaMKII und einem intakten Funktion der PKA, während der Trk-Signalweg, die Aktivierung von Natrium-Kanäle und NO-Signale nicht erforderlich sind.