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 Pexels.com

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 Pexels.com

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!

Silage- Why Do They Do That?

Have you ever wanted to eat a fermented corn plant? No? Yeah, me neither! However, cattle have much different food preferences and diet requirements than we do, and they happen to love fermented corn plants- also known as silage. Luckily for cattle, not only does silage taste delicious to them, but it also fulfills nutrient requirements that they need in their diets. Silage provides both beef and dairy cattle with a highly nutritious, balanced diet. As ruminants, cattle need a lot of forages or roughages in their diet- feeding the whole corn plant to cattle provides them with the forages they need. In feeding livestock, two areas of focus are energy and protein (vitamins, minerals, and water are important, too). Corn silage provides cattle with protein, in the corn kernels, and energy, in the stalks and leaves of the plant.

Photo via Iowa State University Extension and Outreach

There are several different types of silage. Many different types of crops can be ensiled (made into silage) and fed to cattle, like legumes, grasses, small grain cover crops, and sorghum, but this blog will focus on corn silage. We know that silage is fermented corn, but let’s dive into how farmers make it.

First, farmers must grow corn- and not just any corn. Corn that produces high yields makes for the highest quality silage—deciding on which corn seed to plant is a decision made far before planting starts. Some seed companies have developed a hybrid seed to grow corn meant to be ensiled. Also, planting corn for silage means planting more corn seeds- the goal is to have approximately 20% more corn plants than if a farmer was growing corn normally. Then, farmers may apply herbicides to control the weeds and wait for the crop to grow.

Photo from Hay & Forage Grower

After the corn has had time to grow, it’s time to harvest. Harvesting corn for silage requires a balance of waiting for the corn to dry enough, but not waiting too long so that it dries too much to pack. Usually, when farmers harvest corn, they can’t store it above 15% moisture, so they must dry it if it’s wetter than that. When farmers harvest silage, they want the moisture to be 60-70%, so it will pack together well to ferment. Harvesting silage takes place before normal corn harvest. Farmers can use various equipment to harvest silage, but the basic concept is that the harvester takes the whole corn plant, chops it into pieces, and then deposits it into another implement, like a semi or a tractor-pulled cart.

Finally, the silage is stored to begin the fermentation process. That process can look different on different farms. The way silage is fermented can also depend on moisture rates. Let’s dive into some options.

Photo from CDC

Upright Oxygen-Limiting Silos
This option is ideal for low-moisture silage, in the 55-60% moisture range. An upright oxygen-limiting silo unloads from the bottom but gets filled from the top.

Photo from International Silo Association

Upright Stave Silos
These are the most popular type of silo. Metal bands hold the structure up and keep the silo from collapsing due to the pressure of the silage. This type of storage works best for 60-65% moisture silage.

Photo from International Silo Association

A silage bag is a popular, low-cost option for storing 60-70% moisture silage. These plastic bags hold the silage while it ferments.
Venting the bags, appropriately filling them, and avoiding rips or tears in the plastic are concerns for farmers while using this storage method.

Photo from Wieser Concrete

This type of silage storage is best for wet silage in the 65-70% moisture range. This storage facility has concrete walls on three sides. The farmer dumps the silage and then drives over it with a heavy tractor to pack it down. The farmer will cover the packed silage pile with plastic to protect the pile and tires to hold the plastic down.

What now? The silage must ferment for around three weeks. Fermentation starts when the farmer covers the silage pile or puts freshly chopped silage in the silo. That creates an anaerobic environment (no oxygen) for the silage. Next, the microorganisms in the silage perform an exchange by consuming the sugars and some carbohydrates in the silage and producing organic acids. These acids lower the silage’s pH, which preserves the remaining silage.

Photo from Farmer’s Weekly

After the silage has fermented for around three weeks, it is ready for consumption. The silage has a very distinct, sweet smell when it is done fermenting, and the cattle love it!


On-Farm Storage – Why Do They Do That?

In 2018, the U.S. Department of Agriculture (USDA) reported that Iowa had enough storage for 3.6 billion bushels of grain. 2.1 billion of those bushels were stored in what is called “on-farm storage.” That means farmers are drying and storing the grain they


Photo by John Lambeth from Pexels

harvest in personal storage bins, not at a co-op. You can read about co-op storage here. You might be wondering what the difference is, or why farmers would want their own storage. Good questions!

Personal grain storage is different than a grain elevator or co-op in several ways. First of all, location. An ideal location for a grain elevator would be in a rural area with a lot of farmland very close so that farmers don’t need to haul freshly-harvested grain many miles to get it dried and stored. An ideal elevator is also located near a railroad or waterway, like the Mississippi River, so the transport of grain from the elevator could happen efficiently, rather than having to haul the grain again.

Location is also very important to farmers when they decide to build on-farm grain storage. In order to use their on-farm storage most efficiently, they need to build in an area that is close to several of the fields they farm, if possible. Smaller grain storage facilities could be used for just one or two fields, but many modern grain storage facilities are being built to hold several fields worth of grain. Building in close proximity to several of their fields allows farmers to save time during harvest. During harvest, a combine usually dumps grain into a grain cart, which then dumps it into a semi to take to a grain storage facility. If the semi is having to haul grain a distance, it can slow down the process if the combine and grain cart are both full before the semi can get back.

Farmers build their own on-farm grain storage for several reasons; this blog post will highlight three of them.


This is the big one! Marketing is incredibly important to farmers, as it can allow them to get higher prices for their crops. Instead of hauling the grain into the elevator or co-op right away, farmers can choose to wait to sell their grain if they think they can get a higher price later on. “You can delay sales three to six months into the future and be paid well for your patience ($0.20 – $0.40 per bushel)”- Hertz Blog. This gives farmers the opportunity to make more money each year for their crop, if they market it well. For more information on how farmers market their crops, check this blog out.


On our family farm, our large on-farm grain storage site is three miles or less from the majority of our fields. That is four miles closer than the nearest co-op, and that distance IMG_2056does make a difference in how fast we are able to harvest. There’s never a line at our on-farm storage site of other trucks trying to deliver corn. Our site also does not close down at a certain time. Co-ops are not always staffed to operate the facilities all night, but many farmers need to work late into the night to get all of their crops in, especially during years when harvesting conditions haven’t been ideal. It can sometimes feel like a race to get a crop in before snow comes, especially in Iowa when severe weather often happens very unexpectedly! By using on-farm storage, the race to get a crop in can be lessened.


When corn is ready to be harvested, it has 15-25% moisture. If the moisture is more than 15%, it must be dried before it can be stored. That is where a corn dryer comes in. This is essential for grain storage if a farmer is harvesting corn that is even a little bit wet, as wet corn can get moldy when stored. Co-ops have grain dryers, but if a farmer is using on-farm storage, it is cheaper for farmers to dry their own corn. There are many different kinds of grain dryers, but an estimate of an initial cost for one would be around $100,000. Prices can definitely go up from there. The initial investment is a significant one, but when used over many years, the return on investment (ROI) proves it to be a worthy investment. The other option that farmers have is drying their corn at a co-op before storing it there. This costs more for farmers, but comes with the convenience of not having to buy a corn dryer. Here is a comparison of on-farm drying vs commercial drying.

On-farm storage allows for the United States to produce more corn than we use here. We are able to use corn that is stored across the country to export to other countries. According to the National Corn Grower’s website, “Exports are responsible for 33 percent of U.S. corn farmers’ income. More than 20 percent of the U.S. corn crop is exported annually when accounting for corn and value-added products like ethanol and distillers dried grains with solubles (DDGS).” If we did not have on-farm storage, the corn crop would not be able to be stored and exported throughout the year without significant changes in our co-ops.

Unfortunately, on August 10, 2020, Iowa lost a significant amount of grain storage in the IMG_2057derecho. Straight line winds, some reaching estimated speeds of 140 mph, crumpled many bins. Co-ops and on-farm storage units both suffered in the storm. Corn was also flattened in the storm. The USDA’s Risk Management Agency estimated that 8.2 million acres of corn were impacted by the storm. Some of that corn will not be able to be harvested, so the demand for grain storage may go down some. Many farmers will be turning to alternative methods to get their crops out of the fields and try to make some money, and Iowa grain storage construction companies will be busier than ever before. No matter what, it will be important for farmers to rebuild their on-farm storage grain bins as quickly as possible to be ready for next year’s harvest.


Why do They do That? Using Airplanes in Agriculture

This time of year, you may see small, yellow planes flying low overhead. They may fly back and forth over a relatively small area of land. What are they doing? Why are they doing that?

These planes are commonly referred to as crop dusters, but they can have multiple purposes, and there are multiple reasons why they might be used. Read on to find some answers about aerial application in agriculture!

What are the crop dusters doing?

That likely depends on the time of year!

Late in the year, they might be aerial seeding, meaning they are flying on cover crop seeds. These cover crops will grow during the off-season (fall through spring) when the main cash crops are not growing. They help protect soil and water quality.

During the middle of the year, they might be applying pesticides. Pesticides might help control weeds in the field that steal nutrients and water from crops, insects in the field that eat the crops, or fungus growth in the field that attacks the crops. When an airplane (or a different implement) is applying pesticides, most of the liquid is water, which acts as a carrier, with a small amount of pesticide mixed throughout. Since pesticides and aerial application have real costs associated, these are only applied when absolutely necessary to protect a crop.

Though aerial spraying of pesticides may still be the more common use for these machines, aerial seeding is growing in popularity!

What’s the advantage of airplanes?

Airplanes, and sometimes helicopters, can be advantageous because they don’t need to drive through the field. Each time farm implements drive through a field, they compact the soil and run the risk of injuring crops. Because of the risk to the soil of driving back and forth with large implements, farmers also need to be very careful about how wet the field is before they try to enter it with these machines. If the soil is too wet, the soil can be greatly impacted and implements can even get stuck – not a fun day for a farmer!

Later in the season when the crops are fully grown, farmers also need special implements to drive through the field that have narrow wheels and a high clearance to not crush the crops. These implements aren’t cheap and not every farmer would own one, however, some farmers and agribusinesses have them available for custom spraying (can be hired to spray other farmer’s fields).

When thinking about cover crops specifically, aerial seeding can also give more of a window for when those crops are planted. With traditional seeding equipment, the farmer may have to harvest their main cash crop (think corn or soybeans) before they can plant their cover crop. With aerial seeding, the seeds can be sown while the cash crop is still growing, and can already be established and growing by the time the cash crop is harvested. This saves time, and allows extra soil protection for those few days or weeks that the ground might be bare!

Does every farmer use airplanes?

In short, no.

Flying agricultural airplanes is a very skilled and regulated trade. Most farmers that use aerial spraying or seeding will hire it out to a third party company that will service many area farms. All pilots need to have the correct licenses or certifications to be allowed to fly and to apply.

Though we have listed some great pros, there are also some cons for some farmers. First, the price of aerial work might be prohibitive. Second, the location of a farm might be prohibitive. Local businesses will likely need to be consulted to make sure that the farm is on a safe landscape and is accessible for the planes they use.

But why do they fly so low to the ground?

This is a great question! These airplanes, unlike commercial airliners, need to be close to the ground while applying pesticides or seed to minimize drift as much as possible. The higher up the plane is, the more off-target their application can be. That’s why you may notice the plane stops applying before they pull up to turn around and fly the other direction.

If you’d like to learn more about agricultural aviation or ag pilots, check out the National Agricultural Aviation Association. They have resources on what is required for this job, how to train, and what licensures are required. This is a unique job in agriculture with lots of neat opportunities!

What other questions do you have about agriculture aviation? Let us know!


Why Do They Do That? Shearing Sheep

Why do people shear sheep? Does shearing hurt the sheep? What’s the purpose of shearing sheep?


Wool comes from sheep. Wool is a unique type of fiber that just grows on the hide of sheep. Different types of sheep can have wool with different properties. Some sheep have really nice wool. Other sheep, not so much. Some sheep grow “hair” instead of wool, and this fiber is different yet!

But in order to get this wool, sheep need to be sheared, or shaved, like a haircut. Wool is just the fiber (similar to hair or fur) of the animal, and is separate from their hide or skin. For this reason, shearing or shaving sheep does not require the farmer to harvest the animal. In fact, most sheep are sheared once every year throughout their life.

Shearing sheep is a very labor-intensive task that requires skill. Sheep are usually sheared using electric shears, similar to clippers you’d see at the barber shop. A good shearer will shear the entire fleece (wool coat) of the animal off in once piece, not cause any injuries, and complete in about two minutes. It is important to pay attention to the hide of the animal for several reasons. First, cutting the sheep’s hide will cause unnecessary pain to the animal that the farmer does not want. Secondly, the wound on the animal could inhibit wool growth in the future. Thirdly, this slows down the shearing process, which creates a less efficient process.


Though some farmers will shear their own sheep, many will hire out a sheep shearer to come help with the task. However, this can be an expense with little to no return for some farmers. In times when the price of wool is low, it may not even cover the cost of shearing the animals. Even then, farmers will shear the sheep, absorbing the cost. These farmers may not sell the wool, but could use it to insulate a barn or garage, or find another purpose for it on the farm.

Farmers will continue to shear sheep each year, in short, to help the animal. Most sheep grow wool continuously, meaning that without being sheared, their wool can become unruly. The longer this wool grows, the more it can trap urine, fecal matter, rocks, dirt, pests, and pathogens. The organic material it collects can make their fleece heavy and uncomfortable. The waste in the fleece can be a breeding ground for bacteria that could cause health problems. In this way, shearing sheep keeps them moving freely and keeps them more clean.

The fleece can also be quite hot, as you might imagine if you’ve ever worn a wool sweater. In this way, a new fresh haircut can prepare the sheep to deal with warmer summer weather, especially in the warmer parts of the world where sheep are raised. This also means that sheep are not shorn in the winter months, as their wool is protecting them from the elements at that time.

Lastly, wool is a very high quality fiber. It has many properties that make it useful, from the tiny barbs that hold the fiber together, to its insulating properties, to wicking properties, biodegradability, and more. Wool has been a very important resource to humans for centuries. And if you’ll allow me to make a prediction, with folks today paying more attention to using renewable and biodegradable products, I think we will soon see a resurgence in the use of wool in more of our everyday items.


So, farmers do shear their sheep about once a year. This should not hurt the sheep, but instead is done to help keep them healthy and safe.

What other questions do you have about sheep and wool?


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!


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.


Why Do They Do That? Farmers Applying Chemicals

There are lots of questions a consumer might have about chemicals. Why are farmers putting chemicals on their fields? What chemicals are farmers putting on their fields? What do the chemicals do? Are there chemicals in our food? Are there harmful chemicals in our food?

First, though, we need to answer a big question – what is a chemical?

One good definition of a chemical might be a form of matter having constant chemical composition and characteristic properties. That is to say, you cannot break this substance down without breaking chemical bonds.

A chemical bond is a strong association between two different atoms. Remember that all matter is made of atoms – for a long time, science thought this was the smallest thing we could break matter into, but then they found protons, neutrons, electrons and other tiny, tiny stuff inside the atom.

In your high school science classroom there was likely a Periodic Table of Elements. On that table, things like atomic weight and atomic mass are mentioned. Each of these elements has a different type of atom that makes it up. To brush up on atoms, check out this Crash Course video.

In chemistry, we look at the characteristics of these atoms and elements. The way they interact, bond, and perform is chemistry.

The thing that trips us up is really the colloquial way the word “chemical” has been used. When we think chemical, we think of a steaming beaker full of thick, bubbling, lime green acid, right? But really, everything is a chemical. Water is a chemical (H2O), sugar is a chemical (C6H12O6), caffeine is a chemical (C8H10N4O2), and so is salt (NaCl)! We are even made of chemicals! Our DNA is made of four different nitrogenous bases (adenine, guanine, thymine, and cytosine) – each a different chemical.


Photo from Google

Therefore, if you ever see or hear someone try to sell you something that is “chemical free”, you can know it is a marketing gimmick. In fact, the FDA forbids the phrase “chemical free” from being used on meat and poultry labels, because that is an impossibility. Rest assured, you have never purchased anything that was “chemical free”.

However, that still may not answer your questions. You may still wonder what is being used to produce food. Is it safe? How much is used? How is it used? Though there are many different individual products, let’s try to break down purposes and highlight a few representative chemicals in each category.

What chemicals are farmers putting on their fields?

One umbrella term for many products is pesticide. We’ve written a previous blog post about pesticides that you can find here, but we will summarize a little bit here.

Chemical inputs in agriculture

Pesticide is a term that includes many different things. A pesticide is something that is used to control some kind of pest. These pests can be weeds, insects, fungi, or even rodents. Because each of these things would be formulated very differently, it wouldn’t be fair to generalize much more over these lines.

Herbicides (a pesticide used to kill weeds) likely get the most press of the pesticides. To get a rundown on what herbicides are, check out this blog. Farmers use herbicides to kill weeds for a couple different reasons. First, weeds use up water, space, and nutrients that their crops need. This adds extra competition and makes the crops less productive. By eliminating weeds, plants grow better and produce more food. Second, the alternative to using herbicides to kill weeds is either hand-pulling weeds or using tillage. Hand-pulling weeds is likely the most effective but raises humanitarian issues regarding working conditions and the like. Tillage can be effective as weed control but degrades soil structure and leaves the earth susceptible to erosion, which can also contribute to water quality issues.

Insecticides (a pesticide used to kill insects) are used to remove harmful insects from a crop field. For example, this year the thistle caterpillar has been wreaking havoc on soybean fields in the state. When this caterpillar builds its chrysalis, it folds the soybean leaf over itself, and eats its way out after this stage. This means the leaves of the plant are all but destroyed, making it very difficult for the plant to photosynthesize. If the pressure of this insect in a field reaches the economic threshold (the threshold by which it will cost less to use an insecticide than it will cost in crop loss), the farmer will likely choose to spray the field to kill these insects.

Fungicides (a pesticide used to kill fungus) are used to help mitigate disease. Sometimes plants can be susceptible to different kinds of fungus growth that can hurt the plant and even kill it if left long enough. Disease is a major contributor of crop loss globally, with fungi being the number one cause of crop loss. Since fungi growth is dependent on moisture and temperature, this can be difficult to control in a farm field without applying some type of chemical, whether that be organic or synthetic.

Outside of pesticides, farmers may also apply soil amendments. These things help keep the soil healthy. They can range from limestone (calcium hydroxide, in a powder and called “ag lime“) to a range of fertilizers.

Fertilizers help replenish nutrients in the soil so that it remains productive and plants can continue to grow in the same place. Keeping soil productive is a major piece of environmental sustainability. There are many essential nutrients that plants need to be healthy. Therefore, fertilizers can vary greatly depending on nutrient content, geographic location, crops planted, and many other factors. Fertilizers can come from many different sources, from manure from livestock and compost (both organic sources) to anhydrous ammonia (derived from atmospheric nitrogen using the Haber-Bosch process).


An example of some fertilizer types from NEW Coop. Underneath the bold name are three numbers. These indicate the amount of nitrogen, phosphorus, and potassium in the total fertilizer, respectively.

All of these types of inputs have organic and synthetic counterparts. Organic farmers can apply pesticides as can conventional farmers. However, the terms organic and synthetic do not include how effective or toxic to humans the product is. Some products may take a long time to break down and others break down very quickly. Some are much more toxic to humans than others. Some are much more effective and therefore farmers don’t need to apply as much of them. These characteristics are much more important to the safety of the farmer and the landscape than how they were derived.

Are chemicals used in food production safe?

This is a great and very important question. Safe food production is important because we all depend on safe food, and we need to care about the safety of those working in food production. So, is it safe?


Some examples of bulk storage of crop inputs. These inputs are housed at a cooperative. A farmer may hire the co-op to use their own equipment and materials to spray instead of investing in all of the equipment themselves.

Inputs applied to farm fields are regulated. The Environmental Protection Agency leads the charge in the U.S. for overseeing pesticide regulation. They work with the Food and Drug Administration and the U.S. Department of Agriculture to ensure pesticides are being used in a way that maintains a safe food supply. They also work with the Bureau of Land Management and the U.S. Fish and Wildlife Service to ensure the environment remains safe. 

When commercial crop inputs are purchased, they come with a product label. This label can be dozens of pages long (here’s a 58-page long glyphosate label), and acts more like an instruction manual. Many things are dictated in these labels, including when to spray, how much to spray, and how to store and dispose of the material. Not following the label is illegal. However, these inputs do cost money, so it’s not in a farmer’s best interest to use more than necessary, even if it was legal.

These labels are created to ensure safety. Farmers and agronomists using these inputs are educated and trained on how to use everything with thoughtfulness, foresight, and attention.

How are chemicals applied on farms?

Though this can vary, most crop inputs are sprayed on fields using sprayer implements or sprayer planes. However, most of the liquid being sprayed on a field is water. For example, when glyphosate is applied to one acre of land (about the size of a football field), only 32 ounces of the product is used. That’s just a couple of pop cans full! The rest of the tank in the spraying implement is water. The water helps carry the product across the field.

2015-08-13 09.42.19

This sprayer’s boom can fold and unfold, and be raised and lowered. The high cab and skinny tires accommodate row crops better than a traditional tractor.

Some products may use more or less depending on the effectiveness of the product. This application rate is specified in the label, along with sprayer nozzle type, and weather considerations.

Some inputs are solids, meaning spraying doesn’t work as well. For example, ag lime is broken down limestone, which cannot be sprayed. Instead, a tractor may pull a spreader across the field to scatter the lime evenly.

In places where agricultural fields are much smaller, equipment can be much different. There, you might find farmers with backpack style sprayers that hand-spray their crops for insects and fungicides that hurt their crops.


Chemical inputs can be complicated. There are a host of different products and uses that dictate things like dosage, toxicity, half-life, and others. However, it’s important that we evaluate products more by these characteristics than by how they were derived. With the decrease in arable land and increase in population, it is important that we have as many tools in our toolbox as possible to help create solutions that maintain our land quality, food quality, and our safety.


Why Do They Do That? Seed Treatments


Purple, green, orange, yellow, red? No, these aren’t colors of M&Ms. These are some of the colors you’ll see on agriculture crop seeds that have been treated with the latest technologies to fight diseases and pests. Treating seed is nothing new. Farmers have been using different types of seed treatments dating clear back to 60 A.D. In this blog post, you’ll learn more about how farmers use them today and why.

So, just what is seed treatment?
Seed treating is the act of applying a product to a seed prior to planting. When seeds go into the ground, there are many diseases and pests just waiting to take advantage of those young seeds and seedlings for their own benefit. Farmers want to protect their investment so treating seed is one way to help prevent crop loss.

There are a variety of treatments, but the main categories include fungicides, insecticides, and antimicrobial products.

  • Fungicides are chemical compounds or organisms used to kill fungi or their spores. Typically, two or three fungicides are used at a time.
  • Insecticides are substances used to kill insects. In any given field, many different insects want to feed on the seed. Insecticides help protect against both the actual insect as well as their eggs or larvae.
  • Antimicrobial is an agent that kills microorganisms or stops their growth. These biological treatments can also help plants in other ways such as producing their own nitrogen or helping to extend root systems.

Why do farmers use seed treatments?
Every year, between 20 to 40 percent of yield is lost due to pathogens, insects and weeds, according to Bayer Crop Science. Maybe this is why treating seed has been around for centuries. Farmers throughout history have been trying to find ways to protect their crops from damage. The earliest reported use of a seed treatment dates back to 60 A.D. when wine and crushed cypress leaves were used to protect seed from storage insects, according to the American Seed Trade Association.

Besides farm equipment, the purchase of seeds is one of the most expensive products a farmer must purchase. And it’s an annual purchase. Farmers and companies that Treated-Seed-in-planter-300x169 - croplifejpgsupport those farmers continually want to find ways to protect the value of the seed as economically and environmentally responsible as possible. Seed treatments are one way farmers can protect the seed’s value. Seed treatments can also be a more environmentally friendly way of using pesticides and insecticides. Smaller amounts of these chemicals can be used to benefit the seed when comparing seed treatments to spraying. 

Benefits of seed treatments

  • Seed treatments protect seeds and seedlings against early-season insect pests and diseases.
  • Results in stronger, healthier plants, and higher crop yields.
  • Allows for more accuracy and efficiency in crop production inputs.
  • Reduces the environmental impact of the production process by decreasing the number of spray applications needed on any given field. In short, using treated seed allows for less spraying during the growing season. This helps lessen the exposure to pollinators and other wildlife.
  • By applying color with the treated seed, farmers can tell immediately what type of seed and chemical solution is on the seed in the case of accidental spills.

Seed treatment safety


Source: GMO Answers

Agriculture is one of the most heavily regulated industries. It can take a decade or more for a new trait to go from an idea to a seed in the field. New products – both seed and chemical applications alike – go through years of research and testing. Once products are ready for market, agencies such as the Environmental Protection Agency (EPA), U.S. Food & Drug Administration (FDA) and U.S. Department of Agriculture (USDA) evaluate the product for safety purposes.

Treated seeds are no different. Farmers are required to follow safe handling procedures to protect the food industry, wildlife, and the environment. Here are just a few of the procedures farmers must follow to protect the environment.

  • Know which treatments seeds have received to ensure proper handling.
  • Wear proper personal protective equipment (PPE) when handling treated seed.
  • Clean up spills immediately.
  • Avoid generating dust when handling treated seed.
  • Properly dispose of leftover treated seed.

Ultimately, farmers want to give their seeds the best possible chance to mature to a healthy plant ready to harvest. They deeply care for the land, which has likely been in their family for generations and want to see that land continue to produce crops not only for their family but also the world. Seed treatments are one of the tools in their toolbox to help them to just that.


Additional Sources








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.