Soil moisture probes reduce guesswork in cropping decisions
Author: Sharon Watt | Date: 10 Mar 2016
Grain growers and their advisers in the southern cropping region have been told that soil moisture probes can be a valuable tool in informing soil moisture-based management decisions.
Soil moisture probes (SMPs) quantify how much moisture is in the soil, what depth it is at, where plant roots are active and how much moisture is being used by the crop, according to Leighton Wilksch from Agbyte.
Speaking at Grains Research and Development Corporation (GRDC) Grains Research Updates in South Australia and Victoria, Mr Wilksch said multiple years of data could give a clear picture of how much soil moisture there was at any point in time compared to previous seasons.
“This can assist with making decisions associated with when and what to plant during autumn, and how much nitrogen to apply and potential for the crop to reach target yield,” said Mr Wilksch, of Paskeville in SA.
The location of a probe is extremely important: “Generally, a grower will be installing one soil moisture probe and therefore getting it in the ‘median’ soil type of the farm is important.
“Sometimes if a grower is installing two SMPs, they may want to install one in a poorer soil type if that soil type makes up a sizeable portion of the farm.
“Increasingly, we are seeing local networks of SMPs (and weather stations) pop up that allow a grower to invest in one site, but have access to multiple sites set up by neighbouring growers.
“For example, on the northern Yorke Peninsula in SA, there are a number of networks that have three to five neighbouring growers that each have a SMP installed in different soil types,” Mr Wilksch said.
“In any one season, there will also be different crop types planted over the top of the SMP. Data can be displayed on the same webpage so that each grower can look at the others’ graphs and essentially extrapolate the information across their farm where they may have a similar soil type/crop type to their neighbour.
“This also allows for discussion amongst the group which has been found to be useful for getting a better understanding of plant-available water and its use by the crop.”
Some users of SMPs are now installing the tools to a greater depth.
“Often, the first generation of SMPs were placed 80-100 centimetres deep, but now some sites are heading to 1.6 metres deep to better understand what is occurring at depth.”
Mr Wilksch encourages growers to develop a sound understanding of the soil type they are installing into.
“This means recording horizon changes down the profile and even stratifying out a soil sample in order to get it analysed for chemical and physical constraints.”
He says the data from SMPs should be looked at regularly and growers should seek interpretation from those who have experience with the data.
“And consider hooking it up to a weather station so that you can access data that impacts your farming business daily.”
More information on SMPs can be found in Mr Wilksch’s GRDC Grains Research Update paper 'Soil probes for better crop decisions'.
Leighton Wilksch, AgbytePhone 0408 428 714
Sharon Watt, Porter Novelli
Phone 0409 675 100