From a grass perspective, it has been quite a good winter. Last autumn, cattle did have to be housed earlier than planned, but this early closing combined with a steady winter growth means grass supplies are in quite a healthy state.
Of course, most land is still a long way off being fit to graze, but we are at the stage where we should be thinking about our spring grass plans. Slurry and fertiliser spreading should feature highly in these thoughts. We want to put a plan in place where all ground will have received 60-70 units/ac of nitrogen (N) and an application of phosphorous (P) and potassium (K) by the end of March.
Before doing anything, walk your farm – ideally carry out a grass cover, but at the very least, identify the areas with strong grass covers and low covers. If you implemented a 60:40 plan last autumn, this should be easy.ADVERTISEMENT
The slurry spreading season is now open for counties in zones A and B. The four zone C counties – Cavan, Monaghan, Leitrim and Donegal – can start spreading on and after 1 February.
Over 80% of the value of slurry comes from its P and K content. Every 1,000gal of cattle slurry typically contains five units of P and 35 units of K. The remaining value of slurry is in the form of N. Slurry spread in spring typically offers six units of N per 1,000gal. When spread with low-emission equipment, this can be as high as 10 units/1,000gal.
Significantly, because of warmer, drier weather, over half of this N is lost in slurry spread in summer and autumn. For this reason, we should be looking to spread as much slurry as possible in the spring. Also, application early in the year allows for the nutrients to be released over a longer growing season.
Most land is still a long way off being fit to graze, but we are at the stage where we should be thinking about our spring grass plans
Spreading slurry in spring should happen in two stages:ADVERTISEMENT
- The next application will not take place until March. In the meantime, if weather plays ball, we will hopefully be grazing in early February, starting with our heaviest grass covers. By early March, around 30% of your farm should be grazed. This ground should receive 2,500-3,000gal per acre then.
- Spread between 25-30 units/ac of N for this first round.
- In early March, spread 45 units/ac of straight N on the ground that received slurry.
- Spread a compound fertiliser (e.g. 18:6:12) totalling between 35-40units/ac of N on ground that did not get early slurry in January or during the second phase of slurry spreading in March. Finally, at the end of the month, spread 30units/ac of N fertiliser on the ground that receives January fertiliser and early-March slurry.
When spreading, remember: a good day for drying clothes on the line is a bad day for spreading slurry. Ideally, conditions should be overcast with little sunshine, damp and calm. Slurry at this time of the year does bring difficulties also, particularly around agitating.
Take cattle out of the shed before starting to mix a tank.
Because of warmer, drier weather, over half of this N is lost in slurry spread in summer and autumn
On ground that is not receiving slurry, we should spread N fertiliser. This will equate to around 60-70% of the farm. And we should be trying to get out as early as possible, once conditions allow – ground should definitely not be waterlogged (and no heavy rain forecast) and soil temperatures should be above 5°C. I would also like to spread ground before it is grazed – higher grass covers will have higher N uptakes and lower N losses.
Fertiliser applications will also be in two stages – January and March.
The two most common N fertilisers in Ireland are CAN (27% N) and urea (46% N). However, both products are susceptible to N losses – nitrous oxide from CAN or ammonia from urea – under poor soil and/or weather conditions. Quite simply, this is bad for the environment.
Protected urea (typically 46% N) is urea treated with a urease inhibitor (NBPT/2-NPT), which reduces both ammonia and nitrous oxides losses, helping to reduce their impact on both air and water quality. Protected urea can be spread at times when you would spread CAN or unprotected urea.
Early 2020 prices pin urea at €340-350/t, CAN at €240-250/t and protected urea at €380-390/t. Protected urea is typically about €40/t more expensive than unprotected urea.
Traditionally, unprotected urea is the product of choice this time of year. If spread in the right conditions (cool, damp and calm), ammonia losses from this product are typically low. As a result, the benefits of using protected urea at this time of year are likely to be minimal.
Protected urea does offer a good opportunity to replace CAN, however.
Research has shown protected urea yields consistently as well as CAN. It also has the potential to reduce greenhouse gas emissions and it is economically beneficial – about 6c/kg N cheaper, or €10/ha on an average drystock farm’s N application rate.
Ger McSweeney – Cork
My priority this week is to get slurry out and take the pressure off the tanks. I’ll be going out onto my lowest grass covers, the ones I grazed last in the autumn. I’d say they’re about 600-700kg DM/ha. I’ll apply 2,000gal/ac there.
In terms of fertiliser, I’ll go with half a bag of urea (23 units) per acre on my good covers as soon as conditions allow. This was the ground that was closed first which means it’s mainly my drier ground. Hopefully that will be early February. I plan be getting out grazing soon after that but I’ll definitely be trying to get spreading before I graze.
I didn’t buy CAN at all last year. I used protected urea from late spring onwards and I was very happy with it. I didn’t notice any difference in grass growth which was the most important thing. I actually found it was one less thing to be worrying about too. Sometimes it’s hard to know what to spread with weather conditions during the summer but I’m told protected urea is less vulnerable to volatisation.