Fertiliser Update

Fertiliser Update – Until growth drops below 50kgs DM/Ha you should still apply fertiliser as normal.

Once below 50 starts adjusting downwards. Currently there is a soil moisture deficit but growth on average has stayed reasonable and there’s a lot of rain, 25-30 mm, forecast over the coming week. This should help ease any potential moisture related growth check

Keep spreading N to keep grass growing, depending on available allowance 0.8-1u per day (lower on high clover swards, 0.3-0.4 u N/day)

Last week growth rates averaged 59kgsDM/Ha , with a range from 39-78 kgs DM/Ha

Predicted growth for this week is similar @ 57kgsDM/Ha

Current SMD:

Soil moisture deficit and growth:

SMD 25-50 mm – moderate effect on growth

SMD >50 mm – growth will become restricted

SMD >75mm more severe drought conditions set in and perennial ryegrass will begin to go dormant i.e. growth will begin cease and the plants will begin to lose its green colour.

SMD and Fertiliser Application:

If SMD ≥ 50mm and grass growth rates fall to <50 kg DM/ha per day reduce fertiliser N applications in line with demand and top up with additional N once sufficient rain arrives.
If SMD is ≥ 75 (severe drought) and grass growth is << 50 kg DM/ha hold off further N applications until sufficient rain arrives or further rain is forecast. Where re-growths are poor or non-existent, stop spreading fertiliser. Have fertiliser on hand for spreading once growth recommences bearing in mind that a flush of N mineralisation once soils rewet will support initial regrowth.

Fertiliser N applications in line with demand:

For the majority of our supplier base grass growth will be restricted due to low soil moisture levels. Under lower levels of growth, the grass demand for N uptake will also be reduced.

During droughty soil conditions fertiliser N advice needs to be adjusted downwards based on predicted grass growth.