Growing field beans – the agronomy has got to be just right

Farm surveys carried out by Teagasc have confirmed the immense potential that exists to grow field beans successfully in Ireland.

However, the same work has also highlighted the equally immense divergence in the actual crop performance results being achieved at farm level.

Beans can be grown as either winter or spring options. Teagasc trials indicate that winter crops are least predisposed to fluctuations in yield and overall enterprise performance.

Crop management for beans

The first day of the 2021 Teagasc Annual Tillage Conference this week (Wednesday, February 3) allowed for a discussion on the agronomy and crop management procedures that best suit beans.

The first box to be ticked in this regard was the confirmation that bean crops do not require additional nitrogen.

Teagasc research officer, Sheila Alves commented:

“Beans are still a relatively new crop in Ireland. So we are still trying to find out how they best fit into tillage rotations and the best agronomic principles to apply.”

As beans are legumes, they are able to fix their own nitrogen from the air.

Variations in yield

Referring to surveys carried out by Teagasc over the last number of years, Alves pointed to the very wide variations in yield recorded, where beans are concerned, on Irish farms.

“Last year, yields of spring sown crops ranged from 1.2t/ha to 7.6t/ha. The mean figure was 4.7t/ha. The mean recorded yield for the period 2010 to 2020 was 5.3t/ha,” Alves continued.

Alves also confirmed that crop output is a key determinant of profitability. Last year’s Teagasc figures show that farmers securing the mean yield figure generated an overall gross margin of €251/ha.

Those in the bottom 25% performance category generated an actual loss of  €61/ha while those in the top performance category recorded a gross margin figure of €545/ha.

Lynx was the most popular bean variety grown in Ireland last year.

Determining dates

So what are the key agronomy targets that should be met with beans. According to Alves, planting date determines harvest date.

“We recommend that spring crops should be sown out before the end of March. Leaving it to April is too late,” Alves added.

“Growers should target a plant population of between 25 and 35 seeds per square metre.”

According to the Teagasc tillage specialist, chocolate spot is the most prevalent disease that will attack beans under Irish conditions.

“Effective disease control will require two fungicide applications: the first at the mid-flowering stage with the second following while the pods are filling,” she concluded.