Agriculture — Manure left on Pasture Emissions

SIGNAL Earth Structured Data

Object type	Damage Signal
SIGNAL Earth ID	DS-00884
Observable type	—
Unit	—
Temporal structure	—
Monitoring backbone	—

 Agriculture — Manure left on Pasture Emissions refers to the release of methane gas resulting from the decomposition of animal manure deposited directly onto pasturelands. This phenomenon is a component of agricultural greenhouse gas emissions and contributes to the broader context of methane fluxes in terrestrial ecosystems. Understanding these emissions is important for assessing the environmental impact of livestock grazing practices and their role in global methane budgets. Methane is a potent greenhouse gas with a global warming potential significantly higher than carbon dioxide over a 100-year period, making its sources, including manure left on pastures, relevant to climate change studies. This signal captures emissions specifically associated with manure that remains on pasture surfaces rather than being collected or managed through other agricultural processes.

Geographic / System Context

Manure left on pasture emissions occur globally wherever livestock grazing is practiced. Pasturelands span diverse climatic and geographic regions, from temperate grasslands to tropical savannas. The extent and intensity of these emissions depend on factors such as animal density, pasture management, climate conditions, and soil characteristics. Because this signal is not geographically scoped within the SIGNAL system, it encompasses emissions from all pasture-based livestock systems worldwide. Pasture ecosystems serve as the environmental medium where microbial activity in manure under aerobic and anaerobic conditions leads to methane production and release into the atmosphere.

Monitoring and Measurement

Monitoring of methane emissions from manure left on pasture typically involves a combination of field measurements, remote sensing, and modeling approaches. Field studies use flux chambers or micrometeorological techniques to quantify methane release rates directly from manure deposits. These measurements are often complemented by laboratory incubation experiments to understand microbial processes under controlled conditions. Additionally, global datasets on manure nitrogen production and application, such as the gridded data developed for Earth system modeling, provide spatially explicit estimates that support emissions inventories. Institutions involved in agricultural greenhouse gas monitoring include national agricultural research agencies and international bodies like the Food and Agriculture Organization (FAO) and the Intergovernmental Panel on Climate Change (IPCC).

Within the SIGNAL system, this phenomenon is treated as a defined environmental signal whose boundaries and measurement conventions are described below.

Signal Definition

This signal quantifies methane emissions originating from animal manure that is deposited and left on pasture surfaces without collection or treatment. It specifically measures the methane flux resulting from anaerobic decomposition processes in manure under pasture conditions, excluding emissions from manure managed in storage or treatment facilities. The canonical measurement unit and temporal structure for this signal are to be determined within the SIGNAL framework.

Boundary Conditions

Boundary inclusions encompass methane emissions from manure directly deposited by grazing animals on pasture soils, including emissions influenced by local soil moisture, temperature, and microbial activity. Boundary exclusions include methane emissions from manure that has been collected, stored, composted, or otherwise managed off-pasture, as well as emissions from enteric fermentation or other livestock-related sources not involving manure left on pasture. Emissions from synthetic fertilizers or other agricultural inputs are also excluded from this signal.

Aggregation Semantics

Geographic aggregation for this signal involves compiling methane emission estimates across various pasture regions globally, reflecting the widespread distribution of grazing systems. Temporal aggregation considers emission variations over time, including seasonal and interannual changes influenced by climatic and management factors. Cross-signal aggregation may integrate this signal with related agricultural emissions such as those from enteric fermentation and livestock manure management to provide a comprehensive assessment of methane sources within agricultural systems. Aggregation notes specify that care must be taken to avoid double counting emissions across related signals and to harmonize temporal and spatial scales during integration.

Observational Status

Current observational data for manure left on pasture emissions rely on a combination of field measurements and modeled estimates, with ongoing efforts to improve spatial resolution and temporal coverage. The availability of gridded global datasets on manure nitrogen production supports enhanced emissions modeling. However, uncertainties remain due to variability in grazing practices, environmental conditions, and measurement methodologies. Future SIGNAL releases may incorporate refined observational backbones, standardized units, and more detailed temporal structures to improve the accuracy and usability of this signal in environmental assessments.

Related Signals

• Anthropogenic nitrous oxide emissions
• Agriculture — Emissions from livestock Emissions
• Agriculture — Enteric Fermentation Emissions

Key Associated People

• Bowen Zhang (Auburn University) [Lead author]

Sources

• Global manure nitrogen production and application in cropland during 1860–2014: a 5 arcmin gridded global dataset for Earth system modeling — 2017