pollination service to faba bean agroecosystem: quantifying and valuation using field experiment

In this study, pollination service in the faba bean agroecosystem was evaluated and valued with a field experiment. for this purpose, a factorial experiment based on a randomized complete blocks design with three replications was carried out in the research farm of gorgan university of agricultural sciences and natural resources (golestan province, iran), during 2020-2021. the treatments of this experiment included cultivar as the first factor in four levels, including feyz, mahta, barkat and shadan and the second factor in two levels, including open-pollinated plants by insects and limitation of pollination by a cage. in this experiment, each plot included five planting rows with a distance between plants on each row of 15 cm, a planting depth of 5 cm and a distance between rows of 50 cm. also, each plot had a size of 2×2.5 m and the distance between of plots was 75 cm.  during the growing season, with the onset of warmer temperatures and insect activity in late march 2021, plots with limited open pollination are wholly trapped by the nets until the end of pollination. simultaneously with the activity of insects in the field, samples of insects are collected using lattice nets. at the time of crop maturing, green yield and plant biomass were harvested. finally, we quantified the value of pollination service by marketing price and alternative cost methods. in this study, we collected 13 pollinator species from the faba bean agroecosystem. the share of insects in the pollination of faba bean cultivars was obtained between 3.81 and 17.06 %. results showed that the economic value of pollination in the faba bean agroecosystem was between 38,056,136 to 161,000,000 rls.ha^-1. generally, the role of pollinating insects in new faba bean cultivars was more than in the old cultivars, especially, the cultivars such as mahta that use more pollination service than other cultivars. it is necessary that faba bean growers promote and protect pollination service to enhance their economic benefits in agroecosystems.