SSL: Habitats: Mulching *Smith Center Only*
Available: Year-round Time Required: >90 minutes for full lesson; >45 minutes for action only
Next Generation Science Standards Disciplinary Core Ideas LS2.C Ecosystem Dynamics, Functioning, and Resilience Ecosystems are dynamic in nature; their characteristics can vary over time. Disruptions to any physical or biological component of an ecosystem can lead to shifts in all its populations. Crosscutting Concepts Stability and Change Small changes in one part of a system might cause large changes in another part. Environmental Literacy 1. Environmental Issues. The students will develop and implement a local action project that protects, sustains, or enhances the natural environment.
Enduring Understandings: Natural resources are used by living things in a variety of ways. Natural resources need protection and conservation in a given environment. As resources are used in a habitat, the environment is changed. Human resource use can cause changes that have social, economic, and environmental impacts.
Mastery Objectives: Students will be able to: Define erosion and identify effects of erosion on local streams, rivers, and the Chesapeake Bay. Learn how to effectively apply mulch and explain environmental benefits of mulching. Identify the importance of a healthy habitat for native wildlife.
Background (Adapted from http://www.doityourself.com/stry/why-mulch-6-benefits-of-mulching): Mulching is the act of placing a protective barrier (mulch) around your plants and over your bare soil. This protective barrier can be made up of a variety of organic materials including bark or wood chips (from various tree species), pine needles, straw, and even cocoa bean shells.
The environmental benefits include: Weed Control: Through the use of mulch you can limit the amount of weeds that tend to spring up in the open spaces of your garden, because the mulch acts as a barrier, limiting the amount of sunlight that can find its way to the weeds. Retain Moisture: Retaining moisture, especially during hot, dry seasons can not only help out your plants, but it can also help out your water bill. Erosion Prevention: Mulching not only keeps existing water trapped in the soil but it also keeps rain water from washing away your soil. It does this by breaking the fall of the water and therefore lessening the force when the water impacts the ground. Maintains Soil Nutrients: Not only does mulch keep soil nutrients from being washed away with the rain, but it also can release nutrients into the soil if you are using an organic material. This happens as the organic material slowly decomposes on top of the soil. Encourage Earthworms to Move It: Using organic material for mulching can encourage earthworms to occupy your garden soil. And as any good gardener will tell you, earthworms help improve soil structure and nutrient cycling. Although all of the environmental benefits of mulching are important, we have a particular interest in erosion prevention because of our instructional emphasis on watershed protection. Erosion is the process of wind, water, or other natural agents gradually wearing away soil, rock, or land. Mulching can reduce the amount of soil that is eroded by rain, which reduces the runoff sediment in local waterways. Erosion has several harmful effects on water quality: Excess sediment increases turbidity, which reduces sunlight and therefore lowers ability of aquatic vegetation to photosynthesize Excess sediment suffocates fish eggs and benthic macroinvertebrates and clogs gills of fish Excess sediment increases water temperature which decreases dissolved oxygen levels Pesticides, metals, toxins, oil, and grease can cling to sediment and erode into the waterway Phosphate can wash into the water and cause algal blooms, which cause severe decreases in dissolved oxygen
Project Prep 1. Meet with your coordinator ahead of time to become familiar both with the areas that need mulch, and the areas that the piles of mulch are located. 2. For full lesson: a presentation on the Promethean board is available. 3. Gather equipment: a. Carts for transporting the mulch: located near greenhouse b. Shovels and pitchforks for moving mulch from pile to cart: located in locked cage next to greenhouse c. Rakes for spreading mulch on location: located in locked cage next to greenhouse d. Gloves if students are spreading mulch with their hands
Project Details 1. Preparation/Explain (~20% of time) a. Full Lesson a.i. Share presentation with students b. Action Only b.i. Engage students: What is erosion? How can erosion affect water quality? b.ii. Discuss background information and benefits of mulching. 2. Action (~65% of time) a. Full Lesson & Action Only a.i. Divide the students into groups of no more than 5 and assign each group a specific area to mulch. Each group should have one cart, and one tool per student (about half should have rakes to spread the mulch, and half should have pitchforks or shovels to pile mulch into cart). a.ii. Congregate at the pile of mulch closest to your desired mulching area. Review safety information and demonstrate proper tool use. a.iii. Take the spreading students to the mulching area. They can start by weeding and preparing the area until the mulch arrives. a.iv. When the mulch arrives the students can dump it into a pile in the center of the area and the students with gloves or rakes should spread it. a.v. Spread the mulch about 3-4 inches thick. The more mulch the better! a.vi. Mulch one smaller area completely with no holes, bare spots, or gaps, before moving on to another area. a.vii. If mulching in a garden weed and rake the area first. a.viii. If mulching around trees be sure to create a donut shape around the tree – not a volcano – and don’t go too high up the tree. v. Return equipment at the end of the session!!! Account for all equipment and return to the proper location.
3. Reflection (~15% of time) a. Full Lesson a.i. Have students brainstorm and then share with class their answers to reflection questions in presentation a.ii. Record in their journals if applicable b. Action Only b.i. Have students share their answers to following questions: b.i.1. What did you do and how did it benefit the environment? b.i.2. How will you share what you learned and continue your action with your family, community, and school? b.ii. Encourage them to record in their journals if applicable