Data is transforming the agricultural sector—particularly in the field of irrigation. A lack of water is a critical constraint to increasing food production in South Africa, as droughts and other consequences of climate change are making water a scarce commodity. One of the ways that our Group is assisting in combatting this challenge is through Overberg Agri’s irrigation division. In partnership with Valley and Prospera, Overberg Agri recently assisted with a particularly impressive irrigation design that includes a moisture probe and weather station. This advanced technology provides the farmer with real-time data and scheduling relating to soil moisture levels—forecasting when and how much to irrigate for optimum water usage. Irrigation designer, Tian Lourens, shares more details with us below.
According to Tian, the moisture probe installed at SAB’s model farm performs three functions at 10cm intervals of the 60cm moisture probe. The first function is the measurement of soil moisture at the 10cm intervals. “This determines soil moisture volumes in the root zone of the plant,” says Tian.
The second function of the moisture probe is the measurement of soil temperature at different levels, which is important with regard to the germination and root development of the plant.
The third and final function is to measure the soil’s salinity levels. “This is to determine whether the application of fertiliser was done correctly and how the fertiliser moves through the soil profile after irrigation,” continues Tian. He adds that the great advantage of this is to optimise the use of water and fertiliser and thus reduce its use.
Soil moisture in the root zone
Soil moisture over a period
Soil salt content where the movement of fertiliser through the root zones can be seen
According to Tian, the Valley weather station used on SAB’s model farm offers the farmer the opportunity to measure, among other things, temperature, wind speed and rainfall. The information is stored online and makes it possible to compare historical data.
“The following information is measured by the weather station: Temperature, wind speed, wind direction, ‘Wind Gust’, humidity and solar radiation,” says Tian. “The placement of such a weather station gives the farmer the opportunity to see if the weather is of such a nature that he can irrigate in that area or spray fungicides and/or insecticides. The information is also processed to calculate the previous day’s evapotranspiration figure. This figure together with a plant’s growth factor can give a very good indication of the amount of water the plant and soil need by means of irrigation. The solar radiation figures collected over a long period of time, together with online information, also provide the farmer with the opportunity to determine how economically viable a solar pump system will be,” concludes Tian.