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Critical decisions must be taken to maximise yields

It seems that we're not out of the weather rollercoaster ride yet, as we approach the 12-month mark since the weather first broke – and there is still no sign of a reprieve.

The current mix of cold and wet, alternating with colder and dry, is having a bigger impact on winter crops than spring crops at this stage.

Oilseed rape isn't getting a chance for the well-established roots to start work and mop up nutrients for leaf growth. It normally has an amazing capacity to produce leaf.

However, we're now into April and the only green in most fields is still weeds. Given that flowering in a normal year is only four-to-five weeks away, it is likely that yield will be severely impacted.

However, it is not a normal year and critical decisions on remaining expenditure have to be taken, especially fertiliser.

Phosphorus (P) and potassium (K) must be applied where required, and the crop must have sufficient amounts of nitrogen available to meet the requirements for leaf growth once growth commences.

The only saving grace is that if the worst occurs any nutrients not taken up by a poor crop will probably be available for the next crop sown early in the autumn.

Winter cereals are also crying out for some heat and clement weather to start the process of going through their growth stages. It's likely that when growth commences, crops may take their cue from day length and race through the growth stages to catch up with the season.

This will affect green-leaf production and impact on the ability of a crop to maintain tillers and grains in the ear of the plant. However, such deficiencies can be compensated for by successful grain fill later in the season.

It would be a reverse of what happened in 2012, where high numbers of grains just weren't filled.

Rapid crop growth will need careful monitoring as they shoot through growth stages to ensure that critical development stages are not missed.

Weak crops also need a break soon if they are to get back to a healthy state and break even. Apply a small amount of cycocel and a liquid feed with nitrogen and phosphorus to encourage tillering on these weak crops as soon as growth commences.

It might be a good idea to repeat this again seven-10 days later.

There is a question mark over what has happened to the fertiliser already applied to crops this season. P and K are not prone to leaching, but nitrogen in the nitrate form is very prone to doing so – more so than nitrogen in ammonia. Calcium ammonium nitrate (CAN) contains both forms of nitrogen and urea is based on ammonia.

Crops can take up nitrogen very rapidly after application, well before effects are observed. In short, don't assume all fertiliser applied is lost.

The best approach is to continue with the planned application programme and apply a little more later in the season if necessary.

That is on the basis that a field has not been covered with 30cm of flood water or torrents of muddy water at one stage or another over the past few weeks.


If this has been the case, it's a safe bet that a good portion of the fertiliser has been lost.

Nutrients bound to soil particles are safe from leaching, but not safe from loss when the soil particles themselves end up in the river. From an environmental perspective, dilution by floodwater will limit the effects of this nutrient flush.

Spring-sown crops in the ground appear to be safe enough. The cold weather has had some benefit for spring-sown winter cereals which should have received enough cold weather post sowing to achieve vernalisation, which will allow them go through their growth stages successfully.

Most spring-sown crops have just chitted and the only thing to watch out for is attacks from pests, particularly crows.

Given the lack of options available for bird control, regular monitoring combined with bangers, kites and shooting, where necessary, are the only options.

Cold soils are not the ideal way to outgrow these attacks as cold weather slows growth and hungry pests are less choosy and risk-averse than they otherwise might be.

It's still early in the growing season and a few weeks of good growing conditions will turn things around dramatically.

The main priority while waiting for conditions to improve is to prepare for the coming onslaught of work that inevitably builds up in late seasons.

Get all machines ready, calibrate the fertiliser spreader, sprayer and sower and get all fertiliser, seed and spray organised and in place.

Devise a plan to prioritise work and ensure that this plan is implemented.

Dr Richard Hackett is a crop consultant and member of the ACA and ITCA – email:

Irish Independent