Consultant’s Corner: Measuring and managing water – The commercial view
Author: By Craig Topham, Agrarian Management | Date: 31 Mar 2014
The uptake of the decision-making tool Yield Prophet® in Western Australia in recent years is what really sparked the region’s current interest in measuring and managing soil moisture.
As this tool has become more accurate for WA soil types, the level of interest has grown.
There is now a groundswell of activity taking place in the field of soil water measurement and management, with soil moisture probes and automated monitoring of soil water also being used.
I see the new Grains Research and Development Corporation (GRDC) ‘Measuring and managing soil water’ project as one of the key initiatives that will help improve knowledge about effectively using soil water information in farm decision making.
I am one of the representatives on a ‘Soil Water Champions’ panel which is assisting the project by improving links between agencies and providing information on who is doing what and identifying local issues.
I believe that more standardised, accurate methodologies for measuring soil water will be the main benefits of the GRDC project, led by CSIRO’s Yvette Oliver.
Greater consistency in the different systems used to measure soil water will encourage more growers to increase their understanding of soil moisture.
This is important, as the more growers measure and monitor soil moisture, the greater their understanding will be of water use efficiency (WUE).
WUE is about converting rainfall into grain and a key driver of increasing productivity and profitability.
Work so far in WA using Yield Prophet® and moisture probes has highlighted significant variations between the plant available water capacity (PAWC) of different soil types.
Soils with high PAWC have the potential to be highly productive.
With increased knowledge and use of technology we can capitalise on these soils while reducing our exposure to risk on low PAWC soils.
Management of soil water goes hand in hand with variable rate technology (VRT), which allows growers to vary input rates in different zones on their farm.
Smart farmers are already capitalising on their ability to measure and manage water holding capacity.
They are adjusting their management of different soil types and paying more for land with higher water holding capacity.
Growers are saying they need to invest in these soils with a ‘big bucket’ to maximise productivity.
This investment also includes maximising the potential of high PAWC soils by using amelioration methods to overcome soil constraints such as acidity and compaction.
These methods include liming, mouldboard ploughing and spading.
Conversely, growers whose farms include soils with a ‘small bucket’ are reducing their inputs to reduce risk, or changing farming practices including increased grazing rather than continuous cropping.