28 July 2021
Upgrading slurry storage facilities is facilitating herd expansion at a Welsh dairy farm.
Russell Morgan wants to increase his herd size by 50 cows plus heifer replacements.
To achieve this he is scaling up slurry storage volume at Graig Olway, Usk, by creating a 6,500m³ lined earthbank lagoon.
The infrastructure, which is on course to be completed at the end of this summer, will have capacity to hold at least five months’ worth of the slurry produced at Graig Olway from the expanded herd.
With ample capacity, Mr Morgan can target manure applications to crop nutrient requirements, so much so that he is confident he can reduce bagged fertiliser input costs.
“Expanding the milking herd is something I have considered for a long time and knew I would have to upgrade slurry storage to enable this,’’ he said.
“Previously, we had to pump out the lagoon when we needed storage and this meant wasting valuable nutrients in the winter, that will no longer be the case.’’
Through his project work as a Farming Connect demonstration farmer, Mr Morgan has been supported in his decision making by ADAS Environment Advisor, Eoin Murphy.
Among the factors they considered were the measures needed to reduce the runoff of clean water into the lagoon, selecting an appropriate site for the lagoon and ensuring it complied with planning and building warrant legislation.
The system that had been in place was only capable of holding 15% of slurry produced in the five-month storage period required by the new Water Resources (Control of Agricultural Pollution) (Wales) Regulations 2021 for 300 dairy cows and 200 head of youngstock.
In calculating capacity for the new lagoon several factors had to be taken into account – not only the slurry from all livestock but the volume of lightly fouled water such as silage clamp runoff, parlour washings and slurry from open feed yards.
The annual rainfall and freeboard requirement also had to be factored in – lined earth bank lagoons require a freeboard of 750mm and to have capacity to contain surface rainfall.
Overall, this required an excavation 45m wide, 60m long and a depth of 7m at Graig Olway.
The site where the lagoon has been established has shallow soil with a high stone content – soil sampling indicated a need for the lagoon to be fully lined and for leak detection system to be built in.
The system will help reduce the impact from leaks by enabling them to be detected earlier and dealt with promptly.
Although there was an option to build the lagoon in another field, opting for the site nearest to the dairy unit will ease management and provide easy access for pumping slurry.
“It is important to design your storage to meet the farm’s management system,’’ said Mr Murphy.
The old storage system will be used as a reception pit for the slurry, to prevent sand entering the new lagoon and thereby preserving the lining of the new lagoon.
Farming Connect will hold an on-farm event at Graig Olway on 22 September to discuss the project and the calculations and plans that went into making it happen.
Farmers will have an opportunity to see the new lagoon and associated infrastructure.
Mr Murphy will also give an overview of the new water quality regulations.
Farming Connect, which is delivered by Menter a Busnes and Lantra, has received funding through the Welsh Government Rural Communities - Rural Development Programme 2014-2020, which is funded by the European Agricultural Fund for Rural Development and the Welsh Government.