The latest trials conducted by Wageningen University and Lancaster have shown the beneficial relationship between clover and grass often leads to a richer harvest.
It is hardly ground breaking news but they showed that clover plants and grasses transport carbon into the ground more quickly and produce increases biomass if both plant species grow close to each other rather than surrounded by plants of the same species.
Also, when the crops grow together the researchers also found higher levels of both carbon and nitrogen, which is the main food source. The findings which were published in PlosONE show that mixed cropping, in nitrogen-fixing plants and their neighbours results in an improvement in weight and quality for the plants involved.
Clover species live collectively with root inhabiting bacteria that remove nitrogen from the air and make it available to the plants. Non-nitrogen-fixing neighbouring plants benefit as well because nitrogen in clover is released into the soil due via the roots. This relatinoship has been known about for a long time but the question researchers wanted to know, was whether it was reciprocated.
The researcher therefore discovered that there was mutuality benefit between plants fix nitrogen and those that do not. This results in these particular plant species producing a higher yield of mixed crops in comparison to plants from monocultures. Additionally, the plant communities lost less carbon through plant and soil respiration if they were composed of plant species mixtures both compared to when the plant species were cultivated in a monoculture.
The research showed that White Clover in particular rapidly transported the carbon it has absorbed during the day to underground plant parts- but only if it grew in the surrounding of different species. If this was the case then transport was three times quicker and surrounding plants can absorb it faster.
Increased plant carbon translocation linked to over-yielding in grassland species mixtures. by Gerlinde De Deyn, Helen Quirk, Simon Oakley, Richard Bardgett & Nick Ostle. PlosONE 25 September 2012.