
Increasing fertiliser costs have undoubtedly focused minds on reducing input costs but, as detailed in the last issue of KnowHow, depriving a crop of grass of its required nutrients is not cost-effective, even with bagged fertiliser at almost £1,000/t.
So, what alternatives and improvements can be made to reduce the fertiliser bill? Understandably, some farmers have sought to find other sources of nutrients for the growing crop, such as imported manures and digestate from anaerobic digesters. But we should also focus on the resources we already have and ask what we can do to accumulate more available nitrogen from the slurry store and take this off the manufactured fertiliser nitrogen input.
Switching as many applications as we can from autumn and winter to in-season can help, as can moving from splash plate application (see photo above) to dribble bar (see below) or even injection. Making just these seemingly small changes could take up to 40kg N/ha off bought-in fertiliser applications for a dairy system.
We should also examine the options for improving the storage of slurry to retain and enhance more of the nutrients before the application stage. After all, the nutrients in the slurry store have already been paid for by the business. Ruminants are, at best, only 35% efficient in converting feed nitrogen to milk and meat nitrogen so most of the nutrients in the slurry store come from purchased and used feeds and fertilisers.
Slurry covers might seem like a costly option, but they reduce ammonia loss and hold more of the available nitrogen. There is also a growing market for products that add bacteria (microbes) to the store to break down the organic matter, thus releasing vital nutrients which promote grass and crop growth.
As the last issue showed, our unique slurry improver Digest-It is performing better than its competitors both in independent trials and as attested by the two featured farmers. But, even with pre- and post-treatment testing proving the financial return, how can you be sure you are really capitalising on this and utilising your slurry to its full potential? This can only be achieved by looking at the before and after analyses and making amendments to the nutrient management plan to reduce the amount of bought-in nitrogen, phosphorus and potassium.
To manage nutrient inputs for your growing crop as efficiently as possible, Kelvin Cave Ltd is pleased to have joined forces with independent plant nutrition consultant Dr George Fisher to offer the Slurry-Wise nutrient management programme.
When purchasing Digest-It you will also be sent the following:
- Before and after slurry analysis kits
- Pre-cut grass test kits
- Soil analysis kits (if required, at extra cost)
On completion of a simple cropping and soil type participating farmers will then have a phone consultation with Dr Fisher. This will enable him to provide a short and practical written nutrient management action plan aimed at achieving optimum forage yields as cost effectively and sustainably as possible. A further follow-up call is also offered to discuss the report and how best to implement it.

Pre-cut grass testing will help to make informed decisions on timing of cutting which, along with preservative or additive selection and management advice from our team, will ensure the best possible silage is produced to maximise livestock performance from forage. Even with the higher cost of production, milk or meat produced from home-grown feed will always be more profitable than that produced from bought-in concentrates.
Taking this new approach is another step towards better utilisation of on-farm resources, minimising the impact of price volatility and maximising performance and profit. It builds on those seemingly small changes that, put together, can have a big impact on costs. At Kelvin Cave Ltd we trust our products and technical approach, which is the reason for the development of this unique programme.

