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Nitrogen on the farm

Learn about the impact of nitrogen pollution on farms and its effects on the environment, human health, and wildlife. Explore ways to manage and reduce nitrogen pollution through responsible farming practices.

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Nitrogen on the farm

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  1. Nitrogen on the farm LEAF Education Cymru and Pembrokeshire Coastal Forum https://education.leafuk.org / https://www.pembrokeshirecoastalforum.org.uk/

  2. N pollution • Nitrogen is a nutrient that is essential for life. But too much of it causes problems: • Nitrates in rivers cause eutrophication when algae grow too fast and choke other species, affecting wildlife and fisheries • Nitrates in drinking water are bad for human health, causing ‘blue baby’ syndrome and other problems • Ammonia causes air pollution with serious impacts on wildlife and human health • Nitrous oxide (N2O) is a greenhouse gas 298 times more powerful than CO2 www.leafuk.org | Twitter: @LEAF_Farming @OpenFarmSunday| www.farmsunday.org

  3. A problem for politicians www.leafuk.org | Twitter: @LEAF_Farming @OpenFarmSunday| www.farmsunday.org

  4. A problem for farmers www.leafuk.org | Twitter: @LEAF_Farming @OpenFarmSunday| www.farmsunday.org

  5. A global problem In Europe, the cost of managing the environmental and human health impacts of N pollution are €70-320 billion annually. Nitrogen pollution affects marine life globally. www.leafuk.org | Twitter: @LEAF_Farming @OpenFarmSunday| www.farmsunday.org

  6. Nitrogen on farms Nitrogen is essential for life, especially as a part of all proteins. It comes on to farms in three main ways: • Fertilizers • High-protein animal feed • biological fixation from the atmosphere. www.leafuk.org | Twitter: @LEAF_Farming @OpenFarmSunday| www.farmsunday.org

  7. Nitrogen fertilizer Nitrogen from the atmosphere is combined with hydrogen to make ammonia in the Haber-Bosch process. Ammonia then is converted to nitrates and urea. We produce 450 million tonnes of nitrogen fertilizer per year, using 1–2% of the world's energy supply. In combination with pesticides, these fertilizers have quadrupled the productivity of agricultural land. www.leafuk.org | Twitter: @LEAF_Farming @OpenFarmSunday| www.farmsunday.org

  8. Animal feed Although beef and sheep farms grow grass and sometimes grains for their animals, they often buy feed in as well. Poultry and pig farms buy nearly all their feed in. High-protein feed is rich in nitrogen and may be imported from other countries. www.leafuk.org | Twitter: @LEAF_Farming @OpenFarmSunday| www.farmsunday.org

  9. Natural N fixation Certain plants of the legume family carry a bacteria called Rhizobium in their root nodules. This converts atmospheric nitrogen into nitrates that the plant can use. Common species are clover, vetch and beans. www.leafuk.org | Twitter: @LEAF_Farming @OpenFarmSunday| www.farmsunday.org

  10. Where N ends up • In food exported from the farm, including meat, milk, grains and vegetables • As ammonia, a gas produced from animal manure • As nitrates, which are leached from soils by rain if the crop has more than it needs • As N2 and N2O, gases produced by bacteria from nitrates in the soil www.leafuk.org | Twitter: @LEAF_Farming @OpenFarmSunday| www.farmsunday.org

  11. Dairy farming and slurry A major potential source of nitrate pollution is dairy farms, where cows are usually taken indoors for milking and over the winter. Faeces and urine (slurry) are collected underneath the building and pumped into a tank or lagoon. www.leafuk.org | Twitter: @LEAF_Farming @OpenFarmSunday| www.farmsunday.org

  12. Storing slurry Slurry may be stored in tanks or lagoons until it is needed. www.leafuk.org | Twitter: @LEAF_Farming @OpenFarmSunday| www.farmsunday.org

  13. Slurry Slurry is a valuable source of nitrogen and other nutrients, and can substitute for artificial fertilizers. If it is not applied properly however the nitrogen can be lost by • Leaching of nitrates • Volatilization of ammonia • Denitrification (N2 and N2O) What factors (crops, weather, soils) will affect how much N is lost in these ways? www.leafuk.org | Twitter: @LEAF_Farming @OpenFarmSunday| www.farmsunday.org

  14. Spreading slurry – splashplate • A splashplate spreader sprays the slurry over the entire crop and soil surface. • Some of it is lost to the atmosphere as ammonia. • If it’s cold and the crop isn’t growing, it won’t use all the N • If it rains afterwards, some N will be washed away as nitrates. • To see one in action try this video (first 100 seconds) • https://www.youtube.com/watch?v=FNEZQSk3hNk www.leafuk.org | Twitter: @LEAF_Farming @OpenFarmSunday| www.farmsunday.org

  15. Spreading slurry - bandspreader A bandspreader applies the slurry directly to the soil surface, so there is less evaporation. Video – 1 min https://www.youtube.com/watch?v=lPJQ4HdZGko www.leafuk.org | Twitter: @LEAF_Farming @OpenFarmSunday| www.farmsunday.org

  16. Nitrates Leaching of nitrates is high when: • Too much manure or other fertilizer is applied • The soil is very wet Leaching is low when: • There is a fast-growing crop to use up the nitrates • The soil is dry www.leafuk.org | Twitter: @LEAF_Farming @OpenFarmSunday| www.farmsunday.org

  17. Ammonia Ammonia is a bad-smelling gas that is produced from manures. Ammonia volatilization from slurry is high when: • The slurry is sprayed through the air and/or lands on the crop • The weather is dry, warm and windy Ammonia losses are low when • The slurry is applied directly to the soil • The weather is cooler and it rains www.leafuk.org | Twitter: @LEAF_Farming @OpenFarmSunday| www.farmsunday.org

  18. Denitrification In waterlogged soils, bacteria may convert nitrates back into nitrogen (which is harmless) or nitrous oxide, N2O, which is a very strong greenhouse gas. This is called denitrification. www.leafuk.org | Twitter: @LEAF_Farming @OpenFarmSunday| www.farmsunday.org

  19. Decision making Farmers have to decide what to do with their slurry: how much to spread, how to spread it, when to do it. They need to look at the weather forecast and think about what crops they have growing. Software is available to help them plan, for instance MANNER, from ADAS. Let’s look at three scenarios. www.leafuk.org | Twitter: @LEAF_Farming @OpenFarmSunday| www.farmsunday.org

  20. Data analysis • Scenario 1: The tank is full, so the farmers need to empty it quickly, even though it’s January. They apply it a rate of 90 m3/ha, on a field of grass. They use a splashplate spreader, and it rains heavily later that day. • Scenario 2: They invest in a bigger tank, so they can wait till March, then apply it to grass at 90 m3/ha, again using a splashplate spreader. This time the weather is dry, and it’s also very windy. • Scenario 3: They keep it until mid-April. They apply 45 m3/ha then, and 45 m3/ha a month later, using a band spreader, to a field of grass. There is no wind on either day but there is some light rain later on the first day. Complete the table: answers on the next slide www.leafuk.org | Twitter: @LEAF_Farming @OpenFarmSunday| www.farmsunday.org

  21. Answers – N losses Scenario 1 – winter, heavy rain – leaches nitrates Scenario 2 – spring, dry weather, windy – lose ammonia Scenario 3 – two applications with bandspreader - best www.leafuk.org | Twitter: @LEAF_Farming @OpenFarmSunday| www.farmsunday.org

  22. Answers – N efficiency www.leafuk.org | Twitter: @LEAF_Farming @OpenFarmSunday| www.farmsunday.org

  23. Answers – £ savings Cash savings for scenario 3 www.leafuk.org | Twitter: @LEAF_Farming @OpenFarmSunday| www.farmsunday.org

  24. What can farmers do? Using slurry and fertilizers efficiently means more cost-effective food production and is better for the environment. So how can we make that happen? • Technical solutions, such as using software to analyse nutrient requirements, and environmentally friendly farming • Political methods – regulation and reward www.leafuk.org | Twitter: @LEAF_Farming @OpenFarmSunday| www.farmsunday.org

  25. Precision farming Here, satellite imaging assesses crop requirements for N. Using GPS information, the rate of fertilizer or slurry application can be varied minute to minute. www.leafuk.org | Twitter: @LEAF_Farming @OpenFarmSunday| www.farmsunday.org

  26. What can government do? • Penalize farmers who pollute: declare Wales a Nitrate Vulnerable Zone • Reward farmers who don’t pollute • Tax fertilizers “One in eight farmers in Wales poised to quit over NVZ proposals” Daily Post, Dec 2016 www.leafuk.org | Twitter: @LEAF_Farming @OpenFarmSunday| www.farmsunday.org

  27. Payment for Ecosystem Services Here, drones assess crop growth and GPS knows where the tractor is, so it can send instructions and record delivery www.leafuk.org | Twitter: @LEAF_Farming @OpenFarmSunday| www.farmsunday.org

  28. Payment for Ecosystem Services (PES) and Nitrates Regulator Industry Farm NO MORE NITRATES TO BE RELEASED EACH YEAR We want to increase production which would lead to the release of an extra 80 units of nitrates each year We could reduce our nitrate release by 100 units each year. RIVER www.leafuk.org | Twitter: @LEAF_Farming @OpenFarmSunday| www.farmsunday.org

  29. Payment for Ecosystem Services (PES) and Nitrates Regulator Farm Industry Nitrates levels have gone down so we’re happy We pay the farm to reduce their nitrates release by 100 units, which more than compensate for our 80 units. We change our methods or our equipment to reduce our nitrate release by 100 units RIVER www.leafuk.org | Twitter: @LEAF_Farming @OpenFarmSunday| www.farmsunday.org

  30. Payment for Ecosystem Services (PES) and Nitrates Farms Regulator Forestry Industry Domestic Other land uses such as marshland. Trading Certification Advice Finance SELLERS BUYERS www.leafuk.org | Twitter: @LEAF_Farming @OpenFarmSunday| www.farmsunday.org

  31. What can the public do? Customers can choose foods that have been produced in an environmentally friendly way. They may for instance pay extra for food with an organic symbol or the LEAF Marque, both of which means that farmers have been following good practice for nutrient management, for instance limiting fertilizer use. Another label is Pasture for Life which means farms feed their animals entirely on grass, silage and hay, with no extra N-rich feed. www.leafuk.org | Twitter: @LEAF_Farming @OpenFarmSunday| www.farmsunday.org

  32. What do you think? • Penalize farmers who pollute • Reward farmers for good environmental management • Choose food that comes from farms following high environmental standards List one argument for and against each point. www.leafuk.org | Twitter: @LEAF_Farming @OpenFarmSunday| www.farmsunday.org

  33. Some possible answers

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