Smartphone dials into soil-moisture data
Grain growers can now estimate their stored soil water more efficiently, cheaply and reliably following the release of a new app for smartphones
Everyone appreciates the benefits of stored soil water to subsequent crop production, and knowing what you have affects many crop-management decisions.
The preservation and measurement of stored soil water has grown in importance as climate variability has made rainfall events less predictable.
This resource is now regarded as a crucial buffer for crop growth.
For Dr Brett Robinson from the University of Southern Queensland (USQ), knowing your soil water status during the fallow and early cropping period allows more realistic decisions and goals to be set in terms of crop choice, inputs and yield potential.
To this end, he has been developing the SoilWater App since 2013 with colleagues at the National Centre for Engineering in Agriculture – part of USQ’s Institute for Agriculture and the Environment.
Dr Robinson, who spoke at the GRDC Grains Research Update in Goondiwindi this year, believes the new GRDC-funded app will become the most advanced soil-moisture calculation tool so far developed in Australia. He sees it as helping growers and agronomists to improve the seasonal decision-making process and, in turn, helping to lift yields and profits.
The free SoilWater App for iPads and iPhones is user-friendly and enables growers and consultants to track their soil moisture during a fallow and up to a crop’s anthesis for multiple paddocks.
“As scientists, we have had complex models of rainfall and soil water on our big clunky computers for a long time, while farmers have the experience and paddock knowledge necessary to interpret their rainfall patterns – now the two can be brought together, on a phone, out in the paddock,” Dr Robinson says.
How SoilWater App worksThe SoilWater App system uses a ‘water-balance model’ (simulation) to calculate water inflows and outflows through the soil profile at daily intervals. Weather records can be updated daily over the internet, therefore soil water can be estimated through the app without having to go into the field.
If a grower or agronomist wants to know how much water is likely to be in the soil on any given day, the app makes a calculation based on weather and soil data, including any data provided by existing soil sensors.
Online climate data (Bureau of Meteorology (BoM) data from SILO) and local weather data, including rainfall, temperature, evaporation and soil descriptions (ApSoil database and CSIRO’s SoilMapp) are all used to estimate evaporation, run-off, deep drainage, early crop water and soil moisture in each soil layer. Additional sensor information can also be used to ‘calibrate’ these calculations.
The app requires a starting value of moisture, given as a percentage of a full profile at harvest, and then looks at climate and rainfall data over the fallow period. It can also incorporate estimates of soil water from sources such as electromagnetic mapping, capacitance probes and soil coring.
Although the default rainfall data is taken from a selected BoM station, growers can also add their own rain data manually. A ‘wireless’ rain gauge, now under development, will be able to link directly to the app, making updating with local rainfall data much easier.
“In a sense it is an improved version of its predecessors CliMate and HowWet?” Dr Robinson says. “CliMate only uses data from the local BoM rainfall site, whereas SoilWater App enables you to input your own data as well and provide soil-water estimates based on this more local information.”
By incorporating on-farm rainfall figures and paddock specifics, he says the app is able to give the clearest picture yet of a crop’s water supply from the soil.
“SoilWater App allows you to measure or deduce how much moisture is in the soil before you plant, and for winter crops, that can be 30 to 70 per cent of the crop’s entire water supply,” he says.
Queensland grower Rob McCreath has been using a prototype of the app over the past few months on his property ‘Prestbury’, at Felton on the Darling Downs.
“I’ve found the app to be a very handy tool for estimating my soil moisture, and I’ve used it to help decide whether to plant chickpeas into sorghum stubble or leaving it fallow. The crop’s up and growing now, so fingers crossed for the rest of the season,” he says.
Since its development began, SoilWater App has been guided by feedback from a reference group of advisers and growers, such as Mr McCreath, and regional forums have been used to ensure the app reflects practical grower use.
The SoilWater App prototype has been released for wider testing, prior to its release on iTunes at the end of 2015. Growers are encouraged to register on the website and help test the app under different conditions.
“About 250 people are currently interested and there are about 20 users, but we can accommodate up to 1000,” Dr Robinson says.
He points to the CliMate experience as an example of grower interest in this form of technology: “CliMate was launched in 2012 and now has 12,000 users. So we’re hoping growers will think of SoilWater App as an additional tool – an electronic advance on their traditional rainfall diary and push probe,” he says.
At this stage, SoilWater App is only available for iOS devices (iPhone and iPad); however, an Android version is being considered for future development.
More information:Dr Brett Robinson,
0407 313 656,
Growers can register their interest in trialling SoilWater App
GRDC Project Code PRE00003, USQ00014