Inoculant change proves key

John Davey, who farms with sons Matthew and James, crops 1600 hectares of wheat, barley, canola, beans and lentils, and had used granular inoculant on his pulse crops for the past 12 years.

But after supply of the granular product, Nodulator, was pulled, he chose to use a liquid inoculant instead due to its longevity compared with other inoculants.

"The problem with granular and peat inoculants is that they've got a short shelf life, so you've got to use them the year you want them, and if you don't use it, it's lost," John said.

"But with the liquid inoculant, which comes as a freeze-dried powder, you can actually keep that for two years.

"We can make sure we get plenty on hand, if we don't use it we can actually store it in a fridge for the next year."

The Daveys use a liquid inoculant called EasyRhiz, which remains effective for 24 hours after being reconstituted.

John said it was important to use rainwater for the process in order to ensure the survival of the nitrogen-fixing bacteria in the inoculant, rhizobia.

"Because tap water is chlorinated to kill bacteria, if you reconstitute with tap water, within thirty minutes the rhizobia are dead," he said.

Once the reconstituted inoculant is mixed with seed, it remains effective for five hours, and while this is longer than peat (two hours), the short window meant that the Daveys had to inoculate while seeding, rather than beforehand.

"We normally do five hours a fill, so if we inoculated beforehand we'd have to reinoculate a fresh batch every fill, and it would just be a nightmare logistically," John said.

To inoculate while seeding, the Daveys attached a "retired" Hardi Commander 4228 spray cart to the back of their airseeder, and built a new liquid inoculant distribution channel onto the seeder, which added inoculant to the seed stream just prior to sowing.

The roots were well-nodulated, with faba bean root samples showing between 50 and 100 nodules on the main stems at the eight-week mark, and John was pleased the liquid inoculant had proven to be effective.

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"When you change to a different methodology it's very easy to get things wrong, and it is often not as good as what you would like," he said.

"But this year, it's worked very well.

"Farming is a big, expensive business, and if you get these kind of things wrong it will cost you a lot of money."

Clinton Centre cropper John Davey said a liquid distribution channel added to his airseeder had many benefits, in addition to allowing the successful delivery of liquid inoculant.

The inoculated seed and fertiliser are delivered in two separate tubes, in order to ensure the inoculant remains effective.

"We're double shooting so we've got a separate air system for the fertiliser and for the seed, so that means the inoculant is kept away from the channel with fertiliser (which kills rhizobia)," Mr Davey said.

There are now six distribution channels on the airseeder - three liquid and three granular - which Mr Davey said delivered products such as trace elements, fertilisers, inoculant, fungicides and seed.

"We're not always using all six channels on the seeder, it depends on the operation," he said.

Mr Davey said the extra liquid channel would be used to complete nutrient trials, such as testing different rates of liquid phosphorus, and one granular channel was being set up to be able to spread mouse bait, in the event of a mouse plague.