Chasing Marginal Kilos of Grass – Andy Dodd (Chippenham)

We often hear the debate around the cost-effectiveness of chasing marginal litres of milk but what response are you getting from nitrogen applications on your grassland?

The target has always been to grow as much grass per ha as possible, be it for grazing or harvesting but as you run through a typical grazing season, the response to fertiliser applications will change, not only across the farm but field by field.

The clear advice is to soil sample and know what the crop will need but a recent project in Wales has shown some very interesting results in reducing nitrogen application rates from July onwards.  In the trial areas of each field, the farm cut nitrogen applications on their grazing ground by half, from July through to September.  This did result in a reduction in the amount of grass grown, as seen below but the reduction of over 70/kg/N applied over the period is a significant cost saving across the farm.

The soil was then sampled to check nitrogen levels in October, although a base level of nitrogen was found in all trial areas, there was an average of 60kg/ha in the areas that had the full nitrogen application.  This will just leach away over the winter, so the money is just wasted.

Clover leys are also being introduced across the farm, these needed a maximum of 120/kg/ha of nitrogen to maximise grass yields with nitrogen being fixed by the crop and utilised when required.  It is important to note, the clover will not fix nitrogen until mid-May onwards so reduced application of fertiliser is not recommended prior to this to ensure sufficient early season grass growth.  If weeds are an issue in new leys, clover can easily, and cost effectively be introduced into an existing grass ley after weeds are treat.  This can be a simple as adding clover seed into slurry tankers when applying to grassland.

This approach will not work on every field so knowing your soil type and regular soil sampling results will be crucial to successful reduced fertiliser applications.  Measuring grass growth and monitoring the response to reduced applications is key.

What savings can you make and how much money are you wasting on chasing those marginal kilos?  To discuss further, contact Andy at andydodd@fcgagric.com or speak to your local FCG office.