Farm Ireland

Thursday 22 February 2018

Prioritise weed and aphid control


Gerry Bird

The recent weather has disrupted the work plans of many of my growers, with the full range of activities from harvesting to drilling occupying the mind.

Beans are still standing, waiting for the combination of wind and sun to bring the moisture down to the 22pc mark. A few attempts at harvesting resulted in extremely high moisture samples, which were not very welcome at the local merchants.

Beans are generally weather proof, but combining at the end of October isn't a very exciting prospect, though I've seen beans harvested as late as December.

Winter barley crops look well, with complete ground cover common. Weed and aphid control are the priorities. The effects of over anxious rolling are evident when the seed bed was not dry enough, with patchy headlands and roller tracks running the length of the field.

Drilling of wheat after oilseed rape crops took place from mid-September. A lot of these crops had emerged by the end of September and are now at 2-3 leaf stage. Slug activity was an issue with some of these crops despite the early start.

Plant counts on some crops are on the low side. I feel this is due to growers sowing to a specific weight rather than a planned seeds per square metre. Thousand grain weights (TGW) this year are quite high. For example, I found the popular JB Diego variety had a TGW in the 57-60g range this season compared with 51g last year. The good wheat yields were due in part to increased grain size and this has an impact on the number of grains per kilo of seed.


The bulk of the wheat is being sown at present with seed rates in the order of 350-400 seeds/m2 generally being drilled. Seedbed quality is good as a lot of ground was ploughed dry early on and rolled or pressed. From now on, the plough in front of the one- pass is a safer bet. The min-till operators are in their perennial dilemma when the weather is broken and extended dry spells are scarce. The system allows large areas to be cultivated but, with broken wet weather, the drilling surface is sticky and the disc and tine drills find it difficult to establish good seedbeds.

Also Read

Min-till growers have adapted their crop establishment systems in light of recent experiences with deeper coarser cultivations, incorporating break crops in the rotation and using winter oilseed rape in particular.

Some growers have become opportunistic min-tillers, with min-tilling early in the season for oilseed rape, first wheats and barley. Straw removal, late harvest of spring rape and beans, and the application of organic manures, all delay seedbed cultivation -- and if weather breaks, it makes economic sense to bring in the plough. The question of restricted or compacted root zone is a constant concern for min-till practitioners. I have noted that on the heavier clay soils, mild to moderate compaction is not an issue compared to the occurrence on the lighter loamy soils.

Clay soils are much more chemically and physically active relative to the lighter loams, and a natural subsoiling occurs with frost in the winter and cracking in the summer.

The lighter loam soil, with low clay and high silt content, does not react in the same way. Rainfall washes silt down the profile where it congregates and forms a band. The effects of this band can be mild to moderate, or severe after a number of seasons on continuous cereals with a constant cultivation depth.

The advent of the new system of oilseed rape establishment, with the emphasis on subsoiling below the seed, indicates the importance of free movements for the root mass particularly to access water.

This season was a benchmark with good yields and prices, so growers can assess the performance of the cultivation systems and various fungicide programmes. Good crop establishment was the key which maximised the performance of all the other inputs, so drill with care and consideration.

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

Indo Farming