Agricultural Literacy Curriculum Matrix

Students explore pecan production from farm to fork, simulate the process of grafting, and create a nutritious snack. Grades 3-5

acre-foot : a unit of volume of water in irrigation; the amount covering one acre to a depth of one-foot

cross-pollination: transfer of pollen from one plant to another

cultivate: to prepare (land or soil) for the growth of crops; to plant, tend, harvest, or improve (plants) by labor or skill

flood irrigation: a method of irrigation where a field is flooded to a predetermined depth

graft: a shoot or twig inserted into a slit on the trunk or stem of a living plant

husk: a dry outer covering of some fruit, seeds, or nuts

mechanical tree shaker: a device used to shake a fruit tree during harvest

pecan: a smooth pinkish-brown edible nut with an edible kernel that grows on trees in the southern United States and Central America

pecan harvester: a machine used to separate pecans from leaves, sticks, and other debris

pecan sweeper: a machine used to sweep pecans, leaves, and sticks into a windrow

pollination: the transfer of pollen from the anther to the stigma of a plant; the spreading of pollen by insects, birds, bats, and the wind between flowering plants

protein: an essential nutrient responsible for building tissue, cells, and muscle

rootstock: a root or part of a root to which an aboveground plant part is grafted

scion: a young shoot or twig of a plant, cut for grafting

self-pollination: the pollination of a flower by pollen from the same flower or from another flower on the same plant

windrow: a long line of material heaped up by the wind or by a machine

Pecan trees are native to North America, and their history can be traced back to the 16th century. These native trees were wild trees that grew along rivers, lakes, or any large source of water. Pecan is a Native American word from the Algonquin tribe meaning "nut requiring a stone to crack." Because pecans were close at hand, many tribes used wild pecans as a major food source. It is believed that the Native Americans were the first to cultivate pecan trees. Not only did the Native American tribes eat the pecans, they also used the wood to make bows and made oil by boiling pecan pieces in water and straining the mixture.

Through trade, pecans became very popular in the US and throughout the world. In the 1770s, pecans even made their way to George Washington and Thomas Jefferson, who both planted pecan tress on their plantations. The trees are still standing today! It wasn't until the late 1800s that farmers began cultivating pecans in orchards. 

Today, pecans are grown in 15 states in the southern United States including Alabama, Arkansas, Arizona, California, Florida, Georgia, Kansas, Louisiana, Missouri, Mississippi, North Carolina, New Mexico, Oklahoma, South Carolina, and Texas. Georgia, New Mexico, and Texas are the top pecan-producing states. The U.S. is the world's leading producer of pecans, producing about 80% of the world's pecan supply.¹

The pecan varieties with high-quality nuts often come from trees with weak roots. Varieties with strong roots have poor-quality nuts. To get high-quality nuts on strong roots, pecan farmers insert a scion from a high-quality nut variety into a strong rootstock variety. This procedure is called grafting. Once the graft heals, the grafted seedlings will be planted in an orchard.

It takes 7 years for the pecan trees to grow and start producing nuts. During those 7 years, farmers must continually water and take care of the trees. Pecan farmers must invest a lot of money before any money comes back to their farm. Once an orchard is established, farmers must keep them in good condition. Just like humans need nutrients and minerals to live, so do pecan trees. Farmers spray the trees to keep away bugs and disease. If the trees are lacking in any nutrients, farmers will spray those nutrients onto the leaves so the tree can absorb them at once.

Pecan trees require 4-5 acre-feet of water per year. An acre-foot of water is enough water to cover an acre of land (43,560 square feet or about the size of a football field) 1 foot (30.48 centimeters) deep. Farmers will put a couple of inches (about 5 centimeters) of water per acre each time they water. To get enough water to the trees, some farmers release water form ditches to flood the pecan orchards. This practice is called flood irrigation.

Pecan trees are wind-pollinated. Though they can self-pollinate (they have both male and female flowers on the same tree), pecan trees produce more nuts when they are cross-pollinated (having multiple trees close enough to pollinate each other). Pecan trees begin to pollinate in May and the nuts grow for 90 days.

There are two different methods used by farmers when harvesting pecans. Some farmers wait until the temperature drops below 32°F (0°C) to begin the harvest. The freeze opens the husks surrounding the pecan. Harvest usually begins in October or November and can last through January. Other farmers will start their harvest earlier, before all of the husks are open. This allows them to sell their pecans early and get a high price for the first harvest. They will then harvest a second time once all of the pecan husks are open. There are positives and negatives to both practices. Farmers that wait until all of the husks are open save on the cost of harvesting twice, but they get a lower price for their pecans. Farmers that begin harvesting early lose money by harvesting twice, but they get a higher price for their first harvest.

To harvest, farmers first use a mechanical tree shaker to shake the pecans out of the trees. They then use a pecan sweeper to sweep the pecans, leaves, and sticks into a windrow, a long line of material heaped into a row. Once the windrow is complete, a pecan harvester picks up the pecans while spitting out the leaves and sticks. The collected pecans are sent to a facility where they are cleaned, shelled, and packaged ready for you to eat!

Pecans are a natural high-quality source of protein. They contain 19 vitamins and minerals, no cholesterol, and are low in carbohydrates. There is scientific evidence to suggest that eating 1.5 ounces per day of most nuts, such as pecans, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease.² One ounce of pecans provides 10% of the recommended Daily Value for fiber and contains 196 calories.

1. Provide each student with a pecan (in shell), and ask them to open it.
2. After they try, explain that "pecan" comes from the Algonquin word which means "a nut that requires a stone to crack." Pass out a rock to each student, and ask them to use the rocks to open the pecans.
3. Using the Think-Pair-Share technique, ask the students the following questions:
   • Was it hard to crack the pecan shell without smashing it?
   • Are the tiny pecan pieces easy to eat?
   • How can the shell be cracked without breaking the nut?
4. Distribute a copy of the Pecan Value Math Activity handout to each student. After completing the activity, ask the students, "Why do you think the pecan halves are more expensive?"

Activity 1: Pecan Tree Grafting

1. Show the students the Grafting Pecans video.
2. Ask the students if they know what the farmer in the video was doing. Guide the students to understand that the farmer was grafting a pecan tree.
3. Pass out a copy of the From Orchard to Pecan Pie reading sheet to each student. Have the students perform a close reading of the text.
4. Ask the students why farmers graft pecan trees. (With pecan trees, the varieties with high-quality nuts often have weak roots. Varieties with strong roots have poor-quality nuts. To get high-quality nuts on strong roots, pecan farmers insert a scion—a young shoot or twig of a plant—from a high-quality nut variety into a strong rootstock—a living plant—variety.)
5. Explain to the students that they are going to practice the process of grafting using carrots to represent the scion and rootstock.
6. Give each student a 1" (2.54 cm) long carrot piece, a 2-3" (5.08-7.62 cm) long carrot stick, a plastic knife, a thumbtack, and the Grafting a Pecan Tree activity sheet.
7. Following the directions on the Grafting a Pecan Tree PowerPoint Slides, have the students practice the process of grafting.
8. Ask the students to draw and label their finished graft on the Grafting a Pecan Tree activity sheet.
   
   

Activity 2: Pecan Production

1. Give each student a United States Pecan Production Map. Allow them to visit the American Pecans website to gather the information needed to complete the map.
2. Organize the students into small groups. Refer them back to their copy of the From Orchard to Pecan Pie reading sheet from Activity 1. Ask the students to work together with their group to highlight all of the sentences that discuss the pecan production process.
3. Distribute one set of Pecan Production Sequencing Cards to each group. Instruct the groups to sequence the cards to show the steps it takes to get pecans from the orchard to their table in the correct order. Have the students check their work by comparing the order of the cards with the sentences they highlighted. 
4. View the Pecan How Does it Grow? video to show the students the process of growing and harvesting pecans.

Activity 3: Pecan Nutrition

1. Ask the students, "What types of things do you need to consider when choosing a healthy snack?" After hearing their responses, emphasize the importance of choosing snacks that are high in protein, low in sugar, and under 350 calories.
2. Pass out a copy of the This or That activity sheet to each student. Ask them to choose which snack is healthier by looking at the nutrition facts on the activity sheet, and then explain why they made that choice in the space provided. After the students have completed their writing, ask a few students to share. Reveal that choice one is pecans and choice 2 is a cupcake.
3. Ask the students to describe how pecans can be used in different foods (salads, pecan crusted chicken, sweets, and pecan oil). Explore the "Pecan Recipes" section of the I Love Pecans website to discover more ways pecans can be used.
4. Set up a trail mix station that includes measuring cups and spoons and bowls of pecans, pretzels, banana chips, raisins, Cheerios, and any other trail mix snacks. Provide each student with a snack-sized plastic bag and a copy of the Making Trail Mix! Recipe Sheet.
5. Have students measure out at least 4 snacks (1 must be pecans), and mix them together in the plastic bag. Then, have them record the recipe on their recipe sheet.

1. https://uspecans.org/how-pecans-are-grown/
2. https://ilovepecans.org/nutrition-in-a-nutshell/ 
3. http://www.georgia.org/2015/04/14/the-top-5-things-you-didnt-know-about-pecans/
4. https://uspecans.org/pecan-sizing-chart/

• Burn a Peanut- Count Calories
• My Grandpa, My Tree, and Me
• NMSU Field Trip! Video Series
• Nell Plants a Tree
• Nuts Flowchart
• Producepedia