Introduction
⌅Coffee cultivation is widespread in several tropical countries and it supports economically part of the world's population. This is considered one of the agricultural products with the greatest weight in the world market Vasallo et al. (2020)VASALLO-RODRÍGUEZ, L., MONTES-ESPÍN, R., ESCARRÉ-ESTEVE, A., BONET-JORNET, A., FERNÁNDEZ-SANTANA, I.: Los cafetales de sombra y la conservación de la diversidad biológica. El contexto cubano. Revista Científica Agroecosistemas, 8(3), 122-126, 2020., being also the most traded beverage in the world and the second most consumed beverage after water and for these reasons it has become a staple product for many people around the planet (Rojas, 2018ROJAS, O.E. Determinación del potencial agroecológico del café (Coffea arabica) en Costa Rica. Turrialba 39(3): 279-287, 2018.).
In the case of Cuba, coffee production is concentrated in the provinces of Cienfuegos, Villa Clara and Sancti Spíritus and with a marked development in the eastern region of the country, with the most representative volumes in the provinces of Santiago de Cuba, Guantánamo, Granma and Holguín. (García et al., 2013GARCÍA. R.Y, RAMÍREZ B.M, PAUMIER F.Y.: La actividad cafetalera en la comunidad del plan turquino de farallones de Moa. DELOS. Desarrollo Local Sostenible Grupo Eumed.net/Universidad de Málaga y Red Académica Iberoamericana Local Global Indexada en IN-Recs; LATINDEX; DICE; ANECA; ISOC y DIALNETVol 6. Nº 16 Febrero 2013. www.eumed.net/rev/delos/16).
Irrigation is a decisive factor in agriculture to obtain an adequate yield and, therefore, it is necessary to have an impact on good production in order to contribute to food security and sovereignty of the population (Baltazar & Chipana, 2016BALTAZAR, P.I.; CHIPANA, M.G.: Estudio del comportamiento hidráulico relacionado a la uniformidad de aplicación, mediante el método de riego por aspersión en la estación experimental choquenaira. Revista de Investigación e Innovación Agropecuaria y de Recursos Naturales, 3(3), 18-29, 2016, ISSN: 2409-1618.).
According to Nelson et al. (2009)NELSON, G.C., ROSEGRANT, M.W., KOO, J., ROBERTSON, R., SULSER, T., ZHU, T., RINGLER, C., MSANGI, S., PALAZZO, A.; BATKA, M., MAGALHAES, M., VALMONTE-SANTOS, R., EWING, M. Y LEE, D.: Cambio Climático. El impacto en la agricultura y los costos de adaptación. Instituto Internacional de Investigación sobre Políticas Alimentarias IFPRI. Washington, D.C. 30pp, 2009. agriculture is extremely vulnerable to climate change and the increase in temperatures reduces crop production. This, linked with changes in rainfall patterns, increase the likelihood of crop failure, and on that sense is expected that the impacts of climate change will be negative for agriculture, threatening global food security.
To analyze the different impacts of climate change and due to the high uncertainty regarding future climate conditions, the Intergovernmental Panel on Climate Change IPCC (2023)IPCC: Sexto Informe de Evaluación, 2023. advises to work with “scenarios”, which are coherent and consistent descriptions of how the Earth's climate system may change in the future.
Among the various publications about IPCC, the scenarios are defined as Representative Concentration Pathways (RCPs) that provide a range of Greenhouse Gas (GHG) emissions and concentrations that allow exploration of the possible future climatic parameters in a broader way than those used in the past.
It should be reiterated that the RCPs are not predictions or policy recommendations; however, they have been chosen to describe possible future scenarios. They are defined taking as reference the intensity of the radiation in 2100, where the estimates for radiation are based on GHG emissions. These “possible future climate scenarios” are derived from the scenarios of possible future GHG emissions, used in climatic models as input for the calculation of climate projections (Cortés et al., 2013CORTÉS, B.C.A.; BERNAL, P.J.; DÍAZ, A.E.; MÉNDEZ, M.J.: Uso del modelo AquaCrop para estimar rendimientos para el cultivo de maíz en los departamentos de Córdoba, Meta, Tolima y Valle del Cauca, Inst. FAO, Informe técnico proyecto de cooperación técnica TCP/COL/3302, Córdoba, Meta, Tolima y Valle del Cauca, Colombia, 62 p., 2013.).
All simulations are carried out globally on a 0.5° grid, covering the period 1850-2100 and the results are evaluated as a function of transient atmospheric CO2. Temporally, constant management assumptions are made, focusing on the isolated effect of the climatic change on current crop production systems (Jägermeyr et al., 2021JÄGERMEYR, J.; MÜLLER, C.; RUANE, A.C.; ELLIOTT, J.; BALKOVIC, J.; CASTILLO, O.; FAYE, B.; FOSTER, I.; FOLBERTH, J.A.; FUCHS, K.; GUARIN, J.R.; HEINKE, J.; HOOGENBOOM, G.; LIZUMI, T.; JAIN, A. K.; KELLY, D.; KHABAROV, N.; LANGE, S.; ROSENZWEIG, C.: Climate impacts on global agriculture emerge earlier in new generation of climate and crop models. Nature Food, 2(11), 873-885, 2021. DOI: http://doi.org/10.1038/s43016-021-00400-y.).
With the development and popularization of computers, tools are provided to store large volumes of data and perform numerous calculations in agricultural production systems under different management scenarios and contrasting climatic conditions (Flores et al., 2013FLORES, G. H.; OJEDA, W. B.; FLORES, H.; SIFUENTES, E.; MEJIA, E.: Simulación del rendimiento de Maíz (Zea mays L.) en el norte de Sinaloa usando el modelo Aquacrop. Agrociencia, 47(4): 347-359, 2013.).
In recent studies, Camejo et al. (2016)CAMEJO, N.; DÍAZ, Y.; HERRERA, J.: Requerimientos de agua de los cultivos sorgo, maíz y frijol en la “UEB Sierra Maestra” en el municipio Los Palacios, 72pp. Tesis (en opción al título de Ingeniero Hidráulico), Universidad Tecnológica de La Habana-CUJAE, La Habana, Cuba. and Díaz et al. (2016)DÍAZ, Y.; HERRERA, J.; GONZÁLEZ, F.: Estimación de los requerimientos de agua del sorgo (Sorgum vulgare L. Monech) en la región Los Palacios en Cuba, Ingeniería Agrícola, 6(4): 3-10, 2016, ISSN-2306-1545, e-ISSN-2227-8761. used the CropWat model for the calculation of water requirements and irrigation schedules with feasible results. In this context, CropWat is presented as a tool with potentialities to determine irrigation requirements, so it is intended with the present work to estimate in the future the total net irrigation requirements of the coffee plants according to climatic variability in the different areas producing this grain in Cuba.
Materials and Methods
⌅For the selection of the sites of coffee cropping in the mountainous massifs of Cuba where the coffee plantations are developed, (Sierra de los Órganos, Guamuhaya, Sagua-Nipe-Baracoa and Sierra Maestra), (Figure 1), representatives for the definition of future irrigation needs, was consulted the general director the Coffee, Cocoa and Coconut, of the Agroforestry Group (GAF) of the Cuba Ministry of Agriculture (Minag) (Legrá, 2022LEGRÁ, E.: Comunicación personal. Director general del grupo Café, Cacao y Coco perteneciente al Grupo Agroforetal (GAF) del Ministerio de la Agricultura (Minag)., 2022.).
In the processing of the climatic variables involved in the adjustment of climatic scenarios recommended by INSMET, each system was evaluated to verify which of them will be more restrictive for water management and according to the different climatic regions for coffee plantations and finally in the completion of the necessary information for the entry of data in each of the windows of the CROPWAT version 8.0 program, for its subsequent running for the prediction of future of the water needs of the crop.
Within the mountainous massifs, the following sites were selected (Table 1):
| Province | Place | Coordinates | Height (m.o.s.l) | |
|---|---|---|---|---|
| North | West | |||
| Pinar del Río | La Palma | 22˚ 74 ̍ 89 ̎ | -83˚ 55 ̍ 36 ̎ | 150.0 |
| Villa Clara | Jibacoa | 22˚ 01 ̍ 94 ̎ | -79˚ 99 ̍ 19 ̎ | 388.0 |
| Guantánamo | Palenque de Yateras | 20˚ 36 ̍ 94 ̎ | -74˚ 97 ̍ 00 ̎ | 423.0 |
| Granma | Guisa | 20˚ 26 ̍ 14 ̎ | -76˚ 54 ̍ 97 ̎ | 255.0 |
| Santiago de Cuba | Cruce de los Baños | 20˚ 13 ̍ 02 ̎ | -76˚ 32 ̍ 41 ̎ | 189.0 |
| Guantánamo | El Salvador | 20˚ 15 ̍ 39 ̎ | -75˚ 13 ̍ 43 ̎ | 102.0 |
For the study, a 36-year series from 2015 to 2050 was taken from the PRESIS regional model, for the RCP 4.5 scenario, which has a resolution of 125 x 125 km. The variables taken were maximum and minimum temperature, relative humidity, wind speed and rainfalls, which represent the future climatic parameters for the study sites. The water needs of the coffee plants were calculated with emphasis on wet, medium and dry hydrological years. For the selection of the years, the empirical probability was determined from the expression:
Where: m: order number, n: number of members of the series.
Each of the years of the series was classified according to its probability. The scenarios of probability are 25 % wet, 50 % medium and 75 % dry, according to Pérez & Álvarez (2005)PÉREZ, R.; ÁLVAREZ, M.: Necesidades de Riego de la Caña de Azúcar en Cuba, Ed. Academia, primera ed., La Habana, Cuba, 219 p., 2005, ISBN: 959-270-065-6..
The soils in the mountainous regions of Cuba where are the coffee plantations were classified according to the latest Soil Classification established in our country Hernández-Jiménez et al. (1999)HERNÁNDEZ-JIMÉNEZ, A.; PÉREZ-JIMENÉZ, J.M.; MESA-NÁPOLES, Á.; FUENTES-ALFONSO, E.; BOSCH-INFANTE, D.: Nueva versión de la clasificación genética de los suelos de Cuba., Ed. Instituto de suelos, 1999., and their correlation Hernández et al. (2005)HERNÁNDEZ, A.; ASCANIO, M.; MORALES, M.; CABRERA, A.: Correlación de la nueva versión de clasificación genética de los suelos de Cuba con las clasificaciones internacionales y nacionales: una herramienta útil para la investigación, docencia y producción agropecuaria, Inst. Instituto Nacional de Ciencias Agrícolas (INCA), La Habana, Cuba, 18-59 p., 2005. with the Genetic Classification of Cuban Soils (IS-Cuba, 1980IS-CUBA: clasificación genética de los suelos de cuba, Ed. Editorial Academia, La Habana, Cuba, primera ed., La Habana, Cuba, 28 p., 1980.). Once identified, their hydro physical properties were taken from those reported by Cid et al. (2012)CID, G.; LÓPEZ, T.; GONZÁLEZ, F.; HERRERA, J.; RUIZ, M.E.: “Características físicas que definen el comportamiento hidráulico de algunos suelos de Cuba”, Revista Ingeniería Agrícola, 2(2): 25-31, 2012, ISSN: 2306-1545. (See Table 2).
| Province | Place | Soils |
|---|---|---|
| Pinar del Río | La Palma | Yellowish alithic with typical high clay activity |
| Villa Clara | Jibacoa | Typical low clay activity yellowish alithic with low clay activity |
| Granma | Guisa | Fersialithic reddish-brown pulverized soil |
| Stgo. de Cuba | Cruce de los Baños | Typical yellowish alithic with high clay activity |
| Guantánamo | El Salvador | Fersialithic reddish-brown pulverized soil |
| Guantánamo | Palenque de Yateras | Fersialithic reddish-brown pulverized soil |
Once the information was processed, Table 3 was prepared with the data inputted in the CropWat program.
| Place | Field capacity (cm3·cm-3) | Wilting point (cm3·cm-3) | ATD (mm/m) | Infiltration Rate (m·day-1) | Root depth (m) |
|---|---|---|---|---|---|
| La Palma | 0.235 | 0.127 | 108.0 | 2.6 | 0.40 |
| Jibacoa | 0.168 | 0.091 | 77.2 | 6.2 | |
| Guisa | 0.333 | 0.180 | 153.0 | 4.9 | |
| Cruce de los Baños | 0.290 | 0.157 | 133.2 | 2.6 | |
| El Salvador | 0.332 | 0.179 | 152.5 | 1.15 | |
| Palenque de Yateras | 0.333 | 0.180 | 153.0 | 4.9 |
The development phases were taken from Cisneros-Zayas et al. (2015)CISNEROS-ZAYAS, E.; GONZÁLEZ-ROBAINA, F.; MARTÍNEZ-VARONA, R.; LÓPEZ-SEIJAS, T.; REY-GARCÍA, Á.R.: “Respuesta productiva del cafeto al manejo del riego. Función agua-rendimiento”, Revista Ciencias Técnicas Agropecuarias, 24(4): 5-11, 2015, ISSN: 2071-0054. (See Table 4).
| No | Phases | Durations | Average days |
|---|---|---|---|
| I | Flowering-fruiting | February up to April | 89 |
| II | Fructification-fruit development | May up to August | 123 |
| III | Ripen-harvest | September - 1st decade December | 101 |
| IV | Harvest-recovery | 2nd decade December-January | 52 |
Crop Coefficients (Kc): Initial: 1,01 Mid-season: 1,04 Late season: 0,49 Cisneros-Zayas et al. (2015)CISNEROS-ZAYAS, E.; GONZÁLEZ-ROBAINA, F.; MARTÍNEZ-VARONA, R.; LÓPEZ-SEIJAS, T.; REY-GARCÍA, Á.R.: “Respuesta productiva del cafeto al manejo del riego. Función agua-rendimiento”, Revista Ciencias Técnicas Agropecuarias, 24(4): 5-11, 2015, ISSN: 2071-0054.
Sensitivity factor (Ky): 0,52. (González-Robaina et al., 2017GONZÁLEZ-ROBAINA, F.; CISNEROS-ZAYAS, E.; MONTILLA, E.: “Respuesta al déficit hídrico del cafeto (Coffea arabica L.) en diferentes fases de desarrollo”, Revista Ciencias Técnicas Agropecuarias, 26(3): 4-11, 2017, ISSN: 2071-0054.).
Criteria for total irrigation requirements
⌅The criteria for total irrigation requirements are the following: Irrigation timing: Irrigated at critical depletion. Irrigation Application: Refill soil to field capacity. Irrigation efficiency (Field efficiency) 85 %.
Drip Irrigation. Allowable Depletion Fraction; p=40 %.
Criteria for reduced irrigation requirements
⌅The criteria for reduced irrigation requirements are the following: Irrigation timing: Irrigated when the ET is reduced for the stage. Development stage; 4 %. Mid-season: 4 %. Late season: 10 %. Irrigation application: Refill soil to field capacity. Irrigation efficiency (Field efficiency) 85 %. Irrigation system: Drip Irrigation. (See Figure 2).
For the reduction of irrigation requirements, was considered the work carried out in Cuba by Valdés & Vento (1984)VALDÉS, C.R.; VENTO, D.H.: “Estudio del contenido de los principales productos de la fotosíntesis en plantas de Coffea arabica L. var. Caturra cultivadas bajo diferentes dosis de nitrógeno”, Cultivos Tropicales, 6(1): 111-122, 1984. and Valdés et al. (1995)VALDÉS, R.; BARRERA, M.; POMBO, F.; VENTO, D.: “Caracterización del sistema de pigmentos foytosintéticos en plantas de cafetos”, Revista Chapingo, Horticultura, 4: 29-32, 1995., who offer elements to affirm that the coffee trees can be considered as an intermediate species between C3 and C4 due to anatomical changes in the foliar photosynthetic apparatus, as well as the assimilation of CO2. In addition, based on the agronomic management of the coffee trees where is provoked a water stress in the flowering phase for induce and grouping the flowering, it was decided to make reductions in the initial stage of flowering - fruiting and harvest - recovery. It was considered that these reductions did not affect the yield in more than 3 %.
The program CROPWAT, version 8.0, was used to estimate the water requirements of the coffee plants, according to the evapotranspiration of the crop by stages of development year by year from 2015 to 2050. This software allows managing irrigation programs both in unirrigated and in irrigated conditions and it was used to determine the reference evapotranspiration by the FAO Penman-Monteith method starting from the use of the main climatic variables: relative humidity, temperature, wind speed and insolation, as well as the incidence of the effective rainfalls, being processed the new RCP (Representative Concentration Path) scenarios for the coffee growing areas of Cuba (Centella, 2017CENTELLA, A.: La estimación del clima futuro y los escenarios climáticos [Parte 1 y 2], Instituto de Meteorología. La Habana. Cuba, La Habana, Cuba, 2017.).
The estimated irrigation requirements obtained were compared with those approved by the National Institute of Hydraulic Resources (INRH. Resolution 17/2020GOC-CUBA: “Resolución 17- 2020 Instituto Nacional de Recursos Hidráulicos (INRH)”, Gaceta Oficial de la República de Cuba: 35, ISSN: 0864 I-0793, e-ISSN: 1682-7511, GOC 2020-557-061, 2020.) (GOC-Cuba, 2020GOC-CUBA: “Resolución 17- 2020 Instituto Nacional de Recursos Hidráulicos (INRH)”, Gaceta Oficial de la República de Cuba: 35, ISSN: 0864 I-0793, e-ISSN: 1682-7511, GOC 2020-557-061, 2020.).
Results and Discussion
⌅Behavior of the climatic variables of the RCP 4.5 scenario (2020 - 2050) for the study sites
⌅Table 5 shows the average values of the variables maximum and minimum temperature, relative humidity, wind speed and precipitation for the 2020-2050 series studied for each work site. As can be seen, the maximum temperature (T max ) varied between 26.5 and 33.8 ºC, the minimum temperature (T min) between 18.7 and 22,8 ºC, and relative humidity (HR) ranged between 73.6 and 84.6 %. Wind speed (V v ) was between 0,76 and 2.48 m·s-1. Finally, precipitation reached a maximum of 2156,0 mm in Jibacoa, Villa Clara and a minimum of 1 040.94 mm in Cruce de los Baños, Santiago de Cuba.
| Place | T máx. (º C) | T mín. (º C) | HR (%) | Vv (m s-1) | Rainfall (mm) |
|---|---|---|---|---|---|
| La Palma | 31.17 | 22.30 | 75.7 | 1.49 | 1 784.92 |
| Jibacoa | 26.57 | 18.71 | 84.6 | 2.48 | 2 156.00 |
| Palenque de Yateras | 33.19 | 22.88 | 73.6 | 1.51 | 1 256.94 |
| Guisa | 33.80 | 21.23 | 78.0 | 1.72 | 1 040.94 |
| Cruce de los Baños | 32.82 | 20.94 | 76.5 | 0.76 | 1 060.45 |
| El Salvador | 33.16 | 22.98 | 73.6 | 1.49 | 1 093.86 |
When analyzing the behavior of the reference rainfalls and evapotranspiration (ET 0 ) variables for the study sites, for the western and central zones represented by the sites La Palma and Jibacoa (Figures 3a, 3b) for most of the years the rainfalls exceeds the ET 0 , so it could be expected that in the irrigation schedule the total net irrigation requirements will be lower than in other coffee growing sites. In the case of the eastern region represented by the sites Guisa, Cruce de los Baños, El Salvador and Palenque de Yateras (Figures 3c, 3d. 3eCENTELLA, A.: La estimación del clima futuro y los escenarios climáticos [Parte 1 y 2], Instituto de Meteorología. La Habana. Cuba, La Habana, Cuba, 2017.. 3fCENTELLA, A.: La estimación del clima futuro y los escenarios climáticos [Parte 1 y 2], Instituto de Meteorología. La Habana. Cuba, La Habana, Cuba, 2017.) the ET 0 exceeds the rainfalls, which indicates that in this zone the total irrigation norms may be higher. All the sites of the RCP 4.5 scenario (Figure 4) show a similar behavior with what was proposed by authors such as Planos (2014)PLANOS, E.O.: Síntesis informativa sobre impactos del cambio climático y medidas de adaptación en Cuba., Ed. Sello Editorial AMA, La Habana, La Habana, Cuba, 2014, ISBN: 959-300-044-5. and Centella (2017)CENTELLA, A.: La estimación del clima futuro y los escenarios climáticos [Parte 1 y 2], Instituto de Meteorología. La Habana. Cuba, La Habana, Cuba, 2017..
Irrigation demand of coffee plants for each site studied, as a function of rainfall probabilities for the RCP 4.5 climatic scenario
⌅Table 6 shows how crop evapotranspiration (ETc) performed according to the hydrological year, with the highest values at the Guisa site for the three years (wet, medium and dry) and the lowest at the Jibacoa site. The irrigation strategy obtained through programming guarantees that the reduction in yielding does not exceed 3 %.
The same table shows that the total net water requirements varied according to the year, with values ranging from 753.1 mm per year to 920.5 mm per year depending on the site and altitude. The total reduced net water requirements in correspondence with the years, was in the range of 190.5 mm and 746.1 mm per year.
The partial net water requirements reached values ranging from 14,2 mm (142 m3·ha-1) to 26,6 mm (266,0 m3·ha-1) values very similar to those obtained by Cisneros et al. (2006)CISNEROS, E.; REY, R.; ZAMORA, E.; GONZÁLEZ, F.: “Influencia del manejo del riego en el rendimiento del cafeto”, Revista Ciencias Técnicas Agropecuarias, 15(2): 42-46, 2006, ISSN: 1010-2760. irrigating coffee plants in the area of San Andrés Pinar del Rio with a localized irrigation system with micro-sprinklers under the principle of total coverage.
| Place | Rainfalls probability (%) | ETc (mm) | Total net requirements (mm) | Partial net requirements (mm) | Irrigation number | Yield reduction (%) | |||
|---|---|---|---|---|---|---|---|---|---|
| SR | CR | SR | CR | SR | CR | ||||
| La Palma Pinar del Río | 25 | 1 290,0 | 862.3 | 190.5 | 17.25 | 27.21 | 50 | 7 | 2.5 |
| 50 | 1 378.8 | 876.1 | 404.6 | 18.25 | 26.97 | 48 | 15 | 2.3 | |
| 75 | 1 320.0 | 844.7 | 264.6 | 17.60 | 26.46 | 48 | 10 | 2.2 | |
| Jibacoa Villa Clara | 25 | 1 026.6 | 603.4 | 214.2 | 15.47 | 19,47 | 39 | 11 | 2,2 |
| 50 | 1 078.6 | 681,4 | 325.6 | 14,20 | 20.35 | 48 | 16 | 2,5 | |
| 75 | 1 193.4 | 863,5 | 451.8 | 14,16 | 21.51 | 61 | 21 | 3.2 | |
| P. de Yateras Guantánamo | 25 | 1 482.3 | 826.8 | 522.2 | 25.84 | 37.30 | 32 | 14 | 2.7 |
| 50 | 1 441.6 | 815.8 | 569.7 | 26.32 | 37.98 | 31 | 15 | 2.8 | |
| 75 | 1 481.4 | 879.3 | 576.9 | 26.65 | 38.46 | 33 | 15 | 2.7 | |
| Guisa Granma | 25 | 1 544.5 | 857.3 | 422.5 | 25.98 | 38.41 | 33 | 11 | 3.0 |
| 50 | 1 557.6 | 858.3 | 575.1 | 26.01 | 38.34 | 33 | 15 | 2.6 | |
| 75 | 1 563.9 | 893.3 | 546.1 | 26.27 | 39.01 | 34 | 14 | 2.8 | |
| C. de Baños Stgo. de Cuba | 25 | 1 412.9 | 775.3 | 615.7 | 23.49 | 32.41 | 33 | 19 | 3.0 |
| 50 | 1 377.2 | 753.1 | 504.9 | 22.82 | 33.66 | 33 | 15 | 3.1 | |
| 75 | 1 435.6 | 863.7 | 600.8 | 22.73 | 33.38 | 38 | 18 | 3.0 | |
| El Salvador Guantánamo | 25 | 1 415.6 | 886.6 | 702.0 | 26.08 | 36.95 | 34 | 19 | 3.2 |
| 50 | 1 426.5 | 920.5 | 740.3 | 26.30 | 37.02 | 35 | 20 | 3.1 | |
| 75 | 1 489.0 | 895.0 | 746.1 | 26.32 | 37.31 | 34 | 20 | 3.3 | |
Legend: SR: no reduction; CR: with reduction
When analyzing the behavior of the total net water requirements by zones it is appreciated that these vary according to the water balance of the region, since according to the climate scenario RCP 4.5 for the western and central regions in most years the precipitation exceeds the reference evapotranspiration and therefore the difference between the total and reduced norms differs between 48 and 78 % (Figure 5). While for the eastern region, where the balance of the reference evapotranspiration exceeds the rainfalls, the difference between the norms oscillates from 17 % to 51 %. This behavior is normal considering that in the western region a large part of the water demand of the coffee plants is covered by the rainfalls, but this is not the case in the eastern region.
Regarding the number of irrigations (Figure 6), there is a similar behavior. In the western and central regions, the differences between the variant of full and reduced water requirements vary between 39 and 61, with reduced requirements ranging between 7 and 21 irrigations. A similar analysis for the eastern region shows that this range is reduced, with values of 31 and 38 full irrigations. For the reduced water applications these range vary from 11 to 20 irrigations, which means 56 % less than those of the western and central regions on average.
Study of the total and reduced net requirements obtained by CropWat program and approved in INRH Resolution 17/2020GOC-CUBA: “Resolución 17- 2020 Instituto Nacional de Recursos Hidráulicos (INRH)”, Gaceta Oficial de la República de Cuba: 35, ISSN: 0864 I-0793, e-ISSN: 1682-7511, GOC 2020-557-061, 2020.
⌅Table 7 shows the total irrigations approved by INRH in Resolution 17/2020 GOC-Cuba (2020)GOC-CUBA: “Resolución 17- 2020 Instituto Nacional de Recursos Hidráulicos (INRH)”, Gaceta Oficial de la República de Cuba: 35, ISSN: 0864 I-0793, e-ISSN: 1682-7511, GOC 2020-557-061, 2020. and those estimated through the CropWat program. For La Palma site, in the three hydrological years, the estimates are higher than the current one in percentages that vary between 8.8 and 12, so that in the future for the RCP 4.5 scenario, the coffee trees will need higher number of irrigation than the current one to meet water needs.
In the central region, represented by the Jibacoa site, in the wet and medium years, the net water requirements obtained through the CropWat runs are lower than the current ones, overestimating those approved in the Resolution 17/2020 by 25 and 15.3 respectively. The same is not true for the dry year, where it exceeds the current one by 7.3 %.
| Place | Probability of rainfalls (%) | Total net requirements estimated by CROPWAT (mm) | Total net Requirements by INRH (mm) | Difference | % Increment | |
|---|---|---|---|---|---|---|
| SR | CR | SR | ||||
| La Palma Pinar del Rio | 25 | 862.3 | 190.5 | 770.6 | 91.7 | 10.6 |
| 50 | 876.1 | 404.6 | 105.5 | 12.0 | ||
| 75 | 844.7 | 264.6 | 74.1 | 8.8 | ||
| Jibacoa Villa Clara | 25 | 603.4 | 214.2 | 804.9 | -201.5 | 0 |
| 50 | 681.4 | 325.6 | -123.5 | 0 | ||
| 75 | 863.5 | 451.8 | 58.6 | 7.3 | ||
| Guisa Granma | 25 | 857.3 | 422.5 | 823.8 | 33.5 | 4.0 |
| 50 | 858.3 | 575.1 | 34.5 | 4.2 | ||
| 75 | 893.3 | 546.1 | 69.5 | 8.4 | ||
| Cruce de Baños Stgo. de Cuba | 25 | 775.3 | 615.7 | 786.0 | -10.7 | 0 |
| 50 | 753.1 | 504.9 | -32.9 | 0 | ||
| 75 | 863.7 | 600.8 | 77.7 | 9.9 | ||
| P. de Yateras Guantánamo | 25 | 826.8 | 522.2 | 626.0 | 200.8 | 32.1 |
| 50 | 815.8 | 569.7 | 189.8 | 30.3 | ||
| 75 | 879.3 | 576.9 | 253.3 | 40.5 | ||
| El Salvador Guantánamo | 25 | 886.6 | 702.0 | 789.5 | 97.1 | 12.3 |
| 50 | 920.5 | 740.3 | 131.0 | 16.6 | ||
| 75 | 895.0 | 746.1 | 105.5 | 13.4 | ||
Legend: SR: no reduction; CR: with reduction
Palenque de Yateras is where the largest increases in total net water demands are predicted, varying between 32.1 % for the wet year and 40.5 % for the dry year. In this site it is necessary to pay special attention to the management of water resources in the future if it is desired to guarantee a good quality coffee production, taking into consideration the weight of the yields of this site in the Cuban coffee economy.
The Guisa and Cruce de los Baños sites have the lowest increases in future net water requirements, which only exceed the current ones by between 4.0 % and 8.4 % in Guisa. At Cruce de los Baños, the present one is overestimated with respect to the future by 1.4 % for the wet year and 4.2 % for the dry year.
Finally, at the El Salvador site, the increases in net water requirements estimated by the CropWat program compared to the current ones vary between 12.3 % and 16.6 %.
In general, for none of the sites studied, the total estimated future net water requirements exceed the current ones by more than 50 %, so they can be considered as normal if it is taken into account that most of the scenarios according to Planos (2014)PLANOS, E.O.: Síntesis informativa sobre impactos del cambio climático y medidas de adaptación en Cuba., Ed. Sello Editorial AMA, La Habana, La Habana, Cuba, 2014, ISBN: 959-300-044-5. and Cortés et al. (2013)CORTÉS, B.C.A.; BERNAL, P.J.; DÍAZ, A.E.; MÉNDEZ, M.J.: Uso del modelo AquaCrop para estimar rendimientos para el cultivo de maíz en los departamentos de Córdoba, Meta, Tolima y Valle del Cauca, Inst. FAO, Informe técnico proyecto de cooperación técnica TCP/COL/3302, Córdoba, Meta, Tolima y Valle del Cauca, Colombia, 62 p., 2013. tend to a significant reduction in the rainfalls and a significant increase in the average air temperature, climatic variables that directly influence water consumption by crops and therefore the increase in irrigation needs.
Conclusions
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The estimation of the total net irrigation requirements for coffee trees according to climatic variability in the coming years for the study sites indicates that there will be an increase ranging from 8 447.0 m3·ha-1 in La Palma (Pinar del Rio) to 8 793.0 m3·ha-1 in Palenque de Yateras (Holguin).
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The greatest differences between the total and the reduced net water requirements for the RCP 4.5 scenario are in the western and central regions, which vary between 48 % and 78 %, being smaller for the eastern region where they are in the range of 17 % to 51 %.
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When comparing the estimated total net water requirements with those approved in Resolution 17/2020, these are higher by between 8.8 % and 40.5 %, which indicates that there will be strong pressure on water resources in the coffee-growing areas studied.
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The criterion of reducing the net water requirements for coffee plants in the initial phases of flowering-fruiting and the ripening-harvest phase allows significant water savings with yield effects that do not exceed 3 %.