The Virtual Irrigation Academy (VIA) comprises a suite of soil water and solute monitoring tools that give output as colours, coupled to an on-line database and visualisation platform.
The VIA was designed to transform the small-scale irrigation sector through three functions
The VIA deals with the three fundamental problems that prevent the smallholder irrigation sector reaching its potential.
First, there is no cost-effective technology available for farmers to help them manage their water, nutrient and salt. This results in leaching of fertilizer, wasted time and/or energy for pumping, conflict among farmers and low yields.
Second, those responsible for managing, maintaining and repairing irrigation schemes have no information on which to base their decisions.
Third, donors who invest millions in irrigation infrastructure have no way to track the performance of their investment. The VIA provides all these services through a sensor and data analytics platform.
Stirzaker et al (2017) reported that irrigators in Tanzania reduced their water application by at least one third after using the water and solute monitoring tools. Bjornlund et al (2018) interviewed 266 farmers across 5 irrigation schemes in three African countries of whom 100 farmers had access to the VIA tools. Within two years, 194 farmers changed practice – almost always decreasing their irrigation – and 166 farmers increased their yields. This is more than the total number of farmers who had the equipment, showing that lessons learnt by those who had the equipment spread to others who did not have it. Moyo et al (in prep) reported that
ASARECA (2017) listed the benefits of the VIA as:
The VIA was launched in 2016, is now active in 16 countries and has accrued a database of over 2400 monitored crops. We have developed a Chameleon sensor production line and on-line quality control system in Canberra and replicated this in South Africa, producing over 10,000 sensors in the last 12 months. We partner with government agencies responsible for water governance in several countries and train VIA Managers to run the VIA platform at the country level.
This table gives a snapshot of how VIA data is captured in the field and how data is aggregated to provide information to different audiences, including extension workers, scheme managers, researchers, irrigation donors and government agencies.
The Chameleon Reader
A Chameleon sensor array is comprised of three sensors placed at different depths in the root zone. The sensor array is connected to a reader and the water status at each depth is represented by LEDs which show blue (wet soil), green (moist soil) or red (dry soil). These readings are taken by the farmer or extension worker.
The Chameleon pattern
Each sensor array has a unique ID chip and the Reader is Wi-Fi enabled, so the data is sent to the VIA platform and collated for each crop. This produces a three-layer Chameleon pattern over time.
The white/pink/purple circles show the Nitrate status from water samples captured by a Wetting Front Detector, measured using test strips.
The Scheme Triad
Each Chameleon pattern above can be collapsed into a single value by integrating the area of blue, green and red and displaying on a triad diagram. In this diagram, all the maize crops from Nanzolo scheme in a given year can be viewed together (in this case grouped towards the blue corner), with the yield shown by colour.
In summary, the crops are kept very wet and the yields are low. This leads us to suspect excessive N leaching, which is examined further below.
The multi-scheme comparison
We then compare each scheme using box diagrams, which show yields divided into quartiles and the median value for each scheme. This data can be correlated against water and fertilizer management, and varieties to investigate the cause of yield gaps, using the research station (purple) as the benchmark.
In this case, we show yield (left) and nitrogen fertiliser applied (right). The analysis shows that low application of N fertiliser is not the primary cause of low yields.
The multi-year comparison
By comparing two triads showing the same crop at the same scheme over different years, we can see how water management practices and yields have changed in response to the VIA tools.
In this case, we see a shift in crops away from the blue corner, showing that the farmers are using less water.
We also see a concomitant increase in yield. This is indicated by the colour change from red and green (low to medium yield) to green and blue (medium to high yield).
Richard Stirzaker, January 2019