Abstract/Summary

Given the challenges posed to agriculture by future climatic changes, the need to increase production due to a growing population and at the same time, reduce environmental impacts and preserve biodiversity, it is vital that more sustainable and resilient food production systems are in place. Ecological intensification is an approach proposed to partially replace external inputs (i.e. synthetic fertiliser and pesticides) with the provision of biodiversity derived ecosystem services, to either maintain or increase food production. One promising management practice is crop diversification, both temporally and spatially, which has the potential to improve the provision of multiple ecosystem services underpinning agricultural production and to confer resilience to food production systems. Studies conducted over three years, compared the ability of three 4-year crop rotations, along a diversity gradient (simple, moderate and diverse), to enhance the provision of multiple ecosystem services and increase resilience. The ability of each rotation to increase soil ecosystem services (soil fertility), pollination service, resilience under abiotic stresses and provide food resources for pollinators was assessed. Experiments were conducted at the University of Reading’s Crop Research Unit, Sonning, Berkshire, UK in a free draining sandy/silty loam overlaying coarse red-brown sand of the Sonning series. Berkshire has a temperate climate with annual mean temperatures ranging between 6.7 °C and 14.5°C. More diverse crop rotations resulted in higher nutrient cycling and consequently higher nutrient availability (mineral nitrogen) to the crops. However, this presented a trade-off with soil carbon storage in the short term. Increased crop diversity resulted in higher yield stability with reduced external inputs, under varying climatic conditions, with yield increases of 1 t/ha on average, and improved system resilience, but it did not increase the provision of soil fertility and pest regulation under abiotic stresses (heat and drought). Increased diversity and insect pollination had a positive impact on oilseed rape yield components and higher diversity also led to a more stable provision of nectar resources throughout the pollinator flight season, attracting more bumblebees than less diverse rotations. The results presented here suggest that crop diversification is likely to be an important tool in the ecological intensification of agriculture. However, it will need to be combined with other strategies, both at local (e.g. reduced tillage practices and flower strips) and at a landscape (e.g. diversification of flowering crops) level, if ecological intensification is to be implemented broadly and successfully. Results also highlight the urgent need for future long-term research on the potential benefits of crop diversification.