Making more wheat from less
An EU-funded study has successfully generated plant growth from specific root bacteria to improve the yield of top-performing wheat varieties in the UK. For modern farming, this means less use of chemical fertilisers and potentially better quality crops. The RHIBAC ('Rhizobacteria for reduced fertiliser inputs in wheat') project received EUR 2 million in funding from the 'Food quality and safety' Thematic area of the EU's Sixth Framework Programme (FP6). Research conducted under the 4-year study demonstrated that rhizobacterial inoculation of crops grown in the northern hemisphere has the potential to replace 50 kilograms per hectare of applied nitrogen fertilisation normally used in wheat production. RHIBAC's project leader Professor Nicolaus von Wirén from Universität Hohenheim in Germany explained that it has been over 30 years since researchers have been studying the application of plant growth-promoting rhizobacteria (PGPR) in crops like wheat and maize, generating very low success rates and reproducibility. Although he was quick to add that the team's findings still need to be validated over a range of conditions and environments before the value of commercial savings could be quantified, Professor von Wirén noted the findings could prove to be a real breakthrough. 'We are, however, excited about the progress we have made over the past four years in bringing the huge promise of PGPR closer to commercial reality for European cereal growers. In particular, we have developed a far greater understanding of the way these valuable soil microbes work and how they can best be utilised in modern production systems,' he said. Much of the pioneering work generated under RHIBAC has taken place at the project's field trials in Wiltshire, south-west England. A total of four modern wheat varieties were introduced at the farm - Robigus, Viscount, Alchemy, Oakley - and produced with different levels of nitrogen fertilisation, and four RHIBAC strains incorporated with the seed at sowing. On average, results across all 4 varieties yielded over 0.70 t/ha (tonnes/hectare) or 6% growth in 2 separate trials when selected rhizobacteria were added to a standard fertiliser regime. When these results were compared with the nitrogen-only controls, the researchers discovered that bacterial inoculation was worth between 50 and 100 kilograms of nitrogen per hectare (kg N/ha). 'These results are really encouraging for the whole project,' explained Mr Colin Lloyd of Masstock Arable Research in the UK, a RHIBAC project partner. 'Assuming the RHIBAC strains could replace 50 kg N/ha, we're talking about an annual saving of 225 000 tonnes of ammonium nitrate across our current 1.85 million hectares of UK winter wheat alone.' Mr Lloyd went on to say that researchers from RHIBAC partner Yeditepe University in Turkey measured improvements in micro-nutrient uptake and grain yield in parallel trials. 'Also revealing, perhaps, is that we've only started seeing statistically significant results since shifting our trial emphasis from potentially nitrogen-fixing bacteria to those known to have more of a phosphate-solubilising action,' Mr Lloyd added. 'The fact that we recorded these improvements in a winter that saw some of the lowest soil temperatures in recent memory suggests the bugs were perfectly at home in our cold, temperate climate too.' With spin-off savings, production, transport and use as a result of the breakthrough, Mr Lloyd concluded that these would also contribute to national greenhouse gas emission reduction targets.