Insect pollination and soil organic matter improve raspberry production independently of the effects of fertilizers

Intensive agriculture faces the challenge of contributing to feeding the increasing global population while minimizing its adverse effects on the environment. Ecological intensification can help achieve this as it proposes to supplement artificial inputs with ecosystem services such as pollination, nutrient cycling and water retention. The mixed results of previous studies with respect to the potential of using ecosystem services for ecological intensification suggests more data is needed from a wider range of contexts to explore the potential of this approach in practice. We conducted an experiment which studied the effects of all combinations of insect pollination (open pollination vs pollinators excluded), soil organic matter (SOM) content (1.66 % vs 3.73 %) and four levels of fertilizer applications, on the quantity and quality of raspberry (Rubus idaeus L.) production. We were particularly interested in interacting effects on crop yield between the ecosystem services and fertilizer application. Insect pollination significantly increased single berry weight (11 %) and raspberry yield (33 %). SOM content enhanced visitation rate of pollinators and increased the single berry weight by 20.5 %, but SOM did not contribute significantly to fruit number or yield. SOM contributed to the soluble solids content of the fruits; however, this effect interacted with pollination and fertilizer inputs in a non-linear way. Fertilizer application positively contributed to single berry weight, fruit number and thus overall yield but did not influence in any way the effects of pollination and SOM on raspberry production. Our results provide evidence that ecosystem services contribute to fruit production and can potentially be used to (partly) replace artificial fertilizer inputs while maintaining productivity but our results also suggest that yield maximization requires enhancing both ecosystem services and fertilizer application.