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Earth's Systems / Biological processes / Terrestrial ecosystem functioning / Primary production / Nutrient limitation of net primary production

Nutrient limitation of net primary production

How nitrogen and phosphorus supply caps plant growth, and how nitrogen fixation and nutrient losses shape which element limits production over time.

Boundary: where this process starts

Starts with: Plants take up nitrogen and phosphorus from soil solution

Boundary: where it ends

Ends after: Plant-available nutrient lost by leaching or uptake limits the pool; Free-living bacteria fix atmospheric nitrogen when molybdenum or phosphorus allow

PARTICIPANTSRESOURCESPlantsBacteriaNitrogenPhosphorusWaterImpact +3 of 5. Click for details and evidence.Impact 03 of 5. Click for details and evidence.Impact +3 of 5. Click for details and evidence.Impact +3 of 5. Click for details and evidence.↻ balances · moderate · 0.25 Fixed N returnsImpact -2 of 5. Click for details and evidence.Impact -2 of 5. Click for details and evidence.Impact +2 of 5. Click for details and evidence.Plants take up nitrogen and phosphorus from soil solution: uses up Nitrogenuses upPlants take up nitrogen and phosphorus from soil solution: uses up Phosphorususes upPlants take up nitrogen and phosphorus from soil solution: uses WaterScarcer nutrient relative to plant demand limits growth (Liebig minimum or multiple limitation): uses NitrogenScarcer nutrient relative to plant demand limits growth (Liebig minimum or multiple limitation): uses PhosphorusFree-living bacteria fix atmospheric nitrogen when molybdenum or phosphorus allow: makes NitrogenmakesFree-living bacteria fix atmospheric nitrogen when molybdenum or phosphorus allow: uses PhosphorusPlant-available nutrient lost by leaching or uptake limits the pool: uses up Nitrogenuses upPlant-available nutrient lost by leaching or uptake limits the pool: uses Watertaken up from solutionNitrogen: taken up from solutionabsorbed from soilsolutionPhosphorus: absorbed from soil solutioncarries dissolvednutrientsWater: carries dissolved nutrientsscarcest relative todemandNitrogen: scarcest relative to demandlimits growth if scarcePhosphorus: limits growth if scarcefixed into availableformNitrogen: fixed into available formneeded to allow fixationPhosphorus: needed to allow fixationlost by leaching anduptakeNitrogen: lost by leaching and uptakecarries leachednutrients awayWater: carries leached nutrients awayStart: Nutrientlimitation of netprimary productionSTARTStart: Nutrient limitation of net primary productionEnd: Nutrientlimitation of netprimary production ↗1ENDEnd: Nutrient limitation of net primary productionPlants take up nitrogenand phosphorus fromsoil solution📄1Plants take up nitrogen and phosphorus from soil solutionScarcer nutrientrelative to plantdemand limits grow…📄1Scarcer nutrient relative to plant demand limits growth (Liebig minimum or multiple limitation)Free-living bacteriafix atmosphericnitrogen wh…👍1📄1Free-living bacteria fix atmospheric nitrogen when molybdenum or phosphorus allowPlant-availablenutrient lost byleaching or upta…👍1📄1Plant-available nutrient lost by leaching or uptake limits the pool
Line thickness = size of impact (1 to 5)% on a line = chance a fork takes that branch📄 = pieces of evidence on a stepNegative effectLoops backHypothesisResource used up (arrow into the step)Resource used, not used upResource made or released (arrow out of the step)
What am I looking at? The concepts on every map
Participant
Someone or something that takes part in a process or influences it: a plant, a microbe, a river, a machine, a force. Participants are the rows of a map.
Resource
Something a step uses or uses up: water, oxygen, sunlight, a tool. Each step has an arrow down to the resources it uses.
Step
One thing that happens in a process. Every step has at least one participant and carries evidence.
Decision fork
A step where the process can go several ways. Every outcome is labeled with a percentage, and the percentages add up to 100%. It is not limited to yes or no.
Loop
A line that carries the process back to an earlier step. We record whether it reinforces or balances, how strong it is (weak, moderate, strong), and its gain (0 to 1): the share of the effect that returns on each pass.
Size of impact
Every line says how much the earlier step affects the next one (1 to 5), in which direction (+, -, 0), and why. Thicker lines mean bigger impact.
Evidence
The support for a claim: a source and what it shows. Every step, line, change and vote needs it. Click any step or line to read its evidence.
Boundary
Where a process starts and where it ends. Every process, and every subprocess, has a start and an end.
Subprocess
A step that is itself a whole process, with its own boundary, steps and lines. Click a step marked ↘ to open it. Subprocesses nest as deep as the evidence goes.
Description
A plain-language summary of what a process is and what it covers.
Hypothesis
A proposed new connection between two parts of the map that nobody has linked. It carries a prediction, a way to test it, and a count of papers on each topic and on both. It is an unverified idea until someone tests it.

Every step, with its evidence

The same information as the map, as a list you can search and share. Click a participant or resource to see everywhere it appears.

Plants take up nitrogen and phosphorus from soil solution
PlantsNitrogenPhosphorusWater
Evidence (1) · added by Verity
  • Agren 2012, Nutrient limitation on terrestrial plant growth: modeling the interaction between nitrogen and phosphorus, New Phytologist, doi:10.1111/j.1469-8137.2012.04116.x: A model of plant growth and nutrient uptake shows relative growth rate depends on investment in N versus P uptake. (confidence 0.75)
Scarcer nutrient relative to plant demand limits growth (Liebig minimum or multiple limitation)
PlantsNitrogenPhosphorus
Evidence (1) · added by Verity
  • Agren 2012, Nutrient limitation on terrestrial plant growth: modeling the interaction between nitrogen and phosphorus, New Phytologist, doi:10.1111/j.1469-8137.2012.04116.x: Liebig's law versus the multiple limitation hypothesis give a smooth rather than abrupt transition between limiting elements. (confidence 0.8)
Free-living bacteria fix atmospheric nitrogen when molybdenum or phosphorus allow
BacteriaNitrogenPhosphorus
Evidence (1) · added by Verity
  • Dynarski 2018, Nutrient limitation of terrestrial free-living nitrogen fixation, New Phytologist, doi:10.1111/nph.14905: Meta-analysis: free-living N fixation was suppressed by N fertilization, stimulated by Mo, and stimulated by P in tropical forests. (confidence 0.85)
Plant-available nutrient lost by leaching or uptake limits the pool
PlantsNitrogenWater
Evidence (1) · added by Verity
  • Menge 2009, Emergence and maintenance of nutrient limitation over multiple timescales in terrestrial ecosystems, American Naturalist, doi:10.1086/595749: Long-term nutrient limitation depends on whether losses come from plant-available or plant-unavailable pools. (confidence 0.7)