Jesse Jones

Principle to Soil Science: Semester Paper

3/20/2015

Salinization of the Midwest

Over the past 100 years farming has been a main life line for our country economically and

culturally. In the United States, there have been large amounts of agricultural practices that have been

used on the soils of the Midwestern states in the last century. In this short time scale of an environmental

viewpoint of only 100 years, societies in these states have had to figure out how to mitigate for the

consequences seen through the large scale farming practices. The process of salinization within these soils

have been an ongoing issue for the farmers of the early 20th century to present. The process of this issue

will be described and explained through this paper. As well as a large scale study of the Colorado River

being saturated with the salts of the soils of the Midwestern state of Colorado. In the past we have been

greatly mistaken with thinking the proper care of the soils beneath our feet was in thought of water.

Farmers have been paying for this mistake and have been trying to find better ways to balancing out the

salts within the soils throughout all sorts of studies. Salinization as a whole isn’t completely direct with

the misunderstanding of the farming society, salinization can also be exploited through nature causes as

well.

The process of salinization is a concept at first is pretty hard to grasp. Many people misperceive

this issue of the soils being dried out and have evaporates showing up within the soil content. This is

actually not the case in this problem of salinization. The problem occurs when farms irrigate their land

with too much water and over time the water doesn’t infiltrate fully or in a timely manner and gets

evaporated and leaves evaporate behind. In lack of terms, these salts stand on the surface of the soil

profiles throughout the Midwest and pretty much dehydrate the nutrient rich soils to unfertile soils that

are too salty and in this matter create salt water which then is to potent for crops and other habitats to use

for food and hydration purposes. When this occurs the nutritional value of the soils breaks down over

time and the farmer of that area cannot use those agricultural fields for a very long time until the salinity

levels are low enough that the plants can use the water and other elements within the soils for a proper

food source. The greatest areas of salinization occur mostly throughout the Midwest due too there being

large amounts of time of being arid throughout the year. This dryness is a great factor for potential sodic

soils to form within the surface layer of the soil units. When there is extreme droughts the surface layer

can erode down into a clay based soil which can inhibit salinization to occur and crusting to form as well.

Throughout the mid-western states there have been a varied of overwhelming human impacts to

the soils. Impacts that can range from urbanization of big cities around the region, to a large amount of

farming practices like, over grazing of cattle and too much tilling of agricultural fields. There are natural

occur impacts as well, for example, natural brush fires that happen in this arid climate quite frequently.

Impacts have primarily come from the over excessive farming and tillage of the soils around the many

states in the Midwest. In the past century the soils of the Midwest have seen a lot of change and all

different types of weather elements as well as different farming practices being done to them. With the

temperature getting warmer as the years go on and the gusting of winds around the plains, intake of water

from farmers wells are sucking more water than the aquifers can handle which causes the water table to

drop significantly and brings risk to having aquifers running dry. According Michigan States own Bruno

Basso, “Already, there are regions in Texas and Kansas where farmers can’t pump enough water to meet

the demands of their crops (Basso 39).” When this starts to occur the water table will then drop and the

concentrations of salts will start to rise over time as the surface of the soil profiles. Being humans our

reaction is to keep watering and watering the soils so the roots wont dry up and the surrounding soils will

be able to give the crops the nutrients they truly need to grow. When this natural reaction occurs water is

then pumped from an aquifer that is already low and this water is unable to infiltrate the surface soil due

to the process called surface crusting. This process of infiltration is key to making food for these crops.

This crust layer will speed up the process of evaporation, which is bad because the water that was just

used to irrigate the farmer’s crops is then evaporated away leaving behind the sodium that was within the

water. The water being put on these agriculture fields which came from the aquifers below has rising

sodium content from the water table lowering. The process of percolation is being cut off and is not

playing its role of recharging the water table and the aquifers below. The start of this whole process

comes from the improper practices of farmers excessively tilling their soils and on top of that irrigating

these bare soils. Which then, dries up the soil surface and creates this crust and then this plays a role in

negating the natural process of infiltration and percolation of the water being put on these fields and

evaporates into a thin layer of sodium. According to Soils Quality a NRCS collaboration website, “A

surface crust is an indicator of poor infiltration, an unstable seedbed, and reduced air exchange between

the soil and atmosphere. It can also indicate that the soil has a high sodium content that increases soil

dispersion when it is wetted or irrigated (NRCS 1).” This is basically saying what we have been doing for

the past century was the wrong way to sustaining the soils of the Midwest. Over irrigation the last 100

years is starting to show signs of its use through many different variables in the environment. This is a

vital impact that is ongoing and is showing its consequences with the degradation of our soils through

salinization and the large amounts of water being put out on these fields around the Midwest.

There are other impacts that causes saline levels to rise in the Midwest. One by which comes

from the wicked forces of nature called, wild fires. These fires occur during the dry season which can

trigger immense amounts of drought and can spark vegetative fire throughout the lands. This is not good

because this natural process leads to lots of bare soil exposure. When this bare soil is exposed the rate of

salinity levels can increase at large amounts. This is due to the fact of these soils being covered by dense

prairie grasses and these soils were getting proper moisture and nutrients from the root structure of these

grasses above the soil layers. When these fire occur the nutrient content is stripped away from the soils

and in due time these soils will dry up quickly and saline evaporates will appear on the surface from the

extreme effects of the hot temperatures and winds whipping across these arid plains. These fires occur

from the water table receding from high irrigation rates and the decrease to precipitation during the

elongated periods of extreme dryness.

Another variable that needs to be taken into account is the practices of the other farming industry

of the Midwest and the horrific effect of overgrazing. These cattle farmers are coming to the same

problems of these crop farms only taking place within the pastures that these huge numbers of cattle head

are roaming. The proper practices of rotating pastures and splitting up herd cattle is not being taken into

consideration and in this case these farmers are seeing a decreasing soil quality every year and spikes in

salinity on their fields. As the cattle compacts the soils within the pasture the drying of the soils speeds up

exponentially. According to Hurburt Kelly, “The destruction of grazing land follows an all too familiar

sequence of events. Overgrazing by cattle reduces plant cover, eliminating the most desirable forage

species first. This opens land to undesirable weeds, brush, and tress and leads to increasing soil erosion

and lower soils fertility. The land becomes less and less productive (Kelly 19).” This is a prime example

of how overgrazing can increase the level of severity in degrading soils. The relationship of compaction

from the large counts of cattle going over the soils and the elements of high temperature and winds will

trigger the right mixture for unstable saline soils throughout the Midwest. According to NRCS’s

publication of The State of The Land, about 570 million acres of the contiguous United States have a

moderate to serve potential for soil and water salinity problems. At least 48 million acres of cropland and

pasture are currently affected (NRCS 10). This gives a great overview to the big picture on how much

land is used in farming of cattle in the Midwest and how much land is at stake if these farmers don’t

change their traditions. When the salinity levels reach a threshold of not being able to produce any type of

crop or grasses due to the high concentration of salts the soil is considered unfertile and will take long

periods of time before the soil can be used again for agricultural uses like grazing and growing crops. In

the years to come these impacts that are inhibiting salinization will be interesting to see if humans can

adapt to the problems and learn from the mistakes and change farming methods to sustaining great source

of fertile soils around the Midwestern.

One of the biggest bodies of water in the United States that is seeing some of the worst saline

levels is the Colorado River. Flowing through mountainous regions with very arid environments it’s a

body of water that has some of the highest concentrations of sodium due to the surrounding soils and

other geological variables. There is a case study that was done not too long ago that gives a good stand

point for where some of these drier western states along the Colorado River are heading in terms of soils

quality containing high amounts of soluble salts within them. This journal brings our attention to a

different angle to how these soils and geological structures truly become the culprits to saltiness of the

water table and larger bodies of water like the Colorado River. This study was done in 2009 which is very

resent to our knowledge in the environmental mindset. In understanding geological changes which occur

at a very slower rate and we should definitely should be taken into consideration since these geological

issues cannot be fix in the matter of a couple years. The outline to this writing is as so, anthropogenic

activities in the Colorado River basin (for example mining, farming, petroleum exploration, and urban

development) can greatly accelerate the release of constituents from these geologic materials, thus

increasing the salt load of nearby streams and rivers (Tuttle 1). This is an interesting statement to take into

consideration as we move forward in studying how to control these salinity levels throughout the

Midwestern states like Colorado. These human impacts which have developed over the past century have

caused salinity levels to rise in the soils beneath the feet of the societies in the states along the Colorado

River but as water flow there is always more places downstream that will be affected. Mexico has been in

communication the last thirty years due to the fact of huge amounts of sodium loads in the waters of the

Colorado River being brought down to the United States and Mexico border.

Within this study of the many watersheds and geological units in the state of Colorado the

number given from the journal were absolutely demoralizing to see for the future of this state and raises

many red flags to the farming industry and the societies around the area. For example, at least 33 million

people and 4 million acres of farmland throughout the United States depend on the water of the Colorado

River (Tuttle 1). This is a good point to be made with the detrimental impacts of salinization. With there

being 33 million people in the vicinity of the Colorado River there for means large amounts of

urbanization and farming to support these huge communities along the Colorado River. Throughout this

study there is a direct relationship between the anthropogenic activities these communities bring to the

soils and waterways of the Colorado River Basin. With the rise of human activities like farming for

example, there is a decrease in soil quality at the surface which starts a domino effect. With the rise in

sodium levels which in time will leach through the soils down into the bedrock and then goes straight to

the water table and out to the Colorado River Basin. With this cycle consistently happening over the last

century the salinity levels of the Colorado River have sky rocketed and have gotten so bad it has started to

effect international communities in the country of Mexico 30 years strong and after the Clean Water Act

of 1972 was past soon after one of the first state of the art desalinization plants were implemented on the

Colorado river at the United States and Mexico border.

This study along the Colorado River has a pretty interesting concept in methodology to tracing the levels

of sodium throughout nonpoint sources using trace methods in the various sites of study. Throughout the

study the major elements that were formed around the ground and the surface water were calcium,

magnesium, sodium, potassium, chloride, sulfate, and bicarbonate. These solutes are generally

conservative in water, although precipitation of calcite can occur and calcium and magnesium can be

absorbed during cation exchange. The one objective that appeared interesting throughout the study was

the use of tracers in the major geological sources of sodium to the Upper Colorado River. (Tuttle 2).

Using this type of method is helpful to understanding the process of salinization within the soils and water

table below. Reading through the article this study gained lots of information that uncovered levels of

evaporates at the surface and the concentrations from weathering material leading to the increase of

salinization levels. The latter results have important implications for health of human and organisms as

several environments where acidification can occur in the animal’s lungs and stomach, plant root zones,

and amended soils (Tuttle 2). After getting the results through the methodology of using tracers the

concentration levels led to conclusions that the saline levels throughout the water and geologic features

were to be taken with caution due to high acidic levels and could potential cause human and animal health

issues.

As human beings we have played a significant role in the development of the soil erosion process

called salinization. The acceleration of this impact has been made through many farming practices like

lash and burning and over grazing which has led to the tragedy of the Dust Bowl of the 1930’s as well as

other natural effects like grass fires. With the aquifers and water tables on the decline and these soluble

salts on the raise, impacts are starting to form all over these farming communities due to salinization.

Looking to the future, have we come too far to look back and learn from these mistakes or is this a new

beginning to seeking out ways to overcome the degradation of these important soils that truly are the

blood line to these Midwestern communities and the life line to our country’s economy. Research

surveys like the one put together by Michele Tuttle along the Colorado River raises awareness and gives a

true setting for what environmentalist will have to face in order to sustain these soils for future

generations. Studies like this will give way to opening many eyes throughout the environmental soil

studies to understanding and figuring out what will need to be done to set forth sustainable habits for

farmers and to educate the people of these communities on where these generational soils are heading if

change doesn’t start now.

Work Cited

Basso, Bruno, Anthony Kendall, and David Hyndman. "The Future of Agriculture over the Ogallala Aquifer: Solutions to Grow Crops More Efficiently with Limited Water - Basso - 2013 - Earth's Future - Wiley Online Library." The Future of Agriculture over the Ogallala Aquifer: Solutions to Grow Crops More Efficiently with Limited Water - Basso - 2013 - Earth's Future - Wiley Online Library. Earth's Future. Web. 22 Apr. 2015. <http://onlinelibrary.wiley.com/doi/10.1002/2013EF000107/full>.

Andrews, Susan, Michelle Wander, and Holli Kuykendall. "Indicators: Soil Crusts." Soil Quality: For Environmental Health. NRCS East National Technology Support Center. Web. 22 Apr. 2015. <http://soilquality.org/indicators/soil_crusts.html>.

Tuttle, Michele L., and Richard I. Grauch. Salinization of the Upper Colorado River--fingerprinting Geologic Salt Sources. 1st ed. Vol. 1. Reston: U.S. Geological Survey, 2009. 61-62. Print.

Kelley, Hubert W. "How Soil Is Destroyed." Keeping the Land Alive: Soil Erosion--its Causes and Cures. Vol. 50. Rome: Food and Agriculture Organization of the United Nations, 1983. 19. Print.

"Protecting and Enhancing Agricultural Productivity." State of the Land. Vol. 1. Washington DC: Natural Resources Conservation Service (NRCS), U.S. Dept. of Agriculture (USDA), 1997. 9-10. Print.