Members of the public admire climbing beans crop during a tour of exhibition stands at a past University of Eldoret Annual Agri-business Trade Fair. Legumes are seen to be generally beneficial to the environment and economically too. PHOTO | JARED NYATAYA | NATION MEDIA GROUP 

It’s a win-win situation for the environment and the economy when it comes to growing legumes, says a new research carried out by Legume Futures, a team of international scientists.
Across the world, including in Kenya, cereal crops dominate most farms, heaping pressure on the environment through fertiliser application.
“The introduction of legumes such as clovers, lupins, lucerne and a variety of beans can increase the sustainability of agriculture and the supply of protein,” stated Moritz Reckling of the Leibniz Centre for Agriculture Research in Germany and lead author of the study published in Frontiers in Plant Science this week.
Legumes are protein-rich and they also increase the amount of nitrogen available to plants through biological nitrogen fixation, reducing the need for fertilisers.
Reckling and co-workers created a model to determine the effects of integrating legumes into cropping systems. The team set out to evaluate the trade-offs between environmental and economic effects of legume integration.
To demonstrate applicability in different regions, they used five case study areas in Europe with contrasting climatic conditions and cropping systems.
“Legumes are seen to be generally beneficial to the environment, but they are not economically attractive to farmers when compared as single crops, so we wanted to look at the gross margins of crop rotations when legumes are integrated,” he said.
The team confirmed the environmental benefits of introducing legumes and found that in such cropping systems, overall nitrous oxide emissions reduced by approximately 20-30 per cent and fertiliser use was down by 25 per cent to almost 40 per cent in some cases.
The systems the researchers developed did not show increased nitrate leaching into groundwater supplies, and in some systems, with forage legumes leaching was even reduced.
Most significantly, the gross margins evaluated show an increase in all of the forage agriculture systems modelled.
“When comparing the trade-offs between environmental and economic effects, the study shows that positive environmental effects do not necessarily mean that gross margins go down,” concluded Reckling.
Contrary to popular belief, these findings show that the benefits of diversifying cropping systems through the inclusion of legumes is both environmental and economic.
In Kenya, most farmers intercrop legumes like beans with cereals like maize, but scientist encourage independent growing of the crops.
Science Daily