26 February 2024

Beans make sense

Ciarán Collins highlights the growing popularity of beans due to their role as sustainable protein sources and the advantages of crop rotation, making beans an economically viable and environmentally friendly choice.

The increasing interest in beans in recent years stems from two main factors. Firstly, there’s the influence of EU policy and the push for a more sustainable protein source. Secondly, there’s recognition amongst farmers and agronomists regarding the benefits of crop rotation for soil health and, consequently profitability for growers.

Beans make financial sense. In the Teagasc Costs and Returns 2024, only winter wheat and malting barley leave a higher margin than beans. Almost half of the margin from beans comes from the protein payment, estimated at €400/ha. The final protein payment that growers will receive is dependent on the area planted but is likely to be in the range of €350 – €500/ha. The fact that the payment is guaranteed regardless of yield and grain price offers a layer of security in a time of falling grain prices.

Yield variability is often cited as a barrier to a larger bean crop area. The five year yield average from the Teagasc Harvest Report for spring beans is a very acceptable 5.5t/ha however there is greater in season variation in beans than with other crops. Therefore, it is crucial to implement strategies aimed at mitigating the risks associated with potential lower yields.

Drought at flowering and pod setting will reduce yield. Beans are best suited to heavier soil types but can be successfully grown on lighter soils when sown earlier. The spring sowing window is mid-February to mid-March. Good yields can be achieved from later sowing but the risk of a lower yield increases with delayed sowing.

Aim for a target plant population of 25-30 plants/m². Increase target plant population to 40 plants/m²for late sowing or on unproductive soils. Establishment losses can be high if soil conditions are poor so allowance need to be made for this when calculating seed rate. Bean seed is big this year, many seed batches have a thousand grain weight (TGW) in excess of 600g. Seed rate needs to be in excess of 200kg/ha to achieve target plant population for seed with a TGW of 600g.

Don’t forget lime. The optimum soil pH for field peas and beans is 6.8.

Higher yields will come from fields with high fertility. A typical index 3 soil will require phosphorus 20kg/ha and potassium 40kg/ha. Higher rates are needed for index 1 and 2 soils and it is best to incorporate fertiliser in these soils.

It is essential that pre-emergence residual herbicides are used as Basagran is the only approved post-emergence herbicide which controls emerged broad-leaved weeds and it has a very limited weed spectrum. Pre emergence residual products work best on fine seedbeds with some moisture after spraying. Rolling post sowing helps the activity of pre-emergence herbicides by breaking up the clods.

The main pre-emergence herbicide options are; Nirvana 4.0-4.5L/ha, Nirvana 2.5 + Defy 4.0L/ha, Stallion 3.0L/ha and Chanon/Emerger 2.5 + Defy 2.5L/ha.