Design and implementation of an efficient solar powered irrigation management system for drip irrigated maize field

Purpose - The thesis investigates effects of automatic variation of the deficit irrigation level with the growth stage of drip irrigated maize on grain yield and crop Water Use Efficiency (WUE). It further examines the impact of water-efficient irrigation controllers on the solar Photovoltaic energy level requirements for water pumping systems. Methodology - A Wireless Sensor and Actuator Network was deployed to monitor field conditions and actuate irrigation valves according to whether the level of moisture was within the set points. A Control Treatment (CT) field was fully irrigated using constant moisture threshold levels, while an Experimental Treatment (ExT) field had the highest level of deficit irrigation at the early and later growth stages. Full irrigation was applied at the middle growth stage. Irrigation depths and grain yields were measured, while WUE and the solar energy required by the water pumping system were calculated. Findings - The findings show that 880 mm and 560 mm of water were applied to CT and ExT fields, respectively. This represents a 36% water saving and a corresponding water pumping energy saving of 36% in the ExT field. The grain yields were 0.752 kg/m2 and 0.812 kg/m2 for CT and ExT fields, respectively. This shows that, despite applying a lower amount of water, the ExT improved the grain yield by 7.4%. Furthermore, the results show an increase in WUE from 0.86 kg/m3 for the CT field to 1.45 kg/m3 for the ExT field, representing a 69% improvement. Research limitations/implications - This study focused on the maize production under Malawi's weather conditions. However, the concept would easily be replicated in other crops and in other parts of the world with two modifications: firstly, sensor calibration must be done on-site; and secondly, the specific crop coefficient pattern must be used to develop the irrigation scheduling strategy.Purpose - The thesis investigates effects of automatic variation of the deficit irrigation level with the growth stage of drip irrigated maize on grain yield and crop Water Use Efficiency (WUE). It further examines the impact of water-efficient irrigation controllers on the solar Photovoltaic energy level requirements for water pumping systems. Methodology - A Wireless Sensor and Actuator Network was deployed to monitor field conditions and actuate irrigation valves according to whether the level of moisture was within the set points. A Control Treatment (CT) field was fully irrigated using constant moisture threshold levels, while an Experimental Treatment (ExT) field had the highest level of deficit irrigation at the early and later growth stages. Full irrigation was applied at the middle growth stage. Irrigation depths and grain yields were measured, while WUE and the solar energy required by the water pumping system were calculated. Findings - The findings show that 880 mm and 560 mm of water were applied to CT and ExT fields, respectively. This represents a 36% water saving and a corresponding water pumping energy saving of 36% in the ExT field. The grain yields were 0.752 kg/m2 and 0.812 kg/m2 for CT and ExT fields, respectively. This shows that, despite applying a lower amount of water, the ExT improved the grain yield by 7.4%. Furthermore, the results show an increase in WUE from 0.86 kg/m3 for the CT field to 1.45 kg/m3 for the ExT field, representing a 69% improvement. Research limitations/implications - This study focused on the maize production under Malawi's weather conditions. However, the concept would easily be replicated in other crops and in other parts of the world with two modifications: firstly, sensor calibration must be done on-site; and secondly, the specific crop coefficient pattern must be used to develop the irrigation scheduling strategy

Successful Deployment of a Wireless Sensor Network for Precision Agriculture in Malawi

This paper demonstrates how an irrigation management system (IMS) can practically be implemented by deploying a wireless sensor network (WSN). Specifically, the paper describes an IMS which was set up in Manja township, city of Blantyre. Deployment of IMS in rural areas of developing countries like Malawi is a challenge as grid power is scarce. For the system to be self-sustained in terms of power, the study used solar photovoltaic and rechargeable batteries to power all electrical devices. The system incorporated a remote monitoring mechanism through a General Packet Radio Service modem to report soil temperature, soil moisture, WSN link performance, and photovoltaic power levels. Irrigation valves were activated to water the field. Preliminary results in this study have revealed a number of engineering weaknesses of deploying such a system. Nevertheless, the paper has highlighted areas of improvement to develop a robust, fully automated, solar-powered, and low-cost IMS to suit the socioeconomic conditions of small scale farmers in developing countries

Demonstrating the value of generating and sharing data on off-grid energy systems : a case study from Malawi

To achieve electricity access in sub-Saharan Africa, off-grid Distributed Energy Resource Systems, such as microgrids, are required. Sustainability of these systems requires improved business models and efficient maintenance and operations frameworks. However, a lack of technical and economic data from the existing installation base hampers the necessary learning and innovation. This paper describes a case study deployment of DER systems in Malawi, demonstrating the application and benefits of high levels of instrumentation and monitoring. A proposed classification of minimum, preferred and desirable levels of data gathering and sharing is offered as a key recommendation for future DER system deployments in Malawi

Successful Deployment of a Wireless Sensor Network for Precision Agriculture in Malawi

This paper demonstrates how an Irrigation Management System (IMS) can practically be implemented by successfully deploying a Wireless Sensor Network (WSN). Specifically, the paper describes an IMS which was set up in Manja Township, City of Blantyre based on an advanced irrigation scheduling technique. Since the system had to be self-sustained in terms of power, which is a challenge for deployment in rural areas of developing countries like Malawi where grid power supply is scarce, we used solar Photovoltaic (PV) and rechargeable batteries to power all electrical devices in this system. The system incorporated a remote monitoring mechanism through a General Packet Radio Service (GPRS) modem to report soil temperature, soil moisture, WSN link performance and PV power levels. Irrigation valves were activated to water the field. Our preliminary results have revealed engineering weakness of deploying such a system. Nevertheless, the paper shows that it is possible to develop a robust, fully-automated, solar powered, and low cost IMS to suit the socio-economic conditions of small scale farmers in developing countries

Small Scale Rollout of PV Systems in Chikwawa District, Malawi: Remote Monitoring System Effectiveness

Off-grid solar photovoltaic systems in Malawi are deployed increasingly as the primary option for rural public infrastructure such as primary schools and health centres. Overall, grid-connected electricity access has remained stagnant at around 9% with only 1% of rural population connected. To improve the technical sustainability of such systems, a novel remote monitoring technology utilising Wireless Sensor Networks was installed and the systems were monitored over roughly one year. This paper has described the technical design, performance, and benefits received from deployment of the technology. Furthermore, it has evaluated the cost implications for a larger scale rollout and potential benefits

Remote Monitoring System Effectiveness : Small Scale Rollout of PV Systems in Chikhwawa District, Malawi

The Remote Monitoring (RM) strand of MREAP was incorporated within a Strategic Energy Project in Chikhwawa led by WASHTED. RM was deployed as a measure to bolster technical sustainability of the project and to consider its readiness for scale-up. Distributed energy systems in Malawi, particularly solar PV systems, have historically had poor sustainability performance. During MREAP it was included at 4 separate locations comprised of 21 separate electrical systems to capture key technical performance data. These systems were each standalone Solar PV installations on health facilities and primary schools. The technology utilized Wireless Sensor Networks (WSN) and open-source models to communicate via mobile phone networks remotely to WASHTED’s office in Blantyre. Data could then be viewed at near real-time, analyzed, and corrective actions could be enacted. The purpose of the RM strand was to demonstrate the technology’s effectiveness towards improving sustainability of off-grid community energy projects, particularly the technical performance

Remote monitoring for wireless sensor based irrigation system in Malawi

In the recent years there has been an increase in the application of Wireless Sensor Networks (WSNs) in agriculture, specifically aiding automatic application of water, chemicals and fertilizers to the field. Since WSNs are still under development stage, they are at times unreliable, power hungry, fragile and they easily lose communication. Intrinsically, any irrigation system based on WSNs requires close monitoring to guard against any horrendous mishaps. However, monitoring such an irrigation system which, usually, is located at a rural site can be expensive and time consuming. In this paper we developed an efficient, cost-effective and real-time wireless based remote monitoring mechanism for a WSN based Irrigation system situated in Manja Township within Blantyre city. The system archives data that include the soil moisture potential, link performance, electrical power levels, and valve status and subsequently sends the information as a text message over a cellular network to a remote monitoring site located at the Malawi Polytechnic. The remote station has a broadband wireless dongle which is interfaced to a MYSQL database via an open source FrontlineSMS. The information is graphically published on a web browser with the help of a PHP script. Preliminary results demonstrate that a WSN based irrigation system can be monitored remotely at a low cost and in real time

Experimental performance analysis of wireless links for healthcare applications

Wireless networking is currently being deployed for various applications. However, the application of wireless networking in healthcare remains a challenge mainly because of security and reliability concerns. This paper presents experimental results of performance analysis of a wireless network for healthcare application in the City of Blantyre. The results show that the use of wireless networking in healthcare application will be limited by packet loss, delay and jitter when the number of hops involved in the transmission of information is large. Nevertheless, deployment of wireless networking for healthcare applications is viable when the number of hops a packet has to transverse is small