Slurry management
Slurry from housed livestock contains valuable nutrients that should be recycled back to land in an environmentally sustainable manner.
Flooring systems in the CAFRE dairy cow sheds and also in the maiden heifer rearing accommodation have been installed using Dutch designed flooring products. The purpose of these grooved floors is to reduce ammonia emissions from faeces and urine deposited by the animals through minimising contact between the urine and faeces. The floors also provide good gripping surfaces for the cattle which is important to reduce injuries and enhance expression of natural heats. These solid floors are scrapped regularly up to 10 times per day in winter which also reduces ammonia emissions. Slated areas have plastic flaps across the slurry channels to minimise gaseous exchange between the head space of the below ground tanks and the air in the building, thus further reducing ammonia losses.
The majority of slurry produced is kept in covered above ground stores. This system reduces the storage capacity required as rainwater is not collected and also reduces gaseous exchange with air to also reduce ammonia loss. Stores are mixed via a ‘low rate’ aeration system which greatly reduces both methane and hydrogen sulphide production during slurry storage. This has positive environmental benefits including reduced methane emissions and also reduces the risk of injury or death of people and animals from slurry gases released when below ground tanks are mixed. Slurry is always in a mixed state and ready for spreading whenever conditions allow which is another very important feature of this storage system.
Slurry is land spread by trailing shoe or band spreading systems to reduce ammonia loss during the field operations. This improves the fertiliser N value of the slurry. Emphasis is placed on applying slurry to silage fields and arable land in spring at a rate of approximately 3,500 gallons per acre. Nitrogen in slurry is better utilised in spring as a result of reduced ammonia losses leaving more N available for grass growth. Long term grazing land does not receive slurry as soil analysis of these fields indicates that the P and K nutrients are at optimal levels. Slurry will also be applied after 1st and 2nd cut silage at approximately 2,500 gallons per acre with subsequent bagged fertiliser applications reflecting the amount of slurry applied. Soil analysis indicates that P and K status of fields used mainly for silage are very similar to those in long term grazing and are mostly optimal for production, indicating good nutrient and soil management across the farm.
Watch the video to view practical measures used in the CAFRE Dairy Centre
A simple and easy to use method to determine slurry dry matter content and by proxy, N, P & K content, has been developed by CAFRE. Click on the video on the right for more information. The calculator is not yet available online but can be obtained by contacting Stephen Gilkinson by Email: stephen.gilkinson@daera-ni.gov.uk
