Could fodder beet crops provide feed supplements for Northland farmers during summer droughts?
Fodder beet is a crop that has been used in Europe since the Middle Ages.
In New Zealand, it has been grown since World War II, but although its potential as a quality feed source for ruminant animals was known, the lack of specific weed control herbicides and modern agronomy techniques at the time made it a very labour-intensive crop.
Traditionally it was harvested, but in more recent times South Island dairy farmers began to graze it as a winter feeding crop, lessening the costs and leading to a growth in demand over the past eight years. In the past few years, production has grown from 500ha to 10,000ha, largely because of the the crop's high-yielding ability (greater than 20t/ha), and high-energy ratio (ME 12 MJ/kg DM), which can be used not only in winter feeding but also during lactation in autumn and spring.
A recent Northland farmer-led project, supported by DairyNZ, SeedForce and local suppliers, has been assessing the use of fodder beet on the region's dairy farms.
Yields for the drought year discussed at a Northland Fodder Beet Group field day at Roger Kidd's property at Te Kopuru last month ranged from 7-10 tonne/ha for early grazing 107-130 days (from drilling to harvest) to 20 to 24t/ha for crops left for 149-173 days.
In the 2010/11 year, Redhill farmer Allister McCahon reported an average yield of 35t/h and a top yield of 45t/ha. Average costs for producing the crop ranged from $2000-$2800 a hectare.
Dr Jim Gibbs, senior lecturer in livestock health and production at Lincoln University, attended the field day at the Kidds' property. Dr Gibbs was commissioned by DairyNZ in 2010 to intensively investigate the safe and effective use of the crop in New Zealand, and is still involved with the ongoing research, including possible summer feeding. He says preliminary work has shown fodder beet grows well in Northland and is a cost-effective lactation shoulder feed. "The relatively warm environment and generally high soil temperatures of the region suggests there are potential applications for a high yielding summer feed," says Dr Gibbs.
Because of the higher yields, the stocking rate is greater than other crops, thus reducing the land area.
Cost, yields and gains
Sown in spring, it will typically yield 15t/ha in autumn, and can be grazed from March.
Typical yields by June for winter feeding are 20t/ha for dryland, and 25-30t/ha for irrigated crops.
After transition, the crop is fed with a fibre supplement, straw or silage, at about 20 per cent of the total ration, giving a total winter diet cost of less than 20c/kg DM.
The maximal winter diets fed at present are 11-12 kg DM FB + 3-4kg supplement, giving an ME intake of approximately 170 MJ/d, supporting liveweight gains of above a kg/d, or 1 body condition score over the 60d winter.
There are several varieties available, but the dominant grazed variety is "Brigadier", as it is a large, soft type that sits well out of the ground, easily accessed by stock.