INSTALLING an automotive irrigation system can increase production values by reducing manpower.
That was the message from Dr Kelvin Montagu, Applied Horticultural Research, at a recent workshop for vegetable growers.
The workshop, held during the Gippsland Irrigation Expo, at Sale in March, attracted vegetable growers from Orbost to the Mornington Peninsula.
“Installing automotive irrigation systems means you can drop someone off the [irrigation] roster,” Dr Montagu said.
He discussed a range of common issues experienced by growers, based on questions from attendees.
“The easiest thing to do is to push the button to repeat the program for yesterday’s watering,” Dr Montagu said.
“This can lead to overwatering and the danger there, is leaching of nutrients from the system, water in wheel tracks and running down furrows.”
Instead, he recommended utilising software programs that map the terrain, identify soil structure and crop types and monitor the impact of watering schedules across the farm.
When it rains, people think they have water in the bank and will turn off the irrigator. What they should be doing is getting out, feeling and looking at the crop and monitoring the soil moisture – measuring how much water is in the soil by using a tensiometer.
- Dr Kelvin Montagu
These programs include ‘apps’ that growers and workers can access on their smartphones and tablets.
“Technology means mapping has gone from district to farm specific and crop specific,” Dr Montagu said.
“Google mapping is done so regularly now, you can use it to reflect on previous crop growth. The data from evapotranspiration, solar radiation, wind, temperature and humidity is all available online. It’s a matter of finding a program that suits your business model.”
Among his suggestions were ETO prediction models and crop water use and growth modelling using SILO, Sentinel 2 and Landsat, among others.
“Look ahead for the week, look for those 6-7mm evaporation days and schedule watering as appropriate.”
Dr Montagu warned against letting the soil cap during hot weather, which precludes water and affects growth and crop yield. For vegetable growers, rain was a factor that should not exclude irrigation.
“When it rains, people think they have water in the bank and will turn off the irrigator,” Dr Montagu said.
“What they should be doing is getting out, feeling and looking at the crop and monitoring the soil moisture – measuring how much water is in the soil by using a tensiometer.”
The benefits of using water schedules programmed specifically to the crops’ needs directly impacted on plant growth.
“Water enables transport of nutrients – transpiration – into the plant. Getting carbon into the plant is the primary function of transpiration and why plants use irrigation,” Dr Montagu said.
“The carbon becomes sugars, which makes plant cells – replication of cells, like with all organisms – leads to growth.
“Five millimetres of irrigation per day is the cost of doing business for the plant.”
He warned vegetable growers had to take more responsibility for their irrigation schedules than other horticulturalists.
“While orchardists can pull back on irrigation at some growth stages, vegetables have a continual growth stage,” Dr Montagu said.
Specific crops needed specific irrigation schedules. Many of the vegetable growers at the workshops were baby leaf producers.
“With baby leaf … the soil needs daily watering from pre sow to post germination,” Dr Montagu said.
“But that means the soil is quite well able to hold up to evaporation.”
