Grain Moisture Content

Grain Moisture Content

Target Grade Level / Age Range:

9-12

Time:

45 minutes

Purpose:

To help students understand the complexity of science and technology in agriculture using grain moisture content and grain marketing as an example.

Materials:

  • Grain moisture tester
    • Necessary batteries or electric outlets
    • A local cooperative may have one available to borrow
  • 5-10 cups low moisture corn
  • 10-20 cups higher moisture corn
    • Separate into two tubs with about the same amount of corn in each. In one tub, add water to both tubs, with more water in one of the tubs. Let sit for about one day.
    • After one day, drain of excess water, and lay the corn out on cookie sheets or paper towels to air dry. They will retain moisture and still be damp. Let sit for about one day.

Suggested Companion Resources (books and websites)

Vocabulary (with definitions)

  • Grain: a cultivated cereal crop used as food
  • Moisture content: the ratio of the mass of water in a sample to the mass of solids in the sample, expressed as a percentage
  • Grain bin: a large metal structure used to store grains like corn and soybeans
  • Grain dryer: usually an add-on to a grain bin, the grain dryer uses heat and/or fans to remove moisture from grains
  • Cooperative: this is where producers go to buy, sell, or store grain. Also called co-ops or grain elevators, they may also offer other services, such as crop scouting, fertilizer application, chemical applications, and others
  • Inputs: the additional cost of materials and time associated with helping crops grow better. Included but not limited to fertilizers, insecticide, herbicide, and fungicide.
  • Marketing: the action of business of promoting and selling products or services, including market research and advertising
  • Dock: to deduct, especially an amount of money

Background – Agricultural Connections (what would a teacher need to know to be able to teach this content)

The purpose of this activity is to display the use of science, technology, engineering, and math in agriculture. This activity can touch on each of these components if discussed thoroughly. Students will test the moisture content of grains and will use their findings to come to a conclusion. To do this, they will use a piece of modern technology. When making their decisions regarding their grain sample, they will see the math involved in making their decisions (price per bushel, volumes of grain, etc.). They will also understand that moisture content is only one piece of the data that farmers collect, and for each piece of data, there is a piece of technology that was engineered to meet that specific need.

The goal is to give students a scenario about the moisture content of their grain, and have them come up with their own market plan. Attached is a scenario-based activity to use if a grain moisture tester is not available to use.

This lesson talks specifically about corn. Corn, like other annual crops, is planted in the spring and harvested in the fall. In between, farmers manage their fields by applying fertilizers, herbicides, pesticides, and/or fungicides. These things, and other related costs, are collectively referred to as “inputs.” Corn is harvested using a combine starting from October and generally continues into November. The decision making around corn harvest and corn marketing are important aspects in this lesson.

The main factor discussed in this lesson is grain moisture. In order for the corn to store properly, its moisture content should be between 10 and 15%. Farmers will pay attention to this percentage before and during harvest. The longer the corn is left in the field, the more it will dry out. However, if rain is coming or if the plants have been out for too long, the moisture content could be affected or the ears may drop from the stalk. Therefore, choosing a time to harvest can be a bit of a gamble or a mad dash to finish while conditions are still optimal.

The lesson does call for a grain moisture tester. IALF’s Lending Library houses one small grain moisture analyzer. While the machine is simple to use, it would be a good idea to test it prior to the event to ensure it is working properly and that volunteers are able to help students during the event. A machine like this one probably wouldn’t be used by a farmer to test the grain after they’ve already harvested it, but would more likely be used to help the farmer decide if it’s time to start harvesting. Inside the combine many times, there are multiple screens, tablets, or iPads, all tracking various data points including steering the combine, the yield in real time, and the grain moisture content. These data points can be translated into digital maps that can help the farmer analyze wet or low-yielding areas of the field and make better management decisions next season.

In the lesson, three options are given for what to do with the grain after it is harvested. While this is not a comprehensive list, it can help illustrate a few of the factors at play. The three options given are to store the grain, dry the grain, or sell the grain. Some other options real farmers may have are to keep the grain to feed to their own livestock or sell directly to an ethanol plant or other specialty facility. Some of the complexities and options were left out of the lesson itself to help make the activity more straightforward.

Storing grain can happen in two slightly different ways. One way is for the farmer to bring the grain to a cooperative and pay a per diem fee for using their space. The other way is for a farmer to build their own grain bin. This can be a lot of capital up front, but could pay off for them over the years, as they could avoid the per diem fees of a cooperative, but could also benefit from higher market prices a few months after harvest is complete and supply has lowered.

Modern grain drying systems happen in the same kinds of grain bins that would be used to store the grain. The biggest difference is that there would be extra cost with purchasing the drying equipment, as well as running the drying equipment. This could be added to a private person’s grain bin, or could be a part of a cooperative’s storage facilities and services. If this was a part of a farmer’s personal equipment, they would need to pay increased energy costs to run it. If this was a part of a cooperative’s services, there would be increased costs for the energy they would be utilizing.

Selling the grain may seem like the simplest choice, but cooperatives will dock prices if the moisture content is above the 15% specified. We also know that when the supply is high in the fall due to harvest, the prices are also lower. While this still may be the best choice for some farmers that do not want to pay for their own storage facilities or per diem storage costs, it can be another factor when farmers are marketing their grain.

In real life, a farmer would have more information about cost, market prices, and breakeven price than students will receive in this lesson. The important part of this lesson isn’t necessarily that they crunch the numbers to find the clear best answer, but more so that they use the evidence that they do have to argue for what seems like the most reasonable choice in their mind. The amount and variety of input costs, differences in local markets and services, and the spread of equipment available could provide an overwhelming amount of data for students.

This lesson can also provide many good examples of agricultural careers, including agronomists, computer scientists, agricultural economists, agricultural business, agricultural sales, agricultural communications, agricultural engineering, and many others.

Interest Approach or Motivator

Ask students what they know about marketing. What is marketing? Have they ever thought about how corn is marketed?

Procedures

Classroom activity:

  1. Start class by refreshing students on the life cycle of a field corn plant in Iowa.
    1. Seeds are planted in the spring and grain is harvested in the fall. The field may also be fertilized; sprayed for weeds, bugs, or fungi; or tilled.
  2. Spend some time talking specifically about the harvest of corn. How is corn harvested? When is it harvested? What factors might influence when it should be harvested?
    1. Corn is harvested with a combine sometime in mid to late fall. There are many factors to take into consideration, including time, maturity, and grain moisture content.
  3. Now, talk some about what are some purposes of corn. How is corn bought and sold? Who purchases corn?
    1. Lots of corn is used as feed for livestock. In Iowa, this is lots of pigs, chickens, and cattle. Corn is also used in ethanol production, as well as in the production of food for humans (not the same as sweet corn, but corn flour, corn starch, corn oil, etc.), and other products like corn fiber, corn plastic, and vitamins.
    2. Since corn is harvested in the fall, lots of corn is sold to cooperatives in the fall. This means supply is high and demand might be lower, causing prices to be low at this time. If a farmer can store their grain, they may be able to get a higher price a few months later when supply is lower.
  4. Take this time to talk about why moisture content might matter. Talk about grain quality. If the grain is too wet, it can get moldy. Would livestock like to eat moldy grain? Would we want to make corn flour from moldy grain? No, we wouldn’t.
  5. Next, talk about ways that farmers and agriculturalists ensure that their grain is dry.
    1. Grain will dry the longer it matures in a field. But, if the farmer waits too long to harvest the grain, the ear can fall off the stalk.
    2. A Farmer might use a small grain moisture tester before they begin harvesting to help them decide if it is a good time to start harvesting.
    3. Other factors like timing and inclement weather can also impact when a farmer can harvest.
    4. If the grain is harvested before it is dry enough, it can be dried using a grain bin with a drying system. However, there is cost associated with this, because it takes energy to run the drying system, as well to purchase the equipment or to hire it done at a local cooperative.
  6. If a grain moisture tester is available:
    1. Explain to students that they will be testing the moisture content of different samples as if they were the farmer harvesting this grain. They will have three options for what to do with the grain, and will choose an option based on what the moisture content of the corn is.
    2. Tell students that the goal for the moisture content is in between 10 and 15% moisture. Their three options will be to store the grain, to dry the grain, or to sell the grain. (Display Grain Moisture – what next.docx document for students to reference.)
      1. In order to store the grain, the farmer may need to purchase their own grain bin, or pay a per diem cost to use a local grain storage facility. But, the price on grain might increase in the future.
      2. In order to dry the grain, a cost would be associated to use the energy necessary to dry the grain. But, if the grain is dried to the correct moisture content, it can fetch full price at the market.
      3. If the grain is higher than 15% moisture, the cooperative will dock the price on the grain, since they will need to dry it. Also, we know that prices tend to be lower during harvest time than they might be in a few months.
    3. Have one or two students volunteer to test one of the samples of corn with the machine. While they work, ask questions to the class like what do they think the moisture will be? What would they ideally want the moisture to be?
      1. Also use this time to point out modern field mapping technologies using the photos document. Point out that modern combines have the ability to test grain moisture as the grain is being harvested, and use that data to create a map. Agriculture is full of technology, and farmers and agronomists collect a plethora of data about their field and their crops to help them make the best and most efficient decisions possible.
    4. When the moisture tester gives the percentage moisture, announce it to the class, and ask how they would proceed if they were the farmer harvesting this percentage moisture grain.
      1. The important part of this portion of the activity is to make sure students can rationalize their decision. Often, there isn’t a black or white answer, but as long as they use the information given to rationalize their outcome, they can be active in the conversation. The only situation where an answer would truly be wrong, is if the grain is above 15% moisture and a student would suggest storing the grain. This could damage the grain and could make it essentially worthless.
    5. If time allows, test the other samples and talk through those scenarios. How do they differ, or how do the students analyze them differently? Would your decisions be different if you knew you already owned a grain bin? Would your decisions be different if you were a young farmer, or a farmer about to retire? What about if you knew your input costs and the current market prices? Next month’s market prices?
      1. Some other questions include: If one acre of corn yields roughly 200 bushels of corn, and each bushel of corn is worth roughly $3.00, how much can the average farmer make from 300 acres of corn? If input costs are included, can the farmer afford to take the price dock at the co-op for wet grain? Can they afford to build the grain bin? Can they afford to try to wait for a better grain price? Would monitoring fertilizer, insecticide and herbicide inputs using technology help reduce waste and maximize profit? By bringing up some of these questions while they walk through their decision, students can start to understand the complexity of ag business and how science and technology can help farmers make the best decisions possible.
      2. Farmers take these things into consideration. There is often not a clear answer, but they should take all of the data they have and make the best educated decisions they can in order to market their grain effectively.
  7. If a grain moisture tester is not available:
    1. Explain to students that they will be thinking through scenarios as if they were a farmer harvesting their grain. They will have three options for what to do with the grain, and will choose an option based on what the moisture content of the corn is.
    2. Tell students that the goal for the moisture content is in between 10 and 15% moisture. Their three options will be to store the grain, to dry the grain, or to sell the grain. (Display Grain Moisture – what next.docx document for students to reference, or give each student a copy of their own.)
      1. In order to store the grain, the farmer may need to purchase their own grain bin, or pay a per diem cost to use a local grain storage facility. But, the price on grain might increase in the future.
      2. In order to dry the grain, a cost would be associated to use the energy necessary to dry the grain. But, if the grain is dried to the correct moisture content, it can fetch full price at the market.
      3. If the grain is higher than 15% moisture, the cooperative will dock the price on the grain, since they will need to dry it. Also, we know that prices tend to be lower during harvest time than they might be in a few months.
    3. Hand out the Grain Market Plan worksheet. Give students about 10 minutes to work on their own.
    4. When students have finished working, walk through each scenario as a class. Use the worksheet key as a discussion guide.
      1. Ask students how they came to their conclusions. What factors did they pay attention to? What things were important to them? What things did they ignore? Why?

Follow up the lesson by talking about the complexity of growing, harvesting, and marketing grain. Mention the technologies present in field mapping systems, combines, storage facilities, and drying equipment. Talk about farmers and agronomists that collect data from all kinds of sources and use that to make the best decisions they can. Also, talk about economists and agriculture businessmen and women who work in buying and selling the grain.

Essential Files (maps, charts, pictures, or documents)

Did you know? (Ag facts)

  • Iowa produces more corn than any other state.

Extension Activities (how students can carry this beyond the classroom)

  • Have students research the market prices for corn and soybeans in the past year. Where did the prices peak? Where did they fall? Is that consistent to the supply and demand talked about with harvest in the fall, or were there potentially more factors at play?
  • Have students research the grain moisture requirements for soybeans. How do they compare to corn? What might be some different factors to consider with this crop?

Author(s)

Chrissy Rhodes

Organization Affiliation

Iowa Agriculture Literacy Foundation

Agriculture Literacy Outcomes

  • T4.9-12.f: Predict the types of careers and skills agricultural scientists will need in the future to support agricultural production and meet the needs of a growing population
  • T5.9-12.d. Describe essential agricultural careers related to production, consumption, and regulation

 

Education Content Standards

  • 21st Century Skills:
    • 21.9-12.FL.5:Assess the value, features, and planning processes associated with savings, investing, and asset building, and apply this knowledge to achieve long-term financial security with personal and entrepreneurial goals in a global market
    • 21.9-12.TL.3: Apply digital tools to gather, evaluate, and use information
    • 21.9-12.TL.4: Demonstrate critical thinking skills using appropriate tools and resources to plan and conduct research, manage projects, solve problems, and make informed decisions
  • Social Studies:
    • SS-Econ.9-12.13: Apply the concept of scarcity when making economic decisions
    • SS-Econ.9-12.14: Use cost-benefit analysis to argue for or against an economic decision