To my way of thinking, sustainability is an individual and personal ethic that informs, guides, and inspires actions in daily, personal, and professional life. Practicing the tenets of sustainability is motivated by an individual’s acceptance of a responsibility to, quite simply, make decisions that leave our world better able to meet present and future needs (economic, environmental, and social) of individuals and society.
As a wildlife biologist and ecologist I have spent most of my career thinking about and advocating conservation and stewardship of animals and the habitat on which they depend for life. While in the early years, most of my attention was directed toward those species that are rare or threatened with extinction, about 25 years ago, my focus shifted to promote conservation of wildlife and habitat where people live, work, and play. Instead of focusing on specific species, I transitioned to the belief that the key strategy was to encourage conservation and stewardship of wildlife and habitat in general and that the location should determine what species should be the primary focus. Biological diversity is critically important to our future and it is an indicator of our success and failures in regard to environmental stewardship efforts.
Over the past few years I have yet again shifted to believe what is really needed is a major focus on advocating sustainable landscapes. In addition I have come to realize that the foundation upon which we should build sustainable landscapes is connected with healthy and biologically productive soils. Soils are the most biologically diverse habitat on Earth, yet most of us hardly consider the value of soils, and we literally are flushing this valuable resource down our storm drains, down our river systems, and into our oceans. In addition, much of our landscape management efforts are reducing the biological diversity of the soil and destroying many aspects of the soil, upon which a sustainable landscape should be built.
There are many scales of landscapes. On a big scale, we can talk about the landscape of an entire country and on a personal scale we can talk about the landscape of a residential home. But, no matter what the scale, it begins with the soil.
A sustainable landscape is a planned and managed system of green spaces, greenways, recreational lands, parks in combination with natural lands that offer benefits of water conservation, filtration, and absorption as well as air particle removal and heat relief. Sustainable landscapes also contribute to the health and quality of life to people, communities, and entire countries. To achieve those benefits, many communities (and businesses) are, and all should be, using management of natural resources to enhance water quality, abate flooding, lower heat in urban centers, lessen the impacts of climate change and build more resilient communities.
The Importance of Organic Matter in Healthy Soil
Soil is, literally and figuratively, the beginning of a great landscape. Plants take in much of what they need, in terms of oxygen, minerals, water, and food, from the soil. Open any horticultural or agricultural textbook and you will see advice along the lines of, “if a plant is having problems, check the soil and roots first.” If a tree is ailing, the first place to look is not the leaves, but around the trunk and the soil. (The main reason to look at the trunk at all is to see if movement of water and food from the roots to the top of the tree has been disrupted by a girdling of the tree.) For those interested in keeping an organic garden, rich, nutrient-dense soil with high organic matter content is a must. Without good soil, landscapes will be fraught with problems above-ground, which would not be a problem if the soil was healthier.
What Is Organic Matter?
To understand why organic matter is so important for soil, first we need to understand what it is. Chemically speaking, the term “organic” refers to molecules with carbon in them. The benefit of organic matter does happen down at the smallest level-atom exchange. Humus is organic matter that has been completely broken down and can exchange nutrient molecules. Shredded leaves, mulch, and grass clippings are examples of organic matter that has not been broken down. Fully “digested,” “composted,” or “broken down” materials are in a form that can be transported through the soil to plants. It is more accurate to use the term “transported” than “eaten” or “consumed.” The movement of molecules from the soil and the plant cell wall is a chemical reaction based on charges (positive or negative) of the molecules and the plant cell. Without going into really boring botany-class mode, it is pretty interesting how plant roots work at the cellular level to take in water, oxygen, nutrients, and minerals that plants need.
Organic Matter Is Not Just Good for Plants
Organic matter is necessary for plants to have the nutrients they need, and it is from organic matter that plants get their nutrients. Organic matter does so much more, though. It provides food for micro-organisms and macro organisms that live symbiotically with plants. Those organisms break down larger bits of organic matter into molecules small enough for plants to take in. Organic matter improves soil structure. The myth that healthy soil is completely uniform in consistency is just that – a myth. Water and oxygen fills the spaces between soil particles. If the soil is ground to a very fine dust, it is prone to erosion problems, in addition to problems with drainage and oxygenation. Organic matter helps regulate temperature. It also holds water and improves drainage at the same time-something that is almost impossible to replicate with any synthetically produced material.
Ways to Add Organic Matter to the Soil
Organic matter does affect soil differently depending upon the state of decomposition of the compost. Fresh organic matter will be decomposed by soil organisms. During that process, nitrogen can be tied up. If we apply un-composted organic matter to the soil, we may need to add nitrogen. A good organic form of nitrogen is humic acid. Because the organisms that break down organic matter work based on the temperature of the soil, compost breaks down faster during warm weather and slower during cold weather. (This is different than hot and cold composting.) This is why some people spread a layer of shredded leaves or organic mulch in the fall and allow it to slowly decompose during the winter. During the spring they turn over the soil and add the broken down organic matter into the soil. The deeper into the soil the organic matter goes, the more water-holding capacity and drought resistance the soil will have.
There is one instance in which you should not add organic matter into the soil. If you are planting a new tree, you should not add the compost into the hole, as that has been determined to discourage root growth beyond the original planting hole. It is better to top-dress the tree planting, using compost as a kind of mulch, rather than a soil amendment. Additionally, never till in the compost – that essentially defeats the purpose of improving the soil structure. Organisms in the soil will digest the organic matter and disperse it throughout the soil naturally.
What Do Sustainable Landscapes Do?
Counter Pollution: Investing in sustainable landscapes allows nature to restore naturally functioning ecosystems impaired by development, erosion, and storm events. These systems keep pollution under control through natural filters that trap sediments, toxins, and excess nutrients resulting in cleaner air and water. Restoring natural systems saves money on controlling water quality.
Increase Community Resiliency: Conserving valuable wetlands, riparian zones, community trees, and forests helps address climatic changes and improves resiliency during floods and storm events. A loss of natural spaces increases the risk of natural disaster damages that may cost millions of dollars to recover.
Save Energy: Protecting green spaces permits nature to help remove pollutants before they get to a treatment plant. Landscaping elements provide relief from heat island effects in densely populated areas. Trees located near residential buildings also insulate and shade homes, lowering energy bills.
Encourage Exercise and Activity: The construction of parks, trails, and other green spaces encourages people to spend more time outside and exercising. Families spend more time actively playing with children where there is a safe public park or playground nearby.
Create Safer Communities: Sustainable landscape infrastructure creates community cohesion by assisting people to feel a local sense of place and encourages friendliness with neighbors. This results in more community trust and lower crime in an area. Studies have also linked green spaces to improved concentration skills and stress relief.
Improve Land and Property Values: A sustainably landscaped area attracts buyers and retains current homeowners in our communities. Property values increase when there is landscaping and tree coverage and energy savings from shade and insulation attract new residents.
What Should Be Done?
No matter the size of the landscape being managed, a soil management program should be developed and implemented. The first step in that effort is to conduct soil tests to determine the present soil quality and health. With that basic information, a planting program needs to be developed that focuses on choosing the correct vegetation for the region in which the landscape is located. Then, it is important to plan and design the landscape in such a manner that it will be as easy to care for as possible. This includes making sure that the vegetation is easy to “get to” when management activities need to take place and making certain that irrigation can take place in ways that minimize water needs, but maximize the efficient use of water when it is needed.
A critical step is the development of a nutrient management program that is based on what the soil actually needs in order to result in healthy and biologically diverse soils, a program that builds organic matter and results in healthy, drought-resistant vegetation. This step is best accomplished through the use of fertigation systems that apply “micro-doses” of only those materials that are needed, such as organics and other life supporting materials, right through the irrigation system. Thus, liquid nutrients, in micro-dose amounts applied on an as needed basis are the preferred approaches.
A sustainably managed landscape saves money and resources, but it also increases property values, improves the quality of the environment and has been shown to improve the quality of life for people. This is truly a win-win-win…which is the basis of sustainability.
Yes, sustainability is a complex subject. So complex, in fact that many people decide that it is beyond their means to become involved. But, nearly everyone has a landscape and focusing on a sustainable landscape is the best place to start the journey toward a more sustainable future.
About the Author
Ronald G. Dodson is Chairman of the International Sustainability Council (ISC) and also Founder and President of Audubon International. Through Audubon International, Dodson created the Audubon Cooperative Sanctuary and Signature Programs, which are aimed at enhancing biological diversity, where people live, work and recreate. His latest ISC effort is called Sustainable Landscapes International and is aimed at advocating sustainable landscapes around the globe. Dodson can be reached at firstname.lastname@example.org.