Pollination mitigates cucumber yield gaps more than pesticide and fertilizer use in tropical smallholder gardens

摘要

Pollination can be an essential but often neglected ecosystem service to mitigate crop yield gaps. Pollination services are usually studied in isolation, and their relative role and possible interactions with other factors, such as major management practices, is little understood. We tested how pollination (insect vs. wind- and self-pollination) interacts with weed control, fertilization and insect herbivore control and how these factors as well as flower-visiting bees influence fruit set and yield of cucumber Cucumis sativus L. in 13 traditional Indonesian home gardens. Although insect pollination, fertilization and weed control additively increased crop yield, fertilization and weed control alone could not compensate for pollination loss. Pollination individually accounted for 75% of the yield and was, hence, the most important driver of yield. In contrast, herbivore control through insecticides at commonly applied levels did not increase yield. Yield strongly increased with higher number of flower-visiting bee individuals, while the number of bee individuals in turn was not influenced by weed control, fertilization or herbivore control, but increased with higher number of cucumber flowers.Synthesis and applications. Although multiple management practices influence yield, they cannot compensate yield gaps from pollinator loss in cucumber smallholder production in Indonesia. Our results also show that the widespread use of insecticides without considering the impacts on pest reduction is uneconomical. Here, reducing insecticides caused no income loss and, at the same time, reduces potential risks to important pollinators, which needs to be acknowledged by policy-driven regulations for pesticide application in tropical agroecosystems. Our results stress the importance of enhancing bee populations to facilitate pollination services. Bee management practices, such as sustaining additional food resources for pollinators, need to be established.