This article featured in the May 2019 edition of NZ Dairy Exporter.
Words and photos by: Karen Trebilcock.
When lower-order sharemilkers Geoff and Alicia Sewell moved to the hills above the Waitaki Plains almost three years ago they identified grass management as one of the things they needed to work on to make the farm and their 750 (peak milk) cows tick.
With K-line irrigation, two 40-aside herringbone dairies with a herd each and 230 hectares effective that was far from flat, figuring out where the grass was quickly became their focus.
They bought a top-of-the line C-Dax tow-behind and started measuring the farm weekly, downloading the information onto the computer and emailing the results to the farm owners.
Then SPACE came along and the C-Dax is parked in the garage.
SPACE (Satellite Pasture and Cover Evaluation), from LIC, uses satellites passing over New Zealand to take an image of farms and, using algorithms developed by LIC scientists, evaluate pasture coverage.
The owners of Kowhai Dairy took the free six-week trial in August. Geoff did one more ride with the C-Dax to make sure the results correlated, which they did, and now SPACE is what he relies on.
“We got three reports in the first two weeks and then there was a two-week gap with nothing and then we got the last reports in the trial,” Geoff says.
“The reports are sent straight to MINDA on my phone, and to my 2IC and to the farm owners.
“It works really well for the farm owners because they all live off-farm, some of them in the North Island, and by looking at the reports they can visualise the pasture from wherever they are,” Alicia says.
“I love that it’s sent to my phone,” Geoff says. “The information is all in my pocket. There’s no need to download anything and I don’t have to do a thing.”
With him happy, the farm owners took on the annual subscription.
Geoff reckons it pays for itself. Measuring grass on the farm once a week was costing about $1000 of fuel a year and was taking a staff member and a motorbike out for about three hours a week.
“The motorbikes are pretty busy in the spring dusting paddocks, picking up calves, feeding calves, moving K-lines, so to find one to use was getting to become mission impossible.
“Plus there is the cost of the repairs and maintenance on the bike, depreciation and of course staff time.
The reports can be infrequent, with cloud cover affecting the satellite’s ability to capture an image of the farm when it’s passing overhead, but the longest they’ve been without one was three weeks.
“I was about to take the C-Dax out of the garage but then we got a report.
“You can get addicted to paper and figures but with grass you really need to look at your cows and we do that a lot.
“If the cows are still content in their paddock and it’s two in the afternoon then they’ve had enough to eat.
“We train our staff to look at a paddock when they’re setting up breaks, where the grass is in the paddock.
“And the grass is changing all the time. At the moment, because it’s autumn and we haven’t had a decent rain for a while, it’s up at about 18% to 20% drymatter.
“Even though you can have all the figures on paper, you still need to follow your instincts and use your eyes and look at your cows.
“Cows are your best tell of all.”
Part of the SPACE report is a ranking of paddocks from the ones with the most grass to the least – that page gets printed out and put in the dairy so farm staff know which paddocks to go to next.
“We don’t have a round that we follow. With this farm because of the hills and the irrigation we might go to one paddock twice and another one only once in the same period.
“It’s always about which paddock has the most grass.”
SPACE also gives the total cover for the farm – a figure he watches. When it gets too close to 2000kg DM/ha he starts thinking about whether he needs to use supplementary feed and at above 2400 it’s time to make balage.
However, the report also includes the three fodder beet paddocks on the farm and the freshly cultivated paddocks.
“It is one of its weaknesses but you learn to live with the inconsistencies.”
SPACE also identified areas in paddocks which aren’t performing – the slopes and gullies on the farm.
“I know a lot of people use the time spent measuring grass on the farm with a platemeter to check water troughs and weeds and fences but we do that when we’re shifting K-lines so we’re seeing all of the farm all of the time.”
SPACE business manager Rebecca Dalrymple, in Hamilton, says more areas of the country are being included in the service with Taranaki added in late February.
“With each area we’ve got to validate the data and for some regions this has been quicker than others because of the weather and the topography of the area.
“We’ve got to make sure the algorithms we’re using work,” she says.
So far it covers South Otago and Southland, most of Canterbury, Auckland to Taupo and Wellington (except the eastern coast) and Taranaki.
Rebecca says about a third of farmers who had had the free trial had then taken up the annual subscription.
“In Southland it’s less than a third and we think it’s because of the weather.”
Even high cloud or haze could stop a clear picture.
“The satellites are passing over every day but there are times they don’t seem to capture the whole area occasionally.
“We’ll have farms five kilometres apart and one will have a clear image and there will be nothing for the other farm.
“And on each farm there will be gaps either because of slopes or clouds. Every time we send a report we include a shadow and cloud map which shows what we haven’t been able to measure.”
SPACE was first trialled with a small group of Canterbury farmers in December 2017 and now there are 1200 users with some of those on the free trial period.
“The fact that most of the farmers who signed up for the annual subscription are now renewing it shows we must be doing something right.
“And it’s only going to get better with more satellites and also better technology on those satellites and we’re continuously improving accuracy as well with our algorithms.”
Those who had had a free trial and decided not to go ahead with SPACE will be able to give it another go.
“As we do major upgrades we let people know.
“We couldn’t have done any of this 10 years ago.
“Satellites are becoming much more accessible for commercial users like us and in two or three years we should be able to give a lot more information, maybe even see beyond the clouds.”