Dairy Farmers improve their nutrient management skills

A recently completed project by the Institute of Biological Environmental and Rural Sciences’ Grassland Development Centre at Aberystwyth University has helped over 200 dairy farmers across Wales to get more from their slurry and fertiliser nutrients.

The Grassland Development Centre at IBERS carried out the work for the Dairy Development Centre based at Gelli Aur, Carmarthen to help dairy farmers in Wales address how they target both slurry and fertiliser nutrients to their land. The project was supported by European Union Objective One funding.

The GDC Extension team have produced a report for each of the farmers in the project that highlights the key areas where nutrient use efficiency could be improved. Recommendations are based on the results of slurry and soil analysis from each farm and information supplied by the farmer on his current slurry and fertiliser practice. This report can then form the basis of a Farm Nutrient Management Plan. 

The farmers in the project were all members of discussion groups across Wales. These discussion groups formed the platform for a series of on-farm meetings to talk about the key outcomes of the project and for farmers to discuss their individual reports.

The main aims of the project were to flag up the importance of balancing nutrient inputs with soil supply and crop demand and to emphasise the benefits of making decisions based on accurate information rather than just guessing.

Chris Duller, GDC Extension Officer, said “Working out how much fertiliser a silage crop needs after it has had a dressing of slurry is a decision that almost every conventional farmer in Wales has to make. If he gets it wrong, it can either mean losing out on yield by not providing enough nutrients, or else oversupplying nutrients which will be an economic waste, a potential source of pollution and could lead to a poor quality fermentation. However, if he knows his soil nutrient status, slurry nutrient content and application rate it is fairly easy to make an accurate assessment of what is needed from bagged fertiliser to optimise grass growth and quality. This project was all about providing quality information on which to make sound business decisions.”

Standard ‘book figures’ are a good starting point when it comes to making an assessment of the nutrients supplied from slurry. However the samples taken in the project showed a massive variability in nutrient content, depending on storage conditions and feeding regime. This variability (ranging from 20% to over double the book figures) emphasises the value of sampling and analysing your own slurry.

When analysing slurry nutrients it is vital that the sample is representative of what is actually spread. Taking a sample from a well stirred store or even from the tanker in the field are the recommended options. Grabbing a sample from the yard or from the reception pit is not going to give a meaningful result.

The project also revealed a large variability in soil nutrient status. Over 40% of soils were above target index 2 for phosphate, offering opportunities for reducing purchased phosphate fertilisers. Almost 50% of soils were deficient in potash (below index 2+), which would be restricting silage yields.  Only 30% of all soils sampled were in the target pH range for optimum grass and clover growth (6-6.5).

There were a significant number of organic participants in the project. With a sole reliance on the nutrients in the slurry store to drive grass growth it is very important that they have the information on how to best-target their slurry applications. Equally, with a strong reliance on clover for nitrogen fixation, it is important that soil nutrient status is maintained at target levels to optimise clover growth.

The farm reports and the discussion meetings raised many issues that farmers would like to investigate further over the coming months to further improve their nutrient efficiency.

With ever increasing prices there will be many difficult decisions to be made about the most cost effective ways to grow grass.  This, coupled with the threat of NVZ legislation impacting further in Wales, makes it essential that farmers think more carefully about how they store and utilise their slurry to maximise the amount of nutrients that go back into grass growth.

Further information:

Grassland Development Centre, IBERS, Aberystwyth University 01970 823026 / Dairy Development Centre 01554 748570

Notes to Editors:

On 17 April IGER merged into Aberystwyth University. As a result the Institute of Grassland and Environmental Research at the Gogerddan site and two current University Institutes, Biological Science and Rural Sciences, have joined together to form the Institute of Biological, Environmental and Rural Sciences IBERS, creating the UK’s largest group of scientists and support staff in its field.

The Grassland Development Centre provides an extension capability to promote the transfer of science and technology to agriculture and associated industries. The GDC is currently funded through Farming Connect to deliver extension services across Wales in collaboration with other sector Development Centres.

The Dairy Development Centre (DDC) is one strand of a multi-faceted resource for the agricultural industry known as Farming Connect. The purpose of the Centre is to facilitate the development of the Welsh dairy industry through the provision of a pro-active technology transfer service and market intelligence, working in collaboration with key partners to organise events illustrating best practice techniques and new technologies. The Centre is based around a co-ordinating Development Centre and a network of Development Farms, Demonstration Farms and Discussion Groups.