Empty now and benefit later

The Nitrates Directive aims to protect water quality, and one of the requirements of the Action Plan will be a closed period for spreading slurry during the late autumn and winter months. These restrictions will not be in force this autumn. However it is good practice for livestock farmers to empty their tanks before the onset of winter.

The Code of Good Agricultural Practice for the Prevention of Pollution of Water recommends having at least six months storage capacity and states that tanks and stores should be emptied by 1 September. Applying slurry now, after the dry summer, will exploit the potential for growth that will occur once soil moisture levels rise with the onset of wetter weather. Application later in the year, when conditions are less favourable and more prone to nutrient loss, will significantly reduce the impact of any slurry applied. Ideally, storing slurry over winter for application in spring would achieve a higher level of efficiency. However having sufficient storage capacity is essential to allow for this.

	Percentage of Total N	available to next crop
	Application in Autumn	Application in Spring
Cattle slurry 6% DM	20	20
Pig Slurry 4% DM	20	20

(Source: Fertiliser Recommendations RB209)

If slurry storage capacity is limited, you should aim to empty tanks completely. Leaving just 600mm of slurry in a tank measuring 10 m wide by 24 m long, equates to one month's storage on a 70 cow dairy farm. Preventing clean water from entering these tanks can help to maximise storage capacity. Take the opportunity to apply, where practical, on reseeds, aftermaths and on swards with long rotations. Increased winter storage for a spring application,contributes significantly to grass growth and cost effective production, but also brings about environmental benefits.

For further information on spreading slurry to maximise efficient use of N,contact Countryside Management Staff at your local DARD office.