Clover & Agriculture

Every year many people around the world celebrate St. Patrick’s Day on March 17th. When thinking about St. Patrick’s Day, images of leprechauns, pots of gold, green, or Ireland might swarm your head. Did agriculture come to mind? One of the symbols of St. Patrick’s Day, the clover, is a valuable plant to farmers.

I’m not sure about you guys, but I spent a good chunk of my childhood outside intensely staring at the grass, searching for the lucky four-leaf clover. Sadly, after spending hours on the lookout, I never found one on my own.

Photo by Sudipta Mondal on

Clover or Shamrock?

It turns out I wasn’t even looking for a shamrock since a four-leaf clover is just a genetic mutation.

Shamrocks fall under the broad term of clover. Clover is the common name for the species in the Trifolium family, which translates to “having three leaves.” It’s kind of like how dogs, foxes, and wolves all fall under the canine family.

If you ask a botanist or the Irish what kind of Trifolium a shamrock is, most likely, you are going to get at least two different answers. Most botanists believe that the white clover is the same thing as a shamrock. In contrast, those staying true to the Irish tradition believe that the three leaves symbolize the Father, Son, and the Holy Spirit as taught by St. Patrick.

So, how do farmers use it?

While many probably recognize clover growing in their lawns, some farmers will grow it in their fields as a cover crop. Cover crops are planted to reduce erosion between growing seasons and add organic matter to the soil. To learn more about cover crops, check out the blog post “Cover Cropping. Why Do They Do That?”

According to Practical Farmers of Iowa, it is one of the best possible cover crop options. They describe it as the “Cadillac of cover crops.” Clover has many, many benefits as a cover crop. As a legume, it helps contribute nitrogen to the soil, it reduces soil erosion, and it helps limit the number of weeds in the field. Clover also helps a lot with the soil’s moisture hold capacity and water retention, which is great for those dry summers like we had last year.

Photo by Zhanna Fort on

Clover and livestock

Not only do farmers use clover as cover crops, but some feed their livestock with it as well. Integrating clover in pastures through a process called overseeding has its benefits: increase of yield, improve animal performance, Nitrogen fixation and grazing season extension, to name a few. Adding clover to a pasture will help the soil, the livestock and other grasses, but it does come with a warning.

Farmers need to be careful because too much clover could cause bloating. An abundance of clover consumption may cause cattle or other livestock species to have a gas buildup and can be very dangerous if this leads to pressure on the internal organs.

There are ways to prevent this bloating. Farmers can mix the clover with other grass species in the pasture, wait to feed livestock clover until it is drier or rotate their grazing.

Despite these risks, few farmers cut out clover feeding entirely due to its significant protein and fiber amount.


Other than the shamrock around St. Patrick’s Day, another famous clover is the clover emblem of 4-H. 4-H is a youth development organization for 4th-12th graders where members can create projects in health, science, or agriculture fields. The four-leaf clover emblem representing the 4-H organization has an “H” on each leaf, meaning head, heart, hands and health.

As you are celebrating St. Patrick’s Day this year, don’t just think about all of the green you’re going to wear, but think about how much agriculture is tied into this holiday!


Why Do They Do That? –Irrigation

Most of us are familiar with weather and know that it is not consistent every year, and rain doesn’t always come when farmers need it. This is why some large fields resort to using some kind of irrigation system. Even though you may see a large irrigation system while driving down the road, it is helpful to note that most of Iowa’s cropland is not irrigated. According to the USDA, other states outside of the Midwest, such as California, Nebraska, Arkansas, and Idaho, rely more heavily on irrigation systems. This is due to their irregular and infrequent precipitation.

Using this method of irrigation systems to water crops, farmers can control their crops’ water requirements if there is not enough rainfall. Like many things in the agriculture industry, the control of these irrigations systems can be automated and can be done right from the farmer’s phone or tablet. With different technologies, farmers can adjust the water pressure, the amount of water, and more without even being on the field, similar to how you could control your home’s security or temperature with smart technology while being on the road. As advanced as this may seem, these irrigation systems continually advance with the rest of the agriculture industry with solar-powered irrigation systems being implemented more widely in the future.

Photo by Adrianna Calvo on

When deciding what kind of irrigation system to use, farmers have several choices: sprinkler vs. drip and center pivot vs. linear.

sprinkler irrigation system:

This system imitates rainfall by distributing the water above the field surface, allowing it to fall on the crops and soil. All plants on the field should receive the same amount of water, hopefully resulting in similar growth. This system is one of the most popular kinds of irrigation, and you probably have seen them in the fields at one time or another. This system is also similar to what many homeowners use to water their lawns. Like every system, sprinkler irrigation has some advantages and disadvantages. A farmer may decide to go with the sprinkler system because of the reduced cost of overall farm labor and reduced soil erosion. Another farmer may opt out of sprinkler irrigation because of the high initial cost of pipes, motors, and installation, and because of the high water loss due to evaporation.

drip irrigation system:

Compared to a sprinkler system, the drip irrigation system can be more efficient than a sprinkler system because the water is being dripped from a lower point, drop by drop (there is less evaporation water loss). With this kind of system, the soil soaks in the droplets before they can evaporate or be blown away by the wind. The water is applied closer to the roots where it is truly needed. Although drip irrigation may seem like the more beneficial choice, there are some downfalls, including that the water outlets get clogged because they are in direct contact with the ground. These systems also take a lot of training to understand the machine and manage the system.

center-pivot irrigation system:

This type of sprinkler irrigation is just what it sounds like: a mechanical system that moves in a circle with a center point. This machine can also be used to apply fertilizers and pesticides. The chemicals are mixed into the water as the water is sprayed onto the field. This multipurpose system can be used on a variety of crops, including vegetables and fruit trees. The center point is usually a permanent, stationary point where the water is pumped up from an underground well. The long arm of the system stretches across half the field and as it moves in a circle, it waters the entire field. The arm is supported by large wheels that travel across the ground and hold the arm up. If you’ve traveled in a plane over Midwest states like Nebraska, Kansas, and Colorado and looked out the window, you’ve likely noticed the circular fields. Each one of those fields has a center-pivot irrigation system on it.

Photo by Mark Stebnicki on

Linear Irrigation System:

Linear irrigation systems are marketed to irrigate 98% of the field by traveling across the field in a straight line, forward, and reverse working best in square or rectangular fields. This system is another example of a sprinkler system. The water used is either taken from underground or a hose that drags behind the machine’s wheeled cart. In a linear irrigation system, soil compaction is reduced. It is also easier to work in windier conditions, unlike the center-pivot system because they are lower to the ground. Center-pivot systems can work on tall crops like corn. Linear irrigation system are better for shorter crops like alfalfa.

Now that we know what types of irrigation systems are out there, the final question is, why use them? With this kind of technology, crops can be watered in a controlled environment where the lack of rain can be less of a burden on farmers and their yield. Controlling the amount of water applied in a slow and steady manner can lead to less runoff and erosion. Plus, the time that farmers would typically take using more complex kinds of irrigation can now be spent perfecting other areas of the field or farm operation.

Next time you see one of these systems as your driving down the road, now you will have a better idea of what it does! If you’re a farmer, let us know in the comments what works best for you!


Hi! My name is Madison Paine and I am the education programs intern at IALF for the next year. I am currently a junior at Iowa State University studying agriculture communications. I grew up on an acreage outside of Maxwell, IA where my love for agriculture first sparked. I am very excited to be here and can’t wait to see what this next year all entails!

Science 101: Stems

Stems. They may not be as showy or as talked about as other plant parts, but they are important. Stems are the glue that keeps all of the parts together and working as a team.

Stems provide support and elevation for leaves, flowers, and fruits. They arrange leaves in a way that they can get adequate sunlight to perform photosynthesis, a process necessary for life. They position flowers to attract pollination and ensure that fruits have room to grow and ripen in the sun.

Stems transport fluids throughout the plant. They move water and nutrients taken up by the roots to the leaves. This upward movement happens in specialized cells in the stem called xylem. Stems also move the food produced by the leaves to other parts of the plant. The cells that do this work are called the phloem. Unlike xylem cells, phloem moves food up and down.

Stems can also store water or nutrients. Cacti are the best example of water-storing stems.  Their thick, hard-walled, succulent stem stores water, which is infrequent in the dry, arid, locations they thrive.  The inside of a cactus stem can be spongy or hollow. The outside is covered with a thick, waxy coating, which keeps the water from evaporating like it would in other plants.

Not all stems are found above ground. Nutrient-storing stems are located underground. Potatoes and sweet potatoes, for example, store excess energy in underground modified stems called tubers. These plants produce more energy than the growing plant can use at one time. Excess energy in the tubers and provide the plant energy to regrow in the spring.

There are quite a few other stems that farmers grow for food and fiber. Here’s a look at a few products that wouldn’t be possible without stems.

Wood and wood products, like paper, rank just behind food plants in overall value to society. Like all stems, a tree’s trunk is made up of xylem and phloem cells. Each year, the tree forms new cells, arranged in concentric circles called annual rings. Early in the growing season, the cambium produces numerous large cells that form the light-colored springwood. Towards the end of the summer, growth slows down and the cells produced are small with thick walls. These cells form the darker-colored summerwood. This process repeats each year, increasing the diameter of the tree and producing a valuable agricultural product.

Sugar. Sugar cane is a tall perennial grass grown in tropical environments like Florida and South America. The plant stores excess energy as sugar in a sweet juice found in the plant’s fibrous stalks (stems). To produce table sugar, the stalks are harvested, the juice is extracted, excess water is evaporated, and the sugar crystals are dried. While sugar cane is the number one source of sugar, it is important to note that it can also be made from sugar beets, a root crop.

Cinnamon comes from the inner bark of the trunk (stem) of cinnamon tree. Farmers will shave off the outside bark of the tree to get to the cinnamon layer that is harvested and dried. Cinnamon has a natural tendency to curl as it dries, which gives cinnamon sticks their curled appearance.

Straw is a byproduct of cereal grains like wheat, barley, and oats. When the seeds of these crops are harvested the stems, or stalks, are left behind. Most of the stalks’ nutrients were depleted while producing seed, leaving little nutritional value as a feed source. The stalks can, however, be baled and used for straw.

Maple Syrup. Pure maple syrup begins as sap from the xylem of a Sugar Maple tree. The sap is harvested in the spring when days are warm and nights cool below the freezing point. Trees are tapped, and the sap either drips into a bucket or flows down a special tube to a holding tank. Maple sap is clear, slightly sweet, and very thin. The distinctive maple flavor and thick consistency of syrup is developed through careful heating to evaporate most of the water. It takes 40 gallons of sap to make one gallon of syrup.

Onions & garlic. Although usually referred to as root crops, onions and garlic are both underground stems, called bulbs. Like tubers, these modified stems hold nutrient reserves for the following season – and provide a tasty food crop for us!


Note: This is the second post in a series exploring the science and agricultural importance of plant parts.

Milk for Cereal, Cookies, and… Fertilizer?

Nine gallons. Yep, you read that correct – nine. 1, 2, 3, 4, 5, 6, 7, 8, 9. My family of four will go through nine gallons of milk a week. It is the determining factor of when we go to the grocery store. “The milk gauge is on E” is the phrase we use. So it’s off to the market. During this time of social distancing this weekly chore is completed with military precision. Face mask? Check. Hand sanitizer? Check. List? Check. One credit card and one store loyalty card? Double check. I push my cart up and down the one directional aisles not stopping to visit, just getting the job done. Then I get to the dairy section. If it is fully stocked, I’ll grab what we need for the week. If not, I’ll just grab four or five gallons and know I’ll have to make a “quick milk run” sometime in the next few days. So when I discovered farmers were having to dump milk, I had to find out why.
You might wonder why we go to the store for milk. After all, we raise cows on our farm. Why not milk our own cows? Well, we raise beef cattle. Yes, they are cows and yes, they do make milk for their calves, but not an abundance of milk like dairy cows produce. Since we do not have a dairy we do not have the necessary equipment needed to collect the milk. And we have no way to process our cow’s milk.


Kindergarten students try their hands at milking using water and a glove.

Why does cow’s milk need to be processed?

The milk we purchase at the store has gone through a process called pasteurization. This process heats the milk to kill the bacteria. Raw milk, or unpasteurized milk, can contain dangerous microorganisms. Not something that you would want to serve to your family.

In addition to being pasteurized, milk is homogenized, passed through screens with small holes, breaking the milk fat down into smaller particles. This creates a more uniform liquid and is much nicer to drink. You can drink non-homogenized milk by skimming the cream layers off the top, or by shaking it vigorously to evenly distribute the cream.

There are several steps involved to get milk from the farm to the grocery store. I prefer milk from the grocery. The amount of time it would take me to hand milk over a gallon a day, heat it to the proper temperature, skim and/or shake the milk, would not allow me time to complete my job as an agriculture classroom coordinator. This is the reason why we need dairy farmers. Every one of us is allowed the privilege of working a job we want because we have entrusted a farmer with the job of feeding our families.

Photo one

Reading the book, The Milk Makers, to a class of students

Part of my job involves teaching students about where milk comes from. In the lesson All About Milk! (and milk alternatives) students discover the different varieties of milks and milk alternatives available. We read about dairy farmers that raise cows and milk them 2-3 times a day. We discuss how milk is consumed or processed into ice cream, butter, yogurt, and other dairy products. Then the students learn milk is a good source of protein, vitamins and minerals – especially calcium and is rich in potassium and vitamin B12. We talk about how Vitamin D is also added to milk to help with the absorption of calcium. Next, we taste test different samples, chart which types we like best, and read the book The Milk Makers by Gail Gibbons.

Milk Makers

The Milk Makers by Gail Gibbons

Why is milk being dumped?

Due to COVID-19 virus, schools and restaurants were asked to close operations to help “flatten the curve” so our healthcare system wasn’t overwhelmed. This caused our dairy needs to shift.

Keiko Tanaka, a professor of Rural Sociology at the University of Kentucky, authored an article that discusses the challenges the milk industry is currently undergoing. In the article, Why Farmers Dump Food, she underscored that of the two main supply-chains in the U.S. food industry – one for household consumption and the other for commercial use – more than half the spending comes from the large-scale commercial side, which has been practically decimated.

And making an immediate shift for the sudden demand change, she noted, is far from simple. Milk processors, for example, “do not have the equipment to package [excess milk] into smaller containers for grocery stores and retail use” when there has been already a glut of cheese and other dairy products with longer shelf lives. Like vegetable and fruit farmers, dairy farmers have little choice but to dump excess milk,” Keiko and her team of researchers stated.
So what do you do when you have thousands of gallons of milk and the processing plants you used to deliver to are not accepting milk? Farmers are industrious and some are turning lemons into lemonade. More specifically, milk into fertilizer.

Where and how to use it?

Farmers grow crops that require nitrogen, phosphorous, and potassium. And milk contains all three. And, these three nutrients are readily available, unlike manure which contains undigested food that will need to break down before it can fertilize the soil. One thousand gallons of mike can contain 44 pounds of nitrogen, 18 pounds of phosphorous, and 17 pounds of potassium. By using the correct rates for their crop, farmers are recycling surplus milk.

There are some downsides to this alternative fertilizer. Milk has a very high biochemical oxygen demand. That means it will consume oxygen from waterways. Farmers need to be sure they are not applying it where it could run off and damage ponds or streams and potentially kill aquatic life. Surface application is an option, but if you’ve ever left the milk out too long you know it can start to smell bad. Milk degrades quickly, so one way to avoid the rotten smell is by injecting the milk directly into the field. While using milk this way is not ideal, it is a way for some farmers to recoup financial losses that occurred by having to dump gallons and gallons of milk.

Next time you pour your milk on your cereal, or dunk your chocolate chip cookie into a tall, icy cold glass of milk, I hope you can appreciate what went into providing that milk for your use. And maybe think of the farmers who had to try and do the best they could with it, using it to produce another crop. This is what farmers do. They work the hardest they can each year, raising their crops and caring for their livestock, and are always looking ahead to what they can do next year.


The Big Picture of Iowa’s Pork Production Cycle

Iowans are known for a lot of things. Kindness, die-hard loyalty to sports teams (go Cyclones!), and using the word “ope” instead of “excuse me”. However, there’s one more thing that Iowa is really, really good at: raising pigs. Iowa is the number one producer of pigs in the United States and in today’s post we are going to dive into the reasons Iowa can produce so many. The reason is all in one word- sustainability. Sustainability is defined as “the ability to be sustained, supported, upheld, or confirmed.” Iowa’s pork production is very sustainable, as we have the ability to uphold high levels of production, and have for a while now. The reason behind this is that pork production in Iowa is a circular cycle. Let’s take a closer look.

First of all, not only do we grow the pigs in Iowa, we also grow their food right here in Iowa. Pigs require a diet with two major components, corn for energy and soybeans for protein. Iowa ranks number one in corn production, and either number one or two for soybean production (that title alternates with our neighbors directly to the east).


Iowa is the #1 producer of pork in the U.S.

According to the USDA, in 2018, Iowa farmers harvested over 13 million acres of corn and nearly 9.9 million acres of soybeans. Pigs eating the crops we grow creates a cycle, which is part of the overall sustainability circle. Pigs provide a market for the crops, and crops are grown to provide food for the pigs.

Why do we grow the crops here? I’m glad you asked! Iowa is the perfect place for crop production of corn and soybeans due to our rich black soil, our climate, and the manure that we get from our livestock, which includes – you guessed it- pigs! Iowa’s topsoil is some of the best in the country- in fact, it is known as “Iowa’s black gold”! Our climate provides the temperatures and moisture that crops need during the growing season.

Now let’s get down to the matter of manure. This topic is an incredibly vital part of our sustainability cycle of pork production in Iowa. According to the Iowa Pork Producers Association, around 25% of Iowa’s cropland is fertilized by livestock manure. If you’ve ever driven by a farm and it smells particularly potent (manure-y), or seen a large tank with disks being pulled behind a tractor across a field, you’ve witnessed the pork production sustainability cycle in person.


Manure Spreader

 Manure can provide many benefits to cropland, including important nutrients like nitrogen, phosphorous, and potassium – the trio is often referred to as NPK – and it is very valuable to crop production. Manure can provide these elements for Iowa’s cropland, and the process through which it gets from barn to field is part of what makes Iowa’s pork production so special. The manure is pumped out of the pit underneath the barns into the big tanks. Then the farmer can take the manure and spread it in nearby land. The proximity of cropland and barns creates an easy access to spread good fertilizer on farmers’ fields. Farmers don’t like to haul manure long distances, and so being able to have the manure as close as possible to their land is important. This is a large consideration when farmers consider putting up new hog barns, and when they consider buying new farmland. 

Manure creates the ability to produce crops for a lower price, because farmers don’t need to purchase as much fertilizer. In turn, this preparesGray Bubble Cycle Diagram Chart the ground to grow corn and soybeans which will be fed to our pigs.  

Iowa is known for our pork production, and there’s a reason. The sustainability process of producing pork is incredible and allows us to produce the most in the country. Pork production benefits our economy, it allows us to provide more food, and it gives manure a great purpose!



Hello everyone! My name is Ellie Cook and I am the new Education Programs intern with Iowa Agriculture Literacy Foundation. I am from a family farm in Hubbard, Iowa, where we raise corn, soybeans, pigs, and cattle. I’m currently attending Iowa State University, where I major in Agriculture Communications. I’m very excited to be with IALF!


How Far Apart are Crop Rows?

How far apart are crop rows? How close together are crops planted within the row? How many plants can grow in one field?

If you have wondered any of these things before, this is the blog for you!

I wish I could just say a number that was consistent across multiple factors and satisfy your quick internet search with an easy answer, but like most management decisions in agriculture, it’s not that simple!


According to Iowa State University Extension and Outreach, most crop rows in Iowa are between 15″ and 38″ apart. Historically, before the dawn of tractors, row width was governed by the width of your horse, which was generally around 40″. Once horses were phased out, research was done to see if row widths could be narrowed to accommodate tractor tires (30″) instead of horses. This ended up boosting yields per acre and became the standard for many years.

Today there is more research being done to see if 20″ rows or even 15″ rows could be even better. Many farmers have already latched on to the idea of narrow rows.

There are a few reasons and a few factors that could influence this decision, however. One of them is plant population. When farmers plant their field, they try to decide an ideal population for that field. Here in Iowa, with our rich soils, a corn crop may be in the ballpark of 30,000 plants per acre (PPA). For soybeans in Iowa, the population may be in the ballpark of 200,000 PPA. That population can be adjusted if the crop is planted at an ideal time versus later in the season, improved varieties, soil quality, and even seed prices.

For a frame of reference on how environment can impact plant populations, here’s a link to a discussion board on plant populations for corn in drier parts of the country. These folks are discussing what populations to plant at on “dryland” corn, which means land they don’t irrigate. Their population on these acres can be in the ballpark of 14,000; less than half of what we can plant in Iowa. While this can maximize their yield without wasting further money on seed that won’t grow adequately, they then have to worry more about weed pressures, which will be able to get more sunlight when the crops are spaced farther apart.

If a farmer is wanting to increase the plant population on their field, one of the easiest ways to do that is to add more rows to the field. The easiest way to do that is to make narrower rows. If the farmer were to try to increase the plant population significantly without doing this, the crops may get crowded within the row and may not grow ideally.

That brings up another question: how far apart are plants within the rows? This is also variable, given that we know how much plant populations differ and that for a long time, most farmers used 30″ rows. In general, plants are just a few inches apart. Below is a table from the Extension publication Guide for Iowa Corn Planting. Notice how much closer together the crops in the wider row spacings are than in the narrower rows.

Table 2, CROPR3161

From Iowa State Extension and Outreach publication, Guide for Iowa Corn Planting.

One Iowa scientist has made waves in this sector. Harry Stine with Stine Seed has led research and genetics work in high population and narrow row corn. With this work, Stine has discovered genetic traits that lend themselves well to the stress of higher populations. They claim that this paired with the practice of twin rows (two rows of a crop planted 8″ apart with a 12″ spacing to the next twin row) could boost yields to 300 bushels/acre and potentially beyond. Check out the graphic below from Great Plains Ag to see how that setup could look.

Great, so narrow rows, twin rows, and high populations sound like they could be really promising, right? So why isn’t everyone doing it? One of the biggest factors is equipment. Planters and combines aren’t extremely flexible, and farmers may have to alter their equipment, buy new, or even buy custom equipment if they wanted to try a new and different management system. Farmers also need to consider other inputs their crops need, like fertilizers and fungicides. If those costs would go up substantially, would the extra yield cover that cost? It can be hard telling, and when commodity prices are low, that can be a scary gamble.

But now that we’ve touched on the science and math portion of the blog, let’s talk about the technology and engineering to really round out our STEM areas!

We mentioned earlier that plant population is influenced by soil quality, but soil quality can vary not just field to field, but also within the field. It is now possible for farmers to use tractors and planters with precise maps so they don’t put too much seed in one area and not enough in another. That saves resources, saves money, and maximizes efficiency. How cool is that?

To see a video on how one planter works, click here.

I hope that answers some of your questions!


Weather and Climate’s Affect on Agriculture

What’s the weather going to be like today? Do you know if it’s going to be really hot? Should I bring my umbrella? These are all day-to-day thoughts we have about the weather. The outdoor conditions greatly affect our lives, whether it be the outfits we wear, the commute to work, or off-the-clock recreational

To an agriculturist, the weather is the biggest factor when determining what work can be completed each day. Growing up in a family that farms row crops, the nightly weather report was just as coveted to watch as a popular prime-time television drama. In the short span of a few minutes, the local meteorologist gives a brief description of the weather, which affects the productivity of the farm. This variability makes it difficult to plan far in the future, especially since extended forecasts can be difficult to accurately predict. In this sense, farming becomes a gamble and mother nature is the one rolling the dice. Meteorologists have years of professional experience when analyzing charts and predicting future conditions based upon past events. Weather forecasting is an over-looked technology that all farmers use to manage their production systems.

How does weather affect crop growth?

We all know that crops need water to grow, so it’s crucial to be in a climate zone that experiences periodic rain events suitable for a specific plant. However, everything is good in moderation. The start of the growing season is very dependent upon when it rains and when it doesn’t. If there’s too much rain, then farmers cannot physically run equipment through a field without getting stuck. And if they plant right before a strong storm system with lots of moisture, it’s possible to drown out the seeds before they are able to germinate.

soil thermometer

Soil thermometer, image from qcsupply.

This window of time is typically long enough for most producers to accomplish all of their planting, however water isn’t the only limiting factor. If the temperatures aren’t warm enough, the seeds won’t start to imbibe water or respire. When talking about corn and soybeans, the soil temperature should be at 50°F and rising to induce germination. This ground temperature is measured at four inches below the soil surface, and can be done with a specialized thermometer.

Once farmers have seed in the ground, the next hurdle is ensuring the plants receive an adequate amount of water. How much is perfect? Well that’s dependent upon both the species of plants and the particular varieties being grown. There is a lot of research being done to make corn have a higher drought tolerance, which could provide a larger geographical area for maize to be efficiently produced.

If the growing season is ideal for plant growth, the next hurdle to jump is harvest. A field may produce a high yield, but if the harvest conditions are sub-par this will lead to a loss in total production. If the field is too wet, equipment can become stuck in the mud. Some crops such as vegetables are harvested at a high moisture content, which contrasts from a crop like soybeans which must be harvested at a low moisture content. All in all, weather conditions are always a major threat to the agriculture industry.

Are weather and climate the same?

No. Weather and climate both refer to atmospheric conditions but have two completely different meanings. Weather is defined as the events happening each day within the atmosphere. This can change in a minute, couple of hours, or take days. By this definition a hurricane, cold front, or electrical storm can all fall under the realm of weather. But how is this different from climate? Climate is used to describe weather patterns over a much longer period of time. This essentially averages out each individual event and can be used to further categorize parts of the globe. Additionally, climate is used to make generalizations about future weather events. If you’ve ever wondered why different crops are grown in different regions of the United States, and by extension around the world, it’s because they fall into different climate zones! The Koppen-Geiger climate classification system is an excellent visual when learning about climates.

climate map

Image from Koppen-Geiger.

The first major category of climates is defined by temperature. This is split into five areas: equatorial, arid, warm temperate, snow, and polar. The second classification level is determined by precipitation amounts. This varies from the driest desert to an area frequented by monsoons. The third level becomes increasingly specific with temperature and maximums/minimums throughout the year. If you look at where Iowa falls on this map, it’s right around a border between Dfa and Cfa zones. By definition this means the Dfa area will receive snow, full humidity, and arid weather patterns, whereas Cfa will experience hot, full humidity, and warm temperate weather. The simpler way of saying this is frost won’t reach into a C zone. This is why crops with longer growing seasons, such as cotton and tobacco, are unable to be efficiently grown in northern states like Iowa or Minnesota. This also shows California’s advantage to growing many warm temperate fruit and vegetable crops. Hopefully this gave a little insight to why Iowa excels at growing specific crops, and broadens your view on the affects of weather around the world.US map.png

If you’re trying to incorporate this into a lesson, here’s a few resources!

Iowa Ag Today Issue 4 Agriculture in Society
Agriculture Across the USA
Where Does It Come From?


Why do they do that? – Estimating Yields

Like most business owners, farmers are forward thinking. They use data to make decisions and anticipate future needs. Sometimes they can use data that they know is 100% accurate because it is based on scientific tests or proven history. For example, they use soil test results and yield history data to make decisions about what tillage practices, seeds, and fertilizers are best suited to each field.

Other times, like when preparing for harvest, they do not have proven data. They will not know exactly how much grain a crop will yield until the field is harvested, but knowing the crop’s yield potential is key to being well prepared and making good business decisions. Fortunately, there are methods to estimate yields. Farmers use yield estimates to anticipate equipment, fuel and labor needs, ensure they have enough storage available, plan livestock feed supplies, and make early marketing decisions.

Farmers can estimate yields themselves or utilize data compiled by others. The USDA’s National Agricultural Statistics Service (NASS) publishes crop yield estimates in their Crop Production Reports. These estimates are national averages and based on farmer yield surveys and field data collected by the agency.

Farmers also pay close attention to the Pro Farmer Midwest Farm Tour yield estimates. Pro Farmer, a division of Farm Journal Media, sponsors an annual Midwest Crop Tour that sends out teams of 2-4 crop scouts to visit corn fields throughout the Midwest to estimate yields. Teams pull onto rural side roads every 15-20 miles from their primary route to collect data. Scouts measure three ears of corn from just one location in each field. The tour’s sampling methods are designed to get representative results for crop districts, states, and the entire Midwest, not individual fields or counties.

These national and regional estimates are OK, but many farmers prefer to make decisions based on field-specific yield estimates. Farmers and agronomists can estimate corn yields using the yield component method. It is based on the premise that yield can be calculated from estimates of the individual components that determine grain yield. These include number of ears per acre, kernels rows per ear, kernels per ear, and weight per kernel. The first three factors can easily be calculated from samples in the field using these steps:

  • Measure a length of row equivalent to 1000th of an acre. An acre is 43,500 square feet. If corn is planted rows that are 30 inches apart, 1000th of an acre is 17 feet, 5 inches.
  • Count and record the number of ears in the sample site. Example: There are 30 harvestable ears in my sample site
  • On every fifth ear in the sample row, count and record the number of kernel rows per ear and the number of kernels per row. Do not count small kernels near the tip. Example: One ear has 18 rows and 35 kernels per row.
  • Multiply the number of rows by the number of kernels per row to calculate the total number of kernels on each ear. Example: 18 rows x 35 kernels/row = 630 kernels/ear
  • Calculate the average kernels per ear by adding the values of all sampled ears and dividing by the number of ears. Example: (630 + 740 + 612 + 512 + 614 + 576) ÷ 6 = 614 kernels/ear.

The last component that determines corn yield is kernel weight. Since this cannot be measured until the corn is fully dry, a predetermined average kernel weight, expressed as 90,000 kernels per 56-pound bushel, is used. A field sample is 1000th of an acre, so the value 90 represents kernel weight in the yield component method formula.

We can now calculate the estimated yield per acre by multiplying the number of ears in the sample by the average number of kernels per ear, and then divide by 90. Example: (30 ears x 614 kernels/ear) ÷ 90 = 204.6 bushels/acre.

Weight per kernel will vary depending on hybrid and environment, so this method will only give a ballpark estimation of yield. However, it can still be a valuable tool for farmers as they prepare for harvest.


Macronutrients in Crop Production

elements in the environment

When growing crops of any type, it’s important to understand the required inputs in order to receive the desired yields. One of these inputs, arguably the most important and critical one, revolves around nutrient management. All plants have these requirements, whether it be crops grown for biofuels, fruit production, or landscape ornamentals. Each plant needs various amounts of nutrients, which can be used to classify them (by quantity) into macro or micro nutrients. It’s important to remember that each one is vital for plant growth, simply required in different doses. As a sidenote – this blog is going to be mainly focused upon corn production, but all of these elements are necessary for any plant you’re trying to grow! First I have a couple questions to spark your curiosity about nutrients in plants…    

  • A plant can be deficient in oxygen, how is that possible?
  • Plants need calcium just like humans do. If it doesn’t go towards bone and teeth strength, then what’s its purpose?


Let’s start with the big three: carbon, hydrogen, and oxygen. If you’re reading a fertilizer label, they don’t typically advertise for these elements. So, where do plants take them from? Why are they necessary for plant life? Should I be worried that my garden isn’t receiving enough hydrogen? The simple answer is that no one should be concerned about their plants being nutrient deficient in C, H, or O, as long as the plants are surrounded by air!

Carbon (C) – Thanks to many fields of science, we know that carbon is the base for life on Earth! This means that if plants are going to continue to be alive, they must obtain and maintain C. In more direct terms, plants produce and uses chains of carbon with other atoms called carbohydrates, lipids, proteins, and nucleic acids. But what happens if the plant is unable to take in carbon? This would be a very unfavorable scenario for the plant, especially since carbon is essential to photosynthesis. More specifically, without carbon (in the carbon dioxide form) the Calvin cycle wouldn’t occur. This means there’s no G3P, which helps make glucose, and without energy the plant cannot continue to live.

calvin cycle.png

This depicts the Calvin cycle in photosynthesis. Diagram from Khan Academy

Hydrogen (H) – Whenever I think of elemental hydrogen, I don’t normally think of it as a nutrient. I don’t directly eat anything that is marketed as “high in hydrogen”, so how could a plant use it? To start off with, every living organism on Earth needs water (H₂O) to live. Plants use water to obtain hydrogen atoms when splitting H₂O molecules through the light reaction of photosynthesis. The hydrogen ion is then used to create NADPH, which is a crucial ingredient in the Calvin cycle. If a plant is missing this chemical compound, then photosynthesis would cease and the plant would die.

z scheme.png

This shows the light-dependent reactions in photosynthesis, commonly referred to as the z scheme. Image from LibreTexts

Oxygen (O) – Wait a minute – oxygen is a product of photosynthesis, why would a plant need to take in oxygen too? In order to break down food through aerobic respiration, there must be oxygen present. Yes that’s right, plants respire just like humans do! Cells within leaves and stems obtain oxygen atoms that are a product of photosynthesis. However, cells found in areas that aren’t photosynthetically active must find oxygen elsewhere. To solve this issue, roots are able to take in O₂ from the air between soil particles. If the ground is saturated to capacity, then the roots cannot take up oxygen in the gas state. If the area is flooded for longer than 72 hours, it’s likely the plant will run out of oxygen and not recover.


The chemical equation for photosynthesis.

Nitrogen (N) – This is a much more commonly discussed nutrient, especially since it has a huge correlation to high yields in corn production. If you were to walk into a farmer’s field, you would be surrounded by nitrogen in many forms! N₂ is a gas found in the air, whereas NO₃⁻, NH₄⁺, and NH₃ are compounds found in the soil. But if nitrogen is found in the air, why can’t corn absorb it like carbon or oxygen? This is because corn can only take up nitrogen when it’s in a nitrate form, which can be found in solutions and attached to soil particles! When taking a closer look at NO₃⁻, it’s more prone to being lost to the environment due to its negative charge. Soil naturally has a negative charge, which means that a nitrate is more likely to move elsewhere in the environment than wait around to be absorbed by a plant. This is why many agriculturists use anhydrous  ammonia as a N fertilizer, because it contains NH₃ and not NO₃⁻. Overtime soil microorganisms will convert ammonia to a plant available nitrate. Why is nitrogen so important in corn physiology? N is essential to grain fill and development. This means that if the plant is deficient in nitrogen, the kernels and ear won’t fill to their genetic potential. A common symptom of N deficiency is a yellowing midrib on a lower leaf.

nitrogen d.jpg

Nitrogen deficiency in corn. Photo from SDSU Extension

Phosphorus (P) – This is another very important macronutrient! In a similar respect to nitrogen, plants are unable to absorb and utilize the elemental form of P. This creates a problem in fields, because P is most commonly found in a plant unavailable form! Luckily, roots have a symbiotic relationship with Mycorrhizal fungi which are able to turn P into a more usable form. Corn can easily uptake phosphates, and the most common compounds are H₂PO₄⁻ and HPO₄²⁻. Since phosphates have negative charges, they are more prone to leaving the soil than the elemental form (similar to nitrates). This is why synthetic fertilizers that contain significant amounts of phosphorus are delivered in a P₂O₅ compound. Why is phosphorus so important in corn physiology? P is directly correlated to crop maturity, yields, and overall plant growth. More specifically phosphorus is a huge makeup of sugar phosphates, which directly affects ATP. Energy transfer with ATP is crucial, due to it’s role in both RNA and DNA. A lack in P will affect the overall efficiency of any plant. Phosphorus deficiency in corn appears in older leaves and starts as a purple hue. An increase in severity will turn leaf margins brown.

phosphorus d

Phosphorus deficiency in corn. Image from Channel.

Potassium (K) – When applying synthetic fertilizers, it’s common to see potassium in the K₂O form. However, this form is not immediately available to plants. Plants can only take up K+ when it’s in a solution. This form differs from the available compounds of N and P, since potassium is a cationWhy is potassium so important in corn physiology? A deficiency in K can have a multitude of negative affects upon the plant. This could be seen as an increase in susceptibility to drought, temperature stressors, and pests. Agronomists refer to K as “the quality nutrient”, meaning there’s a direct connection to traits like seed vigor, size, color, and shape. To be more specific, potassium helps build cellulose, increase protein content, maintain turgor, and move sugars and starches throughout the plant’s vascular system. K deficiency symptoms start as a yellowing of leaf margins on older leaves, and an increase in severity turns the pale color to a brown necrosis.

K d.jpg

Potassium deficiency in corn. Photo from Thompsons.

Secondary Macronutrients

There are three elements that fall under this category, as they’re needed in higher quantities than micronutrients but lesser amounts than N, P, and K.

Calcium (Ca) – Calcium deficiencies are most common in sandy and/or acidic soils, since the Ca ions can be leached through the soil profile. Similarly to potassium, Ca²⁺ can only be imbibed by plants when in a soil solution. Why is calcium so important in corn physiology? Ca holds a vital role in the creation of cell walls and membranes. Calcium deficiency symptoms are visible in new growth, so in corn this would be around the growing point. It typically appears as a yellowing color, slowed growth, and leaf tips sticking together.

Ca d.jpg

Calcium deficiency in corn. Image from Crop Nutrition.

Magnesium (Mg) – Without Mg, a plant would not be able to photosynthesize. This element is a sizable component within chlorophyll molecules, which is 100% necessary for capturing the sunlight’s energy! Additionally, Mg serves as a phosphorus carrier. Simply put –  if there’s not enough Magnesium then the plant would be unable to uptake P, even if it was available in the soil! Mg²⁺ is the plant available form, and can be heavily affected by the pH and sandiness of soils. Mg deficiencies are first seen in older and lower leaves, starting as a purple interveinal discoloration.

Mg deficiency.jpg

Magnesium deficiency in corn. Photo from The Mosaic Company.

Sulfur (S) – The last, but certainly not least, macronutrient can be absorbed both through the roots and stomata openings. In the environment, sulfur is commonly found in the air as SO₂ and within soil solutions as SO₄²⁻. Unlike the previous secondary macronutrients, this one is taken up as an anion as opposed to a cation. Due to the negative charge on a sulfate molecule, it is mobile in the ground (just like nitrate or phosphate) and can be leached through the soil profile. Why is sulfur so important in corn physiology? Without adequate S, some amino acids and proteins would be unable to synthesize. Sulfur also has a connection to winter hardiness, which is a major trait in certain crops. S deficiency in corn appears as a general yellowing of younger leaves, starting between veins but widening to encompass the entire leaf with increasing severity.


Sulfur deficiency in corn. Image from Successful Farming.

This is merely a glimpse into some of the chemical factors and management systems that a row crop grower oversees each and every year. If you liked this blog or learned something new from it, let us know! Or maybe if you’d like to see a similar breakdown of micronutrients too? Either way I love writing about agronomic science and can’t wait to share another blog with you all!



Scarecrows and Agriculture? Say What?

porch scarecrowFall is in the air. The farmers are out combining their crops in the fields, and fall decorations are set out. Mums, pumpkins, and scarecrows add a festive touch to porch stoops. Scarecrows are now often used as fun fall decorations, but did you know they once served an agricultural purpose?


The origin of the scarecrow dates back to the time of the Egyptians. Farmers installed wooden frames in their fields and covered them with nets. As birds would enter the field, the farmer would scare them into the net and capture them.

Greek farmers also used scarecrows. In 2,500 B.C., Greek farmers carved wooden scarecrows to look like Priapus, the son of Greek goddess Aphrodite. He was believed to be ugly enough to scare birds away from the vineyards and ensure a good harvest. One hand held a club to scare the birds away, and the other hand held a sickle in hopes of a good harvest.

DCF 1.0Japan had their own version of scarecrows called a kakashis. This scarecrow closely resembled a person. It was dressed in a raincoat and a round straw hat. Farmers added bows and arrows to make the kakashis appear to be more threatening.

Scarecrows were also used in the Middle Ages in Europe. Their original purpose was to england scarecrowfrighten away birds from eating crops in the field. For thousands of years, farmers have tried to keep pests like crows from eating the seeds and plants in their fields. Before scarecrows were around, during the Middle Ages, in England, young boys would walk through the wheat fields making loud noises with wooden clappers to scare the birds away. This was the child’s main job on the farm. They were called bird scarers. When the fields got larger, they started to build wooden stands throughout the field for children to sit in during the day. While they sat in the stand, they would bang pots, make noise, and throw rocks at any animals or birds that attempted to eat their crops.

During the Great Plague, many children died and few were left to stay in the field as bird scarers. Farmers had to be creative and find something else that would deter the pests from the fields. Thus, the scarecrow was born in that region. England scarecrow bodies were made from stuffed sacks of straw and their faces made of gourds. Their bodies were leaned against a pole to scare away birds.

homemade scarecrowMake your own scarecrow

You can make your own scarecrow for your garden at home! It is a simple process. Garden scarecrows must stand tall in the wind, rain, or heat so they need to be made from sturdy materials. Start with a strong frame. A wooden poll, PVC pipe or metal fence post works well. Be creative and use recyclables to create your scarecrow! Old milk jugs work well to create a head for your scarecrow. You can even paint a face on it.

The next step is to to create a body for your scarecrow. Use old clothes to dress the scarecrow. Fill a shirt and old pants with straw, hay, or grass clippings. Tie the ends of the clothing items shut so the filling stays inside. Colorful duct tape can be used to secure the scarecrow to the frame. Attach an old straw hat or wig to make the scarecrow even more life-like.

Attach noise makers to frighten pesky birds away from your crops. Metal objects and reflective products work well to keep birds away.

Just in time for fall celebrations, your new scarecrow can serve two purposes! First it can add to your fall décor, and secondly it can help keep birds from disrupting your crops.

Happy fall!