Managing grass growth and fertiliser in an adverse spring 

Over the weekend I had the pleasure of having a chat with John O’Loughlin, Grassland Agro Specialist Advisor, about how silage stocks and slurry storage have come under even further pressure of late due to freak weather.  However the most unsettling issue at the moment on many farms is grass growth or lack thereof. 

Three key questions that arise on farm;


What to do with surplus unprecedented slurry stocks?

Slurry generated as a result of delayed turnout should be diverted towards silage ground.  Using slurry on grazing ground will increase the likelihood of grass tetany due to luxury uptake of potash (K).  This will be compounded by a large increase in grass production which should be around the corner.


Where using slurry on silage ground after it is stopped is impractical due to machinery or proximity it may be wise to consider the use of a band spreader or trailing shoe.  It’s also advised to be disciplined and not allow large applications in excess of field requirements.  Avoid the use of an NPK compound and consider straight N and straight P (Top Phos 0-10-0-9) or an NP compound (NutrigrassP 20-4.4-0-6). 


How to stretch silage reserves?

 Unfortunately silage is already scarce in the country due to poor weather last and the long winter.  Indeed silage has been delivered from earlier ground to the west of the country.  We can’t magic up silage in a yard, but one option is to try and stretch with straw.  But again straw is also scarce and expensive this year for the same reasons as silage. 


The best advice is to do an analysis on the remaining silage stocks to examine the quality.  This will inform the best concentrate to supplement with.  Which will help to minimise costs by increasing efficiency of bought in concentrates.  Contact your local coop / merchant who should be able to advise on silage testing.

How to manage spring fertilizer? 

The two key nutrients required for spring growth are N and P.  The big question on many farms presently is whether to go with a full bag of urea where the first application has been missed on a lot of farms.  The next question is to proceed with a second or third round despite the lack of growth and N uptake. 


A proportion of the N fertiliser in the form of Urea spread already this spring can remain in the soil until soil temperatures improve.  If there were to be a significant improvement in soil temperature it might be possible to have exceptionally high nitrate levels in the grass post magic day.  This could lead to embryonic death and fertility problems. One method to overcome this challenge would be to use N-Process phased release N to increase Nitrogen conversion to crude protein.


What is often overlooked in soil fertility discussions is the actual function of each nutrient.  The primary function of P is to stimulate roots and N is taken up the through the roots of grass.  Where the topic becomes more complex is that P availability is driven by soil temperature.  At colder soil temperatures there is less P available.


The second issue is that P is very likely to be locked up In the soil due to binding to elements such as iron and aluminium.  To overcome this problem Roullier Group, the parent company of Grassland Agro, has developed a new form of phosphorus which is readily available irrespective of soil pH and cannot be bound in the soil.  Top phos is a new straight phosphorus fertiliser with sulphur exclusive to grassland Agro.


Grassland Agro offer a FREE fertiliser planning service which will deliver a fertiliser programme specific to your farm.

Contact your local agronomy specialist.