Irrigation alternatives for avocado (Persea Americana Mill.) in the Mediterranean Subtropical region in the context of climate change: a review

Due to congenital features, avocado (Persea Americana Mill.) trees are substantial water users relative to other fruit trees. The current growing deficiency of water resources, especially in arid and semi-arid avocado-producing areas, has led to the demand for more sustainable water-saving measures. The objective of this review was to analyze the role of deficit irrigation as a strategy to face climate change and water scarcity through achieving efficiency, saving water, and maximizing the benefits that could be achieved at the level of the irrigated agricultural system. Particular attention is devoted to studies performed in the subtropical Mediterranean climate, in which irrigated avocado orchards are common. These studies analyzed irrigation demand, deficit irrigation, and determination of water status through physiological parameters, leading to possible sustainable irrigation programs for avocado in the context of water shortage scenarios. Through these insights, we conclude that under the current climatic circumstances with respect to available water resources, avocado farming requires sustainable resilience strategies to reduce irrigation water consumption without affecting the yield and quality of the fruits. Water stress inevitably affects the physiological processes that determine yield. Therefore, an admissible yield loss is required with smaller fruits and water savings made through deficit irrigation strategies. In addition, modern consumers tend to prefer foods based on sustainability, i.e., there is a high demand for socially responsible and environmentally friendly products

Can Sustained Deficit Irrigation Save Water and Meet the Quality Characteristics of Mango?

Mango is one of the most cultivated tropical fruits worldwide and one of few drought-tolerant plants. Thus, in this study the effect of a sustained deficit irrigation (SDI) strategy on mango yield and quality was assessed with the aim of reducing irrigation water in mango crop. A randomized block design with four treatments was developed: (i) full irrigation (FI), assuring the crop’s water needs, and three levels of SDI receiving 75%, 50%, and 33% of irrigation water (SDI75, SDI50, and SDI33). Yield, morphology, color, titratable acidity (TA), total soluble solids (TSS), organic acids (OA), sugars, minerals, fiber, antioxidant activity (AA), and total phenolic content (TPC) were analyzed. The yield was reduced in SDI conditions (8%, 11%, and 20% for SDI75, SDI50, and SDI33, respectively), but the irrigation water productivity was higher in all SDI regimes. SDI significantly reduced the mango size, with SDI33 generating the smallest mangoes. Peel color significantly changed after 13 days of ripening, with SDI75 being the least ripe. The TA, AA, and citric acid were higher in SDI75, while the TPC and fiber increased in all SDI levels. Consequently, SDI reduced the mango size but increased the functionality of samples, without a severe detrimental effect on the yield

Fruit yield, growth and leaf-nutrient status of mangoes grafted on two rootstocks in a marginal growing area (South-East Spain)

Introduction. Mango (Mangifera indica L.) production is rising in various subtropical zones throughout the world. The main polyembryonic rootstocks used by growers in South-East Spain are Gomera 1 and Gomera 3 (from the Canary Islands) and the most commonly used cultivars are Osteen and Keitt (from Florida, US). In this marginal environment for mango growing, it is important to determine the different rootstock qualities in order to optimise fruit production. The objective of our study was to evaluate the performance of mango cv. Osteen and Keitt on the two aforementioned rootstocks, as measured by fruit yield, scion growth and mineral nutrition. Materials and methods. A 3-year study was conducted in a mature mango orchard (14 years old) of a total of 24 trees, where eight were grafted onto cv. Osteen, another eight onto Keitt (four trees with each of the G1-Ost, G3-Ost, G1-Kt and G3-Kt combinations) and eight were ungrafted rootstocks. Fruit yield and pomological characteristics were evaluated by measuring fruit length, width and weight. Height and canopy diameter, as well as the trunk circumference of the tree, were recorded. Throughout the study period, chemical foliar measurements were taken from all trees. Results. Fruit yield in G1-Ost and G3-Kt trees proved significantly higher than that in the others. The fruit weight and length with the G3-Kt combination were greater than those with G1-Kt. Both cultivars grafted on Gomera 3 rootstock had the highest height and canopy volume. The tree-size data confirmed the vigorous feature of the Gomera 3. The N and P foliar concentration was significantly higher for Gomera 3 than for Gomera 1 in both cultivars. The K concentration was higher in G3-Kt leaves than in G1-Kt ones, but higher in G1-Ost than in G3-Ost. The leaf Mn and Cu concentrations with G3-Kt significantly exceeded those of G1-Kt. Conclusion. The height, trunk cross-sectional area, and canopy volume and diameter proved to be the greatest with Gomera 3, reflecting the vigour of this rootstock. The combinations G1-Ost and G3-Kt registered the highest fruit yield, offering promising possibilities for boosting subtropical productivity in mango

Impact of sustained-deficit irrigation on tree growth, mineral nutrition, fruit yield and quality of mango in Spain

Introduction Mango (Mangifera indica L.) is a crop of major economic importance in the provinces of Malaga and Granada (SE Spain). A field experiment on mango trees was designed to determine the optimum irrigation scheduling over three seasons. The aim was to evaluate the impact of sustained-deficit irrigation (SDI) strategies on fruit yield and quality, tree growth, and mineral status under a Mediterranean subtropical climate. Materials and methods. Three sustained-deficit irrigation treatments were applied to mango trees: SDI-1 (33% ETc), SDI-2 (50% ETc) and SDI-3 (75% ETc). The stress treatments were compared with a control (C-100) irrigated at 100% ETC. The response of fruit yield, number of fruits, fruit size and quality, and macro- and micronutrients in leaves was determined. Results. The SDI-2 treatment proved to be the most appropriate SDI treatment, since it allowed the trees to reach the highest yield (18.4 t·ha-1) and the best water-use efficiency (7.14 kg·m-3). However, fruit size was higher for trees of the SDI-3 and C-100 treatments, since they reached significantly higher length and width. The total soluble solids were affected by the SDI treatments only for one year, being highest in fruits from trees of the SDI-1 and SDI-2 treatments. Macro- and micronutrients in the leaves were affected by the SDI treatment only for the P, Mg and Mn contents. Conclusion The SDI treatment providing 50% of ETC is recommended for mango orchards in order to attain the highest yields and the best water-use efficiency under a Mediterranean subtropical climate

La fruticultura subtropical en los ecosistemas de ladera de clima mediterráneo: cambios en la vegetación

The coast of Granada, in southeast Spain, has a zone of subtropical fruits in hillsides, distributed in terraces. Nitrogen (N) breakdown and release rates for litter were assessed in two ecosystems: (1) unaltered hillside ecosystem (ELI) without agricultural crops, with indigenous vegetation cover and (2) altered hillside ecosystem (ELA) with mango (Mangifera indica L.), avocado (Persea americana Mill.), cherimoya (Annona cherimolia Mill.), loquat (Eriobotrya japónica (Thunb.) Lindl.) and covered with aromatic and medicinal plants (PAM) in terrace slopes. In the ELA, the cherimoya litter breakdown rate was higher; among the PAM, fringed lavender (Lavandula dentata L.), mástic thyme (Thymus mastichina L.) and savory (Satureja obovata Lag.) recorded high Nitrogen release rates. In ELI, olive (Olea europea L.) and bolina (Genista umbellata (L’Hér.) Dum., had low breakdown rates. The PAM and ELA may contribute to resetting natural nutrient recycling cycles, minimizing the effects of change in land use.En la costa de Granada, sureste de España, se encuentra una zona de frutales subtropicales en laderas, distribuidos en terrazas. Se evaluaron tasas de descomposición y liberación de nitrógeno (N) de hojarasca, en dos ecosistemas: (1) ecosistema de ladera inalterado (ELI) sin cultivo agrícola, con cubierta de vegetación autóctona, y (2) ecosistema de ladera alterado (ELA) con frutales de mango (Mangifera indica L.), aguacate (Persea americana Mill.), chirimoyo (Annona cherimolia Mill.), níspero (Eriobotrya japónica (Thunb.) Lindl.), y cubiertas de plantas aromáticas y medicinales (PAM) en los taludes de las terrazas. En ELA la tasa de descomposición de hojarasca de chirimoyo fue la más alta, y entre las PAM la alhucema rizada (Lavandula dentata L.), así como la mejorana (Thymus mastichina L.), alhucema rizada (Lavandula dentata L.) y ajedrea (Satureja obovata Lag.) registraron altas tasas de liberación de N. En ELI acebuche (Olea europea L.) y bolina (Genista umbellata (L’Hér.) Dum., tuvieron bajas tasas de descomposición. Las PAM en ELA pueden contribuir a restablecer los ciclos naturales de reciclado de nutrientes, minimizando los efectos del cambio de uso del suelo

Impact of salinity on macro- and micronutrient uptake in mango (Mangifera indica L. cv. Osteen) with different rootstocks

Two mango (Mangifera indica L.) rootstocks Gomera-1 and Gomera-3, grafted with the scion Osteen, were irrigated at four different NaCl concentrations measured by electrical conductivity (1.02, 1.50, 2.00 and 2.50 dS m-1). The aim was to determine the impact of salinity on macro- and micronutrient uptake. The nutrient imbalances from the effect of salinity on nutrient uptake, availability and partitioning within the plant resulted in less injurious with Gomera-1. Thus, the results corroborated the higher capability of Gomera-1 respect to Gomera-3 rootstocks to better adapt to saline conditions. The saline irrigation in leaves significantly raised the concentration of P, Ca, Fe, Zn and Mn, and lowered the Mg of both rootstocks, tending to decrease the N, and increase K and Cu. In the stem the values for N, Ca, Mg and Cu significantly augmented, whereas Zn tended to decrease. The root system registered a significant decrease of P, K and Mg and increase of N, Fe, Mn and Cu, while the fibrous root tended to concentrate most nutrients with more intensity than did the main root. With Gomera-1 the micronutrient concentrations in roots was higher than Gomera-3 in response to rising NaCl concentrationDos portainjertos de mango (Mangifera indica L.) Gomera-1 y Gomera-3, injertados con el cv. Osteen fueron sometidos a riego con cuatro concentraciones diferentes de NaCl, medidas por la conductividad eléctrica (1,02; 1,50; 2,00 y 2,50 dS m-1). El objetivo fue determinar el impacto de la salinidad en la absorción de macro y micronutrientes. Los desequilibrios nutricionales provocados por el efecto de la salinidad en la absorción de nutrientes, disponibilidad y distribución en la planta resultaron menos perjudiciales con Gomera-1. Así, los resultados obtenidos corroboran la mayor capacidad del portainjerto Gomera-1 respecto de Gomera-3 para adaptarse a las condiciones salinas. El riego salino en ambos portainjertos incrementó significativamente la concentración foliar de P, Ca, Fe, Zn y Mn, redujo el Mg, y además se registró una tendencia al descenso de N y al incremento de K y Cu. En los tallos los valores para N, Ca, Mg y Cu se incrementaron significativamente, mientras el Zn tendió al descenso. El sistema radical registró un descenso significativo de P, K y Mg, y un incremento de N, Fe, Mn y Cu; además la raíz fibrosa tendió a concentrar la mayoría de nutrientes con más intensidad que la raíz principal. Con Gomera-1, en respuesta al ascenso de la concentración de NaCl, la concentración de micronutrientes en las raíces fue mayor que con Gomera-

La fruticultura subtropical en los ecosistemas de ladera de clima mediterráneo: cambios en la vegetación/Subtropical fruit farming in Mediterranean weather hillside ecosystem: changes in vegetation

En la costa de Granada, sureste de España, se encuentra una zona de frutales subtropicales en laderas, distribuidos en terrazas. Se evaluaron tasas de descomposición y liberación de nitrógeno (N) de hojarasca, en dos ecosistemas: (1) ecosistema de ladera inalterado (ELI) sin cultivo agrícola, con cubierta de vegetación autóctona, y (2) ecosistema de ladera alterado (ELA) con frutales de mango (Mangifera indica L.), aguacate (Persea americana Mill.), chirimoyo (Annona cherimolia Mill.), níspero (Eriobotrya japonica (Thunb.) Lindl.), y cubiertas de plantas aromáticas y medicinales (PAM) en los taludes de las terrazas. En ELA la tasa de descomposición de hojarasca de chirimoyo fue la más alta, y entre las PAM la alhucema rizada (Lavandula dentata L.), así como la mejorana (Thymus mastichina L.), alhucema rizada (Lavandula dentata L.) y ajedrea (Satureja obovata Lag.) registraron altas tasas de liberación de N. En ELI acebuche (Olea europea L.) y bolina (Genista umbellata (L'Hér.) Dum., tuvieron bajas tasas de descomposición. Las PAM en ELA pueden contribuir a restablecer los ciclos naturales de reciclado de nutrientes, minimizando los efectos del cambio de uso del suelo

Descomposición de hojarasca y reciclado del nitrógeno de frutales tropicales y subtropicales en terrazas de cultivo en la costa de Granada (SE España)

O experimento foi realizado na região costeira de Granada (SE España). Estudou-se a decomposição das folhas caídas sobre o solo e a ciclagem de nitrogênio a partir de folhas de frutas de origem tropical e subtropical: manga (Mangifera indica L.), cherimóia (Annona cherimola Mill.), nêspera (Eriobotrya japonica Lindl.) e abacate (Persea americana Mill.), empregando a técnica das bolsas. A atemóia apresentou as maiores taxas de decomposição para as folhas, ao passo que as de manga apresentaram-se como as mais persistentes. As constantes de decomposição (k) para as de manga, nêspera, abacate e cherimóia foram de 0,64, 0,84, 0,80 e 1,30 anos-1, respectivamente. O nitrogênio nas folhas de cherimóia e de manga foi imobilizado durante os primeiros meses em 73 e 21%, respectivamente, sendo liberado mais tarde. Em contraste com as folhas de cherimóia e de abacate, que não experimentaram o período de imobilização. O estudo da dinâmica de liberação de nutrientes em solo agrícola e, particularmente, em terras de cultivo é muito importante para prever a disponibilidade e a ciclagem de nutrientes para plantas e, em conseqüência, suas implicações junto ao meio-ambiente.El experimento se realizó en la costa de Granada (SE España). Se estudiaron la descomposición de la hojarasca y el reciclado del nitrógeno en cuatro tipos de hojas de frutales de origen subtropical y tropical: mango (Mangifera indica L.), chirimoyo (Annona cherimola Mill.), níspero (Eriobotrya japonica Lindl.) y aguacate (Persea americana Mill.), empleando la técnica de las bolsas. El chirimoyo tuvo las mayores tasas de descomposición de hojarasca, mientras que la de mango fue la más persistente. Las constantes de descomposición (k) para mango, níspero, aguacate y chirimoyo fueron 0,64, 0,84, 0,80 y 1,30 años-1, respectivamente. El nitrógeno en níspero y mango fue inmovilizado durante los primeros meses en un 73 y 21%, respectivamente, siendo liberado más tarde. En contraste con la hojarasca de chirimoyo y aguacate, que no experimentaron periodos de inmovilización. El estudio de la dinámica de liberación de nutrientes en un suelo agrícola y en particular en terrazas de cultivo es muy importante para predecir la disponibilidad y e

Dinámica de las concentraciones de carbono y nitrógeno en la descomposición de hojarascas de cultivos subtropicales del sureste de España

Litter decomposition is one on the main routes of energy consume in an ecosystem and one of the principal roles in nutrient cycling. On the other side, in the last decades, subtropical crops have expanded importantly along the coast of Granada (SE Spain). To evaluate the cycles a bag technique experiment was carried out by using mango leaves (Mangifera indica L.), cherimolia (Annona cherimola Mill.), avocat (Persea americana Mill.) and loquat (Eriobotrya japonica L.). The main objective of this work was monitoring the dynamic of litter decomposition of these crops leaves and the evolution of their contents in carbon and nitrogen in a Mediterranean subtropical climate context. Bags were buried and recovered at certain time periodically to evaluate carbon and nitrogen concentration as well as mass losses. The results of this study showed that farmers could benefit of the knowledge of nutrient dynamics in litter decomposition to improve soil organic matter in the long term and to incorporate nitrogen. In this sense, loquat and mango showed the highest nitrogen accumulation and as a consequence these types of litters could be used as organic soil amendments in the long term. Contrarily, cherimolia accumulated higher carbon amounts than the rest of the studied crops.La descomposición de la hojarasca es una de las principales vías de consumo de energía en un ecosistema y uno de los pilares básicos en el ciclo de nutrientes. Por otro lado, en las últimas décadas, los cultivos subtropicales se han expandido de forma considerable en la costa de Granada (sureste de España). Para evaluar dichos ciclos se llevó a cabo un ensayo con bolsas utilizando para ello hojas de mango (Mangifera indica L.), chirimoyo (Annona cherimola Mill.), aguacate (Persea americana Mill.) y níspero (Eriobotrya japonica L.). El objetivo de este trabajo fue realizar un seguimiento de la dinámica de descomposición de las hojarascas producidas por el mango, aguacate, chirimoyo y níspero, y de la evolución de su contenido en carbono y nitrógeno en condiciones de clima mediterráneo subtropical. Las bolsas fueron enterradas y se recuperaron cada cierto tiempo para evaluar la concentración de carbono y nitrógeno, así como la pérdida de masa en cada una de ellas. Los resultados de este estudio mostraron de forma evidente que los agricultores pueden beneficiarse del conocimiento de la dinámica de nutrientes en hojarasca para mejorar la materia orgánica en el suelo a largo plazo y la incorporación de nitrógeno. En este sentido, el níspero y el mango mostraron las mayores tasas de acumulación de nitrógeno y, por lo tanto, la biomasa de estas especies podría ser utilizada como enmiendas de tipo orgánico a largo plazo. Por el contrario, el chirimoyo acumuló mayores cantidades de carbono que el resto de los cultivos estudiados

Dynamic of Carbon and Nitrogen Concentrations in the Decomposition of Leaf Litter of Subtropical Crops in Southeastern Spain

Litter decomposition is one on the main routes of energy consume in an ecosystem and one of the principal roles in nutrient cycling. On the other side, in the last decades, subtropical crops have expanded importantly along the coast of Granada (SE Spain). To evaluate the cycles a bag technique experiment was carried out by using mango leaves (Mangifera indica L.), cherimolia (Annona cherimola Mill.), avocat (Persea americana Mill.) and loquat (Eriobotrya japonica L.). The main objective of this work was monitoring the dynamic of litter decomposition of these crops leaves and the evolution of their contents in carbon and nitrogen in a Mediterranean subtropical climate context. Bags were buried and recovered at certain time periodically to evaluate carbon and nitrogen concentration as well as mass losses. The results of this study showed that farmers could benefit of the knowledge of nutrient dynamics in litter decomposition to improve soil organic matter in the long term and to incorporate nitrogen. In this sense, loquat and mango showed the highest nitrogen accumulation and as a consequence these types of litters could be used as organic soil amendments in the long term. Contrarily, cherimolia accumulated higher carbon amounts than the rest of the studied crops