Clover and out: calling time on chemical N
The central thesis revolves around improving clover utilisation of nitrogen (N) from the atmosphere, allied to enhanced soil microbiology, Paul explains: “Bringing the whole package together could result in a huge reduction in the need for chemical N. We’re looking for natural solutions, ones that already exist but which we can enhance and improve. We have two main aims in the project. One is to reduce and even eliminate the need for chemical nitrogen application to our grasslands and the other is to improve the efficiency by which animals graze that grassland: i.e. how much they take out of it, how much they convert the protein contained in clover-rich grassland into meat and milk protein. By doing all that you can reduce greenhouse gas emissions and maintain food production and stocking rates at current levels. Ultimately, that should reduce the cost of food production and improve farm income. So, it’s a win-win for everyone.”
A collaborative project
The British government has provided a grant of €4m euro for the research with Germinal as the lead partner in the project. Origin Enterprises and Aberystwyth University, with which Germinal has a long-standing relationship, are among the other research partners involved. The title of this research is Project NUE-Leg (Nitrogen Utilisation Efficiency-Legume).
Agriculture accounts for about one-third of Ireland’s total greenhouse gas (GHG) emissions, and ruminant livestock are a significant source of these in the forms of methane and ammonia. A near-term sectoral emissions reduction target of 25 per cent has been set for the sector.
Paul delves further into the science: “Farmers are coming under increasing pressure to reduce stocking rates. We want to try and avoid that. We know plants need nitrogen to grow and, particularly, they need it for vegetative growth, for leaf growth. Currently in grasslands, if we restrict the amount of nitrogen we apply, we reduce pasture production.
“The air around us contains 78 per cent nitrogen. Legumes such as white clover can fix atmospheric nitrogen from fresh air to meet their nutritional requirements. They can do this because of a close relationship between the roots of legume plants and soil microbes called rhizobia. This fixed nitrogen also becomes available to meet the nutritional requirements of grass plants in the pasture.”
Soil science
The ‘NUE-Leg’ Project will include testing of a new variety of white clover that has been bred by crossing with Caucasian clover, which has underground rooting stems called rhizomes, to create ‘DoubleRoot’ which resembles white clover but has both stolons and rhizomes and so can survive grazing, fix nitrogen, and resist drought and cold conditions. A significant aspect of the Project NUE-Leg involves improving soil microbiology, Paul says: “What we’re doing is improving that process by putting better rhizobia in with the seed into the soil, ones which are more efficient and can capture more of the nitrogen. And by feeding the clover with the right nutrition packages, we again make them fix more nitrogen. Specially tailored plant nutritional formulations will be developed to support the establishment and persistence of the new legume varieties and maximise their nitrogen fixing and animal nutritional potentials,” he says.
“Currently a very good grass/clover sward, with 30 per cent clover DM content, will fix 100-150kg of nitrogen. We think we can get that up to 300kg. It’s all based on conventional plant breeding. There’s no gene editing, no GM. We are selecting plants and rhizobia from nature that do things better and combining the two together.
“Let’s look at the red clover, which we call ‘Red Runner’ that grows like a white clover. White clover is a fantastic plant. It’s very persistent and used in grazing and cutting swords. It grows with stolons, so it persists. Most red clovers don’t have that stolon, so they die out quite quickly. We use it in silage ground for cutting. We can’t really use it for grazing because it doesn’t last very long. Red clovers contain an enzyme called polyphenol oxidase (PPO) that protects the protein. It slows down the speed of protein breakdown, which means the animal, when it grazes, can capture more of the protein, perhaps up to 50 per cent more from red clover than from white clover. Some naturally occurring red clover varieties do have stolons. They grow like white clover, so we can use those in our grazing swards and get the additional nutrient value of the slow-release protein in the red clover.”
Enhancing soil biology
Paul went on to highlight the role of specific microbes in the soil: “The rhizobia in the soil, the ones we’re concentrating on in this project, are extremely useful. They’re in most soils apart from peaty, wet soils. There are different strains, so it’s important to select the right strain to go with the right clover species and variety you’re growing. Getting them in synchrony is the whole point of this process.
“In general terms, soil microbiology is the future. I think that’s where we’ll be going with all our plant breeding over the next 10 to 20 years as soil knowledge improves and technologies advance. There’s so much we can do underground. For many centuries, plant breeding has concentrated above ground, on leaves, on plants, on seeds and grains. But what’s happening with the roots is really going to be very important in the future.”
Time scale
The benefits of the research being undertaken by Germinal with its partners, Aberystwyth University and Origin Enterprises, could come into commercial use quickly, if Paul’s expectations are realised: “We are going to start this spring, sowing these clover varieties on 14 commercial farms we have signed up and they’re going to be our demonstration units. Then we’re going to be sowing continually on those farms and improving the technology and showing the gains we are making over the next four years. It’s important that we can prove the advantages and the productivity and economic gains that we are making. Those 14 farms are dairy (both extensive and intensive), sheep farms, beef farms, upland loam farms, and will include organic and conventional farms. We’ve got the whole spectrum covered, because we think this can work on every type of farm.
“Ireland and the UK are some of the best places in the world to produce red meat and milk. That’s why we need to improve our systems and we need to keep producing grazing-based produce here because we have the climate and the soils that enable us to do it.”