Teagasc has confirmed that growing spring beans offers the opportunity to reduce the total nitrogen (N) requirement on tillage farms.
This is because the crop only requires phosphorus (P) and potassium (K), depending on soil fertility levels.
In addition, beans will fix N from the atmosphere that remains in the soil for the following crop. This offers a double reduction in farm N requirements at a time of high fertiliser N prices.
Benefits of spring beans
In addition, spring beans currently leave a very good margin due to low input costs plus the bean premium.
Spring beans represent an excellent break crop, deliver many rotational benefits – including improved soil health to weed control options, according to Teagasc.
This latter point is particularly relevant as, within most spring cereal scenarios, break crop options are limited.
Beans will deliver rotational benefits such as higher grain yields in the following cereal crop e.g., grain yields can increase from 0.6-1.5t/ha for winter and spring cereal crops.
In addition, beans have a very good integrated pest management (IPM) profile. This is because they have a low input requirement.
They also act to reduce the incidence of yield robbing disease such as take-all, septoria, net blotch and rhyncosporium in subsequent crops.
Crops after beans
In addition, crops after beans tend to be more vigorous, establish more rapidly and evenly due to the soil health and quality benefits that beans put back into the soil.
Beans are legumes with nodules on the roots which fix N from the atmosphere. In essence, these nodules can be likened to an in-field plant N production factory.
As a consequence, beans can fix their own nitrogen during the growing season thus reducing the need to apply fertiliser N.
There is also residual N left in the soil after harvesting. This is available to the following crop and reduces its fertiliser N requirement by up to 35kg/ha.
Also, planting a different crop species such as beans brings many soil health benefits to any crop rotation.
This is due to a different root architecture and growth habit. In addition, bean crop haulms tend to be chopped and incorporated back into the soil, which adds valuable soil organic matter / carbon.
This biomass provides a food source to feed soil biology. It also acts to improve nutrient recycling and N utilisation.
Over time, the practices associated with the growing of beans add to soil structure and soil health.
Spring beans can be planted out as soon as ground conditions permit.