Soil and Plants Need Each Other

streamline and turbulent wind around different windbreaks

It is common knowledge that plants need soil. However, not often enough is it asked; does soil actually need plants? The relationship between plants and soil is more mutually beneficial than most would think. Soil is the uppermost layer of the earth in which plants grow. It is a composite of rock particles, organic materials and microorganisms. Within the soil there is an entire complex ecosystem of microorganisms, insects, and burrowing critters—their activity is as vital to soil composition as are the nonliving (abiotic) components of soil. 


Floods spread water over a floodplain once soil becomes too saturated to hold additional water. Flood water moves across the earth and erodes soil as it washes over a landscape. Wind, which is also a fluid force of nature, can contribute to soil erosion as well. This is especially the case in certain narrowed areas of the landscape where wind funnels through a “corridor” – this increases wind velocity by reducing air pressure, a phenomenon explained by the Venturi effect. Some erosion is simply a natural process, but as with many things in nature, there must be a balance. Too much

Turbulent eddys form around obstacles

erosion leads to arid soils deprived of organic materials and incapable of supporting life. A cover-crop grown over an underutilized agriculture field can significantly preserve the soil's quality in the area and protect it from abrasive forces. Windbreaks which perpendicularly intercept prevailing winds in an open space also help protect soil, by decreasing wind velocity. These windbreaks can be trees, or even shrubby herbaceous plantings. Windbreaks created by trees in a field can be a critical way for increasing soil health by protecting surface soil from powerful windflows across a wide-open space. Adding vegetation can also protect soil from erosion caused by floods by giving the soil something to “grab” onto as floodwaters sweep an area. Some types of trees can also help decrease a local water table by taking-up water; consider that just one large tree can lift up an average of 100 gallons of water out of the ground.

We are seeing the effects of desertification driven by drought and decreased vegetation coverage in many areas of the world. Adding trees to a space is just one way to increase soil health and combat this ecological threat (a few arboreal-lacking biomes are exceptions). Without vegetation, soil “dies” and without soil, the vegetation dies--once their relationship is disrupted it creates a dangerous negative feedback loop. The maintenance of healthy soil is essential to supporting a functional ecosystem and is also extraordinarily important for food security, as well as preventing species extinction of plants and the animals that rely on those plants. These and other considerations should lead to the realization that soil health is vital for our own survival and we should approach landscape design and land-use planning with that in mind.


By Molly Burhans

catholicgeo.org

Sources:
[photo quote] Pope Francis I. “Laudato Si’ - Encyclical Letter, On Care for Our Common Home, Pope Franci I.” Vatican: the Holy See. Vatican Website. Libreria Editrice Vaticana, 2015. Web. July. 2015.

This whole post is influenced by the work of Richard T. T. Forman.

A nutrient rich upper-layer of of soil, or organic layer, mingles with mineral rich parent material from the lowest layer of soil. In this image it combines and coalesces overtime to form this fascinating stagnogley soil. Stagnogley soils are loamy or clayey soil with a relatively impervious subsurface horizon. The colors can indicate the aerobic conditions of soil with some iron content--this soil was likely very moist/waterlogged for extended amounts of time.

Perspective -- Laudato Si' and Landscape Planning and Design: Great Hopes for Global Environmental Change

Baby Cardinal in Hand. Credit: Public Domain

Laudato Si’ is a call from the Catholic Church for all citizens of the earth to care for all of God’s creation. It is a landmark piece of ecclesiastic writing. This encyclical is sobering, full of truth about the problems of human-driven climate change, and it is also incredibly hopeful. To put the hopefulness in perspective; Laudato Si’ made addressing human-driven climate change a moral imperative for the 1.2 billion Catholics in this world—and they are doing things. Catholics are building rain gardens, fasting and praying rosaries for climate change action, and planting trees alongside ideas for a brighter, more sustainable future for the planet. Some Catholics are taking the Pope’s message more seriously than any of the previous calls to climate action - and when that “some” is a subset of 1.2 billion people throughout the world, the potential impact is huge. I find even more hope in realizing that it is entirely possible that Catholic-affiliated properties comprise the world’s largest non-governmental network of landholdings. Managing just a fraction of this land in an environmentally could have a global impact on the direction of climate change.

Leading up to the release of this encyclical, I found myself inspired to deepen the relationship between my faith and my education at Conway. Since its release, I have come to grasp in a very profound way how ecological design truly is a form of charity—it constantly gives to the communities that encounter and embrace it, as well as the ecosystems it lies within. The landscape is a place where the known and the unknowable can couple together to produce great designs. Landscape planning and design are co-creative acts because they inherently involve many elements beyond the designer’s control.  The verdant areas of academic explorations between faith and design illuminate questions about co-creative spaces of the landscape designer and how the controllable and uncontrollable work into the choreography of plans and designs across a dynamic landscape. Serious academic discussions about the spatial elements of virtuous acts and how spiritual paradigms intersect with design practices and theory provide fertile ground for future explorations. I am glad that Laudato Si' has helped till the soil for more of these discussions.

 

This Pope hears the cry of the poor and vulnerable in the face of human-driven climate change. I heard this cry in the Sahel of Mali, in West Africa, while working on agriculture and water infrastructure planning. It’s the cry that “if there is no rain, we die,” as well as a cry that braces for yet another devastating typhoon. It’s the cry of the victims of violence caused by climate-escalated conflicts related to unjust resource distribution. While climate change may be the most difficult struggle of our times, the potential positive impacts of the Catholic Church with its massive landholdings, large population, and organized structures rallying behind the cause of climate change action is a source of incredible hope. Part of that hope for me is that the world will continue to move toward a future in which the lives of all people are improved, and that consideration for the lives of the most vulnerable among us are placed at the forefront of discussions about planning and design.

Author: Molly A. Burhans
goodlandproject.org

Photo credit: Chris Hendershot, 2015. Well Digging in the Djangoulas [chris.g.hendershot at gmail dot com]. This photo was taken during our time in Mali in our final semester at the Conway School, while partnered with Mali Nyeta. The village residents had to dig 9+ meters to reach the water table and they said the distance was increasing every year. This decrease in water table is due to increasing drought, deforestation and desertification in the Sahel.