NIBIO has, on behalf of Mære Agricultural School, prepared a report on which measures may be appropriate to implement to reduce greenhouse gas emissions from the farm at Mære Agricultural School. The report is part of the project "Zero Emission Farm Mære". Data from the farm, including via the climate calculator, has been used to estimate emissions of nitrous oxide (N2O), and methane (CH4) from livestock manure, nitrous oxide from mineral fertilizer nitrogen (N), and emission intensity in dairy and suckler cow production.
Animal manure
The total emission of nitrous oxide and methane from livestock manure on pasture, from storage and when spreading is estimated at 328 tonnes of CO2-equivalents per year. Almost all fertilizer spread on fields and meadows in Mære is strip-spread using hose-spreading equipment. This reduces emissions from livestock manure by 13 tons of CO2equivalents than if the manure were spread by tanker. The majority of the manure is stored outside in a large lagoon, while some is stored in a manure pit. Both storages lack a roof, and the total effect of a closed roof is estimated at 7 tons of CO2-equivalents per year. Treatment of manure in biogas plants reduces emissions of ammonia, nitrous oxide and methane. At Mære, the effect of treating all wet manure in biogas plants is estimated at 82 tons CO2equivalents per year. This corresponds to 25% of total emissions from livestock manure, and is the single measure that has the greatest effect.
Other measures that can have a positive effect are spreading manure under favorable conditions, avoiding harvest spreading, distributing manure over the entire area, and using smaller amounts on organic soil than on soil with a low content of organic matter.
Carbon balance
Long-term rotation of meadows, preferably with seeding without ploughing, minimises the conversion of organic matter in the soil and reduces greenhouse gas emissions. On cereal areas, the use of catch crops sown together with cereals can reduce runoff and bind CO2. On the area currently used for grain, the use of catch crops could result in an emission reduction of 11 tonnes of CO2– equivalents per year.
Milk production
Emissions from milk production are estimated at 0.89 kg CO2-equivalents per kg fat and protein-corrected milk. This figure is below the average for Norwegian herds. Higher performance, better forage quality, and the use of feed additives that are under development to reduce methane production in the rumen could, in the best case, provide a further emission reduction of up to 46 tons of CO2-equivalents per year.
Suckler cow production
Emissions from suckler cow production at Mære Agricultural School are estimated at 23 kg CO2-equivalents per kg carcass. This emission is low compared to calculations from other Hereford herds. Better forage quality, higher growth, and the use of additives in the feed can also reduce the emission, which is calculated to be up to 11 tons CO2-equivalents per year.
Other agronomic conditions
The following factors are highlighted here that can provide better growth conditions:
- Low pH on some shifts - this can increase nitrous oxide emissions
- Good drainage is important going forward
- Little soil compaction gives better soil structure
- Fertilization under favorable weather conditions
- Increased use of pasture and reduced protein feeding
