Why do they do that? Anhydrous


Early in the spring and late in the fall it is common to see tractors pulling large white tanks across bare farm fields. So, what are these strange white tanks? What’s in them and why is it applied to fields?

They are anhydrous tanks filled with anhydrous ammonia (NH3) – one of the most efficient and widely used sources of nitrogen fertilizer for agricultural crops like as corn and wheat.

Nitrogen is one of the 17 essential elements required for plant growth. Nitrogen is most commonly found in the atmosphere making up approximately 78% of the air that we breathe. But in the air it is in the form of N2 which is not available to plants to use. Nitrogen is part of chlorophyll which makes plants green and allows them to use sunlight to produce sugars (food) from oxygen and carbon dioxide through photosynthesis. Nitrogen supports strong vegetative plant growth, which is vital for good fruit and seed development.

Plants use nitrogen by absorbing either nitrate (NO3) or ammonium (NH4) ions through their roots. Soybeans and other legume plants can convert atmospheric nitrogen into a usable form because of nitrogen fixing bacteria on their root nodules. Other plants, like corn, need to have an ample supply of available nitrogen in the soil. Farmers can add nitrogen to fields in the form of livestock manure, granular urea, liquid nitrogen (UAN solution), and anhydrous ammonia.


When making environmentally and economically sustainable decisions about fertilizers, farmers consider the 4Rs best management practices. This helps them select the right fertilizer source and apply it at the right rate, right time, and right placement in the soil.

Anhydrous ammonia is often a preferred nitrogen source for many reasons. It is more concentrated than other forms of nitrogen, containing 82% nitrogen. It is readily available, because it is used in the manufacturing process of other nitrogen fertilizers. It can be applied long before the crop is planted. It is usually the most economical option as well.

Farmers store and transport anhydrous ammonia in liquid form in pressurized tanks. Using an anhydrous applicator pulled by a tractor, the high-pressure liquid converts to a liquid-gas mixture as the pressure drops while traveling from the tank to the knife outlet on the applicator. The knife slices the soil and injects the fertilizer 6 to 8 inches into the soil.

Once in the ground, the ammonia (NH3) ions react with moisture in the soil and convert to ammonium (NH4). Ammonium ions are very stable in the soil. They carry a positive charge and are bonded to negatively charged soil particles like clay and organic matter. These ammonium ions can be taken in by plants and used directly in proteins. Over time, the ammonium converts to nitrate (NO3) which is the form of nitrogen most used by plants for growth and development. Nitrate does not bond to soil like ammonium does and could leach out of the soil and into waterways. Nitrogen fertilizer stabilizers are often added to anhydrous ammonia before application to slow the conversion of ammonium to nitrate, thus helping to reduce nitrogen loss from leaching.


Because of the stability of anhydrous ammonia (and converting to ammonium) it can be applied in the fall with less potential to leach, volatilize, or to be lost in water runoff than other nitrogen fertilizers. Cooler soil temperatures help keep the ammonium ion stable and so farmers try to apply it in the fall after the soil temperature drops below 50°F. If applied in the spring, it is best to apply it at least 3-5 days before planting to avoid damaging seeds and emerging roots.

Good nitrogen management is critical for growing healthy plants, good yields, and a profitable farm business. Farmers consider crop nutrient requirements, results of soil tests, soil conditions, weather, cost, time, and equipment available before choosing a fertilizer program that is the best fit for their operation.


How to “Look Under the Label”

Recently, I had the opportunity to speak to a women’s group at the 5th Annual Women Gaining Ground Conference presented by Women, Land & Legacy. There we were, many different women with many different backgrounds. Some in attendance were married with kids still living at home, while others were single and maybe still in school. And, there were women present who were wise with lots of valuable life experience. As I looked towards the audience and began my presentation, I pointed out a commonality that we all shared – we all eat!

I don’t know about you, but I try to eat three meals a day, with a snack in-between. As mothers and grandmothers, we feed not only ourselves, but our families too. Our families are the most important thing in the world to us, so we want to feed them the best and the healthiest options we can afford. A quick glance around any grocery store and you’ll be bombarded with many different messages. Grocery store aisles surround us with marketing messages including various food labels, that are trying to get our attention, capture our pocketbooks and claim that status of best and healthiest.

How marketing impacts food labeling

But what is the real story behind these labels? What do they mean? How can we sort out marketing speak from factual information that can have an impact on our health? The definition of marketing is “the action or business of promoting and selling products or services, including market research and advertising.” So, if food labels are marketing, what does this mean for us and how do they affect our decisions at the grocery store?

First, it’s important to recognize there are four types of food labels.

  1. Nutrition Facts labels: These are usually on the back or side of the packaging and are required by law on most packaged foods providing details of nutritional content.
  2. Health Claim labels: These describe the relationship between food and its health benefits or the reduced risk of a disease.
  3. Nutrient Content Claims labels: These are usually found on the front of the packaging and are voluntarily placed by food processing companies to help market their product.
  4. Farm Production Style labels: These describe the type of farming practices used, or not used in producing the food.

While looking at these labels, we should ask ourselves two questions. Is this label telling me something about the product? Or, is it using marketing tactics to convince me to buy the product? In researching the topic of food labeling, these two questions have challenged me to look at grocery shopping in a new way. When I pick up an item off of the shelf I have been asking myself, “Did the label tell me about an item or did the label sell me on an item?”

Labels that ‘tell you’ identify food with an objective, measurable difference from one package or brand to another. The “No Added Sugar” label is an ideal example. This claim can be measured in grams of sugar and verified using the Nutrition Facts Label which is regulated by the Food and Drug Administration (FDA). Choosing a diet with foods low in added sugar has been scientifically proven to help people maintain a healthy weight.

Labels that ‘sell you’ separate foods that don’t actually contain a measurable difference in safety, nutrition or other factors. While these foods may be produced in different ways (eggs produced by chickens housed in cages verses hens in free-range housing) the end product provides the same levels of food safety, quality, and nutrition.

No HFCS, Non-GMO – No Matter the Label, it’s still Marketing


If a label reads, “No High Fructose Corn Syrup” what does that lead you to believe? Possibly that HFCS is bad? That you should pay more for a product that does not contain HFCS?actually no hfcs


Table sugar (typically sucrose which is 50% fructose and 50% glucose) is readily available to the cells in the body to produce energy. High fructose corn syrup is chemically very similar (usually 55% fructose and 42% glucose). So, the claim seems to be a marketing ploy. But, in general too much sugar of any kind (fructose, sucrose, glucose) in the diet is the problem, not necessarily the type of sugar.


When a product is labeled “Non-GMO” what does that lead you to believe?

Genetically modified organisms (GMOs) are a hot topic when it comes to food and food labeling products in the United States. You would think GMOs have bombarded the produce section of the grocery store. You would think it is difficult to avoid GMO fruits and vegetables. But the reality is there are only ten approved varieties of GMO plants. Of those crops, only five could be found in the produce section. They are sweet corn, papaya, potatoes, squash, and the Arctic Apple. (The Arctic Apple won’t be widely available on store shelves for a few more years.


Now what about “organic”?

Are they grown differently? Are they healthier? Are they pesticide free?



actually organic

We can use an analogy to illustrate the difference between a conventional and an organic farm. If you had a tree that needed to be removed, then you would need a tool to cut it down. You could use an ax, a hand saw, a chain saw, or a larger tree cutting machine to get the job done. Each of these tools have pros and cons. Different people see different advantages and disadvantages of each tool and have a different opinion of which tool is “best” for the job.

In organic farming, the farmer only gets to use a limited set of tools. In the case of our tree maybe they just use the ax or the handsaw. Conventional farming has the choice of using a lot more tools including different pesticides, fertilizers, biotechnology, etc. This is represented in our analogy by getting to use any or all of the four tools to cut down the tree. Farmers use different “tools” to grow crops and depending on what they use determines whether they are considered organic or conventional.

By now, I am sure you have started thinking about how food labels impact consumer choices. Consumer choices directly impact the decisions farmers make in the production of our food. To learn more about food labeling and how food is grown visit www.iowaagliteracy.org where you will find this and other classroom lessons.


Five Ways to Celebrate Agriculture During Iowa History Month


New this year, March will be recognized as Iowa History Month. This works great with new Iowa Core Social Studies standards, as each grade has Iowa history standards to meet. Since agriculture plays a huge role in Iowa history, here are a few ways to incorporate agriculture in your Iowa History Month celebrations.

Read a book


The Iowa Agriculture Literacy Foundation has a host of historical, biographical, and Iowa-focused books, all great for learning more about Iowa’s agricultural history. Any resource available in IALF’s Lending Library is free to request and use for a standard two week period, after which time we ask you to return the item. These books all help tell the story of agriculture and agriculture in Iowa.

If you’re looking for a read-aloud book for elementary-aged kids, consider In the Garden with Dr. Carver by Susan Grigsby, The Kid Who Changed the World by Andy Andrews, or Sweet Corn and Sushi by Lori Erickson. These books talk about famous Iowans like George Washington Carver, Henry A. Wallace, and Norman Borlaug, as well as the Iowa Hog Lift, which brought livestock to disaster victims in Japan in 1960.

For books for older students and adults, consider titles like The Man Who Fed the World by Leon Hesser, Industrializing the Corn Belt by J.L. Anderson, How Iowa Conquered the World by Michael Rank, Iowa History Reader by Marvin Bergman, or Iowans Who Made a Difference by Don Muhm and Virginia Wadsley.


Research a famous Iowan


Iowa is home to so many famous and influential people. Many of these people have roots in agriculture and environmental science!

Our most famous Iowa agriculturalists are George Washington Carver, Henry A. Wallace, and Norman Borlaug, but have you heard of Jessie Field Shambaugh, Ada Hayden, Jesse Hiatt, Warren and B.O. Gammon, Aldo Leopold, John Froelich, or Mary Garst? These amazing Iowans have all left a legacy of learning and scientific advancement in agriculture.

For a more extensive list of famous Iowans (including John Wayne, Elijah Wood, Jason Momoa, and Ashton Kutcher) click here.

Visit a historic site


Because of Iowa’s rich history in agriculture, there are many places you can visit to help you learn more about our state’s advancements. Many communities have local museums with agricultural exhibits. There are also statewide treasures you can take a trip to go visit!

In the Metro area, you can visit Living History Farms, Wallace Centers of Iowa, The World Food Prize, or the State Historical Museum. In the Northeast quarter of the state, you can visit any Silos and Smokestacks partner site, including the Froelich General Store and Tractor Museum, Herbert Hoover Presidential Museum, or the Norman Borlaug Boyhood Home and Birthplace Farms!

If you can’t physically visit a historical location or a farm, consider holding a FarmChat® program in your classroom with a modern farm to talk with the farmer about how their operation has changed over time.

Surf the Web


If you want to do some reading and learning on your own, there are lots of good resources online. Some include Iowa Pathways with IPTV, the State Historical Museum online catalog, State Historical Society of Iowa’s Primary Source Sets, National Agriculture in the Classroom’s Growing a Nation, Silos and Smokestacks National Heritage Area’s CampSilos, or Living History Farms’ Learning Fields.

You can also research specific points in Iowa’s agricultural history, like the founding of the Polled Hereford breed of cattle, The Farm Crisis, the floods of 1993 and 2011, the drought of 1977, the invention of the gas-powered tractor, the Homestead Act, or the establishment of Iowa’s land grant university or Extension system. What other major events impacted Iowa and Iowa’s agriculture?



IALF has a wealth of resources, ideas, and connections. Let us help you pick a lesson plan, book, educator guide, or even an applicable blog post to supplement your Iowa history lessons.

Using just a few resources, you can celebrate Iowa History Month in true fashion! Be creative and share your Iowa History Month celebrations using the hashtag #IowaHistory.


Climate Change and Cows

By now you’ve probably heard rumors about cow farts containing greenhouse gases or that reducing the meat in your diet will save the planet. But how true are the things you’re hearing? Today, I’d like to go through and fact check some rumors and claims to see where the truth is.

First of all, I’d like to establish what climate and climate change is. Climate is not weather. Weather is how cold or warm or rainy or sunny it is on one particular day. Climate is the pattern. It’s how consistently it is warm or cold or rainy or sunny during certain times of the year. We are experiencing climate change. Things like warmer Arctic temperatures delivering an Arctic blast as far south as the Midwest and more frequent severe storms during the summer months attest to this.

In agriculture, climate change is especially concerning, because agriculture is dependent on Mother Nature cooperating. We have benefited greatly from advanced crop breeding and management techniques that help keep our corn and soybeans healthy during drought or mild flooding, but if there are multiple feet of water standing in a field when the crop is ready to harvest, no amount of genetic superiority can get a combine out and save that crop from spoiling.

“Rising temperatures, extreme heat, drought, wildfire on rangelands, and heavy downpours are expected to increasingly disrupt agricultural productivity in the United States. Expect increases in challenges to livestock health, declines in crop yields and quality, and changes in extreme events in the United States and abroad threaten rural livelihoods, sustainable food security, and price stability.”

National Climate Assessment, Fourth National Climate Assessment, Volume II

Because we know climate change to be a real threat to agriculture and rural communities, it’s important that we take steps to understand and mitigate its risk. At least one piece of that is hearing arguments and deciphering what is true and what is distracting us from solving the issue.

Cow Farts are Causing Climate Change

I personally started hearing about this idea about 12 years ago. At the time, I thought it was a joke (I mean, I was 12). But now, it’s being taken much more seriously. What is going on with cow farts, and do they really impact our atmosphere?

Cattle, like people and all other animals, do fart and burp. It’s just a thing that happens in a healthy digestive system. When you hear people talk about “cow farts” in conjunction with climate change, they’re really getting at methane (CH4). The kicker is, cows don’t actually fart methane; they mostly burp it.

Yes, cattle do burp (or eructate, in scientific terms) methane. Methane is a greenhouse gas, so naturally, this has been a concern in the climate change conversation.

There are a couple key pieces to this conversation to remember. First, though methane has a higher atmospheric warming potential than carbon dioxide (CO2), it breaks down much faster. Like, 16 times faster.

Secondly, we have to think about where those gases are coming from.

A big part of CO2 being added to the atmosphere comes from burning coal and oil. This is bad, because that carbon used to be stored underground, and we took it out and released it into the atmosphere. This increases the net CO2 in the atmosphere.

With cattle, the net carbon doesn’t necessarily increase because of where the carbon comes from. Grasses use atmospheric CO2 to grow, cattle eat the grasses, they burp methane, the methane breaks back down to CO2, which feeds the grass, which feeds the cow, and so on.

For an illustration on this cycle and how it compares to other forms of greenhouse gases, check out this video from New Zealand.


Land Used to Grow Food for Livestock Should be Used for Human Food

This is a common argument, and on some level it makes sense. It seems almost like cutting out the middle man. Why not just eat the food you grow for livestock instead of wasting the time and energy to feed the animals? Well, mostly because crops aren’t that interchangeable.

Take Iowa for example. We are phenomenal at growing field corn (different from the sweet corn we eat) and soybeans. These crops are key ingredients in many livestock feeds. Therefore, we raise lots of pigs and chickens in the state, which become pork and eggs.

It is sometimes argued that these crops are grown because of a need to feed the livestock, but it’s actually that we raise the livestock because we are easily able to grow what they need. The argument that we should eat the crops instead doesn’t take into account that all crops and all environments aren’t created equally. We cannot use field corn the way cattle can, and lettuce can’t use Iowa land like field corn can. Though it may seem cleaner and simpler to compare all calories as equal, it, unfortunately, doesn’t end up working like that.

More Plant-Based Diets Will Save the Planet

OK, so, cow burps are part of a cycle, and cattle feed depends on the types of feed grown in an area, but should we still think about changing our diets? Will that help?

One argument is that in order to raise more cattle, we will need to cut down more forests to increase grazing land, reducing the amount of trees that are currently helping reduce atmospheric carbon. If this were the whole story, you bet, that would be a huge issue.

This argument, much like the previous statement, has kind of been flipped backwards. In reality, cattle raised on pastures, grasslands, and rangelands, are often raised there because that’s the only way to gain value from that land. We don’t create pastures to raise cattle as much as we raise cattle because we have pastures.

For example, in northern Iowa (on the Des Moines lobe, if you know your geographical features), you find miles and miles of flat land growing acres and acres of row crops. You don’t see a lot of cattle grazing here, because the land lends itself better to using tractors and implements and growing high quality crops. In southern Iowa (on the Southern Iowa Drift Plain), you see steep hills, more forested areas, and lots more pastures. These steep hills are at much greater risk of erosion if they were to be worked under to grow annual row crops. We can still get food from this land, however, because of ruminant animals like cattle. This idea is called upcycling.

cow eating grass 2

The big picture in any major issue is often messy. We innately try to clean it up by quantifying qualitative things or comparing apples to oranges, but that doesn’t actually help solve our problems.

Admittedly, cow burps do contain methane and that methane is contributing to the overall levels of methane and other greenhouse gases in the atmosphere. To curb climate change, we all need to pay attention to this and what we can do to reduce greenhouse gases. But, we can still stand by data stating only 2% of emissions are coming from cattle production, and other agriculture is contributing up to 6% of methane emissions. This is a small piece of the puzzle. While agriculture will work to address these issues, a much larger impact could be made by addressing carbon dioxide emissions from fossil fuels and industrial processes (accounting for up to 65% of global greenhouse gas emissions, according to the EPA). Most of our emissions are coming from using non-renewable resources, like coal and oil.

At least for me, that’s good enough to keep eating burgers.



For additional reading and resources, check out the following:

Beef Research: Beef Sustainability

EPA Greenhouse Gas Inventory Report

Cow farts, climate change, and what really stinks about celebrity diet advice

Beef Sustainability: Balancing Environmental, Social and Economic Impacts

Why Do They Do That? – Grafting

MFAF cover image.pngWe just dropped the sixth book in the series! My Family’s Apple Farm tells the story of Hayden, a 10-year-old who works with his family on an apple farm. The story targets third grade readers and provides non-fiction text for them to practice their language arts skills. The book is paired with two lesson plans that address food safety issues and the variety of specialty crops grown here in Iowa.

The book will give readers a good understanding of how apples are grown and how an orchard works. But there is a lot more science that goes into growing apples and fruit that we could ever put into one book. For example, grafting. What is it and how does it work? Why do farmers use grafting techniques?

Grafting is a horticultural technique. Tissues of different plants are joined together. The tissues fuse together and the two plants continue to grow as one. The resulting plant will have two completely different sets of DNA on its different parts! Farmers can’t combine just any two plants. The plants have to be similar enough that the rootstock won’t reject the scion that is being grafted to it. It is not too dissimilar to blood transfusions in humans. You want to make sure to use the right type of blood. A person with O- blood should only get O- blood if they need a transfusion. Plants that are commonly grafted are different varieties of apples or different varieties of grapes.

Grafting is done for a number of reasons. One reason is that some varieties of fruit have better roots and some have better fruits. Grafting allows farmers to combine the two and have the best rootstock AND the best fruit. It is a way of combining two plants into one…but it isn’t a GMO. Examples abound in the wine industry. Many of the famous wine grapes from France and elsewhere in Europe did not fair well when brought to America. Local pests and pathogens made for an inhospitable environment for the European grapes. There were local varieties of grapes available to early American settlers but they couldn’t compare to the European grapes for flavor and quality.

Enter grafting. By grafting European grapes to the American rootstocks, wine growers got the flavor of the grapes they were looking for and the hardiness of the American rootstocks.


Splice graft from: NC State Extension

This same concept can be applied to other plants – specifically fruit trees like apples, pears, cherries, and others. There are several types of grafting techniques that farmers can use. These include bark graft, side-veneer graft, splice graft, whip and tongue graft, saddle graft, bridge graft, and inarch graft.

As the art and science of grafting becomes more precise, budding has emerged. Budding is a grafting technique that uses a single bud from a desired scion. Budding techniques include t-budding and chip budding.

Scions are usually collected in the fall of the year after the plant has dropped all of its leaves and gone dormant. The scions are saved over winter and then grafted onto the desired rootstock in early spring. The plant is actively growing and will be more likely to accept the graft. However, there is a longer window of viability for budding. It can be done at any time the plant is growing throughout the spring, summer, and fall months. If the graft is successful, the bud will likely stay dormant until the next growing season.

Apples can be grafted with apples. Grapes can be grafted with grapes. What else can be grafted? As mentioned before, the rootstock and the scion have to be similar. But, they don’t have to be identical. Plants that are in the same family are usually similar enough that they can be grafted together. For example, apples are in the pomoideae family. They can be paired with other pomes like pears, crabapples, and quince. Citrus like navel oranges, Valencia oranges, mandarins, lemons, limes, and grapefruit can be paired together. Stone fruit – or fruit in the prunus family – can be paired together; like cherries, peaches, nectarines, plums, and apricots. So you could have one tree with apples and pears growing on it, but you probably won’t be able to have a tree with apples and lemons growing on it.

Grafting can be a fun science experiment to try at home. You can purchase different root stocks and different trees to harvest scions from your local nursery. Think of it a bit like an operation a doctor might do. You need to have the right tools and keep everything clean to prevent disease. You need to have a plan and have everything laid out and ready to go. You need to make clean, precise cuts. Then afterwards, you need to wrap the site of the operation up so that the tree has the best chance to heal. Experimenting can be a lot of fun to see what kind of tree and what kind of fruit you are able to grow. For a tutorial and how to video on how to graft a fruit tree, check this out.

Apple production in Iowa has a long history with the Red Delicious first being developed by Jesse Hiatt. Red Delicious apples may be one of the most famous cultivars of apples. This cultivar was produced by Jesse Hiatt (on accident) in Madison County, Iowa in the 1800s. Hiatt was originally from Pennsylvania but moved to Madison County in 1856 to be near his brother. Hiatt had developed an orchard including Bellflower and Winesap trees, and had developed two other cultivars; the Hiatt Sweet and Hiatt Black. The first Red Delicious tree began growing in between two rows of apple trees (believed to be the Bellflower and Winesap trees). Ten years after it began growing, it produced its first fruit. Hiatt loved the taste of the apple so much, he marketed it under the name Hawkeye. The name was later changed by the nursery that acquired marketing rights to it.

Apple and fruit production has come a long way since the 1880s. Grafting can help unravel the mysteries of biology in fruit trees and help us understand how plants grow. So get grafting! And share your stories of success (or failure) with us in the comments below!


Yellow, Orange and Red – No Matter the Color They’re Chalk Full of Nutrition

Recently, I saw a friend who has chickens in her backyard post on Facebook that she had to use a store-bought egg in cooking alongside her backyard-raised chicken eggs. She posted a picture of the eggs and asked if we could spot which one was store bought. As you can imagine, several people started posting their opinions about which one was store bought and why they thought her backyard chicken eggs were healthier than the store-bought ones. Conversations like this one are happening all the time around the world online and in person, and it can be tricky to distinguish facts versus opinions.

Google ‘egg yolk color’ and you’ll get thousands of responses. Many of the articles have common themes. If it’s this color, the egg comes from a healthy chicken and if it’s that color it’s not from a healthy chicken. Did you know the color of the egg yolk really has to do with the kind of feed the chicken receives and doesn’t relate to its nutritional value?

What’s in an egg?
First, it’s important to understand what makes up an egg. An egg is a nutrient dense food with no added hormones. It’s among the highest quality protein source you can get and is a crucial ingredient in many recipes. But, what makes up an egg?

eggcrosssection-source exploratorium dot edu

Image source: Science of Cooking, Exploratorium.Edu

An egg is made up of many different parts:

  • Shell
  • Inner and Outer Membranes
  • Air Cell
  • Albumen
  • Chalazae
  • Vitelline Membrane
  • Yolk

The shell is made up of calcium carbonate and makes up approximately 9 percent of an egg’s weight. An egg’s yolk makes up about 34 percent of the egg’s liquid weight. The albumen, or egg white, is a thick, clear liquid that surrounds the yolk. It accounts most of the egg’s liquid weight and contains more than half of the egg’s protein. Source: American Egg Board.

What determines an egg’s yolk color?
While you may think the color of an egg’s yolk indicates the quality, taste or nutritional value of the egg that assumption is incorrect. The yolk’s color is actually determined by the hen’s diet – or more specifically the carotenoid intake.

Carotenoids are plant pigments responsible for giving egg yolks their yellow, orange or red color. Carotenoids are only available to animals through their diet. According to the Incredible Egg, if a hen eats plenty of yellow-orange plant pigments called xanthophylls, the xanthophylls will be deposited in the egg yolk. Hen feed can be enriched with carotenoids, which can lead to a darker yolk. For example, hens fed lighter color feeds such as wheat or barley will produce eggs with lighter color yolks. Conversely, if a hen’s feed consists of green plants such as corn and alfalfa they’ll produce darker color yolks.

Farmers carefully balance the feed to include all the hen’s needs such as calcium, vitamin D and phosphorus for egg shells. It’s important to note that artificial color additives are not permitted in egg production.

Egg yolk color varies around the world
Your desired egg yolk color may be dependent on what part of the world you reside. According to the Modern Farmer, egg yolks are typically pale in African countries due to the white corn that’s fed to hens. White corn is lower in carotenoids, so the egg yolks are a paler color. This has no impact on the hen’s health or the egg’s nutritional value. In the United Kingdom, northern regions prefer pale yellow egg yolks while the southern regions prefer golden-yellow yolks. In the Mediterranean, the egg yolks are typically a bright orange-red color.

Eggs pack a healthy punch
No matter the shell or yolk color, eggs pack a nutritious punch with several key nutrients that contribute to good health. They’re a convenient source of high-quality protein and contain 13 essential vitamins and minerals we need to keep our bodies as healthy as possible – all for only 70 calories (one large egg).

Does all this egg talk have your mouth watering? Head over to the Iowa Egg Council for some delicious egg recipes you can cook up at home.

Want to learn more about eggs?
Visit one of our past blog posts Ag 101: Eggs where you’ll learn about the difference between white and brown eggs, where eggs are produced and the difference between free range, cage free and organic eggs, among other facts.

Want to teach your classroom about eggs?
We have several free books and educational kits about chickens available in our Lending Library as well as free lesson plans. Visit the Resources page of our website and search for eggs under Lending Library and Lesson Plans.


Eggs in Schools, Egg Reader
The American Egg Board
Egg Nutrition Center – Egg Nutrition Basics
Eggs in Schools – Eggs 101, A Video Project
Eggs – What Color Variations are Normal
Does Egg Yolk Impact Nutrition Quality?
Help! My Egg Yolks are Freakishly White

Soil – it’s not just dirt!

Harris dirt 2

Pedology – this is a crucial field of science when it comes to growing plants on the land, but what does it actually mean? A popular guess would be that the root ‘ped’ is derived from the Latin word for foot, such as pedestrian, biped, or pedestal. On the other hand, the ‘science of feet’ makes absolutely no sense when talking about agriculture! According to the dictionary, pedology is soil science. In this case, ‘ped’ comes from the Greek (not Latin) pedon meaning ground or earth. To expand upon that a bit, pedology is the study of soil’s physical properties, chemical properties, texture, contributions to an ecosystem, and how it moves. It’s impossible to photo 12imagine a society where there was no soil, no ground, no basis for life. I hope that after reading this blog you give a little more thought to what it is we walk and live on every day.

Physical properties

Did you know the ideal soil for farming is only composed of about 50% solids? This percent can be further broken down into about 5% organic matter, with the remaining 45% being mineral content. But now this begs the question – what is the other 50% of soil made of? The remaining space is split equally between available water, unavailable water, and pore space. Simply put, pore space is the tiny pockets of air that microorganisms live in and plant roots use for gas exchange. Available water is soil water that is held a pressure that is easily taken up by plant roots. Using common sense this means that unavailable water is held at too high of a pressure for plant roots to take up, basically stuck to the soil particles and probably won’t move anytime soon.chart (1)


Chemical properties

Believe it or not, soil has chemistry too! Lots of farmers complete soil tests on their land, which will measure many varying characteristics within the soil. To start off with, soil pH is very important when considering nutrient uptake availability! Even if a nutrient is abundant within the upper portion of a soil profile, a plant cannot use it unless the soil’s pH is ideal for that specific element. The most common way of raising the pH of soil is by adding agricultural lime, also known as calcium carbonate. Another important quality of soil is its cation exchange capacity, also called CEC. Although it may sound complicated, CEC refers to the ability of the soil to hold and exchange positive charges. Some common cations are calcium, magnesium, potassium, sodium, and hydrogen. Farmers and researchers alike are able to calculate their soil’s CEC, which then translates to how many nutrients the soil can hold at a given time.


Soil is composed of three main types of particles: sand, silt, and clay. Each differs from the next in terms of shape, size, and chemical properties.

  • Sand is the largest particle with a size from 0.05 mm – 2.0 mm. Fields with high quantities of sand have good aeration but poor water holding capacity.
  • Silt is unique with it being smaller than sand but larger than clay. Its size ranges from 0.002 mm – 0.05 mm, and it comes with a high available water holding capacity.
  • The final size is clay, which is 0.002 mm or smaller. This is obviously the smallest soil particle, has a high water holding capacity, and exhibits very poor aeration.

When defining a soil texture, a loam is a mixture of all three textures and is ideal for growing crops in the Midwest!

soil triangle

This is a texture triangle, useful when determining your soil’s texture! Photo from FAO


Role in the ecosystem

Soil is found everywhere around the world, from agricultural fields, to big cities, to forests, and everything in-between! Generally speaking, the ground in metropolitan areas will be very compacted and likely not supporting any biota beneath the surface. In contrast, once outside of urban areas the biota dependent upon the soil vastly changes. Some soil microorganisms include bacteria, fungi, nematodes, algae, and many more! Did you know that a fungi called mycorrhiza has a symbiotic relationship with plant roots?

Where will it go next?

You might think it’s uncommon to hear about soil moving, but it has two main mechanisms for relocating to other regions. Erosion can be caused by wind and water, both having potentially detrimental effects on the soil. Water erosion occurs in three steps: 1) sheet erosion, 2) rill erosion, and 3) gully erosion. Sheet erosion is the film of soil moving from the impact of a rain drop or in a film of water. This is the most difficult to spot and occurs over almost all bare soil during a rain storm. Rill erosion occurs once small channels are formed from the movement of water. If the situation becomes too dire, then gullies will form. This is when the big channels are too deep for field equipment to cross. Wind erosion also occurs in three main steps. The first step is called saltation, and this occurs when fine sand particles are bouncing across a landscape. If the wind picks up, the following step is when particles are becoming suspended in the air. The final step of wind erosion is called creep, which is the rolling and sliding of particles that are too big for the air column.

So the next time you’re out driving along a road, walking through a park, or tending to your garden, I hope you’re thinking about more than solely what’s on the top of the soil!



P.S. Yes I am a new name to these blogs, and I’m here to stay for a while! I recently started as the new intern with Iowa Agriculture Literacy Foundation and I’m thrilled for what this year has in store. So a little bit about me – I’m currently a student at Iowa State University double majoring in Agronomy and Agriculture Communications. I love growing plants of all types, and that might show a little in future blogs! I look forward to creating some more intriguing and informative posts that you all can enjoy!