Assessing economic impacts of deficit irrigation as related to water productivity and water costs

Research Paper:SW-Soil and WaterThis study aims at assessing the feasibility of deficit irrigation of maize, wheat and sunflower through an analysis of the economic water productivity (EWP). It focuses on selected sprinkler-irrigated fields in Vigia Irrigation District, Southern Portugal. Various scenarios of water deficits and water availability were considered. Simulations were performed for average, high and very high climatic demand. The potential crop yields were estimated from regional climatic data and local information. Using field collected data on yield values, production costs, water costs, commodity prices and irrigation performance, indicators on EWP were calculated. Results show that a main bottleneck for adopting deficit irrigation is the presently low performance of the irrigation systems used in the considered fields, which leads to high water use and low EWP. Decreasing water use through deficit irrigation also decreases the EWP. Limited water deficits for maize are likely to be viable when the irrigation performance is improved if water prices do not increase much, and the commodity price does not return to former low levels. The sunflower crop, despite lower sensitivity to water deficits than maize, does not appear to be a viable solution to replace maize when water restrictions are high; however it becomes an attractive crop if recently high commodity prices are maintained. With improved irrigation performance, wheat deficit irrigation is viable including when full water costs are applied, if former low prices are not returned to. However, under drought conditions full water costs are excessive. Thus, adopting deficit irrigation requires not only an appropriate irrigation scheduling but higher irrigation performance, and that the application of a water prices policy would be flexible, thus favouring the improvement of the irrigation systems

Separation of Ternary Mixtures by Pseudo-Simulated Moving-Bed Chromatography: Separation Region Analysis

The application of the pseudo-simulated moving bed process, known as JO process of Japan Organo Co., to the separation of ternary mixtures was studied. In order to perform a desired separation, the choice of the different operation parameters such as the duration of each step and its respective flow rates requires the use of a methodology that could provide the best process performance. This issue is addressed by proposing an innovative method to determine the JO operation region, which establishes the operation limits of the process. In addition, a methodology is presented to determine the separation region where a minimum purity requirement is guaranteed. This methodology was applied to a ternary mixture considering linear adsorption isotherms. It was possible to construct a separation region for minimum purity of 99.9% in all the outlet streams and identify the best operation point in terms of the process performance.Financial support by the Portuguese R&D foundation FCT (Fundação para a Ciência e a Tecnologia) and the European Community through FEDER (project PTDC/EQU-EQU/119025/2010) is gratefully acknowledged. This work was cofinanced by FCT/MEC and FEDER under Program PT2020 (Project UID/ EQU/50020/2013).info:eu-repo/semantics/publishedVersio

Enantioseparation of the four nadolol stereoisomers by fixed-bed and simulated moving bed chromatography

In the last decades, the separation and purification of high added value products by liquid chromatography has been a very popular technique. The development of more stable and efficient stationary phases, together with the design of innovative and more flexible separation processes, enhanced the use of chromatographic processes, particularly at preparative and industrial scales through simulated moving bed (SMB) technology and allied techniques. Nowadays, preparative and SMB related techniques are more and more used in the separation of a wide range of high added value products of interest for the pharmaceutical, fine chemistry, biotechnology and food industries. In this context, one of the actual main challenges concerns the design and optimization of these chromatographic processes for multicomponent separations. This includes the development of new and innovative chromatographic processes, combining different design strategies and modes of operation, with different types of stationary and mobile phases. This communication will introduce the multicomponent separation challenge using the commercial pharmaceutical drug of nadolol stereoisomers. The nadolol represents a very interesting case-study of multicomponent chiral separation since it is composed by four stereoisomers, arranged in two pairs of enantiomers. In this way, it introduces the possibility of alternative strategies, using different kind of separation sequences and techniques, the use of different packings (chiral and achiral stationary phases), and the correspondent mobile phase optimization at both normal and reversed phase modes. An extensive set of experimental results obtained at fixed-bed and SMB operations will be presented. The complete methodology will be explained and applied for the pseudo-binary enantioseparation of the more retained and active stereoisomer (1+2+3)/(4), and for the (2)/(3) and (1)/(4) binary enantioseparations after a first achiral pseudo-binary separation of the two nadolol racemates.Financed by projects: NORTE-01-0145-FEDER-000006 - funded by NORTE2020 through PT2020 and ERDF; Associate Laboratory LSRE-LCM - UID/EQu/50020/2019 - funded by national funds through FCT/MCTES (PIDDAC). Rami S. Arafah gratefully acknowledges his Ph.D. scholarship from Funda~ao para a Ciencia e Tecnologia (FCT) SFRH/BD/137966/201B.info:eu-repo/semantics/publishedVersio

Separation of nadolol racemates by high pH reversed-phase preparative chromatography

The separation of nadolol racemates under high pH reversed-phase preparative chromatography is presented for the first time. Three Waters C18 adsorbents (XBridge, Shield and XSelect) are compared for the separation of nadolol racemates using ethanol:water:diethylamine solvent mixtures. Experimental and simulation results are presented to compare the separation performances at preparative scale using both the fixed-bed and the simulated moving bed operations. The Waters XBridge C18 adsorbent and an ethanol:water:diethylamine solvent mixture are selected as a good option for the separation of nadolol racemates. The validated methodology allows the separation of a multicomponent nadolol feed mixture composed by four stereoisomers into two pure racemates (two pairs of enantiomers). This work introduces the potential of using an initial achiral separation step in the global strategy for the complete multicomponent separation of the four nadolol stereoisomers.This work is a result of: Project “AIProcMat@N2020 - Advanced Industrial Processes and Materials for a Sustainable Northern Region of Portugal 2020”, with the reference NORTE-01-0145-FEDER-000006, supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF); Associate Laboratory LSRE-LCM - UID/EQU/50020/2019 - funded by national funds through FCT/MCTES (PIDDAC). Rami S. Arafah is supported by a PhD Grant of Fundação para a Ciência e a Tecnologia (SFRH/BD/137966/2018).info:eu-repo/semantics/publishedVersio

Effect of Sowing Time on Phytomass Production during Early Growth of Two Varieties of \u3ci\u3eStylosanthes guianensis (Aubl.) Sw.\u3c/i\u3e

The objective of this research was to determine the effect of two sowing times on phytomass production of two varieties of Stylosanthes guianensis (var. pauciflora and var. vulgaris). Two experimental periods were studied (1: January - May/1998 and 2: November/1998 - March/1999) using a completely randomized factorial design 2 x 2 x 14 (two periods, two varieties and fourteen ages of evaluation), with four replications. The results showed a difference between the periods concerning the growth and development of Stylosanthes, and that period 2 was the most favourable to this forage plant. There was, also, different adaptability between the two varieties concerning the sowing times. The var. pauciflora was more adapted in period 1, and the var. vulgaris, in period 2. The data showed the possibility of selecting Stylosanthes cultivars adapted to different seasonal conditions

Modelling economic impacts of deficit irrigated maize in Brazil with consideration of different rainfall regimes

Deficit irrigation is often required to cope with droughts and limited water availability. However, to select an appropriate irrigation management, it is necessary to assess when economic impacts of deficit irrigation are acceptable. Thus, the main goal of this study was to evaluate economic water productivity for maize submitted to various levels of water deficits and different irrigation systems. The study was based on two different experiments conducted in Southern Brazil, one using sprinkler irrigation to supplement rainfall and the other using drip irrigation with precipitation excluded by a rainfall shelter to simulate cultivation under dry conditions. Water productivity indicators were calculated referring to: a) actual field collected data, including yields, commodity prices and production costs; and b) a sensitivity analysis to commodity prices and production costs. Alternative centrepivot irrigation scenarios were also developed to assess their feasibility in terms of water use and productivity when irrigation is used to supplement rainfall or when rainfall is scarce. Results show that the feasibility of deficit irrigation is highly influenced by commodity prices and by the irrigation (and water) costs when the irrigation costs are a large part of the production costs. Results also show that deficit irrigation applied when rainfall is abundant is easier to implement than deficit irrigation where rainfall is very scarce, when only a mild stress is economically viable. For well-designed and managed centrepivot systems, results confirm that adopting deficit irrigation when rainfall is scarce is less attractive than under conditions of irrigation to supplement rainfall. It could be concluded that farmers are unlikely to choose a deficit irrigation strategy unless they are facing reduced water availability for irrigatio

Evapotranspiration partition and crop coefficients of Tifton 85 bermudagrass as affected by the frequency of cuttings. Application of the FAO56 Dual Kc Model

ArticleThis study aims to model the impacts of the frequency of cuttings of Tifton 85 bermudagrass on the dynamics of evapotranspiration (ETc) and to derive crop coefficients appropriate for grass water management. Two seasons of experimentation were used with four different cutting treatments which provided field data for calibration and validation of the soil water balance model SIMDualKc for all treatments. Cuttings were performed after the cumulative growth degree days (CGDD) attained 124 C, 248 C and 372 C, thus from short to very long intervals between cuttings. SIMDualKc adopts the Food and Agriculture Organization (FAO) dual Kc approach for partitioning ET into crop transpiration and soil evaporation, thus providing for an assessment of their dynamics. All treatments were irrigated to avoid water stress. Grass ETc was modelled adopting a Kcb curve to describe the ET variation for each cutting cycle, that is, using the FAO Kc curve that consists of a series of Kcb curves relative to each cutting cycle. Each individual Kcb curve consisted of three segments constructed when knowing the Kcb values at the initial, at the end of rapid growth, and at cutting, respectively Kcb ini, Kcb gro and Kcb cut. These Kcb values were first estimated using the equation relating Kcb to the density coefficient (Kd), which is computed from the fraction of ground cover (fc) and canopy height (h) at the same dates. The goodness of fit indicators relative to the calibration and validation of the SIMDualKc model were rather good, with the normalized root mean square error (RMSE) ranging from 4.0% to 6.7% of the mean available soil water. As an example, the standard Kcb values obtained after model calibration relative to the cuttings treatment with CGDD of 248 C are: Kcb ini = 0.86, Kcb gro = 0.91 and Kcb cut = 0.96. Kcb values were smaller when the frequency of cuts was larger because h and fc were smaller, and were larger for reduced cuttings frequency since h and fc were then larger. Because the soil was wet most of the time, the soil evaporation Ke varied little but its value was small due to the combined effects of the fraction of crop cover and plant litter covering the soil. The values of Kc = Kcb+Ke also varied little due to the influence of Ke and the Kc curve obtained a form different from the Kcb curves, and a single Kc value was adopted for each cutting frequency, e.g., Kc = 0.99 for the treatment with CGDD of 248 C. Results of the soil water balance have shown that, during the experimental periods, likely due to the effects of the El Niño Southern Oscillation (ENSO), runoff and deep percolation exceeded ETc. Moreover, the soil evaporation ratio was small: 14% in case of frequent cuttings and less for more spaced cuttings, thus with a transpiration ratio close to 90%, which indicates a very high beneficial consumptive water use, mainly when cuttings are not very frequentinfo:eu-repo/semantics/publishedVersio

Necessidades de água e produtividade económica da rega de milho em condições de escassez

A identificação das necessidades de rega do milho, uma das principais culturas regadas em Portugal Continental, constitui uma medida de preparação para enfrentar as secas e a escassez de água. Definiram-se várias estratégias de rega com o objectivo de redução da procura de água de rega com impactos aceitáveis na produção. O modelo de balanço hídrico e de simulação de calendários de rega SIMDualKc, anteriormente calibrado e validado para a cultura do milho em Portugal, foi utilizado para simular as necessidades de água para condições de seca severa e extrema. Este estudo foi realizado para milho regado por aspersão e aplicado a várias localidades: Vila Real, Bragança e Miranda do Douro no Norte, Coimbra e Viseu no Centro, e Beja, Évora e Elvas no Sul. As alternativas de rega foram avaliadas tendo em consideração a poupança de água de rega e o impacto nas produções; para inferir a viabilidade económica da rega deficitária foram determinados indicadores da produtividade física e económica da água recorrendo a dados sobre o valor da produção e desempenho de sistemas. Os resultados mostram que as estratégias de rega deficitárias poderão ser viáveis quando os défices hídricos forem muito baixos. Como alternativa poder-se-á optar pela satisfação das necessidades totais da cultura mas diminuindo a área cultivada

Production of live larvae following in vitro maturation of zebrafish oocytes.

This study aimed to assess the effects of carp pituitary extract (CPE), follicle stimulating hormone (FSH) and luteinizing hormone (LH) on zebrafish oocyte maturation and the ability of these mature oocytes to be fertilized and developed until hatching. Stage III follicles were matured in eight treatments: five concentrations of CPE (16, 32, 48, 64 and 80 μg/mL), one of FSH (0.5 μg/mL), one of LH (0.5 μg/mL), or one combination of FSH (0.5 μg/mL) and LH (0.5 μg/mL). Maturation rates in CPE treatments were 12.8% (16 μg/mL), 24.8% (32 μg/mL), 27.0% (48 μg/mL), 22.7% (64 μg/mL) and 9.6% (80 μg/mL); in FSH was 15.7% (0.5 μg/mL), in LH was 31.8% (0.5 μg/mL) and in FSH (0.5 μg/mL) combined with LH (0.5 μg/mL) it was 50.4%. In vitro fertilization was performed in all treatments; however, only the treatment combining FSH and LH resulted in fertilized oocytes. After maturation using FSH combined with LH, the cleavage rate was 33.3% and hatching rate of live larvae was 20.0%. These results showed that FSH combined with LH was effective in IVM of zebrafish oocyte