Plants growing in communities (polycultures) of certain mixtures have been shown to yield more biomass \ud than do monocultures of their constituent species, as well as delivering enhanced ecosystem services, \ud better pest regulation, and greater overall economic productivity (e.g. Malézieux et al., 2009). Despite \ud this, there has been surprisingly little commercial uptake of such multispecies systems. We suggest that \ud the scale of use of these systems is fundamental to their successful implementation.\ud Concurrently with the growing debates over land use in large-scale agriculture and competition with other\ud objectives such as conservation and fibre production, there has been a widespread increase in “grow \ud your own” in the UK. There remains, however, a paucity of academic research on the productivity of \ud these household-level systems. This study represents the first investigation of yield from household \ud systems since 1948. \ud We used the principle of higher yield being associated with greater diversity to investigate productivity \ud (per land area, per labour time input, & continuity of production) of food plants in low- (3 species) and \ud high- (12 species) diversity polycultures in family food systems. Vegetable species from a range of plant \ud families were chosen based on spatial occupancy niches & functional attributes, and grown in a \ud participatory trial of 50 households from across the UK. Participants recorded data on yield, time spent \ud on the plots, and also completed pre-and post-study questionnaires. \ud Results show no overall difference in total yield, but significant differences in individual species’ yields\ud which suggests that compensatory mechanisms and competitive ability are important considerations. \ud Yields differed across the country, and increased with increasing input time. People found the less \ud diverse system easier to manage and more “worthwhile”. Interestingly, these systems yield on average \ud the equivalent of 35 tonnes per hectare, with some approaching over 100 tonnes per hectare. These \ud diverse small scale systems have an excellent potential for improving food yields, as well as the potential \ud to meet other targets in low-carbon transition, enhanced biodiversity and improved health and well-being.\ud This may be a solution-driven win-win in the land-sharing/land-sparing debate that simultaneously \ud engages the public with scientific research and inspires a conservation ethos.
Insight - University of Cumbria (http://insight.cumbria.ac.uk/id/eprint/2220/1/NKV2012_How%20does%20your%20garden%20grow_Oxford.pdf)