Soil – Agriculture’s Reservoir

Post submitted by Hanna Bates, Program Assistant for the Iowa Water Center

The soil is like a sponge that holds water so it is available when crops need it. Wetter soil at the surface prevents deeper infiltration and so water is lost as surface runoff. Not only this, but soil moisture is also a variable that influences the timing and amount of precipitation in a given area. This is due to the impact it has on the water cycle. This cycle circulates moisture from the ground through evaporation and plant transpiration to the atmosphere and back to the ground again through precipitation. Therefore, the amount of water stored in the soil can affect the amount of precipitation received during the growing season.

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Satellite imaging from the European Space Agency. The center figure depicts imaging derived from SMOS.

According to Hornbuckle (2014), “we enter each growing season ‘blind’ as to whether or not there will be enough soil moisture and precipitation to support productive crops.” If there were a way to document and record water storage in the soil besides field measurements, we would have a better ability to predict future weather patterns and therefore, make better field decisions. Satellite remote sensing tools such as the European Space Agency’s Soil Moisture and Ocean Salinity (SMOS) and NASA’s Moisture Active Passive (SMAP) can be used to take such measurements. Before these tools can be used to estimate water storage and improve weather and climate predictions, researchers must compare them to what is actually measured within the soil. This process of confirming accuracy of a tool is called validation.

A project led by Dr. Brian Hornbuckle, and funded by the Iowa Water Center in 2014, sought to improve and validate SMOS and SMAP in near-surface soil moisture observations of Iowa. Hornbuckle used a network of soil moisture measurements located in the South Fork Watershed as a standard to validate the accuracy of SMOS and SMAP. At each site, soil moisture and precipitation was measured.

Some of the results of this research project are presented in a 2015 article published in the Journal of Hydrometeorology.  Rondinelli et al. found that SMOS and the network of soil moisture measurements detect different layers of the soil. SMOS takes measurements of the soil surface while the network observes a deeper level of soil. These results will allow scientists to better evaluate the accuracy of measurements from SMOS and SMAP and ultimately enhance our understanding of the water content of the soil surface.  As noted earlier, it is this layer of the soil that determines how much precipitation is lost to surface runoff.

In a subsequent study published in 2016, Hornbuckle et al. published further results that indicate new ways of using SMOS. Researchers found that SMOS can be used to look at water in vegetation, as opposed to water in the soil.  Hence SMOS might be used in the future to observe the growth and development of crops, and perhaps estimate yield and the time of harvest as opposed to conducting field surveys from the ground. It also has the potential to measure estimates of the biomass produced during the growing season, which could be useful to reach bioenergy production goals.

Research like this demonstrates that a single tool can be used in multiple ways to better understand our landscape. Not only this, but preliminary studies of SMOS also show that it is important to verify the accuracy of tools before relying on them. Like all research, the work is not done to identify all the potential uses for SMOS and SMAP.  A new NASA grant, in partnership with the Iowa Flood Center, will help get researchers even closer to making satellite measurements a useful, scientific tool to understand water near the soil surface.

References

Hornbuckle, Brian K. “New Satellites for Soil Moisture: Good for Iowans!.” A Letter from the Soil & Water Conservation Club President (2014): 20.

Hornbuckle, Brian K. Jason C. Patton, Andy VanLoocke, Andrew E. Suyker, Matthew C. Roby, Victoria A. Walker, Eswar R Iyer, Daryl E. Herzmann, and Erik A. Endacott. 2016. SMOS optical thickness changes in response to the growth and development of crops, crop management, and weather. Remote Sensing Environment (180) 320-333.

Rondinelli, Wesley J., Brian K. Hornbuckle, Jason C. Patton, Michael H. Cosh, Victoria A. Walker, Benjamin D. Carr, Sally D. Logsdon. 2015. Different Rates of Soil Drying after Rainfall Are Observed by the SMOS Satellite and the South Fork in situ Soil Moisture Network. Journal of Hydrometeorology. April 2015.

 

View from my Windshield: Observations of soil erosion across Iowa

Post written by Hanna Bates, Program Assistant at the Iowa Water Center

For the past couple of weeks, I have been on the road across Iowa. These trips vary in their purpose, but one thing that remains the same is the evident erosion in the fields along my travels. Regardless of where I am – whether it is in the Loess Hills visiting family or in the Des Moines Lobe for a meeting – spring rains have revealed that there are deep cuts in the bare brown soils where lush, even soils used to be.

Cruse et al. (2016) writes:

“Topsoil thinning is closely linked to loss of crop production potential. Typical statewide average erosion rates have only a minor impact on crop yields in the subsequent year. However, cumulative effects are far more significant and contribute to a loss of state revenue that becomes much more important as time progresses.”

The simple fact is that without soil there would be no life. In Iowa, we have high quality soils that, along with some good science and great farmers, enable us to be the top producers in corn, hog, and egg production. This leads to the question: What may be the ultimate cost of this productivity?

Cruse et al. (2016) conducted a study to determine the effects of erosion on commodity yields and to gauge the future impacts on the agricultural economy in Iowa. Researchers studied seven farm sites in Iowa with cropping history and available yield maps. The Daily Erosion Project was used to estimate crop yield impact on soil depth from 2007-2014. The average state loss across those years was 5.7 tons of soil per acre per year. “Assuming a 2.2 bushel per acre corn yield loss across 14 million acres in a given year and a corn price of $4.00/bu, the next year’s crop production loss would equate to approximately $4.3 million total across this land area” (Cruse et al. 2016). There are informational resources and federal programs available for soil conservation practices, but with a short-term economic market system, there is little motivation to participate.

Cruse et al. (2016) writes:

“Short-term minor yield impacts on a per acre basis create little incentive for investing in short-term soil conservation strategies available for many farmland renters. However, as the cumulative effect compounds the economic effect over time, landowners that have longer term planning horizons are much better positioned to recover their financial investments in soil conservation practices.”

To put is succinctly, a loss of soil leads to a loss of productivity, which leads to a financial loss for the state. The impacts of the above findings on decision-making out in the field may be significant given the short-term mindset of our commodity market. Making present-day investments to maintain soils may pay off in the end when compared to short-term commodity gains from year-to-year. Other research has revealed that there is hardly a piece of land in Iowa that is exempt from the problem of erosion. According to Cruse et. al. (2006), soil erosion affects everyone although it is spatially and temporally variable. With 55% of Iowa farmland leased rather than owner controlled (Duffy et al. 2013), an investment in soil saving practices will require candid conversations and real partnerships between a tenant and landowner.

Overall, the first step in making a change is being knowledgeable about your surroundings. Next time you are on the road, look out in the field and really see where you are travelling. Then, compare that to what the data shows on the Daily Erosion Project. You may be surprised about what you learn.

References

Cruse, R., D. Flanagan, J. Frankenberger, B. Gelder, D. Herzmann, D. James, W. Krajewski, Kraszewski, J. Laflen, J. Opsomer, and D. Todey. 2006. Daily estimates of rainfall, water runoff, and soil erosion in Iowa. Journal of Soil and Water Conservation. 61(4): 191-199.

Cruse, Richard M., Mack Shelley, C. Lee Burras, John Tyndall, and Melissa Miller. 2016. Economic impacts of soil erosion in Iowa. The Leopold Center for Sustainable Agriculture. Competitive Grant Report E2014-17.

Duffy, Michael, William Edwards, and Ann Johanns. 2013. Survey of Iowa Leasing Practices, 2012. Iowa State University Extension & Outreach. File C2-15.

Get to know Alert Iowa

Post submitted by Samantha Brear, Alert Iowa Mass Notification System Program Manager and State E911 Program Planner at Iowa Homeland Security and Emergency Management

Alert Iowa is a statewide mass notification and emergency messaging system. The system can be used by state and local authorities to quickly disseminate emergency information to residents in counties that utilize the system. The system is available, free of charge, to all counties. Eighty-four of Iowa’s 99 counties are using the Alert Iowa system.

AlertIowaMap.JPGAlert Iowa allows citizens to sign up for the types of alerts they would like to receive. Types of alerts may include evacuation orders, boil order notifications, and other local safety information messages. The best way to receive messages is via text message.  However, users can also opt for a voice call and an email.

The system interacts with National Weather Service notifications.  When the National Weather Service issues weather alerts, such as Flash Flood Warnings and Tornado Warnings the system sends these alerts automatically to members of the public who have opted in to receive them.

The map shows the counties that are utilizing the Alert Iowa system. Citizens can sign up to receive alerts on their county’s registration page. If they choose, they can sign up to receive alerts in multiple counties.

Wireless Emergency Alerts (WEA) are another type of emergency messages sent by authorized government alerting authorities through mobile carriers. WEA messages include a special tone and vibration, which are repeated twice, followed by the WEA, which will look like a text message. The WEA message will show the type and time of the alert, any action you should take, and the agency issuing the alert. The National Weather Service can send out Flash Flood Warnings, Tornado Warnings, and Amber Alerts while Iowa Homeland Security can send out Civil Emergency Warnings to every smart phone within a specified threat area. Wireless Emergency Alert service is offered as a free service by wireless carriers.  Citizens do not need to sign up for this service.

Alert Iowa and Wireless Emergency Alerts are only two of the ways citizens can receive emergency alerts. Other sources include NOAA Weather Radio, news broadcasts, the Emergency Alert System on radio and TV programs, outdoor sirens and phone apps.

Please visit http://www.homelandsecurity.iowa.gov/about_HSEMD/alert_iowa.html for more information and how to sign up!

Winter Weather in Iowa

Post submitted by Jeff Zogg, Senior Service Hydrologist for the National Weather Service in Des Moines

This winter, we have experienced a mix of snow, rain, sunshine, and even warm temperatures. With this variability across the state, it is important to document what we’ve evidenced so far and to anticipate the weather to come over the upcoming months. Below is a brief overview of the recent, current, and anticipated weather and water conditions for Iowa.

The past 30 days have featured warm and wet conditions across the Iowa region.  Average temperatures have been 3 to 6 degrees above normal.  Precipitation has been 200 percent or more of normal levels across much of the state.

According to the U.S. Geological Survey, as of January 19th, stream flows across Iowa have been above to much above normal.  According to NOAA’s Climate Prediction Center, soil moisture was above to much above normal across much of the state—with near-record high values for this time of year across far northern and northeastern Iowa.  In contrast, the Drought Monitor stated that abnormally dry conditions existed across southeastern Iowa.

The latest outlook for February calls for equal chances of near, above or below normal temperatures for the state—which means that all three outcomes are equally possible. The normal statewide average temperature for Iowa during the month of February is 24.6 degrees. Aside from a wet signal across far eastern Iowa, there are also equal chances of near, above or below normal precipitation levels across the state.  The normal statewide average precipitation for Iowa at this time of year is 1.1 inches.

For February through April, there are also equal chances of near, above or below normal temperature (statewide normal average is 36.8 degrees).  A wet signal is indicated across the northeast quarter of the state for precipitation, with equal chances elsewhere.  The seasonal drought outlook calls for no change to the abnormally dry conditions evident across the southeastern portions of the state. The normal average precipitation at the statewide level at this time is 6.7 inches.

The National Weather Service will release two spring flood outlooks this season.  They are scheduled for February 16th and March 2nd.  Both outlooks will be released by 5pm each day and will be available on the NWS Des Moines Website at http://www.weather.gov/desmoines.

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