Soil Moisture Monitoring in Dryland Cropping Areas
Risk management through soil moisture monitoring project
The 'Risk Management through Soil Moisture Monitoring Project' commenced in 2011 to provide dryland grain growers with useful information to assist with their decisions around sowing and crop selection. Positive feedback from the 2013 and 2014 SMM survey reports lead to the extension of funding for the monitoring component of this program through the Grains Seasonal Risk Program with the Rain, Grain and Food to Asia projects.
This project, conducted by The Department of Economic Development, Jobs, Transport and Resources (DEDJTR), will assist the grain sector to lift production and improve grain quality to meet the Food to Asia demand. Increasing targeted inputs and improving crop management will be accomplished by helping industry to understand soil and water interactions and critical crop growth stages, as well as factoring in forecasted seasonal predictions.
Crop potential and cropping inputs are increasingly being subject to greater instability and uncertainty due to seasonal variability. Grain growers are under pressure to increase production across a range of seasons, and adding to the complexity is the fact that under climate change, annual rainfall is projected to decrease and its seasonal distribution is expected to change. Monitoring water availability, without the use of SMM probes, makes the process of estimating appropriate inputs and other management decisions difficult. Until recently, the practice of using soil moisture probes has had limited use in the dryland cropping industry and few farmers have had access to this technology.
DEDJTR is providing live, deep soil moisture data to help dryland croppers, farmers, and advisors/managers validate the SMM technology, as well as conducting training to interpret the data for crop decision making. Results are communicated via; regular editions of the 'Soil Moisture Monitoring' and 'The Fast Break' newsletters, 'The Very Fast Break' video, and through farm field days and meetings. A link to live data can be accessed via the SMM newsletter.
Sites and measurements
- Northern Irrigation – Kerang
- South Gippsland – Sale
- Northern East - Youanmite
- Central – Raywood, Coonooer Bridge, Elmore
- South West – Hamilton and Lake Bolac
- Wimmera – Brim (Lah) Taylors Lake and Bangerang (Sheep Hills)
- Mallee – at Speed, Werrimull, Birchip, Ouyen and Normanville
These sites are being monitored using 'capacitance probes' that take hourly measurements of soil water content through the soil profile.
Sensors on the capacitance probes measure zones every 10cm, from a depth of 30cm down to 1m. A total of 8 measurements from 8 probes are taken at each site, with the data collected sent via the mobile phone network to a server which stores the data to allow interpretation through graphing software.
Benefits of the SMM program
Soil moisture probes record absolute soil water content. With over six years of monitoring, the probes have built up knowledge of upper and lower moisture limits for crops under different soil and crop types for many of the sites. Measuring soil moisture will also help provide an indication of:
- Yield potential based on plant available water
- Crop water use
- Sub soil moisture base and reserves
- Rainfall required to refill soil profile
- Water infiltration
- Water logging
- Water use of different crops.
Access to this data enables growers and advisors to:
- Measure moisture at points in paddocks representative of the farm
- Use live soil moisture data from a representative site for a particular rainfall region and soil type
- Monitor localised weather (rain, wind and temperature/humidity) as well as down load historical data from an archive list for farm management records
- Increase production and efficiencies
- Help farmers to adapt to seasonal variability and climate change
- Make informed input decisions such as minimising input in low soil moisture years base and maximising yield potential in more favourable conditions based on current soil moisture levels and incorporating seasonal forecasts probabilities
- Determine if measurements obtained through the life of the project could be relevant at whole farm or even district level.
- Enable crop forecasting models to incorporate the live soil moisture data that is collected from a representative soil in a particular rainfall region, therefore providing more accurate advice and increasing production and $$ for growers.
How to access and use the data
For information on how to access the data and navigate around the soil moisture monitoring site please contact Dale Boyd via email firstname.lastname@example.org or phone (03) 5482 0439.
Soil moisture data is collected hourly by the soil moisture probe sensors. This data is plotted on graphs to display soil water content change over time. With the addition of extra information, these trend lines indicate the timing of water infiltration due to rainfall and active moisture uptake by the crop.
There will also be times when there is no change and a flat line may indicate that the soil profile is at field capacity or dry to the crop lower limit. It also may show that plant roots are not active in the site for that time period. The graph below will assist in explaining what is likely to be occurring:
Below are some examples of options you may choose for your paddocks depending on the soil moisture results obtained. Being able to accurately measure soil moisture when required provides opportunities to aid management decisions at various stages in the production cycle. As more information is collected over a wider range of seasons, confidence levels will increase as comparisons can be made between years.
Early sow long season varieties, canopy management to maximise yields.
Reduce upfront input costs, seed rate, fertiliser, and herbicides. Canopy management for average yields.
Reduce upfront costs, and seed rate. Consider decreasing area sown, target lower risk crops and more productive paddocks.
High confidence in N application, weed and disease management.
Lower confidence level. Reduce rates of N application.
Low confidence level. Reduce costs, consider grazing or hay later in the season.
High confidence. Apply late N, fungicides and pesticides.
Lower confidence. Reduce rates of N.
Low confidence. No N. No forward selling. Consider grazing and hay production
High confidence. Consider forward selling options if favourable. Head counts to determine potential yield.
Lower confidence. Reduce forward selling quantities. Head counts to determine potential yield.
Low confidence. No N. No forward selling, consider grazing and hay production.
Determine potential yields. Adjust insurance estimates.
- Agnote: Choosing the right Soil Moisture Monitoring Device, Note Number: AG1412. Findings
- Risk management through soil moisture monitoring – Evaluation report. Email email@example.com for a copy.
- Twitter: @DPI_Vic_Grains
Do not act on information here without independent advice from your local agronomist or agricultural advisor.