Farm Ireland

Saturday 16 December 2017

Initial oilseed rape yields are encouraging


Gerry Bird

The winter barley harvest is almost completed, with the welcome sight of cleared fields and golden stubble dotted around the north east and the midlands.

Yields have been in the region of 6.7-10.5t/ha at low moistures and good quality. The average was in the region of 8.6t/ha, which was satisfactory. Growers were happy with the various disease control programmes, particularly some of the newer fungicides. A post-harvest assessment is always useful to determine what contributed to yield -- or the lack of it. I always check the grain and stubble quality when a crop yield is lower than expected in an effort to try to establish the reason for the poor yield. Grain quality reflects the effectiveness of the disease control programme, the soil water and nutritional status, and the prevailing weather conditions.

The disease control programme is easy to assess by judging the levels of foliar disease on the top three leaves.

Premature ripening across a field will indicate moisture deficits or root disorders. Met records will indicate the weather pattern over the grain filling period. Examining the stubble can show up the rooting pattern.

A particular problem this year was root heave as a result of the extreme low temperatures in the winter and early spring. Constricted bushy root systems can indicate compaction problems or poor nutritional status and low pH. Aerial roots at the root crown indicate root heave, and blackened roots indicate take-all, very common this year on winter barley. The colour of the stubble should be a bright yellow and flexible, blackened brittle stalks with poor diameter indicate root disease, poor water uptake, low potash levels and soil compaction.

Winter oilseed rape is well dessicated now due to a combination of good rates of Glyphosate and excellent weather conditions. The perennial problem of sowthistle in these crops is very evident. Harvesting has just begun and initial yield reports are encouraging.

Winter wheat crops are at various stages of ripeness. First wheats and crops treated with organic sludges and manures are holding their colour, with continuous crops well on the way to being ripe. Heads are generally clean in my area, with occasional fusarium outbreaks on single glumes, but it's nothing to be concerned about. Septoria nodorum on the head is not a concern either and grain fill is good, and based on the winter barley yields the wheat potential is promising.

The impact of rotation and organic manures is also very evident on spring barley crops, with green heads and awns still visible. Walking spring barley crops, the volume of aphids on the upper leaves is incredible with flag leaves twisted and glistening with aphid debris. Research at Teagasc would indicate yield loss as a result of this level of pressure on the plant, but it remains to be seen if this will occur this season.

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Crops of beans have grown extremely tall this season which is a response to good nitrogen fixing conditions earlier and the current warm spell. You'll see evidence of this in other crops. Chocolate spot is evident at low levels on bean crops, with occasional downey mildew on lower leaves. Crops are too tall to treat, and it is unlikely that fungicide application would be justified. The beans are clustered around the middle third of the plant with virtually no beans on the top and bottom third. The large canopy will intercept maximum light and even at this stage beans are a good size.

Spring oilseed rapes vary a great deal with some at advanced pod filling, while others are still in full flower. This backwardness is a result of pigeon attack. I came across a crop with bad clubroot recently, an indicator of an insufficient gap between oilseed rape crops in the rotation.

The Geological Survey of Ireland (GSI) recently launched the TELLUS project, a comprehensive soil analysis programme of the border counties from Donegal to Louth. The information gathered will be invaluable for tillage and livestock farmers in providing detailed data on soil nutrients and facilitating improved management and husbandry.

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

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