Farm Ireland

Sunday 25 February 2018

Sterile brome has become a major weed enemy for winter barley

Sterile brome lurks unnoticed in many hedges, dikes and ditches all over the country. Once given a fighting chance it will spread like wildfire.
Sterile brome lurks unnoticed in many hedges, dikes and ditches all over the country. Once given a fighting chance it will spread like wildfire.
Pat Minnock

Pat Minnock

While the weather has delayed the completion of the 2016 harvest, it was surprisingly better, yield wise, than expected. Even many late sown spring barley crops produced 3t/ac plus.

Arable areas continue to fall despite relatively good yields. The total cereal acreage fell again by 2.2pc from 2015 to 2016 despite very good yields in 2015. It is likely this trend will continue this season and highly likely that the big increases in winter barley plantings over the last few years will be reversed as a result of the better spring barley yields and returns compared to winter barley this year.

For those considering winter barley the temptation will be to sow early. However, experience has shown that very early sown winter barley can underperform. While early sowing leads to earlier growth, it also leads to greater lodging pressure, increased take-all and particularly higher incidences of barley yellow dwarf virus (BYDV) and disease. Delay sowing until late September or October. The use of Redigo Dieter is essential for early sowing.

There is a significant variation in seed size this year particularly between varieties. You should aim to establish 250-300 plants/m2 which will tiller to produce 1000-1200 heads/m2.

The conventional variety Cassia continues to perform well and will be about 25pc of the seed available, while Tower, also a conventional 2-row, will be the most plentiful (47pc) with Infinity (14pc) and Kosmos a 6-row (1pc) also available.

The hybrid 6-row varieties, Volume (4pc), Quadra (0.5pc) and the new Bazooka (6pc) offer growers the opportunity for higher yield, subject to higher management inputs.

The post mortems of the winter barley yields are in full swing. In my opinion the increased area of the crop over the last few years has resulted in more winter barley being sown on less suitable ground. In addition, management is more demanding, especially with hybrids. This harvest proved again that winter barley yields are better in fresh ground and particularly after break crops, indicating the effect of take-all.

Aphid control and, by association, BYDV control is extremely difficult especially in early-sown crops. However, the main reason for the poorer yields this harvest the loss of approximately 30pc of plants due to the wet winter. Barley does not like 'wet feet' and this crop appears to have suffered from this this year. Sowing in wet or relatively wet ground, where water lodges should be avoided at all costs.

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Furthermore, sterile brome is an increasing problem in winter barley. There is no control for sterile brome in this crop and if there is any indication of sterile brome in the previous crop these fields must be avoided. An apparent light infestation at harvest time will quickly develop into a very high infestation in the following crop and yield reductions will be significant.

Sterile brome has become a major problem in tillage land and needs to be managed properly. Light cultivations (less than 2 cm) with rolling is recommended to encourage germination. When brome has two or three leaves it should be sprayed off with glyphosate. This exercise should be repeated a number of times and preferably, hold off to sow a spring crop. The use of break crops allows treatment of brome in the following crop.

Catch crops - if you are in GLAS you need to have your catch crops sown by Thursday this week. You must use two varieties and a min-till non-plough system.

It is now getting late for sowing winter oil seed rape. There is no doubt, particularly with the current soil conditions, that growers will be tempted to sow for another few weeks. Reasonable results can still be expected if sown into a good firm seed bed as soil moisture, and higher than normal temperatures, will help quick establishment.

Some of the hybrid varieties e.g. SY Harness have good autumn vigour. Keep seed rates up and aim to establish 60-80 plants/m2 with the lower number for the conventional varieties.

Finally, before sowing any crop is the time to consider your greening obligations. If you are growing more than 30ha of arable crops, including 1-5 years fresh grass, you must not have more than 75pc of one crop and must have at least 5pc of a third crop.

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

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