Evaluation and adoption of irrigation technologies: management-design curves for furrow and level basin systems

Abstract The effect of average low-quarter requirement depth of irrigation and uniformity of applied water on the estimation of inflow rate and cutoff time of furrows and level basins is evaluated, using the SRFR-surface irrigation model and different intake rate soil characteristics. The optimum inflow rate and cutoff time is dependent on the irrigation technology and infiltration characteristics. To assist in the task of on-farm water management of furrows and level basin irrigation and the engineering design and planning of these systems management, design charts are proposed that define the optimum combination of inflow rate and cutoff time, given values of required depth and uniformity of application. The charts are plots of average low-quarter requirement depth and uniformity contours on axes of inflow rate and cutoff time. The general form of the curves shows that technical trade-off between systems becomes evident as flow rates and cutoff times decline as fields are levelled to zero slope and irrigated as basins. The relative steepness and the dense nature of the level basin uniformity contour curves reflect the importance of intense management and the greater penalty for management errors with these systems as opposed to furrows

Quality and maximum profit of industrial tomato as affected by distribution uniformity of drip irrigation system

Abstract The tomato industry reformed its system of payment by weight of tomato, introducing a corrective system based on percent level of fruit dry matter produced. Such a decision implies significant changes in the management of irrigation systems, with a need to emphasize the technological quality of the marketable product. Three levels of distribution uniformity of the irrigation system are analysed, and related production functions of crop yield and percent of dry matter are presented as well as their use on the optimisation of dry matter, expected revenues and seasonal applied water. Results are critically influenced by the distribution uniformity. They demonstrate the inter-relationship between crop production, percent fruit dry matter and irrigation management, and the importance of considering non-uniformity in the economic analysis of industrial tomato production. Decreases in uniformity lead to a reduction in dry matter production per unit land. Decreases in dry matter are also observed with increasing levels of seasonally applied water, with the optimal level always lower than the required for maximum yield. Such interaction suggests a continuous and inverse relationship between profit and water applied. However, due to the corrective system of payment, by levels of percent of dry matter produced, for some uniformity, the expected revenue follows the yield-water production function instead of the dry matter function. This fact introduces disturbances in the optimal water applied inducing higher than expected levels of water applied for profit maximisation. The simulated data also show that incentives to switch to new systems or management practices able to raise the distribution uniformity result more from profit losses than increases in water price

Water use, transpiration, and crop coefficients for olives (cv. Cordovil), grown in orchards in Southern Portugal

To improve the scheduling of irrigation for low-density olive trees (Olea europaea L.) grown in a typical Mediterranean environment of Southern Portugal, and to clarify the mechanisms of water uptake by trees, transpiration, soil water status and stomatal response to water deficit were measured in an olive orchard. Olive trees of cv. Cordovil were subject to three irrigation treatments: full-rate irrigation, sustained deficit irrigation (SDI) providing for approximately 60% of water applied at full-rate irrigation, and a regulated deficit irrigation (RDI) with water applied at periods during three critical phases: before-flowering, at beginning of pit-hardening, before crop-harvesting to replenish soil moisture to field capacity. There was also a dry-farming treatment. Trees responded differently to summer rainfall and irrigation water: full-rate irrigation, which received 880 mm of irrigation and 240 mm of rainfall, used 704 mm for transpiration; SDI, which received the same amount of rainfall and 448 mm of irrigation water, used 745 mm of water for transpiration; RDI, which received 69 mm of irrigation water and 240 mm of rainfall, used 638 mm of water for tree transpiration; dry-farming, which received no irrigation, benefited from 240 mm of summer and early autumn rain and used 404 mm of water for transpiration. The results support the hypothesis that trees under RDI and dry-farming satisfy most of their early atmospheric evaporative demand by extracting water from outside of the area wetted by drip irrigation. Scaled-up orchard transpiration was used to define orchard crop and water stress coefficients. With full-rate irrigation and SDI the results showed that during summer droughts olive trees slow down their physiological mechanisms to conserve water, regardless of amount applied. The derived crop coefficient results also indicated that SDI was the most appropriate for scheduling the irrigation of cv. Cordovil orchards in Southern Portugal although applying RDI helped sustain orchard transpiration and yields. Irrigation accounted for 11% of total water used in transpiration, with the balance extracted by roots in the large volume of soil lying in the areas between the trees. However, using the RDI scheme to schedule irrigation appears to be appropriate only in wet years with well distributed late summer rainfall or where there is a shortage of farm irrigation water. In general, and particularly in years with no summer and early autumn rains as can often occur in this region, the SDI regime appears to be more appropriate for scheduling irrigation

Yield and olive oil characteristics of a low-density orchard (cv. Cordovil) subjected to different irrigation regimes

Abstract The impact of different irrigation scheduling regimes on the quantity and quality of olive oil from a low-density olive grove in southern Portugal was assessed during the irrigation seasons of 2006 and 2007. Olive trees were subjected to one of the following treatments: A—full irrigation; B—sustained deficit irrigation (SDI) with 60% of ETc water applied with irrigation; C—regulated deficit irrigation (RDI) with irrigation water applied at three critical phases: before flowering, at the beginning of pit hardening and before crop harvesting and D—rain-fed treatment. Olive oil yield was significantly higher than rain-fed conditions in 2006, an “on year” of significant rainfall during summer. No significant yield differences were observed in the following “off year”. Among the irrigated treatments, olive oil production of treatment B was 32.5% and 40.1% higher in 2006 and 2007, respectively than the fully irrigated treatment A, despite receiving 49% less irrigation water. Such strategy could allow for an efficient use of water in the region, of very limited available resources, and for modest but important oil yield increase. Nonetheless, on the “on year” of 2006 treatment C used 13.9% of the water applied to treatment B and produced only 23.9% less olive fruits which could also make it illegible as the next possible strategy to use for irrigating olive trees in the region, provided that water is secured latter in the summer, a period of vital importance for oil accumulation and very sensitive to water stress as the poor results of 2007 revealed. The different treatment water regimes did not impact on the chemical characteristics of olive oils that were within the set threshold limits. Similarly, the sensory characteristics of the olive oils as well as bitterness and pungency were negligible for all treatments allowing them to be assessed as of “superior quality”.Overall, irrigation treatments had no influence on the commercial value of produced oils, being all classified as “extra virgin”. Such funding may be of vital importance to farmers willing to further their irrigation area, save water and still retain the protected designation of origin (PDO) seal of quality for their oil

Covid-19 and stock market volatility : a clustering approach for S&P 500 industry indices

Mestrado Bolonha em FinançasThe COVID-19 pandemic was the infectious disease outbreak that has had the strongest impact on the U.S. stock market. In this dissertation, we study how this impact affected some of the conditional volatilities of S&P 500 industries, using a new model feature-based clustering method on a fitted threshold generalised autoregressive conditional heteroscedasticity (TGARCH) specification. Rather than using the estimated model parameters to compute a distance matrix for the stock indices, which cannot capture all the information about the dependence of the time-varying variance, we suggest using a distance based on the autocorrelations of the estimated conditional volatilities. Both hierarchical (complete linkage) and non-hierarchical (k-means) unsupervised machine learning algorithms are used to assign the set of industries into clusters. The results show a clear change in the composition of each cluster between the period before the first U.S. COVID-19 case and the period during the pandemic, leading to the conclusion that the similarities or distances between industries underwent a significant change, with the industries most affected by the pandemic being Hotels, Consumer Durable & Apparel, Automobile, and Airlines. It was also made an analysis regarding the forecast accuracy of simple asymmetric GARCH models applied to S&P 500 industries and use the model forecast errors for different horizons to calculate a distance matrix for the stock indices. A hierarchical clustering algorithm is used to assign the set of industries into clusters. We found homogeneous clusters of industries in terms of the impact of COVID-19 on US stock market volatility. The industries most affected by the pandemic and with less accurate stock market prediction (Hotels, Resorts & Cruise Lines, Airline, Apparel, Accessories & Luxury Goods, and Automobile) are separated in Euclidean distance from those industries that were less impacted by COVID-19 and which had more accurate forecasting (Pharmaceuticals, Internet & Direct Marketing Retail, Data Processing & Outsourcing Services, and Movies & Entertainment).A pandemia do COVID-19 foi o surto com maior impacto de sempre no mercado de ações dos EUA. Nesta dissertação, estudamos como este impacto afetou algumas das volatilidades condicionadas das indústrias do S&P 500, usando métodos de clustering aplicados numa especificação de um modelo derivado (threshold) do generalizado autorregressivo condicional e heterocedástico (TGARCH). OS parâmetros do modelo estimado não capturam toda a informação acerca da dependência da variância não constante ao longo do tempo pelo que usamos distância baseada nas autocorrelações das volatilidades condicionais, para calcular a matriz de distância para os índices de ações. Ambos os algorítmos hierárquicos (complete linkage) e não-hierárquicos (k-means), técnicas de unsupervised machine learning, são usados para agrupar conjuntos de indústrias em clusters. Os resultados mostram uma clara mudança na composição de cada cluster entre o período anterior ao primeiro caso de COVID-19 nos EUA e o período durante a pandemia. As semelhanças ou distâncias entre as indústrias sofreram uma mudança significativa, sendo as indústrias mais afetadas pela pandemia, os Hotéis, Bens de Consumo Duráveis e Vestuário, Automóveis e Companhias Aéreas. Foi feita uma análise quanto à precisão da previsão de modelos GARCH assimétricos simples aplicados a indústrias do S&P 500. Esses erros de previsão calculados em diferentes intervalos de tempo, durante a pandemia, foram usados para calcular a matriz de distâncias entre os indices de mercado. Um algoritmo de hierarchical clustering foi usado para agrupar um grupo de indústrias em clusters. Obtivemos clusters homogéneos em termos do impacto do COVID-19 na volatilidade do mercado de ações nos EUA. As indústrias mais afectadas pela pandemia, nas quais os modelos preditivos se mostraram menos precisos em termos preditivos (Hotels, Resorts & Cruise Lines, Airline, Apparel, Acessories & Luxury Goods, and Automobile) estão separadas por uma distância Euclideana das indústrias que foram menos impactadas pelo COVID-19 e as previsões mais precisas (Pharmaceuticals, Internet, Data Processing, e Movies & Entertainment).info:eu-repo/semantics/publishedVersio

Relações Solo-Água-Planta

O interesse nas relações solo-água-planta decorre do facto de constituírem conhecimento essencial e suporte indispensável para aplicações em áreas tão diversas e tradicionais como a agricultura, biologia, hidrologia e hidrogeologia, engenharia dos recursos hídricos e engenharia do ambiente, estendendo-se a outras áreas como a bio-remediação e o controlo de solutos e poluentes no solo e nas águas. O capítulo aborda o âmbito da ciência e da física do solo, a metodologia de estudos dos fenómenos aí tratados e prossegue com a descrição e quantificação dos elementos que constituem as fases do solo. A descrição da fase sólida limita-se às características gerais que permitem diferenciar os solos entre si, e relacioná-los com os fenómenos rápidos de transferência de água e de solutos. Aspetos específicos da interação entre as fases sólida e líquida são detalhados, com abordagem das metodologias mais usadas na caracterização da capacidade geral de armazenamento do solo. Prossegue-se com a análise do estado energético da água e dos fenómenos e leis que explicam a sua retenção no solo, transporte e ascensão para a planta, através das raízes. Expõe-se os conceitos e as leis físicas do movimento e da dinâmica da fase líquida, e os métodos e técnicas de avaliação de escoamentos e fluxos no solo e na planta. Para o aprofundamento dos temas, a bibliografia oferece múltiplas referências

EPIC-PHASE: a model to explore irrigation strategies

bstract The erosion productivity impact calculator phase (EPIC-PHASE) model has been used to simulate, using 1972 to 1994 climatic date, two irrigation strategies with a non-limited water supply: (1) a standard strategy based on simple decision rules advisable for moderately deep soils of the Lauragais region (France) and in the Alentejo region (Portugal); and (2) a model strategy based on the daily development of soil water depletion and daily water stress intensity predicted by the model. At Lauragais, the results show that for the same level of yield it would have been possible with the model to save 73 mm on average, equivalent of two irrigations per year, compared to the standard strategy. These savings are due to an increased soil water contribution during the cycle and to an earlier end of the irrigation supply. At Alentejo, the results show that for the same level of yield as obtained with the standard strategy, it would have been possible with EPIC-PHASE model to save 100 mm of water on average, equivalent of two irrigations per year due to an increased use of soil water during the cycle. Although the results are from simulations it is proved that the standard strategy is inadequate. Regarding the environmental impact, the model management allows for an increase in the level of water depletion at harvest, delaying the risk of percolation and nitrogen losses during the refill period. The EPIC-PHASE model proved to be a tool capable of defining an irrigation schedule better adapted to the Mediterranean region

Villa Cardíllio - contributo para a história da valorização de um sítio arqueológico

Este resumo revela o que será a minha dissertação, destinada a analisar informação textual e iconográfica recolhida sobre os trabalhos arqueológicos realizados no sítio arqueológico da Villa Cardillio, em Torres Novas, nomeadamente informação relacionada à sua valorização turística. Também não esquecendo a ligação da arqueologia com o turismo em contexto global, a caracterização geográfica e geológica da Villa Cardillio e a sua relação com o quadro da romanização da Lusitânia. Neste sentido, proceder-se-á à caracterização do sítio e do território em que se encontra situado, ao mesmo tempo que se procederá à sua análise à luz da história da arqueologia e, mais especificamente, da ligação estabelecida ao longo dos tempos entre o sítio e o movimento turístico organizado em seu torno, cotejando-o a casos similares, designadamente dos que se encontrem geograficamente mais próximos. Por fim, serão dadas sugestões de forma a potenciar o sítio turisticamente, bem como a divulgação de acções realizadas sobre ele para a sua promoção e salvaguarda e o que poderá ser feito mais sobre a Villa Cardillio, noutro trabalho ou projecto de investigação, que não foi possível concretizar nesta dissertação, devido à pandemia que surgiu e persiste neste momento; Villa Cardillio – contribution to the history of valorization of an archaeological site Abstract: This abstract shows what my dissertation will be, which aims to analyze textual and iconographic information collected from the archaeological works carried out at the archaeological site of Villa Cardillio, in Torres Novas, namely information related to its touristic valorization. Also not forgetting the connection between archaeology with tourism in a global context, the geographical and geological characterization of Villa Cardillio and its relation with the romanization of Lusitania. In this sense, the site and the territory in which it is located will be characterized, while the site will be analyzed in the light of the history of archaeology and, more specifically, the connection established over time between the site and the touristic movement organized around it, comparing it to similar cases, namely those that are geographically closer. Finally, will be given suggestions to enhance touristically the site, as well as spreading actions done about it for its promotion and safeguard and what can be done more about Villa Cardillio, in another work or research project, that could not be completed in this dissertation, due to the pandemic that emerged and still persists at this time

A simple numerical analysis software for predicting water table height in subsurface drainage

Abstract A two dimensional saturated-unsaturated Galerkin finite element numerical model was used to predict water table height between parallel drains. A user-friendly software (DRENAFEM) was developed to allow for the calculation of the distance between drains and the water table height at middle space between drains. It also allows for determination of variations of the total head throughout the entire geometric space considered in the model. Such facts lead to the design of flow nets with streams lines and equipotentials. The numerical drain outflow is also obtained by using the radial flow equation, conservation of mass and finite element analysis. The results obtained with the model agree well with Khirkam’s and Hooghoudt analytical solution for the distribution of total head in ideal drains and for the total head calculations midway between drains

Comparative assessment of infiltration, runoff and erosion sprinkler irrigated soils

Abstract The impacts of sprinkler irrigation on infiltration, runoff and sediment loss of ten representative soils of Southern Portugal were assessed by laboratory sprinkler irrigation simulation tests. All soils showed very low permeability to applied water. The mechanical impact of water droplets enhanced soil dispersion and further lowered their infiltration capacity, particularly for high clay plus silt content soils that showed the poorest results. As a consequence, high runoff and sediment losses were also measured, primarily with the first irrigation. More moderate losses were observed thereafter. Soils with higher sand particle size fractions better absorbed the energy impact of droplets and showed higher infiltration rates and lower runoff and sediment losses. Polyacrylamide (PAM) applied to the soils through the irrigation water acted as a binding and settling agent to increase soils aggregate stability and infiltration and reduce runoff and sediment losses. Slope increase, from 2·5 to 5%, decreased overall soils infiltration by 7% and increased runoff and sediment losses by 10 and 27%, respectively. Exposed to the same change in slope, PAM application boosted overall infiltration of treated soils to a 24% difference and increased runoff by only 10%. It had a less positive effect on sediment loss, the 5% slope being responsible for a 52% increase. In agreement with this the tests showed that, compared to the control, exposure of PAM-treated soil on 2·5 and 5% slopes enhanced overall infiltration to 457 and 642% respectively, reduced runoff by 25% on both cases and lessened sediment loss by 39 and 27%. The demonstrated ability of PAM to influence surface soil conditions of specific soils can be used to reduce the environmental risks associated with the intensive use of sprinkler irrigation in Southern Portugal. It offers a safe, practical and non-intrusive management alternative to current costly, labour- and energy-intensive practices of increasing the number of machine turns and building storage basins to control runoff and soil erosion