SoilWaterApp (SWApp) provides farmers with a ready estimate of plant available water (PAW) during fallows, crops and pastures for dryland and irrigated paddocks.
Such a tool is an enormous plus, as knowing the current amount of soil water, either in a crop, pasture or fallow, is critical for many farm decisions. Improved soil water estimates within fallow, crop or pasture phases can also help assess likely future growth and grain yield, should little follow-up rain occur.
Australian grain production is limited in most seasons by water supply. Soil water stored during the fallow and early season determines water supply leading up to the critical time around anthesis.
SWApp is designed to provide a simple tool to reliably estimate soil water content during fallow and crop phases, important for many decisions such as marketing, storage, and agronomy.
In our dual-purpose cropping and livestock business, being able to better estimate future crop and pasture growth, for various scenarios, including no follow-up rain, is important.
These include decisions such as adding in-crop nitrogen, purchasing more store animals or the need to sell down, close crops for grain rather than graze-on at the expense of grain recovery (a late winter decision).
Only iPhone and iPad (iOS) devices run SWApp. For a given paddock it will present operators with the five nearest climate stations for soil water estimates from the 4500 Bureau of Meteorology climate stations across Australia.
SWApp can be more “localised” with manual entry of an individual’s own rainfall data or a new “wireless” rain gauge if considered more useful.
Entering aspects such as soil types for each paddock provides more accurate soil water calculations, because soils can be very different in soil water storage capacity. Commonly within a given property, soil types can range from clays to sandy with contrasting water storage use patterns and reactions to different seasons.
SWApp estimates infiltration, runoff, evaporation, transpiration, deep drainage and soil water levels daily. The app also uses long-term weather data to provide a probabilistic estimate of future water status.
Starting conditions specified by the user can be adjusted with inputs such as soil push probe depths.
Data, securely stored in the cloud, can be accessed from multiple devices using the accompanying web site.
Start date can be set for any given crop or fallow situation. Set aspects such as soil water distribution, soil cover conditions for fallow or crop, and crop plant and maturity type also impact on soil water status and impact at any given time.
Results are shown as text and graphs. Plant Available Water Content (PAWC) percentage and millimetres water available take centre stage with water balance and soil water profile described through the fallow or crop season.
Graphic displays show the pattern of water accumulation and use.
An output screen shows how full the soil profile is, and how water is accumulated or used. SWApp is also valuable as an ideal tool to improve irrigation scheduling, both for timing and amount. SWApp can be downloaded free from the App Store – search for soilwaterapp.
CliMate and SWApp are easy to use and help us better appreciate current and predicted soil moisture situation. The project is funded by the University of Southern Queensland, GRDC and the Commonwealth Government through the National Landcare Programme.
For more information David Freebairn 0408 876 904, david.freebairn@usq.edu.au. SWApp is available for iPhone and iPad (iOS) www.soilwaterapp.net.au
Next week: Clay base pellets improves choices for successful legume nodulation.
- Bob Freebairn is an agricultural consultant based at Coonabarabran. Email robert.freebairn@bigpond.com or contact (0428) 752 149.