VR nitrogen supplies for various NSW growers

An NDVI image from DataFarming of a paddock in Gollan east of Dubbo, where uneven germination and waterlogging justify the use of VR nitrogen application. Image: Binginbar Farms

VARIABLE RATE (VR) nitrogen application yields positive results for three growers in New South Wales who are switching to precision farming for a variety of reasons, and shared their experiences in a webinar on Wednesday hosted by DataFarming.

The Toowoomba-based software company uses NDVI satellite imaging as a means for growers to access low-cost files that growers can use to guide their equipment in VR applications, and heard the webinar from two growers who use them, and one who that is not .

The webinar was viewed by some 300 registered viewers, including growers, agronomists and researchers, and director of DataFarming. Tim Neale said the session was designed to show how precision farming can help overcome seasonal and long-term hurdles.

The biggest this season has been high fertilizer prices, and waterlogging has also clearly shown to be an inhibitor of fertilizer efficiency.

After the webinar, Mr. Neale said that DataFarming is closely monitoring the introduction of VR.

Tim Neale

“We don’t have the exact numbers yet as there are still plenty of crops being planted,” said Mr Neale.

“Canola is largely in, but wheat and barley are way behind.

“We’re just starting to see the kick-up, and the reason we’ve been holding the webinars is that we expect a huge increase in VR usage this season.”

N required despite previous pulse

Entitled Maximize your fertilizer valueheard the webinar first from mark day from Woodlea Ag Enterprises, which uses DataFarming’s rapid zoning images at $0.50 per acre to deliver the “shape file” that Mr. Neale said can be processed in most modern machines.

Mr. Day farms on a family-owned farm near Lockhart in southern Riverina and runs a four-year rotation of pulses, canola, wheat and barley.

The Days began applying variable rates for phosphorus substitution more than 10 years ago, and lime or gypsum has also been added to most of their country during that time.

“We haven’t been into the variable rate nitrogen area even though we have the equipment to do it,” Mr Day said.

“Nitrogen is the most important thing right now and something we all struggle with how to deal with it, especially the price.”

Mr Day said nitrogen anomalies in a 450-acre paddock of rapeseed were evident in the NDVI images available through DataFarming, and a satellite image taken on May 22 set the “shape” for their first VR nitrogen dispersion.

“At the time we had enough for a 100 kg/ha bedding and just wanted to make better use of that on the block.”

Day said the May 22 DataFarming image showed poorer zones needed more nitrogen, and the crop “flew quite well” in better zones.

Canola is very hungry for nitrogen and although the paddock had faba beans last year after wheat the year before, Mr Day gave good zones 80kg/ha, average 100kg/ha and poor 140kg/ha.

The exercise used a total of 44.5 tons across the paddock with varying soil types.

The recent wet weather means that the upcoming application of urea in the crop may be a setback from the previous one.

“Now we’re going to do the reverse; those blocks that are soaked with water… will be limited, and we’ll probably push the dry land a little harder now.

Shallow bottoms a challenge

In Gollan, 50 km east of Dubbo, the Simpson family grows about 3000 ha of the 3850 ha Binginbar Farms in a rotation of canola barley wheat on what Nathan Simpson described as “highly variable bottoms”, ranging in depth from about 10 cm to a meter.

“We have a very shallow bucket.”

“We just can’t store moisture like some of the black earth country can.”

Binginbar also runs sheep and has used DataFarming images this and last year to accompany variable rate applications.

Simpson said DataFarming’s images were used this year to help correct the impact of a non-ideal seeding when a new air seeder failed to arrive in time to seed and contractors had to be called in to complete planting.

“Particularly this year due to flooding and problems with the air seeder, it really made sense to use single NDVI. †

Simpson said that blockages in the air seeder resulted in poor germination in patches, and these will get zero urea in the VR top dressing.

“We have not kept any urea; that’s not the point of what we want to do.

“We want to maximize yield.”

The urea rates applied based on the DataFarming form were zero, 50 kg/ha and 100 kg/ha for barley and zero, 75 kg/ha and 150 kg/ha for rapeseed and wheat.

“We’re around 20c/ha for these regulations, and it really did the job well.”

“It’s too late… to fix anything else, and all you can do is push the yield potential to the right place.”

Only a small number of paddocks in Binginbar Farms don’t get VR nitrogen application, and Mr Simpson said this was mainly because they didn’t have a wide variety of soil types.

“There are certainly big differences in 90 percent of the country.”

Simpson said it seems like a wise decision not to spend money on poorly constructed areas of the crop, especially now that waterlogging is a problem in some paddocks.

“Areas with very low yield potential, we will not put nitrogen on them.”

He said the spread of nitrogen on a swampy land would evaporate immediately.

“It would be wasted money.”

Binginbar has also used satellite imagery and other data from the Western Australian company Laconik and conducted strip trials in 2020 to test NDVI and their broader VR-based strategy.

“It’s a good way to validate the decisions you make about nitrogen in crops.

“Last year we didn’t do it; it was too wet to have any results.”

Protein guides input

breads Holland family farms on sandy loam land that grow 3800 ha and 1200 ha alfalfa clover and run 4500 merino’s at Thuddungra on the southwestern slopes.

Their rotation is a seven-year wheat canola phase and then three years of pasture.

The Hollands don’t use DataFarming images, but are variable-rate applicators of nitrogen using protein maps of the previous year’s wheat to dictate fertilizer rates, which are broadcast after planting.

The strategy is proving successful in reducing the spread of wheat protein from about 8.5-14.2 percent in the 2016 harvest to nearly 1 percent in 2021, and the average wheat yield has also increased from 4.5 tons per hectare. in 2016 to 6 tons/ha in 2020 and 2021.

Using data from protein maps, lime, gypsum, manure and urea are spread at variable rates.

“It’s the easy levers to pull.

“We focus on getting all of those right and then getting our yield maps right.

“I say let’s forget about the yield maps for now and try to get our input right.”

“Low protein gets much more urea; high protein gets less.”

The company has historically blended about 1,000 tons of wheat to avoid discounts that would apply to their lowest-protein wheat.

“Now we are not mixed; there is just no variety.”

Mr Holland said deep N tests on 100 ha, conducted in March 2020, showed a confidence-building correlation between the previous year’s wheat protein and deep N levels.

“In 2020, we will be distributing urea that is completely and exclusively protein-based.”

“Every time I haven’t distributed the card…I’ve kicked myself.”

A protein meter on the farm provides grain results before each load leaves the farm.

“We know what it is going to be for every truckload we deliver.”

The Hollands supply wheat to the flour mills in the region, saying the benefit of delivering loads within a narrow range lies mainly in increased agricultural efficiency, but not in dollars per ton.

However, Mr Holland hopes that this will change.

“There definitely needs to be a discussion to show (mills) that we can send them a single percentage of protein wheat… and get the consistency for them.”

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