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The challenges of irrigation in the COVID19 scenario

This session offers an opportunity to present studies or professional works regarding irrigated agriculture with disciplinary and multidisciplinary approaches copying with the challenges that the COVID19 scenario brings to the researches and society, such as:
• Resilience of irrigated areas at different spatial scales, mainly when water and soil are limiting factors.
• Estimation of crop transpiration/crop water requirement, even considering the possibility to apply controlled water deficit conditions.
• Coupling natural and human systems where ground and surface water and land are limiting resources for irrigation
• Safety in marginal water use in irrigated agriculture
• Traditional, novel, and transitional technologies for irrigation management, control and practical application at different spatial scales.
• Reducing the cost of technology monitoring soil and plant water status, and improving the quality of data acquired from the sensors, as well as on integrating the acquired data into easy-to-use Decision Support System.
• Potential of available remotely and proximal sensed data, mainly referring to those platforms and instruments acquiring frequently high-resolution data, to tackle current and future irrigation problems at different spatial scales.
• Improving the integration of climate change scenarios and weather forecast into agro-hydrological models and decision support systems to improve decisions in irrigation management and in safe surface water-groundwater interactions.
Posters and oral communications are available.

Co-organized by HS13/NH8
Convener: Leonor Rodriguez-Sinobas | Co-conveners: Daniele MasseroniECSECS, María Fátima Moreno Pérez, Giuseppe Provenzano, Alejandro Pérez-Pastor
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Thu, 29 Apr, 09:00–10:30

Chairpersons: Leonor Rodriguez-Sinobas, Daniele Masseroni, María Fátima Moreno Pérez

5-minute convener introduction

Juan Carlo Intriago Zambrano et al.

Smallholder farming is the cornerstone of the agricultural sector in the Global South. It produces 80% of the food in Sub-Saharan Africa and Asia, though it accounts for barely 12% of the global farmland. Its sustainable intensification is therefore paramount in the accomplishment of Sustainable Development Goal 2: Zero Hunger. In this respect, adoption of sustainable water pumping technologies is key to ensure access to irrigation water, thus to secure smallholder production. Sustained uptake of agricultural technologies, however, is a complex process whose attainment is far beyond the sole technology itself. It encompasses a number of intertwined variables of all kinds related to the adopter and the use context: biophysical, financial, institutional, social, cultural, etc.

We argue that innovative business models—like sustainable product-service system (SPSS)—have the potential to ease the adoption process by overcoming many of its constraints (e.g. unaffordable upfront costs, lack of adequate servicing). These business models, unlike traditional linear approaches of technology transfer, have to take into account a broader network of stakeholders. In this way, the technology becomes an agent of interaction between involved parties. It turns into a dynamic element, connected to other products and well-developed services, that caters multiple farming needs. In our paper, we discuss enablers and barriers for the implementation of an SPSS in smallholder contexts under different scenarios. We analyze them based on evidence from Nepali and Indonesian smallholder communities where a novel hydro-powered pumping technology, known commercially as the Barsha pump, has been deployed. The insights gathered reveal many leverage points to create synergies between farmers, entrepreneurs, financial institutions, non-profit organizations and governmental agencies. They also denote the persistent challenges in the required shift of mindset for such an innovative system to come into full operation.

How to cite: Intriago Zambrano, J. C., Diehl, J. C., and Ertsen, M. W.: Sustainable Product-Service Systems: A different approach to secure smallholder production?, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-701, https://doi.org/10.5194/egusphere-egu21-701, 2021.

Brivaldo Gomes de Almeida et al.

Geostatistical and multivariate techniques have been widely used to identify and characterize the soil spatial variability, as well as to detect possible relationships between soil properties and management. Besides that, these techniques provide information regarding the spatial and temporal structural changes of soils to support better decision-making processes and management practices. Although the Zona da Mata region is a reference for sugarcane production in the northeast of Brazil, only a few studies have been carried out to clarify the effects of different management on soil physical attributes by using geostatistical and multivariate techniques. Thus, the objectives of this study were: (I) to characterize the spatial distribution of soils physical attributes under rainfed and irrigated sugarcane cultivations; (II) to identify the minimum sampling for the determination of soil physical attributes; (III) to detect the effects of the different management on soil physical attributes based on the principal component analysis (PCA). The study was carried out in the agricultural area of the Carpina Sugarcane Experimental Station of the Federal Rural University of Pernambuco, 7º51’13”S, 35º14’10”W, characterized by a Typic Hapludult with sandy clay loam soil texture. The investigated plot, cultivated with sugarcane, included a rainfed and an irrigated treatment in which a sprinkler system was installed according to a 12x12m grid. The interval between consecutive watering was fixed in two days, whereas irrigation depth was calculated to replace crop evapotranspiration (ETc) and accounting for the effective precipitation of the period. Daily ETc was estimated based on crop coefficient and reference evapotranspiration (ETo) indirectly obtained through a class A evaporation pan. In both treatments, the soil spatial variability was determined according to a 56x32m grid, on 32 soil samples collected in the 0.0-0.1m soil layer, spaced 7x8m, and georeferenced with a global position system. The soil was physically characterized according to the following attributes: bulk density (BD), soil penetration resistance (SPR), macroporosity (Macro), mesoporosity (Meso), microporosity (Micro), total porosity (TP), saturated hydraulic conductivity (Ksat), gravimetric soil water content (SWCg), geometric mean diameter (GMD) and mean weight diameter (MWD). The results of the descriptive statistics showed that among the studied attributes, Ksat, SPR, and Macro presented higher CV values, equal to 63 and 69%, 35 and 40%, and 32 and 44%, under rainfed and irrigated conditions, respectively. The minimum sampling, adequate to characterize the different soil attributes, resulted in general smaller in the rainfed area, characterized by higher homogeneity. Thus, the GMD, SWCg (both with 2 points ha-1), and SPR (with 6 points ha-1) were identified as the soil physical attributes requiring the lowest sample density; on the other hand, MWD and Ksat, with 14 and 15 points ha-1, respectively, required the highest number of samples. Pearson’s correlation analysis evidenced that soil BD was the most influential physical attribute in the studied areas, with a significant and inverse effect in most of the investigated attributes. The geostatistical approach associated with the multivariate PCA provided to understand the relationships between the spatial distribution patterns associated with irrigated and rainfed management and soil physical properties.

How to cite: Almeida, B. G. D., Mantovanelli, B. C., Schossler, T. R., Freire, F. J., Souza, E. R. D., Almeida, C. D. G. C. D., Provenzano, G., and Simões Neto, D. E.: Spatial variability of the physical-hydric properties of cohesive soils under rainfed and irrigated sugarcane cultivations, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-1526, https://doi.org/10.5194/egusphere-egu21-1526, 2021.

María Fátima Moreno-Pérez et al.

In the present work, a selection of drip irrigation emitters used in greenhouse horticultural crops in the province of Almeria, Spain, were hydraulically evaluated, studying their hydraulic behavior and whether they meet with quality standards. Since manufacturers are offering lower flow emitters less spaced, all drippers tested are low flow. The hydraulic characterization will indicate the discharge and emission uniformity of the manufactured emitters, which are the fundamental parameters for the study of water use efficiency in drip irrigation. In the province of Almeria, water is a limiting factor due to the existence of a semi-arid climate, and, in addition, these limited water resources are used by intensive agriculture which causes a high consumption of these resources.

In total, 21 emitters have been evaluated, including all possible drippers according to their type of insertion (inline, pinched or online and interlinea), hydraulic behaviour (non-compensating and self-compensating) and, within the compensating ones, (anti-draining and non anti-draining). Its flow rates are between 1 and 2.4 l/h, except for a non-compensating interlina emitter of 3.8 l/h.

To carry out these tests, the criteria of the ISO 9261:2004 standard have been followed, calculating the coefficient of manufacturing variation and the emitter discharge equation on a test bench located in the La Mojonera Centre (Almeria) of the IFAPA (Andalusian Institute of Agricultural and Fishing Research and Training).

The results of this study show very good behavior in most of the emitters, and, as a consequence, a low coefficient of manufacturing variation has been obtained. The discharge equation obtained in the laboratory shows a low emisión exponent in the self-compensating emitters, being, therefore, the compensation of the pressures very high in all cases. No statistically significant differences have been found between self-compensating and non-compensating emitters by analysing their manufacturing variation coefficients. Nor have any significant differences been found between self-compensating emitters according to whether they are anti-draining or non-anti-draining, considering also the coefficient of variation. In anti-draining emitters, all closing pressures are not satisfied according to the standard, and are exceeded with very high values. The opening pressure is met for two of the four emitters, and one of those that does not meet it does so with a very large value.

How to cite: Moreno-Pérez, M. F., Baeza-Cano, R., Roldán-Cañas, J., Cánovas-Fernández, G., and Reyes-Requena, R.: Hydraulic characterization of low flow drip irrigation emitters used in intensive horticultural crops in Almeria (Spain), EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-2338, https://doi.org/10.5194/egusphere-egu21-2338, 2021.

Kevim Ventura et al.

The growing need to increase productivity in smaller areas guides agricultural research to develop and improve technologies that seek to meet this demand. The possibility of producing vegetables in areas where land is a limiting factor is something that draws attention, especially for family farmers and residents of urban areas who wish to produce their food. The vertical cultivation system is a technique developed focusing on the production of medicinal, horticultural, and ornamental crops, mainly in places without the ideal space for conventional production, and widely used for those that seek sustainable and organic production. The vertical system build with 200 liters drums allows the farmer to produce 52 plants in about 1 m2, and all the researches carried out with these systems shows high productivity and a water use efficiency superior to conventional production systems. The use of wastewater allows the irrigator to produce in places where clean water is scarce, in addition to taking advantage of the nutritional content present in it, thus reducing fertilizer costs. For this, it is necessary to ensure that the effluent undergoes treatments to avoid possible contamination. As treatment options tested that provide safe agricultural reuse of wastewater, we present three solutions: a low-cost and nature-based treatment system compound by the combination of a biological filter bed (BFB) and a solar disinfection (SODIS) reactor, a low-cost anaerobic filter, and the SODIS reactor + H2O2. The BFB consists of four equals rectangular fiberglass water tanks presenting the following dimensions: 100 x 35x 31 cm. The water tanks were connected in series by a PVC pipe of 50 mm. Gravel with size ranging from 4.8 to 9.5 mm were used as biofilter media. The wastewater filtered by the BFB was directed to the SODIS reactor. The SODIS reactor was made of concrete and shaped in the form of an inverted truncated cone with the following dimensions: 1.0 m of larger radius, 0.25 m of smaller radius and 0.30 m of height. The anaerobic filter consists of six identical plastic 200 liters drums connected in series through a PVC pipe of 32 mm, filled with gravel that presented an average diameter of 14 mm. In order to speed up the SODIS process in the reactor, in a wastewater depth of 0.10 m, it was added 125 mg L-1 of H2O2. Wastewater treatment can provide wastewater with concentrations of fecal coliform ≤ 1000 MPN 100 mL-1. The wastewater treated by the treatment options described here can be safely reused to irrigate crops cultivated in vertical systems. Several studies have been showing that in crops irrigated with wastewater, crop yield can be higher than those irrigated with tap water. It is evident the need to combine treatment strategies to better take advantage of the benefits provided by the reuse of wastewater in irrigated agriculture, while using alternative ways of producing food, thus the producer can grow his food even with little available space, and avoids circulation in public places to purchase their food.

How to cite: Ventura, K., Silva, T., Pitoro, V., and Sánchez-Román, R.: Systems alternative for treating wastewater for irrigation in a vertical production system, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-15431, https://doi.org/10.5194/egusphere-egu21-15431, 2021.

Laura Ponce Robles et al.

Irrigated agriculture is a predominant economic activity in many areas of the Mediterranean region.  However, water scarcity and restrictions on the use of fresh water resources in high agricultural production regions, endangers sustainable agricultural development.  So, alternative water resources are necessary.

The use of reclaimed water for agriculture irrigation makes available a low-cost water source, providing an additional source of nutrients for the plants, helping to reduce the amount and costs associated with the consumption of synthetic fertilizers in agriculture. However, this practice is not a remedy for water scarcity free of disadvantages. Among them, the presence of contaminants of emerging concern (CECs) is one of the most worrying to the scientific community. The problem with these compounds is that they are not completely removed during wastewater treatment, which makes their long-term consequences unpredictable. On the other hand, the absorption and bioaccumulation of CECs in food crops is a matter still to be clarified.

In this work, the absorption capacity, accumulation and persistence of a selected group of CECs in real crops (baby lettuce) irrigated with reclaimed water from a WWTP were evaluated. Results showed different behaviors depending on CECs properties and concentrations, indicating a progressive accumulation when the culture time increased. So, the chemical quality of reclaimed water is a key issue in safe agricultural irrigation.

How to cite: Ponce Robles, L., Bañón Gómez, D., García García, A. J., Pedrero Salcedo, F., Nortes Tortosa, P. A., and Alarcón Cabañero, J. J.: Reclaimed water irrigation: Accumulation of contaminants of emerging concern in food crops, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-13332, https://doi.org/10.5194/egusphere-egu21-13332, 2021.

Alina Buber and Yuri Dobrachev

The problem of obtaining consistently high yields of early potatoes while minimizing the cost per unit of production is very serious. Improving the technology of growing potatoes in the dry steppe zone with the integrated irrigation and fermentation systems is aimed not only at meeting the needs of the population in these products in the region, but also at reducing the demand for the purchase of potatoes abroad.

The dynamics of the main factors of plant life associated with the state of the environment, and the needs of plants at different stages of development may differ significantly from each other, which leads to a decrease in the intensity of the production process and yield. Regulation of the hydrothermal regime of crop during the critical periods of plant vegetation can be a useful agrotechnical method in managing the water regime and productivity of potatoes in the conditions of the dry steppe zone.

The use of digital technology for regulating the water-thermal regime of irrigated crops with using simulation models is caused not only by the specifics of the problem being solved, but also by the requirements for updating irrigation and drainage systems based on the modern technical advances and fundamental knowledge in order to implement highly efficient and environmentally friendly farming on reclaimed land.

Results of multifactor experiments on potatoes cultivation under drip irrigation and finely divided sprinkling in the conditions of the Volgograd region did not allow us to identify optimal technological parameters with apply of statistical methods. In addition to the small number of field experiments over a number of years, the high variation of weather conditions was the dominant factor, that is leading the shifts in vegetative growth period duration and the most significant stages of potato growing.

The prospect to solve this problem is recognized in application of a dynamic model for the potato crop growing that considers the ability to control soil moisture in the root zone and temperature regime of the vegetation cover and simulate them depending on the emerging weather conditions and the actual state of the plants. Using the J. Richie algorithm to determine evaporation and transpiration, it is easy to reconcile the design scheme with soil moisture distribution under drip irrigation, and also consider the agrocenosis water balance with periodic fine dispersion water sprinkling when the set air temperature is exceeded in the hottest hours of the day. Preliminary numerical experiments, based on the retrospective data of earlier field experiments, indicate sufficient flexibility of the model in terms of the formed water-temperature regime simulation and its influence on potato growth processes.

In 2019, the technology of growing early potatoes was tested using a dynamic model in the Ryazan region for the temperate climate of the forest-steppe area. The model showed adequate results of its application to control the hydrothermal regime in irrigation by sprinkling.

The research is carried out under the Grant of the RFBR 19-416-343004 р_мол_а with the support of the Committee for Economic Policy and Development of the Volgograd Region.

How to cite: Buber, A. and Dobrachev, Y.: Hydrothermic regime management of the irrigated field while growing early potatoes in the arid zone, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-5322, https://doi.org/10.5194/egusphere-egu21-5322, 2021.

Olfa Gharsallah et al.

Italy is Europe’s leading rice producer, with over half of the total production, almost totally concentrated in a large paddy rice area in the north-western part of the country, stretching across the border between the Lombardy and Piedmont regions in the Po river valley. In this area, rice irrigation has been traditionally carried out by wet seeding and continuous flooding. The introduction of alternative water-saving irrigation strategies could reduce water needs and environmental impacts; however, before extensively adopting them, their effects at both the field and irrigation district scales must be quantified.

In the context of the MEDWATERICE project (PRIMA-Section2-2018), in the agricultural season 2019 an experimental platform was set-up in a location within the paddy area (Pavia province), to compare different irrigation strategies: wet seeding and traditional flooding (WFL), dry seeding and delayed flooding (DFL), and a ‘safe' wet seeding and alternated wetting and drying (AWD). Six plots of about 20 m x 80 m each were set-up, with two replicates for each irrigation option. One out of the two replicates was instrumented with: water inflow and outflow meters, piezometers, tensiometers, and water tubes for the irrigation management in the AWD plots. A soil survey was conducted before the agricultural season (EMI sensor and physico-chemical analysis of soil samples). Periodic measurements of crop biometric parameters were conducted. Nutrients (N, P, K) and two widely used pesticides (Clomazone, MCPA) were measured in irrigation water (inflow and outflow), groundwater, and porous cups installed at two soil depths (20 and 70 cm, above and below the plough pan). Finally, rice grain yields and quality (As and Cd in the grain) were determined. The experimental activity in the platform was carried out for two years (2019 and 2020), and an upscaling of the results at the irrigation district scale is foreseen in the project.

Soil water balances at the field scale were computed through an approach integrating field measurements of irrigation flows and storages with hydrological modelling, to compare the three irrigation management strategies under similar soil conditions. Results for 2019 showed that DFL allowed a water saving of 10% compared to WFL, while a higher water saving (19%) was achieved with AWD, as expected. Rice grain yield was found to be comparable for all the investigated irrigation treatments. Also, the grain N content was not significantly affected by the water management strategy adopted: the highest values were obtained in WFL and AWD (1.4 N%), while the lowest in DFL (1.2 N%). Total As in grain was not significant for any of the irrigation strategies, but rice Cd level was statistically higher in AWD, although under the legal limits set in the EU even for baby food. As far as water quality is concerned, in surface water, soil solution and groundwater, concentrations for both herbicidesdid not reach significant values, even after treatments, except in limited cases that could depend on relevant concentrations already present in the irrigation inflow. Data for 2020 are under elaboration and first results will be illustrated during the conference.

How to cite: Gharsallah, O., Romani, M., Ricciardelli, A., Rienzner, M., Mayer, A., Chiaradia, E., Ortuani, B., Gilardi, G., Gandolfi, C., Ferrari, F., Voccia, D., Tediosi, A., Botteri, L., Botteon, E., Lamastra, L., Trevisan, M., and Facchi, A.: Alternate wetting and drying irrigation for rice: first experimental activities in northern Italy, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-15130, https://doi.org/10.5194/egusphere-egu21-15130, 2021.

Javier Ezcequiel Colimba Limaico et al.

In Ecuador, tomato (Solanum lycopersicum L.) is a main crop which production has been increase in the latest decade. The crop is grown throughout the country, although it is in the Sierra region where locate the greenhouse production areas. Tomato manufacturers face the water scarcity problems and in addition, the small and medium producers have little knowledge regarding the amount of water they should apply to the crop, and how they should manage. Considering this framework, this study first is aimed at determining the optimal water doses for tomato crop cultivated under greenhouse conditions in the Sierra region and second, it is aimed at establishing the best irrigation frequency. The experimental study was carried out from June to December 2020, in a metallic greenhouse with plastic cover, located in the Natabuela’s parish which belong to the city of Antonio Ante in the Imbabura province. The variables studied were:  two water doses (100% and 120% of the of the evapotraspiration, ET) and four irrigation frequencies (two irrigations and one irrigation a day, one irrigation every other day and one irrigation every two days). In total, eight treatments were evaluated in an 2 x 4 factorial design, under a completely random block distribution, with four repetitions. The results show that the 120% ET irrigation dose produces the highest plant vigor and total and commercial production, while the 100% ET irrigation dose presents a higher citric acid percentage and total soluble solids content. Likewise, both doses do not showed significant differences in their water use efficiency and pH. Therefore, if the increase in production is searching then, it would be advisable to apply the 120% ET dose, although if the search is for the production quality it would be better to apply 100% ET. Regarding the irrigation frequency, one or two irrigations a day produced higher plant vigor as well as higher production and water use efficiency. None of the irrigation frequencies studied had significant differences in plant height and fruit quality variables.


How to cite: Colimba Limaico, J. E., Zubelzu Minguez, S., and Rodriguez Sinobas, L.: Assessing water doses, water use efficiency and tomato quality under greenhouse conditions in Natabuela-Ecuador, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-2911, https://doi.org/10.5194/egusphere-egu21-2911, 2021.

Abdül Halim Orta and Seray Kuyumcu

The aim of this study is to determine the effects of deficit irrigation applications at different levels on the cool-season and warm-season turfgrass species irrigated by sprinkler irrigation. Field experiments were conducted in the Agricultural Production and Research Center (TURAM) of Silivri Municipality in Gümüşyaka District located between the boundaries of Tekirdağ and Istanbul - TURKEY, at growing season 2019. In this research, two different turfgrass types (K: Cool season turfgrass and B: Warm season turfgrass), at three different irrigation threshold were examined in split-plots in randomized blocks design with three replications. Cool season turfgrass types lost its green colour completely after July due to the dry and hot summer season and the total amount of irrigation water applied in different irrigation strategies varied between 101.4 mm - 303.9 mm, seasonal evapotranspiration values varied between 217.7 mm - 391.5 mm, and daily evapotranspiration values varied between 2.4 mm/day - 4.3 mm/day. As for warm-season turfgrass types that managed to stay alive and kept its green colour throughout whole summer period; the same values varied between 203,6 mm - 591,6 mm; 328.4 mm - 593.9 mm; and 2,1 mm/day – 3,9 mm/day, respectively. In the 3-month period (May-June-July) in which both types of grass could survive, the seasonal evapotranspiration values were 11% more in the cool season turfgrass than that of warm season turfgrass. When daily evapotranspiration values were compared, it was observed that it was 10-14% more in cool-season turfgrass than in warm-season turfgrass. Average CWSI values calculated for different irrigation treatments were 0,57-0,66 for cool-season turf, 0,52-0,66 for warm-season turf besides, average CWSI values before irrigation application were 0,68-0,79 for cool-season turf, 0,69-0,79 for warm-season turf. Changes in the vegetation height, fresh yield, dry yield, plant density, color, and quality properties were monitored depending on the irrigation levels. When factors such as the amount of irrigation water applied, water-use and irrigation water-use efficiency, and quality parameters are evaluated together; none of treatments were adequate to keep cool-seasons varieties green after July. In the warm season turfgrass variety, although all irrigation levels provide the desired level for plant growth and quality, S2 treatment has been suggested when all parameters mentioned above are taken into consideration. Besides, Jensen Haise method (JH) was chosen as the best equation when reference evapotranspiration estimation methods were compared for both types of turf and crop coefficient (kc) curves have been prepared for both turfgrass species.

How to cite: Orta, A. H. and Kuyumcu, S.: Deficit Irrigation of Cool and Warm Season Turfgrass Varieties under Sprinkler Irrigation Method, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-11335, https://doi.org/10.5194/egusphere-egu21-11335, 2021.

Niels Schuetze

Due to climate change, extreme weather conditions such as droughts may have an increasing impact on the water demand and the productivity of irrigated agriculture. For the purpose of adaptation to changing climate conditions, the value of information about irrigation control strategies, future climate development and soil conditions for the operation of deficit irrigation systems is evaluated. To treat climate and soil variability within one simulation optimization framework for irrigation scheduling we formulated a probabilistic framework that is based on Monte Carlo simulations. The framework can support decisions when full, deficit and supplemental irrigation strategies are applied. For the a global analysis the Deficit Irrigation Toolbox (DIT) is now adapted for a global analysis using ERA5 reanalysis data and large ensemble CESM scenarios for the global climate . It allows the analysis of the impact of information of (i) different scheduling methods (ii) different crop models, (iii) climate variability using recent and future climate scenarios. The results show a prove of concept which facilitates the development of an easy-to-use support tool for decisions about the value of management, climate and soil data and/or a cost benefit analysis of farm irrigation on a local scale.

How to cite: Schuetze, N.: Prove of concept of a global evaluation of the value of information for the management of deficit irrigation systems, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-14820, https://doi.org/10.5194/egusphere-egu21-14820, 2021.

Anatoly Zeyliger and Olga Ermolaeva

Until recently, new technologies introduced into irrigated agriculture were mainly aimed at developing one or several related control actions. However, the needs of society to increase the volume and improve the quality of agricultural products have led to significant qualitative changes in irrigated agriculture. The various robotic systems used for this have proven their effectiveness in the mechanization and automation of the irrigation process, as well as in the application of chemical fertilizers and chemical protection of agricultural crops from diseases and pests. This resulted in higher yields while lowering production costs.Nowadays, biotechnologies currently being developed and being introduced into irrigated agriculture, as well as systems for controlling and monitoring environmental impacts, are aimed at solving problems related to further increasing the efficiency of the use of natural resources, while minimizing the risks of negative impact on components and services of the environment.This is largely due to the impact of the rapid development of IC and sensor technologies aimed at creating production management systems based on the cyber-physical systems (CPS) paradigm. For this, there are using a holistic vision of the structure and cybernetic methods of management, artificial intelligence technologies, as well as digital platforms for integrating information flows between sub-subsystems of management, control, monitoring and decision support.In this context, the main difference between developed agricultural CPSs from the existing industrial agricultural systems focused on current economic efficiency lies in the plane of making agricultural production sustainable in the long term based on a balance between economic efficiency and the quality of natural resources used and services of the environment. From this point of view, irrigated agriculture focuses on the efficient use of natural resources, which are water, soil and air, as well as renewable and non-renewable (fossil) energy. At the same time, weather are considered as the impact of the external environment providing an irreplaceable source of water, heat and energy resources but with stochastic characteristics that are difficult to formalize. In connection with this diversity, a CPSs are built taking into account a complex compromise that takes into account many aspects of the negative impact of intensive agricultural production technologies on the qualitative and quantitative characteristics of these resources, not only in the place of their use, but also on the external environment beyond these limits. In this regard, water resources are one of the most important factors necessary, on the one hand, to impart long-term sustainability to irrigated agriculture, and on the one hand, as a factor that can lead in the near future to a significant decrease in fertility, as well as to a negative impact on the environmental services of the surrounding area. This contribution discusses some points of the development of an agricultural irrigation CPS’ subsystem aimed to monitor the soil moisture content at the root zone of the soil cover at the scale of irrigated agricultural crops and their relationship with industrial sprinkling technologies.Acknowledgments: The reported study was funded by RFBR, project number 19-29-05261 mk

How to cite: Zeyliger, A. and Ermolaeva, O.: Cyber Physical direction of irrigated agriculture development , EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-7265, https://doi.org/10.5194/egusphere-egu21-7265, 2021.

Giuseppe Provenzano and Daniel Alberto Segovia-Cardozo

For annual cropping systems sensitive to water stress, such as citrus, efficient water management can allow facing their large water consumption and enhancing crop sustainability. However, to apply water-saving strategies it is necessary to monitoring soil and/or plant water status. In the last decade, a wide number of sensors providing indirect measurements of volumetric soil water content based on soil physical properties, such as dielectric permittivity or matric potential, have been developed. Among the sensors using the frequency domain reflectometry technique, the “drill and drop” (Sentek, Inc., Stepney, Australia) multi-sensor probes allow continuous acquisition of soil moisture dynamic every 10 cm starting from the soil surface; these data hide important information on root water uptake and actual crop evapotranspiration.

The objective of the paper was to analyze the temporal dynamics of soil water content profiles detected with multi-sensor probes during three years of field observations (July 2017- August 2020) in a citrus orchard, to estimate root water uptake and crop transpiration by three methodologies. Simultaneous measurements of sap fluxes and climate variables also allowed estimating the basal crop coefficient, Kcb, often considered for estimating crop water requirement.

The experiments were carried out in a 30 years-old citrus orchard (C. reticulata Blanco cv. Tardivo di Ciaculli) with trees spaced 5.0x5.0 m. The field is irrigated with a subsurface drip system installed in 2018, with two lateral pipes per plant row at 30 depth and distance of 1.1 m from the trunk. Integrated sensing methodologies supported by the Internet of Things and cloud computing technologies (Agrinet/Tuctronics, Walla Walla, WA, USA), linked with a suitable communication infrastructure, were used to acquire continuously, in real-time and from remote soil water contents and climate variables. Four soil moisture profiles corresponding to as many plants were monitored with 120 cm long drill and drop sensors installed at a distance of 30 cm from one emitter. A standard weather station (Spectrum Technologies, Inc) was also installed to acquire, once every half hour, wind speed and direction at 2 m height, solar radiation, air temperature, relative air humidity and precipitation. In both years, sap fluxes were also measured hourly on two citrus trees, by using two Granier’s thermal dissipation probes (TDP) per tree. Each hour, the difference of temperature between the upper heated and lower un-heated needles, combined with the temperature difference at night allowed to estimate the sap velocity and then the hourly sap fluxes.

The analysis evidenced the characteristic declines of soil water content after rainfall events, from which it was possible verifying that the hourly dynamic of root water uptake followed that of the corresponding sap flow sensors. Moreover, the knowledge of daily root water uptake, associated with the simultaneous values of reference evapotranspiration allowed obtaining suitable estimations of the basal crop coefficient. The proposed approach provided interesting insights into the dynamic of root water uptake of citrus trees and can represent a promising tool for precise irrigation scheduling.

How to cite: Provenzano, G. and Segovia-Cardozo, D. A.: Detecting crop water requirements indicators in irrigated agro-ecosystems from soil water content profiles: an application for a citrus orchard, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9172, https://doi.org/10.5194/egusphere-egu21-9172, 2021.

María R. Conesa et al.

In a low water availability scenario, as is increasingly frequent in Mediterranean areas threatened by climate change and endemic water scarcity, to achieve the best irrigation water efficiency is of vital importance. This study aimed to assess the feasibility of an automated irrigation scheduling strategy based on real-time threshold volumetric soil water content values (VSWC), monitored with capacitance probes, in adult early-maturing nectarine orchard (Prunus persica (L.) Batsch cv. `Flariba’, on GxN-15 rootstock). Two drip irrigation practices were tested: one control treatment (T-0) based on conventional crop evapotranspiration calculations (ETc, FAO-56), and one automated treatment (T-A) based on management allowed depletion (MAD) threshold values, derived from VSWC data, with a feed-back control system. Furthermore, for both treatments agro-physiological responses were evaluated under two different water availability scenarios (each one comprised of three consecutive growing seasons): no water restrictions (high water availability), and deficit irrigation (low water availability), in which reduced water to irrigate nectarine trees involved regulated deficit irrigation criteria.  In the high water availability scenario, T-A (MAD = 10%) and T-0 (ETc = 100%) irrigation treatments showed no significant differences in the plant-soil water status, vegetative growth, yield, and nectarine fruit quality parameters. The VSWC was not a limiting factor and full irrigating to achieve a maximum yield was a profitable option. In the low water availability scenario, the T-A treatment (subjected to MAD = 10% during pre-harvest and 30% during post-harvest) received 43% less water than the control, which promoted moderate plant and soil water deficits, leading to a decrease in vegetative growth (winter pruning weight and tree canopy cover), without compromising the total yield and nectarine fruit quality parameters (including an increase in the total soluble solid content). The crop water use efficiency increased by an average of 34%. The proposed automated irrigation strategy, based on MAD seasonal threshold values, combined with regulated deficit irrigation phenological criteria could be considered a promising tool that could be eventually extrapolated to other stone fruit orchards under water scarcity conditions. Acknowledgements: This work was funded by Spanish Agencia Estatal de Investigación (PID2019-106226RB-C21/AEI/10.13039/501100011033) and Fundacion Séneca, Región de Murcia (19903/GERM/15) projects.

How to cite: Conesa, M. R., Conejero, W., Vera, J., and Ruiz-Sánchez, M. C.: Automated soil water content-based irrigation under high and low water availability scenarios for a nectarine orchard, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-11033, https://doi.org/10.5194/egusphere-egu21-11033, 2021.

Fatma Hamouda et al.

In this work, we propose to transfer a soil moisture-based wireless sensor network (SM-WSN) to support the reduction of irrigation water consume in the Tuscany region (Italy). The SM-WSN was designed and validated in a commercial pear orchard during two growing seasons (2019-2020) in which the smart irrigation strategy was implemented and applied.

Initially, the micro irrigation system was assessed based on its performance in terms of water distribution uniformity (DU) evaluated with field measurements of emitter flow rates. Then, a zoning analysis was carried out to divide the orchard into homogeneous areas according to the normalized difference vegetation index (NDVI) detected with unmanned aerial vehicle (UAV) and GIS tools. These areas were used to define the topology of the SM-WSN and to investigate how water distribution uniformity can affect the vigour of the trees. A total of 6 “drill & drop” capacitance probes (Sentek Pty Ltd, Stepney, Australia) were installed in the field, after following a simplified laboratory calibration procedure. The hardware and the smartphone-based application, AgriNET, used to download from remote the sensors’ readings were provided by Tuctronics (Walla Walla, Washington, USA).

Assuming that the zoning outcome was only associated with the soil spatial variability, the effect of DU on the vigour of the trees has been identified. Moreover, unlike the ordinary irrigation scheduling applied in the farm, the smart system allowed maintaining the soil water content within a pre-defined optimal range, in which the upper and lower limits corresponded respectively to the soil field capacity and the threshold below which water stress occurs. Based on the smart irrigation management, a water-saving up to 50% of the total water supplied with ordinary scheduling was achieved during both the investigated growing seasons. Moreover, the quality of the productions (i.e °Brix, fruit size and firmness) were in line with the standard required by the farmer. The adoption of the new technology, aiming at identifying the most appropriate irrigation management, has the potential to generate positive economic returns and to reduce the environmental impacts.

How to cite: Hamouda, F., Puig Sirera, À., Giusti, S., Sbrana, A., Tuker, J., Bonzi, L., Iacona, M., Massai, R., and Rallo, G.: Design and validation of a soil moisture-based wireless sensors network for the smart irrigation of a pear orchard, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-11894, https://doi.org/10.5194/egusphere-egu21-11894, 2021.

Sandra María Martínez-Pedreño et al.

In water scarcity areas, it is necessary not only reducing the water applied as much as possible, but also optimizing nutrients application to avoid soil salinization and aquifers pollution because of leaching bellow the root zone. Increasing the sustainability of fertirrigation needs technology to adjust the irrigation time, knowing more precisely the soil water retention capacity and facilitate water absorption by the crop. The aim of this trial was to establish protocols for sustainable fertirrigation in melon crop under semi-arid conditions, both at an environmental and economic level, based on the use of soil water status indicators measured by sensors that allow us to increase the irrigation water use efficiency. Two irrigation treatments were established: i) Control (CTL), irrigated to satisfy the water requirements of the crop, according to the farmer's criterion throughout the crop cycle and ii) DI, deficit irrigation, irrigated to allow a maximum soil water depletion of 20%, with respect to field capacity throughout the crop cycle, from sensors located below the 20 cm depth horizon, in order to limit water leaching into the soil. An experimental design was established with 4 repetitions per treatment distributed at random, with 5 plants per repetition. Macro and micronutrients concentration of soil solution, leaves and fruits were analysed. The crop water status was determined fortnightly by measurements taken at solar midday of stem water potential, net photosynthesis, evapotranspiration rate and leaf conductance. Whereas photosynthetically active radiation absorption, basal stem and fruit equatorial diameters were determined to estimate plant and fruit growth. The physical (longitudinal and equatorial fruit diameters, fruit weight, pulp width and firmness) and chemical (titratable acidity, pH and total soluble solid of the juice, total phenolic content, total antioxidant capacity and total ascorbic acid) characteristics of harvested fruits were determined. Total water applied in CTL treatment was 3,254 m3 ha-1 throughout the crop cycle whereas DI received 2,284 m3 ha-1, a 29.8% lower. In both cases, the volume of water applied was lower than recommended by FAO. The regulation of the irrigation time in the DI treatment respect to the CTL promoted a reduction of the soil water content from 30 cm depth, mitigating the water loss below the root system, along with a lower contribution of nutrients, around of 43, 41.8 and 22% of N, P and K, respectively, and less salinization of the soil profile. No significant difference between treatments was detected in the concentration of these nutrients at leaf level. No difference was observed at harvest, with 0.53 and 0.59 g fruit g-1 total dry mass of harvest index in CTL and DI, respectively. Fruit quality was not negatively affected in DI but improved since ascorbic acid was higher. This means that DI treatment not only did not negatively affect the crop water status and the amount and quality of the yield, but also improved its biochemical quality while reducing water and nutrients use and leaching.

How to cite: Martínez-Pedreño, S. M., Berríos, P., Temnani, A., Zapata, S., Forcén, M., Lopez, J. A., Pavón, N., and Pérez-Pastor, A.: Optimisation of fertigation scheduling based on indicators of soil water status in melon growing in semi-arid areas, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-15032, https://doi.org/10.5194/egusphere-egu21-15032, 2021.

Ana Belén Mira-García et al.

Lime tree growing area is increasing in Mediterranean temperate regions. In these areas, climate change scenario is expected to raise air temperature and water shortages. Such scenario requires new approaches to implement a precision irrigation in agriculture. In order to use water more efficiently, it becomes necessary to accurately determining the crop water needs, which are estimated by crop evapotranspiration computations (ETc). In this study the ETc of young lime trees grown under Mediterranean conditions were determined using the soil water balance method. For this purpose, two-year old lime trees (Citrus latifolia Tan., cv. Bearss) grafted on C. macrophylla rootstock were cultivated in pot-lysimeters, equipped with capacitance and granular matric sensors for real-time monitoring of the soil water status. Irrigation, drainage, and pot weight were also monitored continuously. All measurements were integrated into a telemetry platform. Agro-meteorological variables, plant water status (stem (Ψstem) and leaf (Ψleaf) water potentials), and leaf gas exchange parameters (stomatal conductance (gs) and net photosynthesis (Pn)) were measured. Along the experiment, an automated irrigation protocol based on volumetric soil water content (θv) threshold values were programmed, guaranteeing an adequate lime tree water status. Irrigation dose was calculated based on a feed-back strategy maintaining θv within 30% management allowed depletion.

During the experimental period, the lime trees were well irrigated as revealed midday Ψstem values that were maintained above -0.8 MPa. Also, the mean seasonal values of ≈ 7 µmol m−2 s−1 and 80 mmol m−2 s−1, for Pn and gs, respectively, indicated optimal gas exchange values. The computed water balance parameters yielded values for the crop evapotranspiration from 0.25to 2.56 mm day-1, in winter and summer months, respectively, with maximum values in July when evaporative demand conditions were the highest. This soil water balance was daily validated by the pot weight balance through the year.

In conclusion, the automated irrigation of young potted lime trees, using soil water content as a control system variable, has ensured an adequate lime tree water status. A simple, robust weighing/drainage lysimeter, with real-time monitoring of the soil water balance parameters, has been proved practical and economical tool for crop evapotranspiration measurements.

Acknowledgments: This work was funded by Spanish Agencia Estatal de Investigación (PID2019-106226RB-C2-1/AEI/10.13039/501100011033) and Fundación Séneca, Región de Murcia (19903/GERM/15) projects.

How to cite: Mira-García, A. B., Vera, J., Conejero, W., Conesa, M. R., and Ruiz-Sánchez, M. C.: Young lime tree evapotranspiration measurements in lysimeters with automated irrigation, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-11027, https://doi.org/10.5194/egusphere-egu21-11027, 2021.

Giacomo Ferrarese et al.

Irrigated agriculture is currently one of the most water-consuming human activities at global level. Furthermore, in the next years, water demand for irrigation is expected to increase within a challenging framework characterized by the effects of climate change and dynamics such as the population increase. In this context and considering that up to now irrigation networks have experienced a limited access to innovation (such as e.g., several areas of the Mediterranean region, above all in the North African side), the opportunities offered by digitalization could be crucial in the next future. New technologies and IoT solutions can effectively improve the management of limited resources and the quality of service to users. In the present work, the advances in management of the irrigation networks that can be reached using a smart control valve, the GreenValveSystem (GVS), are discussed. The GVS is an innovative electro actuated control valve able to harvest part of the energy of the flow to enable high frequency monitoring of pressures and flow rate and real time operation on the valve, without the necessity of external power supply. It has been, up to now, positively tested and adopted in drinking water supply systems. A model of an on-demand pressurized irrigation network is used to provide, through hydraulic simulations, a proof-of-concept of the potential of such devices to support the selection and implementation of specific management strategies to limit (or even avoid) the occurrence of hydrant failures (i.e. an insufficient pressure or discharge ), and to guarantee an effective and sustainable use of water resources. In the study a procedure to find the best placement of the GVSs and some basilar management rules that limit failures is showed. This preliminary study demonstrates some of the improvement that the use of innovative devices based on IoT concepts, like cloud management of data and remote operations, can bring to water agencies and users.

How to cite: Ferrarese, G., Pagano, A., Malavasi, S., and Fratino, U.: New management perspectives in pressurized on-demand irrigation systems using innovative smart control valves, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-7560, https://doi.org/10.5194/egusphere-egu21-7560, 2021.

Meet the authors in their breakout text chats

Thu, 29 Apr, 11:00–11:45

Chairpersons: Giuseppe Provenzano, Alejandro Pérez-Pastor, Daniele Masseroni

Giuseppe Provenzano and Matteo Ippolito

Crop evapotranspiration (ET) plays a key role in many hydrological processes involving the soil-plant-atmosphere system. The concept of reference crop evapotranspiration (ET0) was introduced to estimate the atmosphere evaporation demand independently of crop type, development stage and management practices. Among the available methods to estimate ET0, the Penman-Monteith equation proposed by the Food and Agriculture Organization of the United Nations (FAO56-PM), is considered one of the most accurate, so that it is assumed as a reference to calibrate other simplified procedures. In several regions of the world, the limited availability of meteorological observations to estimate ET0 can be overcome by using gridded reanalysis dataset created by data assimilation of weather observations. Different datasets with relatively high spatial resolution but different in terms of Spatio-temporal resolution have been generated and are freely downloadable at the global scale. The latest ERA5-Land product released in 2019 is characterized by a spatial grid to 0.1° latitude and 0.1° longitude. The database provides several land variables at hourly time-step including, among others, air temperature, dew point temperature and solar radiation at 2.0 m above the soil surface, as well as the wind speed components at 10 m height.

The objective of the research was to assess the suitability of ERA5-Land dataset of climate data to predict daily reference evapotranspiration in Sicily, Italy. For the period 2006-2015, the performance of the reanalysis data to capture the local climate variables was assessed based on the comparison with the corresponding ground data measured by a network of 39 climate stations in Sicily belonging to the Agrometeorological Information Service (SIAS). After evaluating the statistical errors associated with each climatic variables retrieved from the ERA5-Land, the comparison between daily ET0 values obtained with the FAO56-PM and considering both the dataset was carried out.

The analysis showed that air temperature, solar radiation and wind speed retrieved by the ERA-5 dataset resulted in quite good agreement with the corresponding measured on the ground, with an average root mean square error (RMSE) equal respectively to 1.8°C, 2.9 MJm-2d-1, and 1.3 ms-1 and corresponding mean bias errors (MBE) of -0.4°C, 1.0 MJm-2d-1  and -0.1 ms-1. On the other hand, relative air humidity was characterized by average values of RMSE and MBE respectively equal to 10.3% and 5.6%. When considering all the examined climate stations, the RMSE and MBE values associated with ET0 ranged from 0.4 to 1.3 mm d-1, and -1.0 and 0.0 mm d-1, supporting the possibility to consider the ERA-5 data to obtain suitable estimations of crop reference evapotranspiration even for other Mediterranean countries where measured climate data are not available.

How to cite: Provenzano, G. and Ippolito, M.: Using the ERA5 dataset of atmospheric variables to estimate daily reference evapotranspiration in Sicily, Italy., EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-4151, https://doi.org/10.5194/egusphere-egu21-4151, 2021.

Marta Rodríguez-Fernández et al.

The estimation of the water status in the vineyard, is a very important factor, in which every day the winegrowers show more interest since it directly affects the quality and production in the vineyards. The situation generated by COVID-19 in viticulture, adds importance to tools that provide information of the hydric status of vineyard plants in a telematic way.

In the present study, the stem water potential in the 2018 and 2019 seasons, is analysed in a vineyard belonging to the Rias Baixas wine-growing area (Vilagarcia de Arousa, Spain), with 32 sampling points distributed throughout the plot, which allows the contrast and validation with the remote sensing methodology to estimate the water status of the vineyard using satellite images.

The satellite images have been downloaded from the Sentinel-2 satellite, on the closets available dates regarding the stem water potential measurements, carried out in the months of June to September, because this dates are considered the months in which vine plants have higher water requirements.

With satellite images, two spectral index related to the detection of water stress have been calculated: NDWI (Normalized Difference Water Index) and MSI (Moisture Stress Index). Stem water potential measurements, have allowed a linear regression with both index, to validate the use of these multispectral index to determine water stress in the vineyard.

Determination coefficients of r2=0.62 and 0.67, have been obtained in July and August 2018 and 0.54 in June of 2019 for the NDWI index, as well as values of 0.53 and 0.63 in July 2018 and June 2019 respectively, when it has been analysed the MSI index.

Between both seasons, the difference observed, that implies slightly greater water stress in 2019, is reflected in the climate conditions during the summer months, with an average accumulated rainfall that doesn’t exceed 46 mm of water. Although, the NDWI index has allowed to establish better relationships in the 2018 season respect to the MSI index and the 2019 season, (r2=0.60 NDWI in 2018), as well as greater differences in terms of water stress presented in the vineyard.

With the spectral index calculated, it has been possible to validate the use of these index for the determination of the water stress of the vineyard plants, as an efficient, fast and less expensive method, which allows the application of an efficient irrigation system in the vineyard.

How to cite: Rodríguez-Fernández, M., Fandiño, M., González, X. P., and Cancela, J. J.: Estimation water status of the vineyard by calculating multispectral index from satellite images, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-2187, https://doi.org/10.5194/egusphere-egu21-2187, 2021.

Luz Karime Atencia et al.

Olive is the main fruit tree in Spain representing 50% of the fruit trees surface, around 2,751,255 ha. Due to its adaptation to arid conditions and the scarcity of water, regulated deficit irrigation (RDI) strategy is normally applied in traditional olive orchards and recently to high density orchards. The application of RDI is one of the most important technique used in the olive hedgerow orchard. An investigation of the detection of water stress in nonhomogeneous olive tree canopies such as orchards using remote sensing imagery is presented.

In 2018 and 2019 seasons, data on stem water potential were collected to characterize tree water state in a hedgerow olive orchard cv. Arbequina located in Chozas de Canales (Toledo). Close to the measurement’s dates, remote sensing images with spectral and thermal sensors were acquired. Several vegetation indexes (VI) using both or one type of sensors were estimated from the areas selected that correspond to the olive crown avoiding the canopy shadows.

Nonparametric statistical tests between the VIs and the stem water potential were carried out to reveal the most significant correlation. The results will be discussing in the context of robustness and sensitivity between both data sets at different phenological olive state.


Financial support provided by the Spanish Research Agency co-financed with European Union FEDER funds (AEI/FEDER, UE, AGL2016-77282-C3-2R project) and Comunidad de Madrid through calls for grants for the completion of Industrial Doctorates, is greatly appreciated.

How to cite: Atencia, L. K., Gómez del Campo, M., Camacho, G., Hueso, A., and Tarquis, A. M.: Estimation of water stress in olive orchards through remote sensing data analysis, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9521, https://doi.org/10.5194/egusphere-egu21-9521, 2021.

Pablo Berríos et al.

Mandarin is one of the most important Citrus cultivated in Spain and the sustainability of the crop is subject to a constant pressure for water resources among the productive sectors and to a high climatic demand conditions and low rainfall (about 250 mm per year). The availability of irrigation water in the Murcia Region is generally close to 3,500 m3 per ha and year, so it is only possible to satisfy 50 - 60% of the late mandarin ETc, which requires about 5,500 m3 per ha. For this reason, it is necessary to provide tools to farmers in order to control the water applied in each phenological phase without promoting levels of severe water stress to the crop that negatively affect the sustainability of farms located in semi-arid conditions. Stem water potential (SWP) is a plant water status indicator very sensitive to water deficit, although its measurement is manual, discontinuous and on a small-scale.  In this way, indicators measured on a larger scale are necessary to achieve integrating the water status of the crop throughout the farm. Thus, the aim of this study was to determine the sensitivity to water deficit of different hyperspectral single bands (HSB) and their relationship with the midday SWP in mandarin trees submitted to severe water stress in different phenological phases. Four different irrigation treatments were assessed: i) a control (CTL), irrigated at 100% of the ETc throughout the growing season to satisfy plant water requirements and three water stress treatments that were irrigated at 60% of ETc throughout the season – corresponding to the real irrigation water availability – except  during: ii) the end of phase I and beginning of phase II (IS IIa), iii) the first half of phase II (IS IIb) and iv) phase III of fruit growth (IS III), which irrigation was withheld until values of -1.8 MPa of SWP or a water stress integral of 60 MPa day-1. When these threshold values were reached, the spectral reflectance values were measured between 350 and 2500 nm using a leaf level spectroradiometer to 20 mature and sunny leaves on 4 trees per treatment. Twenty-four HVI and HSB were calculated and a linear correlation was made between each of them with SWP, where the ρ940 and ρ1250 nm single bands reflectance presented r-Pearson values of -0.78** and -0.83***, respectively. Two linear regression curves fitting were made: SWP (MPa) = -11.05 ∙ ρ940 + 7.8014 (R2 =0.61) and SWP (MPa) = -13.043 ∙ ρ1250 + 8.9757 (R2 =0.69). These relationships were obtained with three different fruit diameters (35, 50 and 65 mm) and in a range between -0.7 and -1.6 MPa of SWP. Results obtained show the possibility of using these single bands in the detection of water stress in adult mandarin trees, and thus propose a sustainable and efficient irrigation scheduling by means of unmanned aerial vehicles equipped with sensors to carry out an automated control of the plant water status and with a suitable temporal and spatial scale to apply precision irrigation.

How to cite: Berríos, P., Temnani, A., Zapata, S., Forcén, M., Martínez-Pedreño, S., López, J. A., Pavón, N., and Pérez-Pastor, A.: Single hyperspectral bands are highly sensitive to water stress in adult mandarin trees, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-12594, https://doi.org/10.5194/egusphere-egu21-12594, 2021.

Pedro José Blaya-Ros et al.

Reduced water availability is the main limiting factor for crop production in semi-arid and arid regions. For this reason, irrigation water management needs to be based on reliable information and data that are rapidly and easily acquired. The aim of the present study was to assess the sensitivity and variability of several soil and plant water status indicators in response to two cycles of withholding and resuming irrigation in sweet cherry trees. The experiment was carried out during the summers of 2018 and 2019 in an experimental orchard of sweet cherry trees [Prunus avium (L.) ‘Lapins’] in SE Spain. Three irrigation treatments were studied: control, CTL, irrigated to ensure non-limiting soil water conditions (115% ETc) and two water stress treatments, medium water stress, MS, and severe water stress, SS. The threshold values of midday stem water potential (Ψstem) proposed to the first and second drought period for MS trees were -1.3 and -1.7 MPa and for SS trees were -1.6 and -2.5 MPa. After every irrigation withholding period, MS and SS trees were fully irrigated until reaching Ystem values of CTL trees. The experimental design was a completely randomized block design with three blocks per treatment. Soil and plant water status were assessed by measuring the soil volumetric water content (θv), the Ψstem, the daily trunk growth rate (TGR), the maximum daily trunk shrinkage (MDS), the temperature of the canopy (Tc), the difference between Tc and air temperature (ΔT) and the crop water stress index (CWSI). The signal intensity (SI), the coefficient of variation (CV) and the sensitivity (S = SI/CV) of θv, Ψstem, MDS and Tc were determined.

θv at 25 cm dropped significantly during the drought periods. Ψstem of MS and SS trees reached minimum values close to those thresholds proposed both years of study. MDS and TGR had a rapid response to the irrigation regimen applied. Tc, ΔT and CWSI increased as an effect of the stomatal closure. Ψstem and Tc were the water stress indicators with the highest sensitivity. MDS showed SI values greater than that of Ψstem and Tc, although it also had greater variability (CVMDS ≈ 29%). Ψstem showed high SI values and low CV both study years. When the linear relationships between Ψstem and the other plant water status indicators were calculated, it was observed that the Pearson correlation coefficients exceeded 0.75 in all cases, except for TGR. The relationship obtained between MDS and Ψstem was linear from −0.5 MPa to a threshold value of around −1.3 MPa, from that value onwards, Ψstem decreases were not related to MDS values. In contrast, ΔT and CWSI were always linearly related to Ψstem. These results suggest that: i) MDS could be used as a water stress indicator up to moderate water deficit; ii) Ψstem is a sensitive water stress indicator with low variability; and iii) the thermal indicators (Tc, ΔT and CWSI) can rapidly and easily assess sweet cherry tree water status.

This study was funded by the Spanish Economy and Competitiveness Ministry (AGL2013-49047-C2-1-R; AGL2016-77282-C33-R).

How to cite: Blaya-Ros, P. J., Blanco, V., Torres-Sánchez, R., and Domingo, R.: Sensitivity and variability of soil and plant water stress indicators in response to withholding and resuming irrigation cycles in sweet cherry trees , EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-16101, https://doi.org/10.5194/egusphere-egu21-16101, 2021.

Matteo Ippolito et al.

Estimation of evapotranspiration using the crop coefficient method is one of the most common approaches for irrigation water management. The crop coefficient, Kc, can be estimated as the ratio between maximum crop evapotranspiration, ETmax, and reference evapotranspiration, ET0. However, in the last few decades, many correction factors have been proposed to split Kc into separate coefficients to account for water stress conditions, as well as to estimate separately crop transpiration and soil evaporation. Furthermore, the remote sensing data collected from various satellite platforms have shown their full potential in mapping various vegetation indices (VI), which can be directly related to the spatio-temporal variability of Kc values. Despite various VI-Kc relationships have been proposed in the past years, only recently, thanks to the availability of new sensors with higher temporal and spatial resolutions, it is possible to retrieve new relationships able to follow the variability of the crop coefficient during the different crop phenological stages.

This study aimed at identifying a VI-Kc relationship suitable to map actual evapotranspiration of a citrus orchard based on an extended time-series of NDVI images retrieved by Sentinel-2 platform and combined with a set of field micro-meteorological measurements.

The experiments were carried out during 2019 and 2020 in a commercial citrus orchard (C. reticulata cv. Tardivo di Ciaculli) with tree spacing of 5 x 5 m, located near the city of Palermo, Italy, in which different irrigation systems and management strategies were applied in three different portions of the orchard. In particular, the first portion was irrigated with a traditional micro-sprinkler system (TI) whereas the other two with a subsurface drip system maintained under full irrigation (FI) and deficit irrigation (DI) applied during the phase II of fruit growth (from 1-July to 20-August). The orchard was equipped with a standard weather station (WS) and an Eddy Covariance (EC) tower to acquire, every half-an-hour, precipitation, air temperature and relative humidity, wind speed and direction, global and net solar radiation and, finally, sensible and latent heat fluxes. During the entire period, a weekly dataset of Sentinel-2 images characterized by a spatial resolution of 10 m was acquired and processed in a GIS environment to obtain the spatial and temporal distribution of NDVI. Using the data acquired in 2019, a functional relationship between Kc and NDVI was calibrated accounting only for those periods in which the crop was maintained in the absence of water stress. The values ​​of Kc were determined as the ratio between actual daily ET measured by the EC tower and reference Penman-Monteith ET0 obtained as indicated by the Food and Agriculture Organization of the United Nations. The procedure was then validated with the data recorded in 2020, by comparing estimated crop ET ​and the corresponding measured by the EC tower. The comparative analysis indicated root-mean-square-error and mean-bias-error associated with estimated ET of about 0.5 mm/d and 0.2 mm/d, respectively. Finally, based on the NDVI maps it was possible to derive the spatial variability of Kc and actual ET, under the different irrigation systems and management strategies.

How to cite: Ippolito, M., De Caro, D., Minacapilli, M., Ciraolo, G., and Provenzano, G.: Estimating Crop Coefficients using multitemporal Sentinel-2 remote sensing data to estimate actual evapotranspiration of a citrus orchard, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-4650, https://doi.org/10.5194/egusphere-egu21-4650, 2021.

Francisco Pedrero Salcedo et al.

A pioneering study in Murcia within the framework of the ASSIST (Use of Advanced information technologies for Site-Specific management of Irrigation and SaliniTy with degraded water) research project, seeks to lay the foundations for a new integrated system for the assessment of salinity through combined use of traditional techniques (soil and plant sampling) and new technologies (multispectral aerial videography or satellite observation; and image analysis) to help quantify and map soil salinization / degradation and the effects of soil-plant interactions (salinity-toxicity) on the growth and yield of irrigated crops. In this sense, the initial objective was to evaluate the salinity of the soil and the development of lettuces irrigated with unconventional water resources through thermal and multispectral images. Different soil and plant salinity indices were studied, observing that the temperature (on plant) and salinity index (SI) (on soil), had a moderate correlation with the soil salinity. Although the results obtained have been encouraging, more research is needed to develop specific equations capable to predic soil salinity from the values of these indices taken remotely. In this context, a review of the spectral salinity indices has been prepared to be applied at a regional scale. As an experimental area, El Campo de Cartagena located in the southeast of the Iberian Peninsula has been chosen, since there is intensive irrigated agriculture in a semi-arid environment. Due to this, farmers resort to using non-conventional and saline water sources, consequently the use of saline irrigation water is causing salinization of the soils and damage to the crops. Values from existing salinity records combined with soil salinity data obtained in various plots, provided information that was correlated with time series of Landsat images (1984-2020). Regression models were also applied in which environmental variables provided an improvement in the estimation of soil salinity. The results allowed us to determine the main salinity concentration areas, as well as inputs to establish criteria for improvement in the management of irrigation systems.

How to cite: Pedrero Salcedo, F., Alarcón Cabañero, J. J., and Pérez Cutillas, P.: Assessing soil salinity using remote sensing in Campo de Cartagena, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-14478, https://doi.org/10.5194/egusphere-egu21-14478, 2021.

Ceres Duarte Guedes Cabral de Almeida et al.

Several methodologies and techniques are available for irrigation management in protected environments. Despite the cultivation of vegetables in the greenhouse is largely present in the northeastern region of Brazil, not many research has been aimed at supporting growers for accurate irrigation management.

The objective of this study is to evaluate yield and irrigation water use efficiency of Capsicum crop cultivated in a greenhouse under different methods to define the daily irrigation depth, based on the soil water status and the atmospheric evaporative demand. Moreover, two different strategies to apply the estimated irrigation depths (single or double daily application) were also examined.

The experiment was carried out in a greenhouse in the Federal Rural University of Pernambuco (UFRPE), northeastern of Brazil (8° 01’ 07” S and 34° 56’ 53” W, altitude 6.50 m). Based on a completely randomized design, the experimental units were distributed according to a 4 x 2 factorial scheme with eight replications, with a total of 64 experimental units. Four methods to estimate daily irrigation water requirement were evaluated: two based on soil sensors (soil water content sensors EC-5, SWS, and tensiometers, TS), whereas the other two were based on the atmospheric evaporative demand (weighing lysimeter, WL, and Piché evaporimeter, PE). Moreover, the daily irrigation depths were applied with a single watering (at 8:00 am) or split into two applications (the half at 8:00 am and the half at 4:30 pm). The commercial yield of the examined crop was calculated through the relationship between the weight of fresh fruit and the area occupied by the plant.

The statistical analysis showed that the water use efficiency, the total water volume applied and the commercial yield of capsicum were significantly influenced by the method used to estimate crop water requirement, as well as the irrigation strategies. The total irrigation depth applied during the entire crop cycle resulted in equal to 509 mm, 678 mm, 716 mm, and 790 mm for treatments with WL, PE, SWS, and TS, respectively. The seasonal applied irrigation depths corresponded to an average daily crop water requirement ranging, according to the treatments, from 5.4 to 8.3 mm day-1; these values are consistent for the examined crop cultivated under protected conditions. The highest yields of commercial fruits were obtained in the treatments in which the highest irrigation depth (SWS and TS) was applied. On the other hand, the highest values of water use efficiency were obtained in those treatments in which the irrigation depth was defined based on SWS and WL. Splitting the estimated daily irrigation depth in two applications promoted greater commercial productivity and water use efficiency (10.73 t ha-1 and 1.60 kg m-3) compared to a single application (8.14 t ha-1 and 1.22 kg m-3), with an increase of both variables of about 31%. These results evidenced that splitting the daily irrigation depth is a promising strategy to increase water use efficiency for vegetable crops in protected environments.

How to cite: Almeida, C. D. G. C. D., Gordin, L. C., Almeida, A. C. D. S., Santos Júnior, J. A., Almeida, B. G. D., and Provenzano, G.: Assessing yield and water use efficiency of Capsicum annuum L. cultivated in a greenhouse under different irrigation strategies, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-8349, https://doi.org/10.5194/egusphere-egu21-8349, 2021.

Leonor Rodriguez-Sinobas et al.

This study presents a novel method for controlling and monitoring irrigation of urban green areas based on Geographical Information Systems (GIS). The proposed procedure was applied to the Spanish Valdebebas Urban Development, located in Madrid, which comprises 18 ha occupied by urban parks irrigated by subsurface drip irrigation fully automated. Its irrigation network conveys water to 67 different irrigation units, irrigating very heterogeneous plants typology. The GIS model considered the smallest irrigation unit, as the pixel size and it was fed with the information on: discharging flow, irrigated area and irrigation times of each irrigation unit. The study was performed with data from the three irrigation seasons from 2017 to 2019. Likewise, daily information from the weather station located at the urban development, used for the irrigation network operation, was also incorporated into the GIS. The results showed the spatial and temporal variability of the garden coefficients (and water needs) and the water use efficiency. The study also estimate the evolution of irrigation rates and water use efficiency indices under three different climate change forecasting scenarios (namely Representative Concentration Pathways– RCP–45, RCP 6 and RCP85). This method can assist technicians and irrigation managers to make better decisions on operating the parks’ irrigation network.

How to cite: Rodriguez-Sinobas, L., Canales-Ide, F., and Zubelzu, S.: Mapping irrigation efficiency in large urban green areas, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-11074, https://doi.org/10.5194/egusphere-egu21-11074, 2021.

Daniele Masseroni et al.

Selecting the best irrigation management is required for improved use of water resources and for achieving sustainable crop productions. That selection implies accurate predictions of crop water requirement in response to meteorological variables and phenological stages. A plethora of irrigation models are reported to date in literature, many of which are based on three different approaches proposed by the FAO organization, the single and double crop coefficient methods and, the canopy-cover curve determination included in the AquaCrop model.

The objective of this study is to compare irrigation needs and scheduling obtained by the three aforementioned approaches in the agricultural context of the Po River Plain (northern Italy). The first and the second approaches were simulated respectively by Sim1Kc and IdrAgra models, which implemented the algorithms and crop parameterizations reported in FAO paper 56 for a crop water requirement estimation. While the third approach was simulated by the open source version of AquaCrop software.

Models were tested on a maize plot located in the lower-east part of Lombardy Po River Plain characterized by a humid sub-tropical climate, according Köppen classification. A single sandy-loam layer profile of medium-textured soil 1 m deep was considered for the simulation. Crop parameters values in Sim1Kc and AcquaCrop models were mutuated from the IdrAgra model, which is routinely applied in the region as the reference model for the assessment of crop water requirements.

Actual evapotranspiration and irrigation needs were evaluated respectively in rainfed and irrigated simulations. These latter were performed replacing soil moisture at the field capacity when 70% of TAW was reached. Results achieved in three agrarian seasons characterized by low, medium and high rainfall volumes (from June to September) were compared (respectively the years 2009, 2002 and 2014 with about 41 mm, 116 mm and 152 mm of rainfall).

The results show that in rainfed conditions, for each year, actual evapotranspiration simulated by the models were consistent with each other, with an average RMSE, calculated comparing the models in pairs, of about 1 mm over the season. Differences among the models were mainly observed in the first part of the season (respectively before the thirtieth day after the sowing) and for each year, probably caused by a still limited crop and root development, which highlights the differences in simulating water fluxes exchanges in soil-vegetation domain proposed by three modeling approaches.

Concerning irrigations, IdrAgra and AquaCrop appear very consistent with each other in volumes and frequency, especially during mid-crop stages and in all years with a total irrigation volume of about 400, 300 and 180 mm and with 10, 12 and 8 irrigation interventions respectively in the years 2009, 2002 and 2014. Results of Sim1Kc were consistent with those obtained by the other models only in mid and end crop season, whereas no irrigations were suggested in the first part of the season.

How to cite: Masseroni, D., Gangi, F., Castagna, A., and Gandolfi, C.: Comparing different FAO approaches for assessing irrigation needs and scheduling: application on a maize field in Mediterranean area, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-10992, https://doi.org/10.5194/egusphere-egu21-10992, 2021.

José Roldán-Cañas et al.

Abstract: The development of the wet bulb under drip irrigation in stratified (sand covered soils) presents a different behavior from that observed under homogeneous soils. The presence of a very active crop as it happens in intensive greenhouses also imposes a series of variations that have not been fully characterized. The aim of this work is to present the data acquisition methodology to calibrate and validate the Hydrus-3D model to safely define the evolution of moisture in wet bulbs generated in stratified “sanded” soils characteristic of greenhouses with tomato and pepper crops grown intensively under drip irrigation.

The procedure for collecting and processing moisture data in stratified soils has been defined. The soil and permeability curve has been adjusted experimentally for each material. It has been proved that the Hydrus-3D model can reproduce the behavior of a sand covered soils and it has been possible to verify that the predictions are adequate to what has been observed in the field.

How to cite: Roldán-Cañas, J., Zapata-Sierra, A. J., Reyes-Requena, R., and Moreno-Pérez, M. F.: Application of the Hydrus 3D model to determine the wet bulb in drip-irrigated soils of intensive greenhouses, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-14512, https://doi.org/10.5194/egusphere-egu21-14512, 2021.

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