1) Soil releases 10 times more carbon dioxide than human activities through the process of soil respiration. Grassland soil stores large amounts of carbon and releases less carbon than other land uses in warmer conditions. 2) Factors like soil temperature, moisture, and vegetation influence soil respiration rates. As temperatures increase from climate change, soil respiration may also increase up to a threshold. 3) Restoring grasslands can lower the global carbon footprint by storing carbon in soil for long periods, decreasing the amount of carbon dioxide in the atmosphere.

1. Soil Solutions: Avoiding Future Toil by Restoring Grasslands and its Soil
Both soil and human activities release carbon dioxide (CO2) to the atmosphere. But on a global scale, soil releases
10 times more than we do through the process of soil respiration, which is carbon released by all living things in
the soil. Grassland soil stores large amounts of carbon, and in warmer conditions, they release less carbon through
soil respiration than other land uses. By restoring these ecosystems we can lower the global carbon footprint,
slowing the effects of climate change.

2. Diagram 1: Photosynthesis and respiration in plants
Plants breathe in CO2 and absorb sunlight through their leaves during photosynthesis. They use these materials to
make food. Oxygen is released from the plant in this process.

3. Respiration:
All living things (including plants) need oxygen to be able to use the food to maintain their bodies. Not all of the
carbon in food is used to grow; some is exhaled in the form of CO2 during the process of respiration. Soil
respiration is important because it has been shown to account for the majority of respiration by an ecosystem.
Carbon can be released by: respiration from live roots, respiration from above ground and below ground litter
decomposition, and respiration from living animals in the soil.
Diagram 2: Three groups of organisms contribute to soil respiration:
1. Live roots- Root respiration through the use of food to maintain tissues (prairies have large carbon storage

4. capacity in this category since they have such extensive root systems).
2. Litter decomposition - Respiration by bacteria (Mycorrhizae and other rhizosphere-associated micro fauna) as a
result of above- and belowground litter decomposition.
3. Living animals in soil - Respiration by insects and other living animals (soil micro- and macro fauna) in the soil.
Factors that influence soil respiration:
The amount of carbon released from the soil depends on a number of factors, including soil temperature, soil
moisture, and vegetation.
1. Soil Temperature - When soil temperature goes up, the rate of soil respiration goes up. When the soil is warmer,
the plants and animals living there are more active, eating more food. When soil temperature goes down, the rate of
soil respiration also goes down.
2. Soil Moisture - As soil moisture increases, soil respiration also increases until a certain point. Above that point,
respiration starts decreasing. This is because water suffocates the organisms by trapping CO2 released through soil
respiration and also by blocking oxygen. As soil moisture goes down, respiration goes down because the organisms
in the soil don’t have enough water to survive.
3. Soil Moisture and Soil Temperature - Soil temperature and soil moisture both influence soil respiration
independently, but they also interact and affect respiration rates.
4. Vegetation - It seems that soil respiration increases in a tall grass prairie because there are more plants. As

5. mentioned earlier, plant roots release carbon, so more plants means more roots and more soil respiration.
Climate Change: affects soil temperature, which affects soil respiration by increasing CO2 up to a threshold.
Map 1: Models of Climate Projections Over the Next Century Compared to Constant CO2 Emissions
The source of Diagram 3 is the Intergovernmental Panel on Climate Change (IPCC), an international body that
reviews scientific, technical, and economic information to assess climate change. It is predicting a global rise of
temperature of about 3.2 °F (1.8 °C) - 7.2 °F (3.4 °C) over the next century. It has also been predicted that there
will be more intense and more frequent severe weather events. For Iowa specifically, with a global temperature
increase of that much, it has been predicted that summers will be 3 °F hotter. Summers are also predicted to be

6. drier (20% less rain) and the other seasons wetter. It is also predicting that there will be more frequent and severe
short term droughts during the summer with frequent severe storms separating drought periods. This pattern would
show alternating periods of drought and flooding. Another effect of that increase would be heavy rains being more
common during spring, fall, and winter, causing more flooding problems.
Climate Change and Soil Respiration:
Map 2: Global Average Temperature and Carbon Dioxide Concentrations, 1880 - 2004

7. Soil respiration responses to increased temperatures as a result of climate change vary across ecosystems. Studies
have found that an increase of temperature does not necessarily imply an increase in soil respiration. In a tall grass
ecosystem soil respiration did not significantly change in a warmed condition. There is a certain temperature,
above which soil respiration will no longer significantly increase. The tall grass prairie has reached its threshold
temperature. A clear explanation why soil respiration won’t increase further has not been determined, however
other studies have been done to determine temperature thresholds in many ecosystems.
Climate models also predict more frequent and severe weather events. Among the climate predictions for Iowa are:
periods of drought during the summer separated by severe storms causing drought and flooding problems; and
flooding problems in the other seasons. During the summer, with these climate predictions, soil respiration may
increase initially with hotter temperatures. But with periods of drought and flooding soil respiration could decrease.
But these relationships are complicated by the effects climate change will have on agriculture. Wetter springs
would delay planting and drier summers would reduce crop yields possibly leading to less respiration due to less
plants or more respiration by decomposition of dead crops.

8. Respiration, Climate Change, and Restoring Grasslands:
Diagram 3: The Storage and Flow of Carbon

9. The diagram above to the left shows where carbon goes in an ecosystem and how long it stays in different parts. A
prairie soil profile is on the right. The top layer is dark and fertile with a lot of carbon stored there.
In addition to releasing CO2, soil also stores carbon in living organisms, litter, and humus, which is partially
decomposed litter. Grassland soil stores 10-30% of the world’s soil carbon, the most soil carbon of any ecosystem.
A large amount of carbon in grassland soil can be stored for long periods of time, decreasing the amount of CO2 in
the atmosphere and thus slowing climate change.
This is one of many reasons why we feel that ecological restoration is so important here at Neal Smith National
Wildlife Refuge. The issues associated with climate change are complicated by uncertainty, but if possible
projections come to pass, then the consequences to our way of life as well as wildlife could be severe. As the old
proverb says, “Hope for the best, prepare for the worst.” Taking action to prevent this from happening is a
necessity, and a method for doing so is restoring native ecosystems where possible.

10. The diagram above to the left shows where carbon goes in an ecosystem and how long it stays in different parts. A
prairie soil profile is on the right. The top layer is dark and fertile with a lot of carbon stored there.
In addition to releasing CO2, soil also stores carbon in living organisms, litter, and humus, which is partially
decomposed litter. Grassland soil stores 10-30% of the world’s soil carbon, the most soil carbon of any ecosystem.
A large amount of carbon in grassland soil can be stored for long periods of time, decreasing the amount of CO2 in
the atmosphere and thus slowing climate change.
This is one of many reasons why we feel that ecological restoration is so important here at Neal Smith National
Wildlife Refuge. The issues associated with climate change are complicated by uncertainty, but if possible
projections come to pass, then the consequences to our way of life as well as wildlife could be severe. As the old
proverb says, “Hope for the best, prepare for the worst.” Taking action to prevent this from happening is a
necessity, and a method for doing so is restoring native ecosystems where possible.