This figure shows annual departures from mean annual temperature in Alaska in degrees Fahrenheit from 1949 to 2016. The figures come from the Alaska Climate Science Center.

This figure shows annual departures from mean annual temperature in Alaska in degrees Fahrenheit from 1949 to 2016. The figures come from the Alaska Climate Science Center.

Soil: A complex ecosystem under your feet

  • By Dawn Robin Magness
  • Thursday, June 7, 2018 6:39pm
  • Sports

Soil has a unique place in the history of the National Wildlife Refuge System. Farming practices coupled with drought in the 1930s caused the Dust Bowl. Dust storms, large enough to engulf entire communities and lasting for weeks, blew away soil and destroyed wetlands.

In 1937, President Franklin D. Roosevelt wrote a letter to the state governors that stated: “The Nation that destroys its soil destroys itself.” President Roosevelt’s multifaceted response included appointing a presidential committee to conserve ducks affected by the Dust Bowl.

The committee included wildlife leaders, such as Thomas Beck, Aldo Leopold and “Ding” Darling, and their recommendations led to the Duck Stamp Act of 1934. Waterfowl hunters are required to buy Duck Stamps as part of their license and the revenue is directly used to purchase or lease wetlands. The land purchases helped to build your National Wildlife Refuge System. Refuges conserve and manage habitat for ducks along their Continental flyway routes.

As stated so eloquently by President Roosevelt, soil loss is destructive because soil develops very slowly as rock is broken down by weathering. On the Kenai Peninsula, we have young soils due to glaciers scouring much of our landscape during the last ice age. Here, soils have only had several thousand years to develop.

Soils are described in layers, called horizons, that have different properties. The bottom layers reflect the parental geology. The dark surface layer and lighter colored subsoil layer just below the surface are biologically active. In Alaska, plant roots only survive and anchor into the top 6 inches.

The biologically active layer is known as mineral soil. Mineral soil consists of mineral particles, air and water, generally in equal proportions, and a small amount (about 5 percent) of organic materials.

The organic material consists of diverse microbe and fungal communities, and the plant and animal parts they are decomposing. The process of decomposition is both complex and important because it converts minerals, such as nitrogen and phosphorous, into compounds that can be used by plants.

According to the Alaska Climate Research Center, Alaska’s annual temperature has increased by 3.7 degrees Fahrenheit over the last 70 years. There are seasonal differences with average winter temperatures increasing by 6.7 degrees Fahrenheit and average summer temperatures by 2.3 degrees Fahrenheit.

Average temperatures are variable across years and there is a regional temperature shift in 1977 that corresponds to the Pacific Decadal Oscillation (see figure). Soil temperatures are tightly linked with air temperatures. What can we expect with warming soils?

Warming soil temperatures increase decomposition rates and, therefore, the nutrients that are available to plants.

Soil nitrogen has been extensively studied because it strongly limits plant growth. Nitrification, the process where bacteria converts nitrogen into a usable form, is highly dependent on temperature.

In cold soils, slower nitrification rates slow plant growth. When soils are experimentally warmed, nitrification increases on average of 50 percent and plant productivity increases. If not used quickly by plants, nitrogen is highly water soluble and easily flushed out of the soil in runoff.

Microbial communities also change when exposed to warmer soil temperatures. Often microbial communities increase in warmer temperatures. But in boreal black spruce forests, a soil warming experiment changed the composition and reduced the abundance of bacteria and fungus in the soil. The decrease was thought to be linked to the soils dying out.

Cold soil temperatures slow enzymatic processes in the soil microbial communities that cycle nutrients and in the growing plant tissues. Plants species have minimum temperatures that they can tolerate. Once soil temperature falls below this threshold their root growth is severely limited.

For example, paper birch trees require soil be 39 degrees Fahrenheit to grow roots. Trees and other plant species also have specific soils temperature and water requirement for their seeds to successfully germinate.

Soil properties interacting with warming temperatures have the potential to change vegetation. We are starting to measure soil temperatures on the Kenai National Wildlife Refuge and to understand the complex interactions between soil, microbes and plants.

Dr. Magness is a landscape ecologist at Kenai National Wildlife Refuge. Find more information at http://kenai.fws.gov or http://www.facebook.com/kenainationalwildliferefuge.

More in Sports

Kenai Central's Sawyer Vann controls Nikiski's Wyatt Maguire at 125 pounds Tuesday, Nov. 23, 2021, at Nikiski High School in Nikiski, Alaska. Vann notched a 7-6 victory. (Photo by Jeff Helminiak/Peninsula Clarion)
Area wrestlers collect mat time before Thanksgiving break

Area wrestlers got in some mat time Tuesday before the Thanksgiving break.… Continue reading

Soldotna junior Liam Babitt holds a grip on South Anchorage’s Britten Hamilton during the 215-pound final of the Lancer Smith Fall Varsity 2021 Invite on Saturday, Nov. 20, 2021 at the Menard Arena in Wasilla, Alaska. (Photo by Jeremiah Bartz/Frontiersman)
Soldotna crowns 4 champions at Lancer Smith

The Soldotna wrestling team finished fourth Friday and Saturday at the Lancer… Continue reading

Kenai River Brown Bears forward Bryce Monrean tries to find a way through the defense of the Springfield (Illinois) Jr. Blues during a first-period power play Friday, Nov. 19, 2021, at the Soldotna Regional Sports Complex. (Photo by Jeff Helminiak/Peninsula Clarion)
Jr. Blues come back to take series from Bears

The Springfield (Illinois) Jr. Blues lost not only a 2020-21 season to… Continue reading

Assistant coach Taylor Shaw leads the Kenai River Brown Bears during a game Thursday, Nov. 18, 2021, against the Springfield (Illinois) Jr. Blues at the Soldotna Regional Sports Complex in Soldotna, Alaska. (Photo by Jeff Helminiak/Peninsula Clarion)
Brown Bears start search for new head coach

The Kenai River Brown Bears issued a press release Friday about staff… Continue reading

tease
Hockey roundup: SoHi sweeps in Kodiak; West wins End of Road tourney

The Soldotna hockey team swept Kodiak in the first high school games… Continue reading

A brown bear feeds on a salmon. (Photo by C. Canterbury/USFWS)
Refuge Notebook: Bears, uniquely built to respond to winter

With the new snow and temperatures dipping into the single digits, you… Continue reading

Kenai Central's Caden Warren surveys the ice against West at the End of the Road Tournament at Kevin Bell Arena in Homer, Alaska. (Photo by Sarah Knapp/Homer News)
Kenai, Homer hockey lose to open tourney

The Kenai Central and Homer hockey teams both opened the End of… Continue reading

Caden Triggs of the Kenai River Brown Bears celebrates his first-period goal against the Springfield (Illinois) Jr. Blues on Thursday, Nov. 18, 2021, at the Soldotna Regional Sports Complex in Soldotna, Alaska. (Photo by Jeff Helminiak/Peninsula Clarion)
Brown Bears topple Jr. Blues

By JEFF HELMINIAK Peninsula Clarion The Kenai River Brown Bears received two… Continue reading

Michael proposes to Sarah at the Kenai National Wildlife Refuge on Sunday, Nov. 7, 2021. (Photo by Ashlyn O’Hara/Peninsula Clarion)
Out of the Office: Falling in love one snowflake at a time

Do you want to know what I’ve been looking forward to the… Continue reading

Kenai River Brown Bears forward Caden Triggs carries the puck against Anchorage Wolverines defenseman Campbell Cichosz on Friday, Nov. 5, 2021, at the Soldotna Regional Sports Complex in Soldotna, Alaska. (Photo by Jeff Helminiak/Peninsula Clarion)
Brown Bears to host 1st place Jr. Blues

The current stretch of the schedule for the Kenai River Brown Bears… Continue reading

Soldotna's Isaac Chavarria wrestles to a major decision over Kenai Central's Andrew Gaethle at 152 pounds during a dual meet at Kenai Central High School on Tuesday, Nov. 16, 2021, in Kenai, Alaska. (Photo by Jeff Helminiak/Peninsula Clarion)
SoHi wrestlers take dual meet from Kenai

The visiting Soldotna wrestling team defeated Kenai Central 69-6 in a dual… Continue reading