Consider switching to new urea products to save 30c/kg of nitrogen

TILLAGE

Pat Minnock

Pat Minnock

Already this year there has been over 30pc of the average annual rainfall and while it looks like there may be some respite on the way, it will be some weeks before most land can be worked.

At this stage seed bed conditions are more important than trying to force early sowings in poor conditions. The very wet and relatively mild winter will ensure that winter crops will again have different problems this season.

While disease levels in winter wheat, barley or oats do not currently appear particularly high there is no doubt once growth starts eye spot and septoria in wheat and rhyncosporium and net blotch in barley will be much more prevalent.

There are many discussions ongoing at conferences currently as to the best strategy particularly for septoria control in wheat but until we see growth and the actual situation with disease levels the decision on a fungicide strategy, particularly a T0 application, should wait for a few weeks.

My colleagues and I will revisit this and suggest options when nearer to the relevant application times. Advance barley and wheat crops are nearing growth stage 30 so decisions on fungicide treatments may be sooner rather than later.

Initially, however, the first fertiliser split on winter crops should be considered. Field work should not start until soil conditions allow and deep rutting of tramlines should be avoided if at all possible. The application or use of machinery in wet fields leading to deep rutting will mean that these ruts will remain with you for the season and cause more problems.

Delayed nitrogen applications to winter barley crops will not be overly penal as these crops continue to remain in a vegetative phase and therefore continue to lay down grain sites which will ultimately lead to higher grain numbers per ear and should have little effect on yields.

In my opinion it is more important that once fertiliser applications commence that crops continue to be fed and not set back, due to lack of fertiliser during the growing season.

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The first split of nitrogen to winter wheat should be 50-70kg/ha (40-56 units /ac), with potential take-all situations receiving an additional 20-30kg. For winter barley a third of the projected nitrogen application (60kg or 48 units) should be applied over the next two weeks. For thin crops little and often will give better results and lead to fewer nitrogen losses. Around 15kgs of sulphur per hectare should also be included.

COSTS

With the high cost of fertiliser, consideration should be given to using urea in place of CAN for the first split. The price differential can be significant, with nitrogen from CAN costing approximately €1.10/kg, while nitrogen from urea costs about €0.80/kg.

While some losses of nitrogen when using urea might occur, particularly in dry or recently limed soils, if urea is applied under cool, moist conditions, when rain is imminent these losses are virtually eliminated.

This year a number of new urea products are available namely Koch Advanced Nitrogen (KAN) and Goulding Enhanced Nitrogen (GEN). These compete favourably with CAN in price per kg of N available. Sulphur should also be included in the first split with a minimum of 15-20kg/ha for cereals recommended.

Most winter crops received an autumn herbicide, however, due to the prolonged and heavy rainfall the persistence of the IPU in particular may have been affected, with the possibility of greater grass weed problems. Winter oilseed rape has established well and there are well structured crops this spring with weed control generally good.

A graminicide may be required for volunteer cereals or wild oats. Crops with good canopy cover require a different nitrogen strategy than those areas grazed by pigeons.

Nitrogen and sulphur should be applied immediately to thin or grazed crops with up to 225kg/ha (180 units) of nitrogen allowed at index 1. A further 175kg (140 units) should be applied by early stem extension. Nitrogen should be held back and applied as close as possible to flowering. This will prolong green leaf area during pod fill.

Oilseed rape is very responsive to sulphur and a minimum of 30kg/ha (24 units) is recommended. ASN is probably the most appropriate fertiliser for the first split. A minimum of 5kg/ha of Solubor should be applied, especially to those crops that received no Boron in their base fertiliser.

A word on buffer margins. Remember to leave a 2m uncultivated and unsown strip alongside all surface waters identified on the six inch OSI map. Allowances will be made in 2014 for winter cereals already sown or ground already ploughed for spring cereals. However, if ground is ploughed do not sow in this margin in 2014.

It is now too late to sow winter wheat varieties. Sowing priorities should be given to beans, spring wheat and oats once soil conditions and weather improves.

Pat Minnock is a Carlow based agricultural consultant and a member of the ACA and the ITCA. www.minnockagri.ie

Indo Farming


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