I. Introduction

Agriculture is a decisive and strategic sector for the Cuban economy. The rational and efficient use of water and energy carriers in this branch is one of the most important items in the country’s politics. Generally, in this sector, high consumption is generated due to excessive irrigation. Therefore, the correct operation of these systems allows a quality production and the saving of considerable volumes of this important natural resource (Jimenez, 2011).

Cuba has experienced increasingly prolonged periods of drought in recent years. There is a tendency of extensive droughts, as a result of climate change (González, 2016; Vázquez & Solano, 2013). Currently, although irrigation systems are implemented in several types of crops, exceptional attention is required to the cultivation of sugarcane, due to the high volumes of water it uses. Agricultural irrigation systems, which are generally used, are manually controlled, which causes, in many cases, the waste of water and electricity (Carranza, 2016).

Despite the efforts made, the control of irrigation systems in Cuba is not automated. Irrigation programming in many places remains empirical, and there are low irrigation efficiency rates reported. Hence, it is intended to increase the surfaces under irrigation, including the assembly of new electric center pivot machines, which are characterized by their high efficiency (Clavelo, & Seguí, 2012). Therefore, important investment programs have been developed for the manufacture and acquisition of modern equipment that integrates the new technologies of automation, control, and communications, with the aim of developing a sustainable and productive agriculture (Jimenez, 2011).

In this context, the current study aims to propose a control solution through a programmable automaton and remote supervision using wireless technology for the automated operation of center pivot irrigation machines.

As a contribution of the current research, thanks to the remote supervision of the operation of this type of irrigation machine, it is possible to control it remotely, as well as carry out operations to control its execution, such as the programming of the irrigation time, the direction of rotation, and the hours of work. It responds to the challenge imposed by the context of an agricultural application, proposing a communication solution based on wireless transmission. The architecture of the system and the control proposal have the necessary flexibility that the system can be applied in correspondence with the specific communication possibilities of the place where its implementation is decided, as well as the user needs. At the same time, the remote supervision of the irrigation machine operation allows managers to know, in real time, the status of their functioning, alarms, reports, and historical irrigation schemes, which represents the information availability of the variables necessary for decision making. It can also be generalized to a set of irrigation machines. All the above impacts from the economic, social and environmental perspectives, by making more efficient use of water resources, making better use of energy carriers, improving production levels and reducing the costs of agricultural production.

The research applies the hypothetical-deductive method, when developing the research hypothesis based on the results derived from the bibliographic review, the theoretical framework preparation, and the problem approach. It also uses the systemic method, by relating several problems to obtain a broader issue and consequently propose the respective solutions; and the experimental method, when performing the experimental tests to check and evaluate the performance of the system as a whole.

II. Development

Irrigation can be defined as the science of the artificial application of water to land or soil (USDA, 1991; Pasha & Yogesha, 2014), its main objective is to supply the necessary moisture to the crop. It can be done to help growth of agricultural plantations or for the maintenance of landscapes or soil vegetation in dry areas and during periods of low rainfall. Irrigation has some other uses in crop production, which include: protecting plants against frost, suppressing weeds, and preventing soil consolidation (Kumar, Pramod, & Sravani, 2013). Regardless the irrigation method used, the purpose of irrigation is to periodically replenish the storage of soil moisture in the root zone of the plant (Camargo, 2013).

Irrigation methods and techniques are responsible for driving and applying water for irrigation, from the supply source and the conduction network, in order to achieve the necessary soil moisture status. Therefore, it is essential that they meet the irrigation regime defined for crops that benefit, guarantee adequate labor productivity and encourage the mechanization and automation of the irrigation process (Kumar et al., 2013).

Basically, there are three irrigation methods used: surface irrigation, sprinkler irrigation and localized irrigation (Santos, De Juan, Picornell, & Tarjuelo, 2010). This study focuses specifically on sprinkler irrigation using center pivot irrigation machines, which are characterized by their high efficiency.

A. Center Pivot Irrigation Machines

The center pivot irrigation machines (Figure 1) use sprinkler irrigation technologies and guarantee irrigation efficiency of 80% (Rodríguez & López, 2014; Rodríguez & Puig, 2012). They consist of a tower center and a varied number of structural sections with their corresponding mobile towers. The machine irrigates in a circular way, in the process, the diffuser nozzles are selected appropriately for each section in question (Tarjuelo, 2005). As the flow rate of the pivot is constant, the water applied per unit area is smaller at higher rotational speed of the machine. Therefore, the amount of water to be applied is controlled according to the speed of the machine (Pérez, 2010).

Figure 1
Center pivot irrigation machine

Its advantages include: it is possible to apply frequent (daily) irrigations, which contributes to a better water and nutrients management. It allows fertilizers to be applied, in a process known as ferti-irrigation, which reduces the use of other external machineries. It is a system that works at low pressure; therefore, the energy expenditure is lower; and it is possible to modify rainfall, which allows the system to adapt to different types of soil and crops.

However, these machines also have some disadvantages such as: the high initial cost; the demand of qualified operators to obtain an efficient use of water. On the other hand, since it is a circular irrigation system, the land must be prepared in an appropriate way or irrigation surface can be lost in the corners (Pérez, 2010).

Currently, the standard irrigation machines have an elementary level of automation, very typical of their work functions, to be controlled by an operator; they have a control panel, from where their fundamental functions are governed, including starting and stopping the machine, selecting the operating mode (manual-automatic), and selecting the direction of rotation and speed of rotation (Figure 2). In automatic mode, the condition of not allowing the machine to work is conceived if the pumping station is not supplying water, which prevents it from turning dry. It also establishes that, in the case that the machine stops rotating, the pumping of water must be stopped, thus guaranteeing not to irrigate on the same point. The operating time is controlled by the percentage relay, which conforms the desired irrigation standard. There are other basic automations such as: adjusting the pressure switch for a specific pressure range and measuring the voltage, as well as protecting the limits of permissible supply voltages (Tarjuelo, 2005; Pérez, 2010).

Figure 2
Central pivot irrigation machine: Example of control panel

Modern irrigation techniques using pivots make it possible to include tools for the collection, analysis, and transmission of data in real time, with the aim of facilitating decision-making to develop precision agriculture (Capraro, Tosetti, & Vita-Serman, 2014; Kranz, Evans, Lamm, O’Shaughnessy, & Peters, 2010). In this context, the center pivot machines stand out, which have a high degree of automation, generated by the technological advances reached recently in the agricultural sector.

There are several companies in the world that produce this type of technology. Its products include systems that control the total operation of the equipment from a panel center or through remote access. These companies have developed electronic sensors, controllers, and communication protocols to meet irrigation requirements. Such is the case of the firms “IRRIMEC”, “Cuñat Agrocaja” and “Valley Irrigation” (Reductores CUÑAT S.A., 2017; Reinke Irrigation, 2017; Valley Irrigation, 2017). However, these technologies have a high cost. In Cuba, several of these machines have been imported, many of them destined for the sugarcane cultivation. In addition, they occur at the national level, with the aim of reducing imports and investment costs. Therefore, the issue of implementing the operation and remote monitoring in the pivot machines constitutes a strategy to follow in the agricultural sector, in order to obtain important advantages from the economic, environmental, and energy points of view.

B. Wiireless Technology in Irrigation Systems

Specifically, in center pivot irrigation machines, the selection of communication technology for remote operation and control is an important aspect to consider, since it guarantees better exploitation and machine supervision.

In the agricultural context, wireless communications play an increasingly important role, since they allow information transmission services over long distances, which are impossible to implement using cables (Kranz et al., 2010; Smith, Baillie, McCarthy, Raine, & Baillie, 2011). This is influenced by local and regional topography as well as the cost of the technology to be used, with the aim to guarantee the reliability of the supervision system (Pfitscher et al., 2011).

The sensor networks based on radiofrequency communication (RF, VHF, UHF) are among the different wireless transmission routes that are applied in agriculture. The VHF bands [Very High Frequency] and UHF [Ultra High Frequency] constitute a technology that offers higher data transmission speeds than most conventional radio modems, and also provides greater flexibility in terms of monitoring and control of radio frequency irrigation systems, which are located at great distances from the control points. Other methods of wireless transmission are: WiFi networks, Bluetooth, and GSM mobile networks [Global System for Mobile Communications] and GPRS [General Packet Radio Service]. These types of mobile telecommunications enable the transfer of large volumes of data at high speeds. Communication systems based on mobile telephony allow the operator to consult the main control panel or the base computer from any location and at any time (Chávez, Pierce, Elliott, & Evans, 2010; Dong, Vuran, & Irmak, 2013; Pavithra & Srinath, 2014).

C. Supervision and Control of Irrigation Systems

In recent years, the use of SCADA control and supervision systems (Supervisory Control and Data Acquisition) has increased in process automation (Gurban & Andreescu, 2011), in almost all types of industries where the monitoring and control of the variables associated to the process is required; mainly, when the decision making can be carried out remotely and in real time.

Regarding agricultural irrigation systems, the use of SCADA systems represents a global trend, due to its implementation, it is possible to control and supervise the irrigation system at a distance. In this way, the farmer can have full access to the process by viewing it on a computer screen, telephone or tablet. Therefore, he can obtain the information of the process and the state of the crop variables in real time. It also allows to store information in historical records, handle alarms and events, generate periodic reports and manage databases for information processing and decision making (Navarro, Martinez, Domingo, Soto, & Torres, 2016).

Another of its utilities is that the supervisor system can easily be integrated with other systems based on interactive platforms and web pages, through access to the history of the alarms in such a way that, if any system failure occurs, either electrical or communication, the supervisor can quickly stop the process and avoid major problems (Alghazali, Alkhaddar, & Hadi, 2013).

Generally, stock control and data acquisition irrigation system can be performed by programmable logic controllers or other control devices associated with the SCADA (Joshi, Bhujbal, & Kurkute, 2016).

In the literature, numerous publications are reported where programmable automatons are used for irrigation control. This technology is characterized by its high reliability and robustness, and accessibility to wired or wireless industrial communication (Maheshwari & Sindha, 2014).

The Schneider Electric company is one of these devices manufacturers, which produces and markets a whole range of automata for different control applications. The TM241CE40R automaton firm Schneider Electric is one of the hardware devices that have the features and functionality in its design to control center pivot irrigation machines (Schneider Electric, 2017). Therefore, this device is used in a suitable configuration of I / O to implement the proposed solution (Avello, Izaguirre, Martínez, & Hernández, 2017).

III. Results and Discussion

Taking into account the availability of an integrated Ethernet port, which offers FTP services and a Web Server, in the TM241CE40R PLC, we propose the design (using the own device programming software) of a web display in HTML5 format, which guarantees the supervision and remote operation of the irrigation machine in real time. This type of web page format allows the easy integration of control systems with the machines remote supervision. The above through applications for smartphones, tablets and computers, an important feature in the context of agricultural applications.

A. Control and Supervision Solution

As a first step, it is proposed to implement the solution for remote control and supervision whose general architecture is shown in Figure 3. Given the difficulties of communication through wired systems in the context of agricultural applications, a wireless transmission solution is proposed economically feasible, taking advantage of the possibilities offered by the programmable automaton selected to operate as a Web server, and the availability of hardware and software resources that are used.

Figure 3.
Proposal of remote control and supervision applied to a central pivot irrigation machine

The programmable automaton will be located as a local station, physically close to the control panel of the irrigation machine. It is also programmed to control the irrigation functions. The inputs and outputs are properly configured and connected to the control and drive devices, arranged in the control panel of the machine, which does not undergo substantial modifications with respect to its original design.

In the internal memory of the automaton can be stored the historical results of important variables related to irrigation, such as, for example: irrigation hours, machine speed, irrigation frequency, number of turns made by the machine, or others variables decided by the client.

A WiFi wireless access point connected to the PLC’s Ethernet port will be used for the data transmission, using TCP / IP communication protocol. Subsequently, the control and supervision of irrigation parameters can be done from a remote station, using smart mobile devices, tablets or laptops, looking for flexibility, according to the possibilities and client needs. It can also operate from the local station itself, where it will have access to the PLC and its hardware configuration. Then, the information handled by itself, may be displayed on a web page that can be re-designed for each specific machine or for a set of them, providing the ability to process the irrigation data for decision making. The above, according to the characteristics and the application context (crop type, water resources availability, maintenance needs, etc.).

B. Web Visualization

Depending on the proposed solution, the graphical user interface shown in Figure 4 is designed. The programming of its visual elements and dynamic links with the system variables is done using the SoMachine v4.1 SP2 software.

Figure 4
Proposed Web interface for supervision and control of central pivot irrigation machines

The features provided by the interface are:

• Selection of the machine working time: Adjustable according to the established irrigation norm.

• Operation time recording: It allows to measure the operation time of the machine by an hour counter.

• Selection of the work rate: It is done by selector buttons that allow distinguishing the manual-automatic mode of the machine operation.

• Selection of the machine rotation direction.

• Operation functionalities: It includes the machine start and stop buttons and a switch to turn on or off the interior light and others.

• Indicators: They allow to visualize the status of the operating parameters through indicator lamps.

The functionality of the supervisory system, the reports, the historical reports, the alarms and the information to be displayed, among other elements, are dependable of the user needs and the communication possibilities that exist in each sector where the system is implemented, which provides flexibility to the proposed solution.

IV. Conclusions

The proposal of automation and wireless control for center pivot irrigation machines ensure the monitoring of the operating status of these machines by managers and operators. It contributes to achieving greater efficiency in terms of water and energy savings in agricultural irrigation systems in Cuba.

The remote control solution based on wireless technology allows the visualization and operation of the machines through web pages, being able to get an access from various devices, such as cell phones, tablets, computers, etc.

Depending on the communication possibilities that may exist in the application place of our proposal, it can be adapted to the use of other technologies, for example GPRS service (in mobile telephony), information transmission in the UHF band and link via a radio modem. The above provides a level of flexibility and applicability to the current research.

References

Alghazali, N., Alkhaddar, R., & Hadi, H. (2013). The use of SCADA system in water resources management, management of Shatt Al-Hilla in Iraq as a case study. International Journal of Environmental Monitoring and Analysis, 1(5), 237-247. doi:10.11648/j.ijema.20130105.19

Avello-Fernández, L., Izaguirre-Castellanos, E., Martínez-La Guardia, A. S. & Hernández-Santana, L. (2017). Solución de control y supervisión remota para máquinas de riego de pivote central empleando tecnología inalámbrica. [ponencia en XVII Simposio de Ingeniería Eléctrica, 2017, Universidad Central “Marta Abreu” de Las Villas.

Camargo, M. (2013). Sistema de control de riego automático mediante el monitoreo de humedad del suelo vía Internet [thesis]. Universidad Autónoma de Querétaro: México. Retrieved from: http://ri.uaq.mx/bitstream/123456789/1306/1/RI000591.pdf

Capraro, F., Tosetti, S., & Vita-Serman, F. (2014). Supervisory control and data acquisition software for drip irrigation control in olive orchards: An experience in an arid region of Argentina. Acta Horticulturae, 1057, 423-429. doi: 10.17660/ActaHortic.2014.1057.53

Carranza, J. (2016). Soluciones de automatización para sistemas de regadío en caña de azúcar [thesis]. Universidad Central “Marta Abreu” de Las Villas: Santa Clara: Cuba

Chávez, J.L., Pierce, F.J., Elliott, T.V., & Evans, R.G. (2010). A remote irrigation monitoring and control system for continuous move systems. Part A: Description and development. Precision Agriculture, 11(1), 1-10. doi:10.1007/s11119-009-9109-1

Clavelo, J.L.A. & Seguí, J. P. (2012). Programación del riego de la caña de azúcar en la provincia de Villa Clara, Cuba. Revista Ciencias Técnicas Agropecuarias, 21(4), 61–66.

Dong, X., Vuran, M.C., & Irmak, S. (2013). Autonomous precision agriculture through integration of wireless underground sensor networks with center pivot irrigation systems. Ad-Hoc Networks, 11(7), 1975-1987. doi:10.1016/j.adhoc.2012.06.012

González, O. (2016, May 24). La Cuba moderniza sistemas de riego. Granma [on-line]. Retrieved from: http://www.granma.cu/cuba/2016-05-24/la-cuba-moderniza-sistemas-de-riego-24-05-2016-23-05-09

Gurban, E. H. & Andreescu, G.-D. (2011). SCADA element solutions using Ethernet and mobile phone network. In: Intelligent Systems and Informatics, 2011 IEEE 9th International Symposium on, (pp. 303-308). IEEE

Jiménez, E. (2011). Parámetros de explotación y uniformidad de riego en la máquina de pivote central OTECH-IRRIMEC. Revista Ingeniería Agrícola, 1(1), 7-12

Joshi, G. S., Bhujbal, N. V., & Kurkute, S. M. (2016)Agriculture at a Click Using PLC & SCADA. International Journal of Emerging Trends in Science and Technology, 3(5), 3928-3932. doi:10.18535/ijetst/v3i05.13

Kranz, W.L., Evans, R.G., Lamm, F.R., O’Shaughnessy, S.A., Peters, T.R. (2010). A review of center pivot irrigation control and automation technologies. In: 5th National Decennial Irrigation Conference Proceedings. American Society of Agricultural and Biological Engineers. doi:10.13031/2013.35832).

Kumar, N.D., Pramod, S., Sravani, C.H., (2013). Intelligent irrigation system. International Journal of Agricultural Science and Research (IJASR), 3(30), 23-30.

Maheshwari, C.V. & Sindha, D. (2014). Water irrigation system using controller. International Journal of Advanced Technology in Engineering and Science, 2(1), 240-249.

Navarro-Hellín, H., Martinez-del-Rincón, J., Domingo-Miguel, R., Soto-Valles, F. & Torres-Sánchez, R. (2016). A decision support system for managing irrigation in agriculture. Computers and Electronics in Agriculture, 124, 121-131. doi:10.1016/j.compag.2016.04.003

Pasha, B.R.S. & Yogesha, D.B. (2014). Microcontroller based automated irrigation system. The International Journal of Engineering and Science (IJES), 3(7), 6-9.

Pavithra, D.S. & Srinath, M.S. (2014). GSM based automatic irrigation control system for efficient use of resources and crop planning by using an Android mobile. IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE), 11(4), 49–55.

Pérez, J. (2010). Diseño agronómico de un sistema de pivote central en la pequeña propiedad los arenales [thesis]. Universidad Autónoma Agraria “Antonio Navarro”: Torreón, México.

Pfitscher, L.L., Bernardon, D.P., Kopp, L.M., Ferreira, A.A.B., Heckler, M.V.T., Thome, B.A., Montani, P.D.B., Fagundes, D.R. (2011). An automated irrigation system for rice cropping with remote supervision. In: 2011 International Conference on Power Engineering, Energy and Electrical Drives. IEEE. doi:10.1109/PowerEng.2011.6036452

Reinke Irrigation. (2017). Reinke pivots. Retrieved from: www.http://skoneirrigation.com/reinke-pivots/

Reinke Irrigation. (2017). Reinke pivots. Retrieved from: skoneirrigation.com/reinke-pivots/

Rodríguez, M. & López, T. (2014). Comportamiento de la zona radical activa del banano en un ferrasol bajo riego por goteo superficial y subsuperficial. Revista Ciencias Técnicas Agropecuarias, 23(3), 5-10.

Rodríguez, M. & Puig, O. (2012). Comportamiento hidráulico de los sistemas de riego por goteo superficial y sub superficial. Revista Ciencias Técnicas Agropecuarias, 21(3), 23-28.

Santos, L., De Juan, J., Picornell, M., Tarjuelo, J. (2010). El riego y sus tecnologías. Albacete, España: Centro Regional de Estudios del Agua (CREA), Universidad de Castilla-La Mancha.

Schneider Electric. (2017). Automatización de máquinas y procesos. Rueil-Malmaison, France: Schneider Electric.

Smith, R.J., Baillie, J.N., McCarthy, A.C., Raine, S.R., & Baillie, J.N. (2011). Review of precision irrigation technologies and their application [NCEA Publication 1003017/1]. Toowoomba, Australia: National Centre for Engineering in Agriculture University of Southern Queensland Toowoomba

Tarjuelo, J.M. (2005). El riego por aspersión y su tecnología. Madrid, España: Mundi-Prensa.

United States Department of Agriculture [USDA] (1991). National engineering handbook. Washington, DC: USDA.

Valley Irrigation. (2017). Irrigation products leading the industry with advanced irrigation systems. Retrieved from: http://www.valleyirrigation.com/valley-irrigation/us/irrigation-products

Vázquez, R.J. & Solano, O.J., 2013. Determinación del peligro por sequía agrícola. Revista Cubana de Meteorología, 19(2), 154-168.

Author notes

Additional information

Acknowledgments : We are grateful for the support provided by the Sugar Cane Research Institute [INICA] (Villa Clara, Cuba), for the disinterested help of specialists, managers and technicals, and for providing us the necessary technical tools for the execution of the experiments carried out in the Agro-Industrial Complex Carlos Baliño of the municipality of Santo Domingo.