Farm Ireland

Saturday 16 December 2017

Get your fertiliser strategy correct to make a solid profit

Gerry Bird

The sight of lime dumped in gateways is another sign that the growing season is about to take off, and it won't be long until the first fertiliser spreaders take to the fields.

A minority of dairy farmers in the northeast have released cows from the confines of the winter quarters for some daytime grazing, all signs of the favourable ground conditions.

Tillage farmers are ploughing away, with drilling of wheat and beans being considered.

The perennial question as to whether to drill a winter or spring wheat variety at this time is a topic of conversation.

My experience is that after mid-February, a spring variety is preferable to drill, with similar yield potential to the winter varieties but with an earlier harvest date and possible milling potential. Late harvests have resulted in delayed drilling and subsequent establishment problems for some of my growers over the past few seasons and should be avoided if at all possible.

Sprayers are on the move tidying up weed control mainly on winter wheat crops. Weed size is critical if applying the traditional winter cereal programmes based around IPU, DFF and pendimethalin herbicides.

The excellent growing conditions are good for the weeds and the crop, and the problem weeds -- cleavers, meadowgrass, speedwells, fumitory and pansies -- are generally at advanced growth stages which are difficult to control.

There are plenty of product choices to deal with these weeds now or later on. However, early control is important with cleavers in particular.

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Wheat crops are well tillered with some up to growth stage 30. Septoria tritici is evident on all crops, so the inclusion of chlorothalonil as a T0 would be a good strategy to reduce the disease levels as the crop starts to produce new leaves after the first nitrogen split.

A factor to consider when spraying is the quality of the water used. I recall dealing with poor fungicide performance some years back. The hardness of the water was a considerable factor affecting the performance -- a fact not easily accepted by the farmer.

The hardness of water is related to the calcium content, and also is affected by other elements, such as iron and magnesium. The pH of the water can also impact on the potential pesticide performance. The calcium in the water can bind with the active ingredients of certain products, particularly where the pesticide formulation is poor and less than satisfactory product performance can result. Hard water indicator strips and products designed to mop up the calcium and other elements and reduce the solution pH are available from merchants and are well worth considering.

The past few days have been spent completing nitrates and pesticides records for last year and setting out the fertiliser allowances for this year. The extra nitrogen and phosphorus allowances for high-yielding cereal crops and malting barley are to be welcomed.

The price of fertiliser and the quantities used on the average tillage farm make fertiliser the most expensive input in growing a crop. The 'recovery' of applied fertiliser is variable, with values as low as 20pc for crop uptake of nitrogen possible where soil pH is low, soil is compacted and the root mass is poor. Nitrogen moves through a soil quickly, so where soil temperatures are low, with poor plant rooting, and excessive soil water, nitrogen recovery will be poor. An important factor is also the levels of soil calcium, magnesium, potash and sulphur.

The application of trace elements such as magnesium and sulphur in the early season, to help nitrogen uptake, should be part of the fertiliser management plan if they are known to be deficient.

The use of urea at the first split, if phosphorus and potasium has already been applied in the autumn, is cost effective as a source of nitrogen. The application of urea comes with a health warning however. Make sure there is a good crop cover; apply in dull, damp conditions; and watch the spread pattern over wide tramlines.

Fertiliser contributes up to 50pc of the crop potential and the correct fertiliser strategy is the difference between profit and loss.

Gerry Bird is a crop consultant and member of the ITCA. Email:

Indo Farming