Pollination benefits are maximized at intermediate nutrient levels

Abstract

Yield production in flowering crops depends on both nutrient availability and pollination, but their relative roles and potential interactions are poorly understood. We measured pollination benefits to yield in sunflower, combining a gradient in insect pollination (0, 25, 50, 100%) with a continuous gradient in nitrogen (N) fertilization (from 0 to 150 kg N ha) in an experiment under realistic soil field conditions. We found that pollination benefits to yield were maximized at intermediate levels of N availability, bolstering yield by approximately 25% compared with complete pollinator exclusion. Interestingly, we found little decrease in yield when insect visits were reduced by 50%, indicating that the incremental contribution of pollination by insects to yield is greater when the baseline pollination service provision is very low. Our findings provide strong evidence for interactive, nonlinear effects of pollination and resource availability on seed production. Our results support ecological intensification as a promising strategy for sustainable management of agroecosystems. In particular, we found optimal level of pollination to potentially compensate for lower N applications.

Orthogonal fitness benefits of nitrogen and ants for nitrogen‐limited plants in the presence of herbivores

“…As studies of the effects of nutrient addition on plant mutualisms mount (e.g., Tamburini et al. ), it will be useful to consider the effects of such additions on the chemistry of plants and of their mutualistic rewards.…”

“…We propose that the Law of the Minimum, previously suggested to be a useful predictor of plant-mycorrhizal mutualism (Johnson et al 2015), may also help to predict the outcomes of plant defensive mutualism. As studies of the effects of nutrient addition on plant mutualisms mount (e.g., Tamburini et al 2017), it will be useful to consider the effects of such additions on the chemistry of plants and of their mutualistic rewards. FIG.…”

Soil eutrophication shaped the composition of pollinator assemblages during the past century

“…Impacts on plant community are well-recognized, including losses in species diversity (Stevens et al 2004, Bobbink et al 2010, and these may propagate to primary consumers (Stevens et al 2018). While there has been recent research into effects on herbivores (Nijssen et al 2017, Pöyry et al 2017, WallisDeVries and van Swaay 2017, the potential effects of soil eutrophication on those feeding on pollen and nectar (potential pollinators) are largely unexplored (Stevens et al 2018, but see Betzholtz et al 2013, Tamburini et al 2017, Ramos et al 2018. Such potential bottom-up effects could be mediated by reduction in nectar or pollen availability or quality (Petanidou et al 1999, Vanderplanck et al 2017.…”

A Nature-based solution in practice: ecological and economic modelling shows pollinators outperform agrochemicals in oilseed crop production

“…Insect pollination has been shown to increase OSR yields both in experimental [22,34] and on-farm 301 studies [24,40], but the effect of interactions between pollinators and agricultural practices on yield and 302 income remain largely unknown. Though, the practical implications for farmers, as decision-makers, 303 and for policy-makers are critical [55]. Based on a very large dataset spanning four and six years, this 304 study provides a comprehensive analysis of synergy and antagonism between farming practices and 305 biodiversity, and their effects on yield and income.…”