Quantitative analysis of almond yield response to irrigation regimes in Mediterranean Spain

Almond plantations are expanding worldwide, specifically in Spain; the new orchards are often designed under more intensive systems in comparison to the traditional rainfed orchards frequently found in the Mediterranean Sea basin. In these new areas, water is the main limiting factor, and therefore, the present research is aimed at quantitatively analyzing previous findings obtained in irrigation field trials carried out in Spain with mature almond trees. The goal was to derive applied water-production functions and compare sustained and regulated deficit irrigation strategies to provide robust information on the marginal water productivity and the preferred irrigation option to be applied under water scarcity conditions. This quantitative analysis reported a yield increase as water application increased, with the highest potential yield of about 2500 kg/ha achieved with around 1000 mm of irrigation water applied. Under severe water restrictions, similar responses were observed regardless of the deficit irrigation technique employed. In contrast, under moderate water stress, it seems more advantageous to apply a regulated deficit irrigation strategy rather than a sustained deficit strategy. The reported results are useful for deriving more sustainable irrigation protocols and highlight the need to optimize other inputs in addition to water to take full advantage of the irrigation intensification to be carried out in the new almond plantations.Publishe

Conservation Agriculture as a Sustainable System for Soil Health: A Review

Soil health is a term used to describe the general state or quality of soil, and in an agroecosystem, soil health can be defined as the ability of the soil to respond to agricultural practices in a way that sustainably supports both agricultural production and the provision of other ecosystem services. Conventional agricultural practices cause deterioration in soil quality, increasing its compaction, water erosion, and salinization and decreasing soil organic matter, nutrient content, and soil biodiversity, which negatively influences the productivity and long-term sustainability of the soil. Currently, there are many evidences throughout the world that demonstrate the capability of conservation agriculture (CA) as a sustainable system to overcome these adverse effects on soil health, to avoid soil degradation and to ensure food security. CA has multiple beneficial effects on the physical, chemical, and biological properties of soil. In addition, CA can reduce the negative impacts of conventional agricultural practices on soil health while conserving the production and provision of soil ecosystem services. Today, agricultural development is facing unprecedented challenges, and CA plays a significant role in the sustainability of intensive agriculture. This review will discuss the impact of conservation agricultural practices on soil health and their role in agricultural sustainability

Response of three almond cultivars subjected to different irrigation regimes in Guadalquivir river basin

10 páginas.- 8 figuras.- 5 tablas.- referenciasAlmond (Prunus dulcis Mill.) has been traditionally associated to marginal areas in Andalusia, being cultivated under rainfed agriculture conditions. In the last few years, it has been progressively introduced in many irrigated areas of the Guadalquivir river basin which has promoted a growing interest about irrigation water management for this crop i.e. the potential irrigation requirements, or the best irrigation strategy under sub-optimal conditions (aiming at obtaining balanced nut yields, saving water without affecting yield). This work examines the response of three almond cultivars (cvs. Guara, Marta and Lauranne) subjected to different irrigation regimes in a semi-arid Mediterranean environment (SW Spain). The trial was conducted over two seasons (2017–2018), in a commercial orchard with three irrigation regimes: i) a full-irrigation treatment (FI), which received 100% of crop evapotranspiration (ETC) as a control; ii) an over irrigated treatment (150-ETC), which received 150% of ETC during the whole irrigation period; and iii) a regulated deficit irrigation treatment (RDI65) which was irrigated at 100% ETC during the whole irrigation season, except during the kernel-filling period, when it received the 65% of ETC. In order to assess the crop water status, the leaf water potential (Ψleaf) and the stomatal conductance to water vapour (gs) were measured. At the end of each season, the yield, kernel unit weight and irrigation water productivity were determined. Significant differences in physiological behaviour and yield responses among cultivars were found. According to the final yield obtained during the experimental seasons, Guara and Lauranne did not show significant improvements in the 150-ETC in relation to FI and RDI65, whereas cv. Marta showed significant improvements under 150-ETC. Moreover, yield response followed the physiological trend observed in the different irrigation treatments for each cultivar. Those cultivars (Guara and Lauranne) that had not shown significant differences in terms of yield, evidenced a similar pattern in terms of gs, unlike Marta. The obtained results allow us to conclude that there is a clear differential response in terms of the cultivar, taking into account the adaptation capacity of different cultivars to different irrigation doses.The author S. Gutiérrez-Gordillo has a contract co-financed by National Institute of Agrarian and Food Research and technology (FPI-INIA 2016) and European Social Fund (ESF). Part of this work was sponsored by the research project “Impact of climate change and adaptation measures (INNOVA-Climate)" (AVA.AVA2019.051), Research and Technological Innovation Projects for period 2019-2021 "Andalusia moves with Europe. “The European Social Fund invests in your future”.Peer reviewe

Fostering sustainable water use in almond (Prunus dulcis Mill.) orchards in a semiarid Mediterranean environment

18 páginas.- 6 figuras.- 2 tablas.- 78 referenciasThis work examines the long-term effects of deficit-irrigation (DI) practices in almond crop (Prunus dulcis Mill.) in agronomical and physiological terms. The trial was conducted during four-year monitoring period (2014–2017), in an experimental orchard (SW Spain), subjected to three irrigation regimes; i) a full-irrigation treatment (FI), which received 100% of crop evapotranspiration (ETC); ii) a regulated-deficit irrigation (RDI50), which received 50% of ETC during the kernel-filling period; and iii) a low-frequency deficit irrigation (LFDI), that was subjected to continuous periods of irrigation-restriction defined in terms of threshold values of leaf-water potential (Ψleaf) during the kernel-filling period. During the water stress period, there were monitored Ψleaf, stomatal conductance (gs) and canopy temperature (TC). Significant improvements in terms of water-use efficiency were found, as no differences in terms of yield between FI and LFDI were found, leading to the conclusion that significant water savings (between 27 and 40%) can be achieved without compromising the yield. Moreover, threshold values of Ψleaf and thermal indicators were defined which will allow establishing future irrigation scheduling without compromising almond yield, especially when DI strategies are being applied.Part of this work was sponsored by the research project ‘Integrated management of the cultivation of almond andother nuts (INNOVA-Nuts)’(AVA.AVA201601.18), within the Operational Program FEDER 2014-2020 “Andalusia moveswith Europe“. The author I. Garcia-Tejero has a contract co-financed by the Operational Program of the EuropeanSocial Fund (ESF) 2007-2013 ‘Andalusia moves with Europe’Peer reviewe

Determining evapotranspiration in an olive orchard in southwest Spain

8 páginas, 4 figuras, 16 referencias.-- Trabajo presentado al VI International Symposium on Olive Growing, celebrado del 9-13 de septiembre 2008, en Évora, Portugal.The aim of this work was to evaluate, for an olive orchard in the Aljarafe county, the method developed by Orgaz et al. (2005) for determining the crop evapotranspiration (ETc). We compared the calculated ETc (ETc Orgaz) values with those determined by the crop coefficient approach (ETc crop coef), as described by Fernández et al. (2006), who used coefficient values previously calibrated for our orchard conditions. In addition, we compared the tree transpiration (Ep) values estimated with the mentioned Excel application (Ep Orgaz) with those simulated by a transpiration model (Ep sim) based on Penman-Monteith, validated for our orchard conditions. Results showed that the Excel application is a user-friendly tool valid for calculating reasonably accurate values of ETc from very few easy-to-measure inputs. The crop coefficient approach does not have this limitation, but years with unusual leaf area density may lead to errors on the calculated ETc. Ep sim is highly affected by variables difficult to measure in commercial orchards, such as the leaf area and the available soil water. In addition, processes related to leaf aging, soil temperature and recovery after drought are not include yet in the model, which affects the reliability of the Ep sim values at the end of the irrigation.This work has been funded by the Spanish Ministry of Education and Science, research project No.AGL2006-04666/AGR, and by the EU, research project ref. STREP 023120.Peer reviewe

Water use and fruit yield of mango (Mangifera indica L.) grown in a subtropical Mediterranean climate

15 páginas.- 4 figuras.- 2 tablas.- 49 referencias.-Mango (Mangifera indica L.) is one of the most important fruit crops in tropical and subtropical regions worldwide. On the coast of Granada and Malaga (SE Spain), irrigated subtropical fruit species have been introduced and cultivated on terraces with a considerable economic importance as the only European production region. The subtropical fruit production in this zone is possible with intensive irrigation on terraces, which are economically more profitable than traditional rainfed crops (almond and olive), which have been replaced or abandoned. A 2-year monitoring period was conducted using drainage lysimeters to determine the crop coefficients (Kc) and fruit yield in mango (Mangifera indica L. cv. Osteen) orchards. Also, some quality parameters such as titratable acidity, total soluble solids, and vitamin C were evaluated under these conditions. The averaged Kc values of mango trees varied within production cycle of 0.43, 0.67, and 0.63 at flowering, fruit set, and fruit growth, respectively. In this study, the fruit yield under full water requirements (100% ETC) averaged 24.1 kg tree−1, amounting to 21.2 kg ha−1 mm−1 in terms of water-use efficiency. The quality parameters of the mango fruits harvested in the study area were satisfactory. Thus, this study highlights the need to optimize the irrigation-water use according to actual mango requirements, thereby achieving more sustainable Mediterranean subtropical farming in orchard terraces.Part of this publication was sponsored by the following research project: “Impact of deficit irrigation on productivity of subtropical fruit crops: tools for sustainable water stress management” (PP.AVA.AVA201601.8), and co-financed by the European Regional Development Fund (ERDF) within the Operational Programme Andalusia 2014-2020 “Andalucía is moving with Europe”.Peer reviewe

Water Use and Leaf Nutrient Status for Terraced Cherimoya Trees in a Subtropical Mediterranean Environment

11 páginas.- 3 figuras.- 3 tablas.- 36 referenciasWater scarcity in many semi-arid agricultural areas, in particular for the Mediterranean basin, is promoting changes in irrigated agriculture, with alternative strategies being introduced for water-use optimization. The coast of Granada and Malaga (Southeast Spain) is an economically important area for subtropical fruit cultivation. This intensively irrigated agriculture is characterized by requiring extra amounts of water and the adoption of sustainable practices to improve agricultural water management. A two-season experiment was conducted to assess (1) the water use in terraced cherimoya (Annona cherimola Mill. cv. Fino de Jete) orchards under conventional and organic production systems with drainage lysimeters, and (2) the impact on fruit yield and nutritional effects between the two considered production systems. Crop coefficient (Kc) values for cherimoya were 0.60–0.66, 0.64–0.71, and 0.48–0.62 at flowering, fruit set, and fruit growth, respectively. Fruit yield was similar in both systems, ranging from 47.1 for conventional to 44.1 kg tree−1 for organic farming, averaging 13.2 and 12.3 t·ha−1, respectively. No differences between these systems were observed in terms of leaf nutrient status, with variations in the N, P, and K contents during the different phenological stages. The N, P, and K lessen during flowering and fruit growth; the highest levels of these nutrients were fixed at harvest. These patterns were the opposite in Ca and Mg, ascribable to the antagonism between K and both Ca and Mg. Thus, these findings highlight the need to establish the optimal use of irrigation water with respect to crop requirements, thereby encouraging sustainable subtropical farming in terraces.Part of this research was funded by the following research project: “Innovations for sustainability, productivity, and improvement of subtropical crops (mango and cherimoya)” (PP.AVA.AVA2019.38) and co-financed by the European Regional Development Fund (ERDF), Internal call for Research Projects and Technological Innovation for the period 2019-2022.Peer reviewe

Enhancing Nut Quality Parameters and Sensory Profiles in Three Almond Cultivars by Different Irrigation Regimes

13 páginas.- 3 figuras.- 7 tablas.- 47 referenciasThe climate change is already affecting many agricultural systems and human environments, and the implementation of adaptation strategies, especially those related to irrigated agriculture in semiarid regions, is urgent. In this regard, deep knowledge about the effects that irrigation has on the food quality parameters will allow us to estimate the potential benefits of deficit irrigation (DI) strategies. This work presents the effects on the quality parameters of three almond cultivars (Marta, Guara, and Lauranne) subjected to three irrigation doses: (i) full-irrigated treatment (FI) at 100% crop evapotranspiration (ETC), (ii) an overirrigated treatment at 150% ETC (150% ETC), and (iii) regulated deficit irrigation (RDI65) treatment, in which irrigation was done as in FI, expect during the kernel-filling period when this treatment received 65% ETC. According to experimental findings, the cultivar most sensitive to water stress was Marta, having the most significant improvements for RDI65. In general, the effects of the irrigation dose on the morphological and physicochemical parameters were not huge but some improvements were observed in key parameters such as the color and contents of specific sugars, organic acids, and unsaturated fatty acids. Thus, it can be concluded that the irrigation dose did not drastically affect the fruit almond quality, although it is possible to improve several key parameters when a moderate RDI strategy is applied.This work has been partially sponsored by the research project “Climate change impact and adaptation strategies to ensure the sustainability of Andalusian agroecosystems (INNOVA-Clima)”(AVA.AVA2019.051), within the Operational Program FEDER 2014-2020“Andalusia moves with Europe”, anda coordinated research project (hydroSOS), funded by Agencia Estatal de Investigación / Ministerio de Ciencia e Innovación and Ministerio de Universidades), including the Universidad Miguel Hernández de Elche (AGL2016-75794-C4-1-R, Productos hidroSOStenibles: identificación de debilidades y fortalezas, optimización del procesado, creación de marcapropia, y estudio de su aceptación en el mercado europeo,hydroSOS foods) and the Universidad de Sevilla (AGL2016-75794-C4-4-R) (MCI/AEI/FEDER); these last two projectshave been funded by the Fondo Europeo de Desarrollo Regional (FEDER)“Una manera de hacer Europa”/Ministerio de Ciencia e Innovación (MCI) - Agencia Estatal de Investigación (AEI). The author S.G.-G. has a contract co-financed by the National Institute of Agrarian and Food Research andTechnology (FPI-INIA 2016) and European Social Fund(ESF) “The European Social Fund invests in your future”.Peer reviewe

Thermal imaging at plant level to assess the crop-water status in almond trees (cv. Guara) under deficit irrigation strategies

11 páginas.- 7 figuras.- 6 tablas.- 54 referenciasAlmond (Prunnus dulcis Mill.) has been traditionally associated to marginal land cultivation and rain-fed agriculture in South Spain. However, in the last years, this crop is being progressively introduced in more productive agricultural areas within the Guadalquivir river basin, where the available water resources are not enough to satisfy the adequate crop-water requirements. Considering this limitation, a more precise irrigation scheduling to maximize the yield is required. Infrared thermal imaging emerges as alternative to other traditional methodologies to assess the crop-water status, especially when deficit irrigation (DI) strategies are being applied. The aim of this study was to define the methodology to assess the almond water status by means of thermal information. The trial was conducted during 2014, during the kernel-filling period, in an almond experimental orchard (SW Spain), with 5-year-old trees, subjected to three irrigation regimes: i) a full-irrigation treatment (C-100), which received 100% of ETC; ii) a regulated deficit irrigation (RDI-50), which received 100% of ETC except during the kernel filling period, when this treatment was irrigated with 50% of ETC; iii) and a low-frequency deficit irrigation treatment (LFDI), which received 100% of ETC except during the kernel filling period, when it was subjected to continuous periods of irrigation-restriction, defined in terms of the threshold values of shaded leaf water potential (Ψleaf). Three daily curves of canopy temperature (TC), stomatal conductance to water vapour (gs) and Ψleaf with measurements at 8:00, 11:00, 14:00, 17:00 and 20:00 were developed. Additionally, Crop Water Stress Index (CWSI), temperature difference between canopy and the surrounding air (ΔTcanopy-air), and the relative index to stomatal conductance (IG) obtained at different scales (canopy and row) were estimated. Significant correlations of infrared thermal information vs. Ψleaf and gs were obtained (p ≤ 0.05 and p ≤ 0.01), in particular, by using the thermal readings taken at 11:30, 14:30 at 17:30 h, especially robust were the relationships obtained between TC and CWSI with Ψleaf at 11:30 h; and between TC and CWSI with gs, and Ψleaf at 14:30 h. Finally, considering the infrared thermal monitoring procedure (readings at tree and row level), similar values of TC were obtained, and therefore, the images taken at row level offered a better information with a higher feasibility in terms of image processing.Part of this work was sponsored by the research project “Integrated management of almond and other nuts crops” (AVA.AVA201601.18), within the Operational Program FEDER 2014-2020″Andalusia moves with Europe ". The author I. Garcia-Tejero has a contract co-financed by the Operational Program of the European Social Fund (ESF) 2007-2013″Andalusia moves with Europe".N

Deficit Irrigation and Its Implications for HydroSOStainable Almond Production

20 páginas.- 3 figuras.- 7 tablas.- 58 referenciasDeficit irrigation (DI) strategies are considered essential in many arid and semi-arid areas of Mediterranean countries for proper water management under drought conditions. This fact is even more necessary in crops such as almond (Prunus dulcis Mill.), which in the last recent years has been progressively introduced in irrigated areas. An essential aspect to be considered would be the ability to improve fruit-quality parameters when DI strategies are imposed, which can boost the final almond price and ensure the sustainability and competitiveness of this crop. This work examines the effects of sustained deficit irrigation (SDI) on three almond cultivars (Marta, Guara, and Lauranne) on parameters related to almond functionality, aroma and sensory profile, which consequently influence its marketability and consumers acceptance. SDI strategies allowed the improvement of physical parameters such as unit weight, kernel length, kernel thickness or color. Moreover, higher total phenolic compounds, organic acids and sugars were found in SDI almonds. Finally, the highest concentrations of volatile compounds were obtained under SDI, this being a clear advantage in relation to almond flavor. Thus, moderate SDI strategy offered relevant improvements in parameters regarding the marketability, by enhancing the final added value of hydroSOStainable almonds with respect to those cultivated under full irrigation conditions.This work has been partially sponsored by the research project “Impact of climate change and adaptation measures (INNOVA-Climate)” (AVA.AVA2019.051) both co-financed by the European Regional Development Fund (ERDF) within the Operational Programme Andalusia 2014–2020 “Andalucía is moving with Europe” and the Spanish Ministry of Economy, Industry and Competitiveness; through the research project (hydroSOS mark) including the Universidad Miguel Hernández de Elche (AGL2016-75794-C4-1-R, hydroSOS foods) and the Universidad de Sevilla (AGL2016-75794-C4-4-R). The author S. Gutiérrez-Gordillo has a contract co-financed by the National Institute of Agrarian and Food Research and technology (FPI-INIA 2016) and European Social Fund (ESF) “The European Social Fund invests in your future.”Peer reviewe