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.

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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.


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.

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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.


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.

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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.

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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.

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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.

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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.

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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.

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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.

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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!



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.


Why do they do that? Fall Fieldwork

Corn and soybean farmers breath a sigh of relief once they finish harvesting crops in the fall. But that doesn’t mean their work in the field is done for the year. Depending on their type of operation and soil conditions, they have several more weeks of field work left before they can park their tractors in the shed for the winter.

So what type of field work do farmers do after harvest and why?

  • Tillage. While no-till is a common practice, many farmers choose to till some or all of their of crop ground for multiple reasons. Fall tillage can alleviate compaction caused by combines and other large, heavy equipment;break-down and incorporate plant residue, like corn stalks, into the soil; and help heavier soils warm up and dry-out quicker in the spring. Farmers consider factors such soil type, soil moisture, ground slope, and next crop rotation when deciding to till and what tillage equipment tool to use.
  • Seeding cover crops. Unless farmers choose aerial application, cover crops must be planted after the fall crop is harvest. Cover crops are used to add organic matter to the soil and hold the soil in place to reduce erosion.
  • Fertilizer Application. Many farmers choose to apply manure, anhydrous and other fertilizer in the fall. Farmers consider the 4Rsof nutrient management when deciding when and what to fertilizer apply.
  • Installing & repairing fences. Many beef cattle farmers let their cattle graze on harvested corn fields after harvest. The cattle clean-up any corn that fell before or during harvest. This can give their pastures additional late-season growing time and provide an additional food source after pastures are covered with snow. Before they can move cattle to the fields, they need to ensure that the fields are well secured by installing new or fixing existing fences.
  • Baling cornstalks. While corn residue is incorporated or left on the soil surface in most fields, some producers bale the residue for use as livestock feed and bedding. This is a particularly common practice for beef cattle producers who rise cattle in open lots, hoop barns, or mono-slope buildings.
  • Soil Sampling. Fall is a good time to collect soil samples and test the soil to help make future decisions. Farmers and agronomist use the results from soil tests to determine fertilizer application rates and if it is necessary to apply lime to increase the soil PH.
  • -Cindy

    Why Do They Do That? – Crop Scouting

    crop scoutLast summer my time was spent walking the corn and soybean fields of Southeast Iowa searching for weeds and pests that did not belong in the field. But why was I needed as a crop scout? Farmers’ livelihoods depend on their crops. Weeds and pests can easily overtake the field if not carefully controlled. It was my responsibility as a crop scout to identify the weeds and other possible concerns in the field and inform the farmer.

    So what are crop scouts looking for in the field? First they look for any abnormalities in the plant. When plants are off-colored, chewed, stunted or dead, that could indicate issues that the farmer needs to be aware of. The causes could be soil, pest, or nutrient related, but it is important to determine the cause of the problem so it can be solved quickly.

    The purpose of scouting is to give a representative assessment of the entire field. While scouting, it is important to look at multiple areas of the field. It depends on the size of the field for how many samples are taken. The rule of thumb is to check a minimum of five locations in fields of less than 100 acres. In fields greater than 100 acres, a minimum of 10 samples should be taken. Taking random samples is imperative to having a representative assessment of the field. Scouts do not just focus on the entrance, edges, waterways, high, and low areas, but rather randomly select various spots in the field to collect samples and stand counts. 

    A crop scout keeps busy early in the season identifying weeds that are in the field. Scouting for weeds before planting seeds allows the farmer to know what weeds are growing in the field, the growth stage of the weeds, and the weed populations. Controlling weeds before they reach four inches tall can help eliminate yield loss. After the weeds have grown over four inches tall, they are harder to control.  Knowing what weeds are in the field allows the farmer to make better management decisions while it is easier to combat the weed issue in the field.

    Scouting after the seeds are planting can show farmers seed damage, early pest damage, and many other factors. When plants start emerging, taking stand counts helps the farmer decided if they need to replant. They can also evaluate their management decisions and make changes for next years planting season. When taking a stand count measure 1/1000 of an acre. This measurement can be found by using the table below. Then count the number of plants in the measured area. Take at least six samples throughout the field. Then take the average number of plants and multiply it by 1,000 to calculate the final plant population per acre in the field. Most farmers plant corn at a rate of 29,000 to 38,000 seeds per acre and soybeans at a rate of 130,000 seeds for 21 inch row spacing and 210,000 seeds for 7 inch rows per acre based on 90% germination and 90% emergence rate.

    crop row spacing

    Crop scouts also keep a watchful eye out for insects. The scout must identify the insects present in the field, what ones are harmful, the amount of insects, and assess the damage caused by the pests. Damage can be seen by observing the foliage, seed heads and pods, stems and roots. By swinging a net over the top of the crop canopy, scouts are able to capture insects in the net and get an accurate estimate of how many insects there are per square meter. Inspecting the top individual leaves for insects can also be done in addition  to using a sweep net. It is important to observe the stem and roots to look for any signs of damage. Punctures on the stem can indicate insect damage. Signs of chewing can be an indication of insect damage even when you do not see any insects at the time of the scout.

    Knowing the symptoms of plant diseases, is another important skill for crop scouting. Plant diseases can be caused by weather, fertilizers, nutrient deficiencies, herbicides, and soil problems. Watch this video for a quick rundown of corn diseases from an Iowa State University Field Pathologist.

    Farmers want to make sure they know what is occurring in their fields, so they are sure to scout for weeds, pests, and diseases. Next time you drive by a corn or soybean field, take a look to see if there is someone out scouting a field.


    P.S. Did you ever spend time walking fields as a crop scout? Tell us about your experience in the comments below.

    Why do they do that? Floor Slats in Pig Barns

    Earlier this fall, I was attending a STEM Festival, where we were presenting our Feed Sacks Pork Lesson. In this activity, students make a snack mix based on the feed rations a pig gets. As part of our set up, we had some photos on the table of modern pig barns, and some real pig feed samples.

    At this event, one family came to our booth very curious about what they were seeing. They told me that they had recently moved to Iowa from Alabama, and were not familiar yet with Iowa agriculture.


    Upon seeing one of the pictures, the mom asked why the floors looked the way they did. Since many people don’t get the opportunity to see inside the pig barns they notice from the road, I thought this was a great question. Why do they make pig barn floors the way they do?

    The flooring in pig barns is slatted, meaning there are long, narrow holes in the floor. This essentially creates a waste disposal system in the barn, making sure that the pigs don’t have to lay around in messes. This is also a much less labor intensive system than having to scoop or remove the waste regularly.

    Slatted floors can look different. In the photo above, the floor is cement. Other flooring systems with the same concept could be plastic, or metal coated with rubber. Different producers or different barns might use different styles of flooring depending on cost, the size of their barn, and how safe the flooring will be for their pigs.



    But what happens to the waste that falls through the flooring? Does it just fall to the ground and stay there? Not quite! Underneath pig barns like these, there are manure pits. Other types of barns have systems where the manure is then moved to a pit outside of the barn instead of directly underneath it. All of these pits are monitored carefully for air quality to make sure there are no accidents that can harm either humans or the pigs. Sometimes the gas produced can be collected and made into biogas, which can generate energy for the farm!

    So then what happens with the manure? About twice a year, these pits get pumped out into tanker trucks, and the manure is used as a fertilizer for farm fields. Manure can be tested for nutrients (along with the soil from the fields), and this can help make sure the farmer applies just the right amount of the manure to the field. Manure is most rich in nitrogen, but it is also rich in phosphorus, potassium, and other nutrients essential for plant growth.

    In modern manure pits, the waste is stored as a slurry, meaning it’s mostly liquid. This makes it easy to move, and easy to apply to the field. Today, many farmers will inject the manure into the ground instead of applying it to the surface. This is beneficial for multiple reasons. First, this means that the manure is less susceptible to the elements and is less likely to be washed away into a nearby stream. Secondly, by injecting the manure into the soil, it also helps to stabilize the nitrogen in the manure for longer. If the nitrogen was applied to the surface, it would be more susceptible to volatilization, meaning it can transform easily into a chemical form of nitrogen that isn’t available to plants.




    This whole system of dealing with the messy side of livestock is called manure management. It can also include innovative and interesting ways to keep the smell under control, like using windbreaks and even creating air biofilters out of things like woodchips.

    Though manure may be smelly, it plays a big role in Iowa agriculture. We grow crops to feed our livestock, and our livestock produce fertilizer for our crops. It’s an elegant system for an un-elegant topic, don’t you think?

    What other agriculture questions have you had? Let us know in the comments, and you might see another “Why do they do that?” blog about your question!


    6 Reasons Farmers Use Cover Crops

    There is a challenge that farmers are faced with every day of their career—how do we protect the land we work on? Farmers work with the land everyday of their lives and work to protect and restore the land for future generations. They understand how the land provides for them—after all, without taking care of the land they work they would not be able to grow a product, such as corn and soybeans, and be able to make a profit for their livelihood. One way farmers work to protect the land is through cover crops.

    What is a cover crop? This is a plant that is grown in fields to protect land quality for the future. There are many benefits of implementing the use of cover crops—and here are 6 reasons farmers use cover crops in their operation.sloans-cover-crop-in-corn-stubble

    1.)Soil Erosion: One thing I will always remember from my American History lesson of the Dust Bowl is that bare ground is not the answer. Open topsoil is something to avoid in farming practices. Wind and water can carry the soil away through erosion. My dad always said that we can’t rebuild the soil, and he’s right—it takes many years to produce organic matter that makes up Iowa’s rich topsoil. By planting cover crops we help stabilize the soil and protect the topsoil layer by not exposing it to erosion by wind and water.

    2.)Nutrient Management: Cover crops are a great way to add valuable nutrients back to the soil. Not only that but cover crops also add back organic matter to the soil as they decompose. In my agronomy class at Iowa State University, I am learning how certain types of legume plants have the ability to ‘fix’ nitrogen in the soil, such as hairy vetch and winter peas. Nitrogen is an essential element in plant growth. By adding in certain cover crops we are also adding in ways to produce nitrogen. Adding in nutrients is not the only benefit, but also balancing nutrients in the soil is a great perk of cover crops too. Adding in certain cover crops, such as non-legumes cover crops (radishes and rye), also have the ability to tie up the nutrients and prevent them from runoff or leaching. Which leads us into our next reason, water quality.

    3.)Water Quality: With nitrogen in the soil also comes nitrogen runoff—both which farmers work towards maintaining. Our water streams are easily exposed to nitrogen runoff and other pollution sources. Not only do some cover crops help produce nitrogen, but others like, radishes and rye, also work to lock in nutrients and keep them from producing runoff or leaching. If you think about it, cover crops work as an extra filter system on fields.

    4.)Biodiversity: Not only are farmers introducing a new plant onto these fields, they also introduce new interactions of all types of life. Cover crops bring in new habitats, they bring in beneficial or repelling insects, they attract wildlife, and provide protection against wind and water erosion. Creating an area of diverse species only boosts the circle of life and provides new opportunities to grow.

    5.)Weed Suppression: Competition is a real thing in the plant world and farmers use cover crops as a way to eliminate weeds from their fields. Roots of cover crops extend deep down into the soil to take up any nutrients or water available. While doing so they also ‘weed’ out other weeds (no pun intended) for those nutrients. Not only do cover crops compete with weeds below the soil surface, but they also compete above the surface for sunlight and space. The competition from cover crops is too stressful for the weeds to handle, making it easy for farmers to have complete weed control.

    6.)Green Pasture: Some farmers who also have cattle also have the option of grazing their cattle on the cover crop fields. Its just another way farmers can save feed costs. Cattle love to graze on certain forages, especially crops like clover, radish tops, and rye. Not only can the farmer feed his cattle, but he can also fertilize his fields in the process. The cattle’s manure makes a great source of fertilizer—so basically it’s a two for one deal here.screen-shot-2017-02-07-at-11-47-14-am

    There are many reasons why farmers use cover crops—each reason presents an opportunity to improve soil and land quality for the future. Now you may wonder why not all farmers use cover crops. Well even though there are benefits there are also challenges. Cost is a big challenge facing farmers and one of the key reasons that they do not use them. Although cost takes a toll in the present, the benefits can outweigh the costs for the future. For example adding in nutrients and managing weeds work to boost yields, not to mention protecting the topsoil works to help plant growth too. A farmer may be faced with many challenges each day, but they also know how they can work to make the best decision for their operation as well as for the land to be worked on in the future.

    -Hannah Pagel

    Fertilizing – Why do they do that?

    We all know that plants need nutrients to grow. But don’t they get those nutrients from the soil? Why do farmers need to apply fertilizer?

    You might hear Iowa farmers talking about ‘applying manure’ or ‘dragging anhydrous’. What they are really talking about is the application of fertilizers to fields with the hopes of increasing crop productivity. All plants need a variety of nutrients to grow and be healthy. A lack of any one nutrient might cause symptoms like yellow leaves or brown spots or other unhealthy symptoms like wilt or susceptibility to diseases like mold or insects.

    Plants need a whole host of nutrients to stay healthy. They need micronutrients like boron (B), carbon (C), chlorine (Cl), copper (Cu), hydrogen (H), iron (Fe), manganese (Mn), molybdenum (Mo), nickel (Ni), oxygen (O), and zinc (Zn). Recycling plant matter is an excellent way of providing micronutrients to growing plants. They also need secondary macronutrients like calcium (Ca), magnesium (Mg), and sulfur (S). But plants need the most of primary macronutrients which are N-P-K. These nutrients are usually lacking from the soil because plants use large amounts for their growth and survival. The three primary macronutrients are nitrogen (N), phosphorus (P), and potassium (K).

    26e53c8Nitrogen is part of all living cells and helps transfer energy in plant cells. It is part of chlorophyll which makes the plants green and allows them to produce food through photosynthesis. Nitrogen supports quick plant growth and maintains strong leaves and good fruit production. Nitrogen can be fixed from the air through the nitrogen cycle or it can be added to fields in the form of fertilizer.

    Phosphorus is also an essential part of photosynthesis. It helps the plants form oils, sugars and starches. Phosphorus aids in turning solar energy into chemical energy and helps the plant withstand stress.

    Potassium benefits plants in building protein and producing high quality fruit. It also helps plants be more resistant to diseases.

    Soil can hold some of these nutrients in place so that they are available to the plants when the plants are ready to use them. So often times farmers will apply manure (high in organic matter and nitrogen) or anhydrous (high in nitrogen). Because the soil can hold these nutrients, farmers can take advantage of slower seasons like the fall (after harvest) or spring (before planting) to apply fertilizer. But soil can’t hold an infinite amount of these nutrients. If there is too much nitrogen it can leach into waterways with a big rainstorm. Nitrogen in water can be a problem for wildlife and humans that rely on that water.

    27067Farmers try very hard to only apply the correct amount of fertilizer. Too little and the corn or soybeans won’t grow well. Too much and the nitrogen will be wasted and potentially run off into the watershed. Precision application can use soil testing data to apply fertilizer only to the parts of the field that need it.

    Anhydrous ammonia application in the fall should be done after the soil temperature is below 50 degrees Fahrenheit (usually around the first week of November). This prevents nitrogen losses from leaching. In the spring it is best to apply nitrogen within two weeks of planting the crops to avoid loss.

    Once the crop is growing it may need some additional fertilizer (nitrogen) to maximize growth and yield. Even legume crops like soybeans (that have nitrogen fixing bacteria) sometimes need some extra nitrogen to help them grow. In that case it is important to apply the fertilizer as close to the period of maximum crop growth as possible. This ensures that it is available for the plant and won’t leach into the waterways.

    Soil-water-conserv-weekApplying fertilizer takes a lot of scientific understanding of plant physiology, the nitrogen cycle, soil testing, and good management decisions. But with good management of fertilizer, crops can produce their maximum yield and we can still protect water quality here in Iowa. This is one small way that farmers celebrate Soil and Water Conservation Week – April 24 through May 1, 2016!


    Why do they do that? And why does it smell so bad?

    If you drove around Iowa at all this spring you may have noticed an aroma. And not a pleasant aroma. An odorous aroma. Why does it smell so bad?

    What you are smelling is possibly swine manure that has been spread out on fields. Luckily the smell is short lived and soon dissipates after farmers finish spreading the manure on their fields. But, why do they do that? What benefit is there from spreading manure on fields?

    2Plants need a series of nutrients to grow well and three of the most important nutrients that plants need are nitrogen, phosphorus and potassium or N-P-K. Manure is an excellent natural source of nitrogen. When spread on a field, it decomposes and acts as a fertilizer for the growing corn and soybean plants. These plants are able to put the nitrogen to good use. Using manure also saves farmers money. By using this natural form of fertilizer they don’t have to apply commercially produced nitrogen to their crops. Corn especially has positive increases in bushels per acre when manure is applied.

    A new slotted floor over an underground pit is being installed at a hog farm.

    A new slotted floor over an underground pit is being installed at a hog farm.

    So how does that swine manure get from the hog barn to the field? It all starts with a farmer developing a Manure Management Plan that works best for their operation. A good plan will take into consideration soil tests, crop rotations, manure collection, manure storage, and manure transportation. Many hog barns are now built with slotted floors that allow manure to fall through the floor to collection points underneath. Some barns might scrape the floors regularly to keep the barns clean and collect the manure. Outdoor swine lots are scraped every week or two to control odor and ensure rainfall runoff stays mostly free of manure.

    20080414ddm042Once collected, manure is transported to a storage facility until it can be spread on cropland. Some manure is handled as a solid and can be transported by front end loader to truck. But a lot of swine manure is handled as a liquid and once collected is mixed with water that can be pumped through pipes to the storage facility.  In liquid form it can also be more easily spread onto fields.

    Liquid manure from a hog feeding operation in northeast Iowa is being pumped onto cropland from a wagon.

    Liquid manure from a hog feeding operation in northeast Iowa is being pumped onto cropland from a wagon.

    Many new swine facilities manage manure in underground pits or in sealed watertight structures rather than open pits or lagoons. This enclosed system obviously helps reduce the smell, but it also helps retain the nutrients. Open systems can lose up to half or three-quarters of the nitrogen in the manure. Closed systems might only lose a quarter of the nitrogen value.

    Many farmers spread manure on fields in the spring. The manure has been collected throughout the winter. Spring application ensures that the nitrogen is readily available for those newly growing plants.

    Liquid manure can be injected directly into the ground.

    Liquid manure can be injected directly into the ground.

    Solid waste is put on fields with a manure spreader. A conveyor belt carries the manure to beaters which flail the manure onto the field trying to evenly distribute it. Liquid manure can be pumped into trucks of up to 10,000 gallons. These tank wagons can spray the manure onto the field or inject the slurry directly into the ground. Injection helps reduce the odor, but it can only be done when the soil is not frozen or too rocky. Ultimately the goal is to get the manure onto the fields in an efficient and effective way.

    So the next time you are driving around Iowa and crinkle your nose to the smell, think about the complex system that farmers manage to recycle manure and keep plants healthy with a great source of nitrogen.