Replace lost nutrients after silage harvesting
Summer is on its way, and many farmers have been utilising the warmer, drier weather to harvest silage. If you’ve just
completed harvesting silage, Ballance Agri-Nutrients Technical Consultant Aaron Stafford says now’s the time to consider
replacing the nutrients removed from the soil during the process.
‘Nutrients vital to sustaining the long term production capability of the block are removed from the soil during
production of high quality silage,’ explains Aaron. ‘Consideration should be given to replacing these nutrients
immediately after the crop has been removed to encourage re-growth of desirable pasture species and allow a more rapid
return to the grazing round to help build up feed prior to the drier summer period.
The amount of nutrients that should be replaced with fertiliser following the harvest of silage depends on a number of
factors. For example, in cut and carry systems (e.g. when harvested from a runoff block and fed out within the milking
platform) silage is not fed out back onto the land from where it was harvested. Hence, the net export of nutrient (and
therefore fertiliser nutrient requirements) is much greater in this scenario, than where silage is harvested and then
partially or entirely fed out back on to the same area. In addition, where soil fertility is above optimum (e.g. soil
potassium levels on effluent blocks), withholding fertiliser inputs following silage harvest may be a viable option to
mine back these levels.
‘A silage crop yielding 4 tonnes of dry matter/ha will remove around 16 kg/ha of phosphate, 80 kg/ha of potassium, 14
kg/ha of sulphur, and 8 kg/ha of magnesium. It’s important this is replaced, otherwise over time the paddocks will
reduce production and start reverting to poorer quality species. Ballance pasturemag 15K or pasturezeal G2 Hay & Silage are good options for most scenarios, with both options containing nitrogen to stimulate faster recovery, or set
up the paddock for a further harvest.’
‘It’s also important to remember that a post-harvest fertiliser application does not replace your normal maintenance
fertiliser,’ says Aaron. ‘It’s an extra application that takes care of the nutrients that have been removed in the
harvest of silage alone.’
Contact your local Ballance Agri-Nutrients technical sales rep on 0800 222 090 to design a fertiliser programme to meet
the demands of your farm.
ENDS