03564nas a2200601 4500008004100000245012300041210006900164300001600233490000700249520175600256653002402012653001802036653001302054653002102067653002302088653002102111100002202132700001902154700002602173700002502199700002802224700001402252700002502266700002302291700002202314700001602336700001902352700002002371700002302391700002002414700002102434700001802455700002202473700002702495700001902522700002002541700002602561700002802587700002302615700002602638700002502664700002202689700002402711700002102735700002102756700002002777700001902797700002102816700001902837700001602856700002302872856006702895 2019 eng d00aBelowground biomass response to nutrient enrichment depends on light limitation across globally distributed grasslands0 aBelowground biomass response to nutrient enrichment depends on l a1466–14770 v223 a
Anthropogenic activities are increasing nutrient inputs to ecosystems worldwide, with consequences for global carbon and nutrient cycles. Recent meta-analyses show that aboveground primary production is often co-limited by multiple nutrients; however, little is known about how root production responds to changes in nutrient availability. At twenty-nine grassland sites on four continents, we quantified shallow root biomass responses to nitrogen (N), phosphorus (P) and potassium plus micronutrient enrichment and compared below- and aboveground responses. We hypothesized that optimal allocation theory would predict context dependence in root biomass responses to nutrient enrichment, given variation among sites in the resources limiting to plant growth (specifically light versus nutrients). Consistent with the predictions of optimal allocation theory, the proportion of total biomass belowground declined with N or P addition, due to increased biomass aboveground (for N and P) and decreased biomass belowground (N, particularly in sites with low canopy light penetration). Absolute root biomass increased with N addition where light was abundant at the soil surface, but declined in sites where the grassland canopy intercepted a large proportion of incoming light. These results demonstrate that belowground responses to changes in resource supply can differ strongly from aboveground responses, which could significantly modify predictions of future rates of nutrient cycling and carbon sequestration. Our results also highlight how optimal allocation theory developed for individual plants may help predict belowground biomass responses to nutrient enrichment at the ecosystem scale across wide climatic and environmental gradients.
10abelowground biomass10aFertilization10anitrogen10aNutrient Network10aoptimal allocation10aphosphorus roots1 aCleland, Elsa, E.1 aLind, Eric, M.1 aDeCrappeo, Nicole, M.1 aDeLorenze, Elizabeth1 aWilkins, Rachel, Abbott1 aAdler, P.1 aBakker, Jonathan, D.1 aBrown, Cynthia, S.1 aDavies, Kendi, F.1 aEsch, Ellen1 aFirn, Jennifer1 aGressard, Scott1 aGruner, Daniel, S.1 aHagenah, Nicole1 aHarpole, Stanley1 aHautier, Yann1 aHobbie, Sarah, E.1 aHofmockel, Kirsten, S.1 aKirkman, Kevin1 aKnops, Johannes1 aKopp, Christopher, W.1 aLa Pierre, Kimberly, J.1 aMacDougall, Andrew1 aMcCulley, Rebecca, L.1 aMelbourne, Brett, A.1 aMoore, Joslin, L.1 aProber, Suzanne, M.1 aRiggs, Charlotte1 aRisch, Anita, C.1 aSchuetz, Martin1 aStevens, Carly1 aWragg, Peter, D.1 aWright, Justin1 aBorer, E.T.1 aSeabloom, Eric, W. uhttps://link.springer.com/article/10.1007%2Fs10021-019-00350-4