Measuring Efficiency at Hoddom & Kinmount Estate
6 September 2024Carbon audits
Completing a carbon audit is another way for a farm business to look at performance and identify areas where there may be scope to reduce emissions and improve efficiencies.
A baseline carbon audit was prepared for the farming enterprises at Hoddom and Kinmount Estate for the crop year 2023. Input and output data was provided by James Marshall, the farm manager from invoices and farm records; the carbon audit was prepared using Agrecalc.
This audit indicated that the farming enterprises produced 0.34 kg CO2e per kg output. Fertiliser were the main source of emissions, followed by enteric fermentation i.e., methane from ruminant digestion by the cattle and sheep.
Optimising output through good technical management and reducing use of inputs are two ways farm businesses can reduce their carbon footprints. As a result of implemented management changes, the farm enterprise was able to reduce their CO2e emissions by 76.9 tonnes.
Benchmarking of the beef and sheep enterprises and crops at Hoddom and Kinmount Estate indicated that:
- Good technical performance of the livestock had contributed to higher output; crop yields although variable were generally average for the region.
- Emissions from electricity, lime and fertiliser were generally higher.
Electricity
Due to the various activities on the Estate allocating electricity usage between the enterprises and activities was harder compared to what it would be for a standalone farm business. To improve allocation of usage, meter readings through the grain store will be carried out in the future.
Lime
In the crop year assessed 325 tonnes of lime was applied to the arable land and the grassland. Lime was applied in response to soil analysis results with an aim of increasing pHs to recommended levels. While the use of lime results in embedded emissions that are allocated to a farm business, the benefits in terms of improved crop and grass yields will be evident going forward. James sources his lime from a local quarry on the Estate, which will have a lower emission factor compared to lime that has greater transport miles. Although not quantified by Agrecalc, this will have a positive impact on the estates carbon footprint, resulting in it being lower than calculated.
Fertiliser
Soil sampling is regularly carried out, fertiliser is applied according to results, taking into account crop offtakes and farmyard manure (FYM), slurry and digestate applications. This autumn James intends to carry out GPS soil sampling, which will help to identify variations within fields allowing lime and phosphate (P) and potash (K) fertiliser to be applied in a more targeted way next year.
Management changes
Targeted applications of FYM
A 13 hectare field of field beans was grown with an aim of reducing fertiliser use. Soil analysis of the field prior to sowing identified that K levels were moderate, and P levels were high. FYM was sourced from a local farmer and applied to the field at a rate that provided the beans with all its K requirements. This crop will be harvested as wholecrop in mid-September.
This action resulted in a saving of 2.4 tonnes of Muriate of Potash (MOP); 2.5 tonnes of Carbon Dioxide equivalents (CO2e).
Feeding wholecrop beans
Due to wholecrop beans being grown, James was able to change the growing and finishing cattle ration. Incorporating 7 kg/head/day of wholecrop beans into the ration resulted in 1.5kg/head/day of a blend of wheat distillers and rapemeal and 2kg/head/day of crimped cereals not having to be included.
Feeding wholecrop beans resulted in a saving of 12 tonnes of wheat distillers, 12 tonnes of rapemeal and 48 tonnes of crimped cereals; 28.9 tonnes of CO2e.
Establishing winter barley by direct drilling
On the lighter land, 20 hectares of winter barley were direct drilled after beans. This land was chosen due to the field beans having helped to improve the structure of the soil and it being more suited than the heavier clay land to direct drilling. Compared to ploughing and establishing winter barley with a combination drill, 500 litres less diesel was used over the 20 hectares; it also took the contractors three hours less time.
Direct drilling the crop resulted in a saving of 1.3 tonnes of CO2e from less fuel being used.
Growing red clover silage
36 hectares of red clover silage was grown, whereby red clover makes up 50% of the mix. The nitrogen-fixing ability of red clover not only benefits the clover, but the ryegrasses too, reducing the requirement for applied nitrogen. Red clover can fix up to 250 kg N per hectare. It also leaves residual nitrogen behind for the following crop.
Compared to growing conventional grass silage James was able to reduce bagged nitrogen use, saving 6.7 tonnes of 40% Urea; 44.2 tonnes of CO2e.
Management changes as detailed above are not only helping to reduce the amount of emissions generated by the business but it is also improving its efficiency, sustainability of the land and reducing costs.
In addition to continuing with the implemented management changes stated above, going forwards James intends to:
- Target organic manure applications to land that is further away from the steadings, helping to increase P and K levels, reducing bagged fertiliser use and improving the soil structure.
- Depending on soil analysis results, reduce amount of digestate applied to the red clover silage.
- Use crop rotation to improve soil structure of the fields, with an aim on increasing the amount of land direct drilled.
- Carry out GPS soil analysis on the arable land to help even out pHs and P and K indices.
- Regularly weigh the cattle to quantify weight gains.
- Graze the sheep on clean land thereby reducing the lamb finishing period.
Gillian Reid, SAC Consulting
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