As the closed period ends there will be a balancing act for farmers to create space in slurry storage tanks while aiming to maximise the efficient use of their slurry.
The nutrient value of slurry at application is influenced by two things - weather and the method of application.
The Phosphorus and Potassium content will be influenced by the diets your animals consume and the dry matter of your slurry. Now is a good time to think about getting your slurry tested and use your soil analysis to create a Nutrient Management Plan for this coming year.
Soil analysis is valid for four years and many farmers in Zones 1 and 2 of the Soil Nutrient Health Scheme will have received a comprehensive soil analysis of all the fields on their farm. Results for Zone 3 farmers will be received in forthcoming weeks.
Soils will still be water-logged after recent rainfall events, so it is advisable to wait until there is a period of dry weather before trafficking with heavy tractors and tankers on fields. Compaction is a real risk with for example a full 2,000-gallon slurry tank estimated to weigh around 13 tonnes.
Soil biology will increase in function as soil temperatures increase and these soil micro-organisms help with the uptake of nutrients from slurry. However, many of them need oxygen to function and exchange nutrients from the slurry and soil to your grass roots.
Compacted soils have reduced air spaces and oxygen within the soil profile so aiming to spread slurry when conditions are dry to reduce compaction and when soil temperatures get warmer will lead to more efficient use of slurry.
Grass starts to grow when soil temperatures are consistently above 5 degrees and legumes will grow when soil temperatures are 8 degrees and above. If you have the capacity in your tanks, aim to apply slurry in the right ground conditions and when the soil temperatures increase.
The typical growth curve shows grass starts to grow markedly from the end of February into early March, which is when you will get an improved response to slurry and fertiliser.
More farmers are making use of LESSE such as a dribble bar or trailing shoe to reduce ammonia emissions and improve nitrogen use efficiency. These machines have a much higher slurry flow rate in comparison to the traditional splash plate tanker, therefore forward speed will need to be increased to ensure application rates are appropriate.
Applying slurry at the right rate, at the right time and in the right place will all help to minimise loss to watercourses on your farm and improve water quality. Improvements in water quality will cut down on watercourse eutrophication (excessive richness of nutrients in a lake or other body of water, frequently due to run-off from the land, water treatment works or septic tanks which causes a dense growth of plant life).
If you do plan to spread slurry in February, remember to stay 15 m back from any waterway (this decreases to 10 m from 01 March) and spread 30 m away from lakes (this decreases to 20 m from 01 March). Also, in the month of February you should apply no more than 2,700 gallons of slurry per acre.
Species that live in the water (fish and invertebrates) and around the water (birds and otters) will all benefit from improvement in water quality as well as people who swim and drink water from these water bodies.