Related Experiment Video
Updated: May 12, 2026
10:16
Design and Operation of a Continuous 13C and 15N Labeling Chamber for Uniform or Differential, Metabolic and Structural, Plant Isotope Labeling
Published on: January 16, 2014
Nutrients and defoliation increase soil carbon inputs in grassland
Carly Ziter1, Andrew S MacDougall
1Department of Integrative Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada.
Ecology
|April 23, 2013
Summary
Nutrient addition and simulated grazing in grasslands boost soil carbon storage by increasing plant production and root inputs. These factors enhance the capacity of managed grasslands to act as atmospheric CO2 sinks.
Area of Science:
- Ecology
- Soil Science
- Plant Biology
Background:
- Grasslands regulate atmospheric CO2 through nutrient cycling, plant production, decomposition, and soil carbon sequestration.
- Anthropogenic nutrient inputs and grazing practices significantly influence grassland carbon dynamics, but their net effects remain unclear.
- Soils in grassland ecosystems store approximately 20% of the global carbon pool, highlighting their importance in climate regulation.
Purpose of the Study:
- To quantify the individual and interactive effects of nutrient addition and simulated grazing on grassland plant production, tissue quality, and soil carbon inputs.
- To test the hypothesis that combined nutrient and grazing treatments would reduce recalcitrant litter inputs, thereby decreasing carbon storage.
- To determine how these management practices influence the grassland's capacity to sequester atmospheric carbon dioxide.
Main Methods:
- Field experiment in a western North American grassland using nutrient addition and simulated grazing (mowing).
- Quantified above- and belowground biomass production, root and shoot tissue quality (lignin content), and decomposition rates.
- Monitored soil organic matter and soil carbon accumulation over three years.
Main Results:
- Nutrient addition significantly increased root (37%) and shoot (23%) biomass, with no impact on decomposition.
- Simulated grazing (defoliation) increased short-lived, lignin-rich root production (33%), enhancing root litter inputs.
- Neither nutrient addition nor defoliation affected root tissue quality; combined treatments increased soil organic matter and soil carbon by 15%.
Conclusions:
- Contrary to the hypothesis, nutrient addition and simulated grazing synergistically increase soil carbon inputs and storage in grasslands.
- Managed grasslands with nutrient inputs and moderate grazing can accumulate more soil carbon, enhancing their role as atmospheric CO2 sinks.
- Grassland management practices can be optimized to improve carbon sequestration potential and mitigate climate change.
Related Concept Videos
02:11The Roles of Bacteria and Fungi in Plant Nutrition
Plants have the impressive ability to create their own food through photosynthesis. However, plants often require assistance from organisms in the soil to acquire the nutrients they need to function correctly. Both bacteria and fungi have evolved symbiotic relationships with plants that help the species to thrive in a wide variety of environments.
02:23The Soil Ecosystem
Plants obtain inorganic minerals and water from the soil, which acts as a natural medium for land plants. The composition and quality of soil depend not only on the chemical constituents but also on the presence of living organisms. In general, soils contain three major components:
01:27C4 Pathway and CAM
Most plants use the C3 pathway for carbon fixation. However, some plants, such as sugar cane, corn, and cacti that grow in hot conditions, use alternative pathways to fix carbon and conserve energy loss due to photorespiration. Photorespiration is the process that occurs when the oxygen concentration is high. Under such conditions, the rubisco enzyme in the Calvin cycle binds O2 instead of CO2, which halts photosynthesis and consumes energy.
C4 Pathway
The C4 pathway is used by plants such as...
C4 Pathway
The C4 pathway is used by plants such as...
01:29Soil Microbial Ecology
Soil microbial ecology is defined by highly diverse, spatially structured communities that drive nutrient cycling, organic matter turnover, and overall ecosystem stability. Although a gram of soil can contain thousands of bacterial and archaeal taxa, the ecological processes they mediate are even more crucial for sustaining terrestrial life.Microhabitats and NichesSoil is a heterogeneous mixture of minerals, organic matter, water, and air. Microbes inhabit distinct microhabitats formed by...
01:20Overview of Nitrogen Metabolism
Nitrogen is a very important element for life because it is a major constituent of proteins and nucleic acids. It is a macronutrient, and in nature, it is recycled from organic compounds and stored in the form of ammonia, ammonium ions, nitrate, nitrite, or nitrogen gas by many metabolic processes. Many of these metabolic processes are carried out only by prokaryotes.
The largest pool of nitrogen available in the terrestrial ecosystem is gaseous nitrogen (N2) from the air, but this nitrogen...
The largest pool of nitrogen available in the terrestrial ecosystem is gaseous nitrogen (N2) from the air, but this nitrogen...
02:35Key Elements for Plant Nutrition
Like all living organisms, plants require organic and inorganic nutrients to survive, reproduce, grow and maintain homeostasis. To identify nutrients that are essential for plant functioning, researchers have leveraged a technique called hydroponics. In hydroponic culture systems, plants are grown—without soil—in water-based solutions containing nutrients. At least 17 nutrients have been identified as essential elements required by plants. Plants acquire these elements from the atmosphere, the...