One way to introduce agriculture to preschoolers is by bringing it to school. Grow a vegetable or herb garden together. A variety of resources are available for soil testing and preparation, choosing plants and upkeep. Check websites for university agricultural extensions or government websites. Schedule gardening several times a week into your lesson plan so the plants stay healthy. Discuss with students how different plants grow, depending on what you're cultivating, and how they help the ecosystem around them -- by attracting butterflies, for instance.
Help your students make a connection between what they eat and agriculture. Incorporate this into daily snack and lunch, discussing what each item on the plate is and where it came from. If available, give students two healthy items to choose from. For example, at snack time allow kids to choose from carrots or sugar snap peas. This encourages them to take their nutrition into their own hands. Have a weekly cooking activity where students choose from a selection of healthy meals ahead of time and prepare it together in the classroom. Use items from your vegetable garden, if available.
Visit the farmers market or so your preschoolers can meet the people who work in agriculture and discover new foods. Talk to kids about what a farmers market is and how some of the fruits and vegetables are a bit different than what they see at the grocery store, (organically or locally grown). Discuss how to shop for quality, ripe items. A yummy peach, for instance, is just a bit soft and has a bright color. Have each student pick out a fruit or veggie.
While hands-on activities give preschoolers a chance to actually experience agriculture, supplementing these ideas with in-class projects also helps. Have them draw a garden, color a worksheet with different farm animals or make a picture book about their gardening, cooking or market experiences. Read a story that correlates to the agricultural activity that day or week, or have an agriculture professional talk to the kids about what she does.