Vetch delivers versatility

Mr Nagel was a guest speaker at the recent GRDC Grains Research Update in Adelaide, where he sung the praises of the "versatile" crop, but also warned that careful management was needed.

"Growers need to treat vetch like every other crop, it's not just a set and forget break in the cropping regime - the more you put in the more potential returns you will have," he said.

Traditionally, vetch was considered a "low rainfall legume", with the SA and Vic Mallee the "heartland".

"But in the past four to five years, we have seen vetch expand into the mid to high rainfall zones," Mr Nagel said. "This is where growers really need to be mindful of the differences and limitations of each species."

There are three types of vetch - common, woolly pod and purple - and all have different flowering times.

"Common varieties are generally shorter season, flowering between 85-115 days, while WPV doesn't flower until about 125 days, so could be suited as a later hay variety," he said.

Mr Nagel said vetch's many end uses - grazing, silage, hay or grain - also needed to be considered before choosing to sow a variety.

"Common is the most versatile variety, it's tolerant to grazing and very palatable; WPV produces the most biomass, but you have to worry about seed issues; while purple produces late biomass, but also has seed issues, but is also the most tolerant of water-logging," he said.

"The different species all have different characteristics, and therefore need different management, but all produce good fodder and return large amounts of nitrogen to the soil."

RELATED READING: Research narrows in on diseases behind pulse root rot

RELATED READING: Croppers urged to protect GM technology

Mr Nagel said knowing paddock history was also important as vetch had limited broadleaf control options, especially in-crop.

"There are some in-crop broadleaf control options, but it can set your crop back, while with WPV, you can not use metribuzin," he said.

"The best option is to use registered herbicides post-sowing pre-emergent, but it pays to make sure paddocks are relatively free of broadleaf weeds."

But Mr Nagel said some growers used vetch to target chemical-resistant weeds by spray-topping or cutting the crop for hay, attacking grasses before seed set.

That was the benefit of vetch, its versatility, he said.

"If you have a bad season, you can change your mind as to how you use it, whether its grazed, baled or harvested," he said.

"You can't do that with pulses, you can't just terminate early, particularly if you are targeting resistant weeds.

"But with vetch you can do that early enough and still maintain moisture."

SARDI vetch breeder Stuart Nagel said many croppers chose to grow vetch for its nitrogen fixation.

Mr Nagel said SA trials in the past few years showed that after green manuring vetch, up to 150 kilograms of N could be fixed into the soil.

Vetch could also break the cycle of soil-borne diseases, he said.

But he said growers needed to make sure they kept on top of their pests and diseases when growing vetch, with botrytis causing havoc last season and past reports of livestock photosensitivity due to cow peach aphid infestations.

"Botrytis really attacked vetch late in the season last year," he said.

"One reason was because people started sowing vetch in March last year after early rains.

"The canopies then went nuts and canopy closure came in June. This meant the last possible fungicide was applied in June, which gave botrytis a long window to develop underneath.

"We ended up seeing large areas of crop going down with symptoms due to time of sowing."

Mr Nagel said appropriate time of sowing was crucial to avoiding disease, particularly as foliar treatments weren't always effective.

"There are also withholding periods to consider if you plan to graze or export the crop," he said.

"Farmers can also graze it lightly in June/July - this opens the canopy enough to get airflow in, and then you can also get a late spray in."