The use of wind pumps for greenhouse microirrigation: A case study for tomato in Cuba

A methodology based on daily estimation balance between water needs and water availability was used to evaluate the feasibility of the most economic windmill irrigation system. For this purpose, several factors were included: three-hourly wind velocity (W3 h, m/s), flow supplied by the wind pump as a function of the elevation height (H, m) and daily greenhouse evapotranspiration as a function of crop planting date. Monthly volumes of water required for irrigation (Dr, m3/ha) and in the water tank (Vd, m3), as well as the monthly irrigable area (Ar, ha), were estimated by cumulative deficit water budgeting taking in account these factors.

Managing drought economic effects through insurance schemes based on local water availability.

In many arid or semi-arid Mediterranean regions, agriculture is dependent on irrigation. When hydrological drought phenomena occur, farmers suffer from water shortages, incurring important economic losses. Yet, there is not agricultural insurance available for lack of irrigation water. This work attempts to evaluate hydrological drought risk and its economic impact on crop production in order to provide the basis for the design of drought insurance for irrigated arable crops. With this objective a model that relates water availability with expected yields is developed. Crop water requirements are calculated from evapotranspiration, effective rainfall and soil water balance. FAO?s methodology and AquaCrop software have been used to establish the relationship between water allocations and crop yields. The analysis is applied to the irrigation zone ?Riegos de Bardenas?, which is located in the Ebro river basin, northeast Spain, to the main arable crops in the area. Results show the fair premiums of different hydrological drought insurance products. Whole-farm insurance or irrigation district insurance should be preferable to crop specific insurance due to the drought management strategies used by farmers.

Irrigated agriculture: Water resources management for a sustainable environment

In the last decade, research on irrigation has mainly been aimed at reducing crop water consumption. In arid and semi-arid environments, in relation to the limited water resources, the use of low quality water in agriculture has also been investigated in order to detect their effects on soil physical properties and on crop production. More recently, even the reduction of energy consumption in agriculture, as well as the effects of external factors, climate change and agricultural policies, have been major research interests. All these objectives have been considered in the papers included in this special issue. However, in the last years, approaches aimed at reducing crop water requirements have significantly changed. Remote sensing with satellites or unmanned vehicles, and vegetation spectral measurements, among others, represent in fact the newest frontier of existing technologies. Knowledge of soil hydraulic properties, often forgotten because of the difficulty of their estimation, can also be considered as a new way to reduce water consumption.

Water use efficiency and water productivity in the Spanish irrigation district ¿Río Adaja?

A study of the assessment of the irrigation water use has been carried out in the Spanish irrigation District “Río Adaja” that has analyzed the water use efficiency and the water productivity indicators for the main crops for three years: 2010-2011, 2011-2012 and 2012-2013. A soil water balance model was applied taking into ccount climatic data for the nearby weather station and soil properties. Crop water requirements were calculated by the FAO Penman- Monteith with the application of the dual crop coefficient and by considering the readily vailable soil water content (RAW) concept. Likewise, productivity was measured by the indexes: annual relative irrigation supply (ARIS), annual relative water supply (ARWS), relative rainfall supply (RRS), the water productivity (WP), the evapotranspiration water productivity (ETWP), and the irrigation water productivity (IWP. The results show that in most crops deficit irrigation was applied (ARIS<1) in the first two years however, the IWP improved. This was higher in 2010-2011 which corresponded to the highest effective precipitation Pe. In general, the IWP (€.m-3) varied amongcrops but crops such as: onion (4.14, 1.98 and 2.77 respectively for the three years), potato (2.79, 1.69 and 1.62 respectively for the three years), carrot (1.37, 1.70 and 1.80 respectively for the three years) and barley (1.21, 1.16 and 0.68 respectively for the three years) showed the higher values. Thus, it is highlighted the y could be included into the cropping pattern which would maximize the famer’s gross income in the irrigation district.

Irrigation efficiency and water-policy implications for river-basin resilience

Rising demand for food, fiber, and biofuels drives expanding irrigation withdrawals from surface water and groundwater. Irrigation efficiency and water savings have become watchwords in response to climate-induced hydrological variability, increasing freshwater demand for other uses including ecosystem water needs, and low economic productivity of irrigation compared to most other uses. We identify three classes of unintended consequences, presented here as paradoxes. Ever-tighter cycling of water has been shown to increase resource use, an example of the efficiency paradox. In the absence of effective policy to constrain irrigated-area expansion using "saved water", efficiency can aggravate scarcity, deteriorate resource quality, and impair river basin resilience through loss of flexibility and redundancy. Water scarcity and salinity effects in the lower reaches of basins (symptomatic of the scale paradox) may partly be offset over the short-term through groundwater pumping or increasing surface water storage capacity. However, declining ecological flows and increasing salinity have important implications for riparian and estuarine ecosystems and for non-irrigation human uses of water including urban supply and energy generation, examples of the sectoral paradox. This paper briefly considers three regional contexts with broadly similar climatic and water-resource conditions – central Chile, southwestern US, and south-central Spain – where irrigation efficiency directly influences basin resilience. The comparison leads to more generic insights on water policy in relation to irrigation efficiency and emerging or overdue needs for environmental protection.

Sugarcane water use from shallow water tables: implications for improving irrigation water use efficiency

The resource potential of shallow water tables for cropping systems has been investigated using the Australian sugar industry as a case study. Literature concerning shallow water table contributions to sugarcane crops has been summarised, and an assessment of required irrigation for water tables to depths of 2 m investigated using the SWIMv2.1 soil water balance model for three different soils. The study was undertaken because water availability is a major limitation for sugarcane and other crop production systems in Australia and knowledge on how best to incorporate upflow from water tables in irrigation scheduling is limited. Our results showed that for the three soils studied (representing a range of permeabilities as defined by near-saturated hydraulic conductivities), no irrigation would be required for static water tables within 1 m of the soil surface. Irrigation requirements when static water tables exceeded 1 m depth were dependent on the soil type and rooting characteristics (root depth and density). Our results also show that the near-saturated hydraulic conductivities are a better indicator of the ability of water tables below 1 m to supply sufficient upflow as opposed to soil textural classifications. We conclude that there is potential for reductions in irrigation and hence improvements in irrigation water use efficiency in areas where shallow water tables are a low salinity risk: either fresh, or the local hydrology results in net recharge. (C) 2003 Elsevier B.V. All rights reserved.

Desalination of brackish water by a batch reverse osmosis desalink system for use with solar thermal energy

For remote, semi-arid areas, brackish groundwater (BW) desalination powered by solar energy may serve as the most technically and economically viable means to alleviate the water stresses. For such systems, high recovery ratio is desired because of the technical and economical difficulties of concentrate management. It has been demonstrated that the current, conventional solar reverse osmosis (RO) desalination can be improved by 40–200 times by eliminating unnecessary energy losses. In this work, a batch-RO system that can be powered by a thermal Rankine cycle has been developed. By directly recycling high pressure concentrates and by using a linkage connection to provide increasing feed pressures, the batch-RO has been shown to achieve a 70% saving in energy consumption compared to a continuous single-stage RO system. Theoretical investigations on the mass transfer phenomena, including dispersion and concentration polarization, have been carried out to complement and to guide experimental efforts. The performance evaluation of the batch-RO system, named DesaLink, has been based on extensive experimental tests performed upon it. Operating DesaLink using compressed air as power supply under laboratory conditions, a freshwater production of approximately 300 litres per day was recorded with a concentration of around 350 ppm, whilst the feed water had a concentration range of 2500–4500 ppm; the corresponding linkage efficiency was around 40%. In the computational aspect, simulation models have been developed and validated for each of the subsystems of DesaLink, upon which an integrated model has been realised for the whole system. The models, both the subsystem ones and the integrated one, have been demonstrated to predict accurately the system performance under specific operational conditions. A simulation case study has been performed using the developed model. Simulation results indicate that the system can be expected to achieve a water production of 200 m3 per year by using a widely available evacuated tube solar collector having an area of only 2 m2. This freshwater production would satisfy the drinking water needs of 163 habitants in the Rajasthan region, the area for which the case study was performed.

Jujube fruit water relations during fruit maturation stage under different water deficit conditions

The fruit maturation stage is considered the optimal phenological stage for implementing water deficitin jujube (Zizyphus jujuba Mill.), since a low, moderate or severe water deficit at this time has no effect onyield, fruit volume or eating quality. However, no information exists at fruit water relations level on themechanisms developed by Z. jujuba to confront drought. The purpose of the present study was to increaseour understanding of the relationship between leaf and fruit water relations of jujube plants under dif-ferent irrigation conditions during fruit maturation, paying special attention to analysing whether fruitsize depends on fruit turgor. For this, adult jujube trees (cv. Grande de Albatera) were subjected to fiveirrigation treatments. Control plants (T0) were irrigated daily above their crop water requirements inorder to attain non-limiting soil water conditions in 2012 and 2013. T1 plants were subjected to deficitirrigation throughout the 2012 season, according to the criteria frequently used by the growers in thearea. T2 (2012), T3 and T4 (2013) were irrigated as T0 except during fruit maturation, in which irrigationwas withheld for 32, 17 and 24 days, respectively. The results indicated that the jujube fruit maturationperiod was clearly sensitive to water deficit. During most of this stage water could enter the fruits viathe phloem rather than via the xylem. From the beginning of water withholding to when maximumwater stress levels were achieved, fruit and leaf turgor were maintained in plants under water deficit.However, a direct relation between turgor and fruit size was not found in jujube fruits, which could bedue to an enhancement of a cell elasticity mechanism (elastic adjustment) which maintains fruit turgorby reducing fruit cells size or to the fact that jujube fruit growth depends on the fruit growth-effectiveturgor rather than just turgor pressure.

WATER USE AND SYSTEM RELIABILITY UNDER DIESELGENERATOR AND SOLAR PHOTOVOLTAIC POWERED PUMPING SYSTEMS: A CASE STUDY OF SOLLA TOGO

Access to improved potable water sources is recognized as one of the key factors in improving health and alleviating global poverty. In recently years, substantial investments have been made internationally in potable water infrastructure projects, allowing 2.3 billion people to gain access to potable water from 1990-2012. One such project was planned and installed in Solla, Togo, a rural village in the northern part of the country, from 2010-2012. Ethnographic studies revealed that, while the community has access to potable water, an estimated 45% of the village’s 1500 residents still rely on unprotected sources for drinking and cooking. Additionally, inequality in system use based on income level was revealed, with the higher income groups accessing the system more regularly than lower income groups. Cost, as well as the availability of cheaper sources, was identified as the main deterrent from using the new water distribution system. A new water-pricing scheme is investigated here with the intention of making the system accessible to a greater percentage of the population. Since 2012, a village-level water committee has been responsible for operations and maintenance (O&M), fulfilling the community management model that is recommended by many development theorists in order to create sustainable projects. The water committee received post-construction support, mostly in the form of technical support during system breakdowns, from the Togolese Ministry of Water and Sanitation (MWSVH). While this support has been valuable in maintaining a functional water supply system in Solla, the water committee still has managerial challenges, particularly with billing and fee collection. As a result, the water committee has only received 2% - 25% of the fees owed at each private connection and public tap stand, making their finances vulnerable when future repairs and capital replacements are necessary. A new management structure is proposed by the MWSVH that will pay utilities workers a wage and will hire an accountant in order to improve the local management and increase revenue. This proposal is analyzed under the new water pricing schemes that are presented. Initially, the rural water supply system was powered by a diesel-generator, but in 2013, a solar photo-voltaic power supply was installed. The new system proved a fiscal improvement for the village water committee, since it drastically reduced their annual O&M costs. However, the new system pumps a smaller volume of water on a daily basis and did not meet the community’s water needs during the dry season of 2014. A hydraulic network model was developed to investigate the system’s reliability under diesel-generator (DGPS) and solar photovoltaic (PVPS) power supplies. Additionally, a new system layout is proposed for the PVPS that allows pumping directly into the distribution line, circumventing the high head associated with pumping solely to the storage tank. It was determined that this new layout would allow for a greater volume of water to be provided to the demand points over the course of a day, meeting a greater fraction of the demand than with the current layout.

Adapting fruit production to climate change: how to increase intrinsic fruit quality and save water through deficit irrigation scheduling.

Fruit crops are an important resource for food security, since more than being nutrient they are also a source of natural antioxidant compounds, such as polyphenols and vitamins. However, fruit crops are also among the cultivations threatened by the harmful effects of climate change This study had the objective of investigating the physiological effects of deficit irrigation on apple (2020-2021), sour cherry (2020-2021-2022) and apricot (2021-2022) trees, with a special focus on fruit nutraceutical quality. On each trial, the main physiological parameters were monitored along the growing season: i) stem and leaf water potentials; ii) leaf gas exchanges; iii) fruit and shoot growth. At harvest, fruit quality was evaluated especially in terms of fruit size, flesh firmness and soluble solids content. Moreover, it was performed: i) total phenolic content determination; ii) anthocyanidin concentration evaluation; and iii) untargeted metabolomic study. Irrigation scheduling in apricot, apple and sour cherry is surely overestimated by the decision support system available in Emilia-Romagna region. The water stress imposed on different fruit crops, each during two years of study, showed as a general conclusion that the decrease in the irrigation water did not show a straightforward decrease in plant physiological performance. This can be due to the miscalculation of the real water needs of the considered fruit crops. For this reason, there is the need to improve this important tool for an appropriate water irrigation management. Furthermore, there is also the need to study the behaviour of fruit crops under more severe deficit irrigations. In fact, it is likely that the application of lower water amounts will enhance the synthesis of specialized metabolites, with positive repercussion on human health. These hypotheses must be verified.

Carbon and nitrogen cycling in a tropical Brazilian soil cropped with sugarcane and irrigated with wastewater

Carbon (C) and nitrogen (N) dynamics in agro-systems can be altered as a consequence of treated sewage effluent (TSE) irrigation. The present study evaluated the effects of TSE irrigation over 16 months on N concentrations in sugarcane (leaves, stalks and juice), total soil carbon (TC), total soil nitrogen (TN), NO(3)(-)-N in soil and nitrate (NO(3)(-)) and dissolved organic carbon (DOC) in soil solution. The soil was classified as an Oxisol and samplings were carried out during the first productive crop cycle, from February 2005 (before planting) to September 2006 (after sugarcane harvest and 16 months of TSE irrigation). The experiment was arranged in a complete block design with five treatments and four replicates. Irrigated plots received 50% of the recommended mineral N fertilization and 100% (T100), 125% (T125), 150% (T150) and 200% (T200) of crop water demand. No mineral N and irrigation were applied to the control plots. TSE irrigation enhanced sugarcane yield but resulted in total-N inputs(804-1622 kg N ha(-1)) greater than exported N (463-597 kg N ha(-1)). Hence, throughout the irrigation period, high NO(3)(-) concentrations (up to 388 mg L(-1) at T200) and DOC (up to 142 mg L(-1) at T100) were measured in soil solution below the root zone, indicating the potential of groundwater contamination. TSE irrigation did not change soil TC and TN. (C) 2009 Elsevier B.V. All rights reserved.

Sodicity and salinity in a Brazilian Oxisol cultivated with sugarcane irrigated with wastewater

Changes in soil sodicity-salinity parameters are one of the most characteristic alterations after treated sewage effluent (TSE) irrigation in agro-systems. Considering the importance of these parameters for agricultural management, as well as the economical value of sugarcane for Brazil, the present study aimed at evaluating effects on soil sodicity and salinity under tropical conditions over 16 months of TSE irrigation in a sugarcane plantation at Lins, Sao Paulo State, Brazil. Soil samplings were carried out in February 2005 (before planting), December 2005 (after 8 months of TSE irrigation) and September 2006 (after 16 months of TSE irrigation) following a complete block design with four treatments and four replicates. Treatments consisted of. (i) control, without TSE irrigation; (ii) T100, T150 and T200, with TSE irrigation supplying 100% (0% surplus, total of 2524 mm), 150% (50% surplus, total of 3832 mm) and 200% (100% surplus, total of 5092 mm) of crop water demand, respectively. Compared to initial soil conditions, at the end of the experiment increases of exchangeable sodium (from 2.4 to 5.9 mmol(c) kg(-1)), exchangeable sodium percentage (ESP) (from 8 to 18%), soluble Na (from 1.4 to 4.7 mmol L(-1)) and sodium adsorption ratio (SAR) of soil solution (from 3.6 to 12.6 (mmol were found in the soil profile (0-100 cm) as an average for the irrigated plots due to high SAR of TSE. Associated with the increments were mostly significant increases in clay dispersion rates at depths 0-10, 10-20 and 20-40 cm. Electrical conductivity (EC) of soil solution increased during the TSE irrigation period whereas at the end of the experiment, after short term discontinuation of irrigation and harvest, EC in the topsoil (0-10 and 10-20 cm) decreased compared to the previous samplings. Moreover, despite increasing sodicity over time mainly insignificant differences within the different irrigated treatments were found in December 2005 and September 2006. This suggests that independent of varying irrigation amounts the increasing soil sodicity over time were rather caused by the continuous use of TSE than by its quantity applied. Moreover, also plant productivity showed no significant differences within the TSE irrigated plots. The study indicates that monitoring as well as remediation of soil after TSE irrigation is required for a sustainable TSE use in order to maintain agricultural quality parameters. (C) 2008 Elsevier B.V. All rights reserved.

Redes de rega de campos de golfe

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Mecânica

Optimização do tratamento por lamas activadas do efluente líquido da Mundotêxtil

A Mundotêxtil foi fundada em 1975 tendo iniciado a sua actividade na área comercial de produtos têxteis. Actualmente é o maior produtor nacional de atoalhados de felpo e emprega 575 colaboradores. Como resultado do seu crescimento e sobretudo da actividade de tingimento de fio e felpo, as necessidades de água são consideráveis e o volume de efluentes gerados nos processos industriais é cada vez maior a empresa avançou com a construção de uma estação de tratamento por lamas activadas, colocando-a em funcionamento em Setembro de 2004. Inicialmente surgiram dificuldades para a remoção da cor e da concentração da Carência Química de Oxigénio (CQO) de modo a cumprir os limites máximos de emissão permitidos nas normas de descarga no rio Ave e no Decreto-Lei nº 236/98, de 1 de Agosto. Com a descarga de parte dos efluentes no SIDVA e a utilização de um coagulante adicionado ao reactor o tratamento passou a apresentar melhores resultados. O intuito deste trabalho é o de apresentar soluções de modo a optimizar o funcionamento do tratamento biológico da Mundotêxtil. A optimização pode começar na concepção dos produtos, pode incidir no processo de fabrico para além de poder ser efectuada no seio da estação de tratamento biológico. Foi efectuado um estudo do tratamento biológico por lamas activadas no Laboratório de Tecnologia Química Profª Doutora Lída de Vasconcelos, laboratório tecnológico do Instituto Superior de Engenharia do Porto (ISEP) que decorreu nos meses de Maio, Junho e Julho de 2010. O estudo laboratorial foi efectuado para três situações distintas: 1) tratamento do efluente bruto sem qualquer tipo de pré-tratamento (ensaios 1 a 3); 2) tratamento do efluente bruto submetido a pré-tratamento com coagulante Ambifloc BIO MD (ensaios 4 e 5) e 3) tratamento com adição de fungos ao tanque de arejamento (ensaio 6). Foram utilizadas duas instalações de tratamento alimentadas a partir do mesmo tanque de alimentação. Os dois sistemas eram idênticos, diferiram nos caudais de alimentação de efluente que foram alterados ao longo do estudo. O efluente a tratar foi fornecido pela empresa Mundotêxtil, sendo recolhido por diversas vezes ao longo dos ensaios. Este efluente foi retirado após o pré-tratamento da empresa, ou seja este efluente é o mesmo que alimenta o tratamento biológico da Mundotêxtil. Devido a este facto o efluente usado no estudo laboratorial teve uma variabilidade no período em que decorreu o estudo, nomeadamente em termos de concentração de CQO e cor. A relação entre a Carência Bioquímica (CBO5) e a CQO situouse entre 0,47 e 0,63 o que traduz que está dentro dos valores típicos para um efluente têxtil. Os melhores resultados globais de remoção de CQO foram obtidos no ensaio 5 e estiveram compreendidos entre 73,2% e 77,5% para o ensaio 5.1 e entre 62,9 e 73,2% para o ensaio 5.2. Neste ensaio foi utilizado o coagulante. Todos os valores de concentração de CQO obtidos nos efluentes dos decantadores para os ensaios 2, 5 e 6 são inferiores aos valores limite de descarga definidos nas normas de descarga no rio Ave e o Decreto-Lei 236/98. Os valores de concentração de Sólidos Suspensos Totais (SST), pH, fósforo, CBO5 e cor nos decantadores cumpriram os limites de descarga definidos nas normas de descarga no rio Ave e no Decreto-Lei nº 236/98 em todos os ensaios. Os parâmetros cinéticos obtidos para os ensaios com descorante são os que melhor se ajustam ao projecto de uma instalação de tratamento biológico por lamas activadas do efluente da Mundotêxtil. Os valores obtidos, após ajuste, são os seguintes: k=0,015 L/(mgSSV*d); Sn=12 mg/L; a=0,7982 kgO2/kgCBO5; b=0,0233 [kgO2/(kgSSV*d); y=0,2253 kgSSV/kgCBO5; kd=0,0036 kgSSV/(kgSSV*d. Com base nos parâmetros cinéticos obtiveram-se os seguintes resultados para o projecto de uma estação de tratamento biológico por lamas activadas: · Tempo de retenção hidráulica no reactor de 1,79 d, · Volume do reactor igual a 3643 m3 · Consumo de oxigénio no reactor de 604 kg/d · Razão de recirculação igual a 0,8 · Volume total do decantador secundário igual a 540 m3 · Diâmetro do decantador secundário igual a 15 m A quantidade de oxigénio necessário é baixa e o valor mais adequado deverá ser da ordem de 1200 kg/d. Também foi efectuada uma análise aos produtos químicos consumidos pela empresa na área das tinturarias com a finalidade de identificar as substâncias com uma maior influência potencial no funcionamento da Estação de Tratamento Biológico. O encolante CB, Cera Têxtil P Líquida, Perfemina P-12, Meropan DPE-P, Meropan BRE-P, Indimina STS e Benzym TEC são os produtos químicos que têm uma influência potencial mais significativa na qualidade dos efluentes. Devido ao facto das temperaturas do efluente alimentado ao tratamento biológico da Mundotêxtil oscilarem entre 35 ºC e 43ºC efectuou-se um estudo às necessidades de água quente das tinturarias e por outro lado à capacidade de aquecimento dos efluentes disponíveis. Actualmente a racionalização dos consumos de água é cada vez mais premente, por isso também é apresentado neste trabalho um estudo para a substituição das máquinas convencionais das tinturarias com uma relação de banho 1:10 por máquinas de banho curto (1:6,5). Verifica-se a redução de consumos de 40% de água, 52% de energia eléctrica, 35% de produtos químicos, 51% das necessidades de vapor e por consequência um aumento da produtividade. A empresa pode reduzir os consumos de água em cerca de 280.000 m3/ano. A utilização do pré-tratamento com o coagulante permitirá baixar a concentração da CQO e reduzir a cor à entrada do reactor tratamento biológico. Deste modo é possível manter um tratamento eficiente à saída do tratamento biológico nas situações de descarga de cores carregadas e carga orgânica elevada. Com este conjunto de soluções, quer sejam aplicadas na totalidade ou não, a empresa Mundotêxtil pode enfrentar o futuro com mais confiança podendo estar preparada para fazer face à escassez de água e custos cada vez maiores da energia. Por outro lado pode tratar os seus efluentes a custos menores. A substituição das máquinas de tingimento por máquinas com relação de banho mais baixa (banho curto) implica investimentos elevados mas estes investimentos são necessários não só por motivos ambientais mas também devido à grande competitividade dos mercados.

Web GIS to support irrigation management: a prototype for SAGRA network, Alentejo Portugal

Dissertation submitted in partial fulfilment of the requirements for the Degree of Master of Science in Geospatial Technologies