'Double Legumes, Multiple Benefits?' Does intercropping of multiple Legumes enhance their ecosystem potential?

As global demand for sustainable and resilient food systems increase, the cultivation of legumes within rotations, including via intercropping, presents a multifaceted solution to enhance food and feed security. Legumes uniquely collaborate with soil bacteria (rhizobia) to perform Biological Nitrogen Fixation (BNF), a critical ecosystem service benefit that can reduce reliance on synthetic (mineral) fertilizers while boosting agronomic yields. Studies using intercropping (sowing two different crop species in the same space), have already demonstrated potential for improved resource sharing in crops, reduced pest and disease incidence, and therefore boosting productivity whilst reducing land- and resource-use. A select few studies have also shown increased BNF from intercropping different legumes crops; although the mechanisms and trade-offs remain poorly understood. In addition to this, whether or not this increase in BNF, and perhaps other hidden changes in nutrient cycling, actually provides enhancements to any following non-legume crop remains to be seen.

This PhD project aims to investigate the impacts of intercropping of different varieties of faba bean (or field bean, Vicia faba L.) and pea (Pisum sativum L.), focusing on their BNF capabilities and other ecosystem service benefits or risks, to gain a holistic understanding of the potential of from legume-legume combinations. Utilising field- and glasshouse-trials at the James Hutton Institute, PGRO, and Cranfield University, this research will address key knowledge gaps regarding the optimisation of legume-legume intercropping for improved protein yield, reduced nitrogen losses from leaching and any benefits to follow-on crops. Some analysis on the wider environmental impacts such as reducing feed imports through promoting domestic plant-protein production and offsetting synthetic fertiliser use. GHG (greenhouse gas) emissions will likely be assessed using Life Cycle Analysis. Collectively, the findings should help promote national and global calls to increase the production and consumption of ‘home grown’ legumes.'

Sponsors:

Student:

Sam Holden

Start Date: October 2024

Duration of study: 4 years