Managing living mulch (cover crops) to improve soil health (including nutrient cycling) and encourage natural enemies

The use of living mulch in orchard fruit crops is receiving increasing attention. Living mulch has the potential to significantly improve previous weed management by incorporating conservation biocontrol (providing refuges for key natural enemies), carbon sequestration, nutrient cycling, and soil health (microbiology). However, how to maximize the potential benefits of these cover crops while minimising the efforts required to manage them is not yet clear.
We will evaluate several candidate cover plant species in monoculture and mixtures in orchards, with specific emphasis on conservation biocontrol and soil health in terms of nutrient cycling and abundance of key microbial groups important to plant growth (e.g. plant growth promoting rhizobacteria, mycorrhizal fungi). We will also consider the use of cover crops for table-top strawberry production with the primary objective on conservation biocontrol. Although the exact research contents over the four-year period may change in response to emerging novel research findings, the following aspects will be covered:
(1) Population dynamics of cover crops in relation to depletion of soil nutrients and climatic conditions; this will have implications on cover crop management, carbon sequestration, and availability of nutrients to fruit crops
(2) Assess dynamics of key natural enemies for apple and strawberry pests in relation to crop development stage and pest dynamics; we will also characterise plant-associated volatiles to understand the nature of the observed population dynamics of natural enemies and the ability of plants to deter or attract specific organisms.
(3) Characterising soil microbiota with the emphasis on those microbes associated with nutrient cycling and general beneficial organisms; in this area, we will pay particular attention to the relationship of these microbes (and their activities) with plant/tree growth.
(4) In addition to laboratory research, a new apple orchard will be planted, specifically designed to study the use of candidate plant species as living mulch.