Lateral move irrigator boosts WUE and increases yields
Author: Alice Long | Date: 12 Jun 2014
Terry McFarlane integrated a new irrigation system into his farm four years ago to help improve crop yields after nearly a decade of drought.
Terry, who farms with his wife Maxine, crops 250 hectares under irrigation, growing sunflowers, sorghum, soybeans, seed vegetables, faba beans, canola and wheat.
“We were looking to improve our water use efficiency and decided to invest in a 500-metre, lateral-move irrigator, with the view of getting more yield per megalitre,” Terry said.
“The lateral irrigator we installed is a little unique in that it is fed by a concrete channel. The channel is about 1m wide and about 600 millimetres deep and supplies 6 megalitres a day to the irrigator.”
Terry chose the concrete-fed system rather than a large, open-channel system so the machine can be pivoted over to irrigate the adjoining bay.
This is his fourth season of soybeans using the overhead system, which he has contracted to Vitasoy for milk. Terry’s push for efficiency and profitability means he will not plant a crop without a contract in place that outlines what he will receive at the end.
Terry direct-drilled the soybeans on December 8 last year and then irrigated with the overhead sprinkler for two weeks to keep the profile moist, before following up with furrow irrigation to save on energy.
“At the moment we are still using the irrigator at the start and end of a summer crop, but during the growing season we are switching back to the furrowed irrigation,” Terry said.
“The main benefit is evenness of distribution of water. Just like a rain event, if we use it for the entire season we get a very even crop all the way through.”
Current operating cost for the overhead irrigation is $50/ML, which Terry says is expensive. He says the lateral irrigator is a fantastic way to get crops established, although it is not the only benefit he appreciates with the irrigation system.
“A great advantage I see is with cereals and canola, you can top-dress and then hit it with a ‘rain’ just to take that nitrogen into the soil and into the root zone,” Terry said.
“Often when top-dressing cereals and canola, you’re looking for a rain event to take that in. During the irrigation season, we can water-run our nitrogen requirements through the syphons and it will distribute into the root zone. But when the irrigation season is down and you’re trying to get nitrogen into your crops, you need a way of getting it in, and we find it great for putting 20mm of rain over a urea application.”
The 36ha of soybeans were sown after a wheat crop which yielded 6.5 tonnes/ha when harvested on November 20.
“The wheat and soybean rotation only just works, because of the importance of the timeliness of sowing every crop, but I like to have soybeans in by the first week of December.
“The trouble with doing it post a wheat crop is if you try and go in there and drill fertiliser down into dry ground. Unless you irrigate it, you’re creating a very poor seed bed situation. We’re finding that pre-planting it prior to the wheat has worked, the soybean crop has been accessing the fertiliser that we put down underneath its plant line.”
Terry harvested the soybeans in the first week of May and they yielded 3.3t/ha. He says yields may have been higher if the overhead had been used for the entire season to achieve best subbing. The paddock is sown to wheat for 2014.
Watch a video of Terry McFarlane here
Region South, North