Question: What does the term “groundwater recharge” mean and why is it important? Answer: Let’s start with the term “groundwater.” Groundwater is defined as the water that is obtained by pumping from below the ground surface from storage units commonly called aquifers. This water is an important source for agriculture irrigation as well as domestic consumption…. More
Today’s post, written by James Urban, FASLA, originally ran in 2011. But understanding soil organic matter – a sometimes mysterious-seeming property of healthy soil – remains a fundamental component of any discussion about planting trees for long-term success. -LM As a soils guy, I have a lot of discussions with clients and colleagues about the quantity… More
Q: What does it mean to say we are losing soil? Where does it go? A: You may hear the phrase: “We are losing our soil.” Sounds serious…but how do we lose soil? Where does it go? Soil erosion is the movement of soil by wind or water, and it’s through erosion that soil is “lost.” If… More
Q: I recently got into a conversation with someone who claimed soils are a renewable resource because the nutrients in them can be replaced with fertilizers. But I’ve heard that soil takes a really long time to form, so that to me makes it non-renewable. What’s your opinion? A: The idea that soil is renewable… More
We write a lot about the benefits that trees and soils have on water quality. But what, exactly, do they improve? Back in 2011, landscape Nathalie Shanstrom tackled this topic, explaining in easy-to-understand terms what we mean by when we refer to water quality improvements. While seriously impaired runoff is not a concern on most sites,… More
A recent issue of the Ontario Association of Landscape Architects (OALA) magazine, Ground, contained a great discussion between nine professionals on the topic of soil. James Urban, FASLA, ISA, wrote to the magazine to add a few more comments to the piece – taking issue with the contention that what we plant in shouldn’t be… More
Question: What makes that “fresh earth” smell in spring? What is that? Answer: In a word, geosmin. Geosmin is an organic compound released by a group of soil microorganisms called actinomycetes. Actinomycetes are filamentous “prokaryotes.” In other words, they are microscopic organisms whose cells have no “nucleus” enclosing their DNA. Organisms that do have cell nuclei—like plants,… More
“The soil here is terrible.” This is something we hear a lot during design discussions. People often assume that soils in heavily developed environments can’t possibly be biologically sound for plant life. In some cases, this is true. But in others it isn’t, and the only way to know for sure is to do a… More
One of our specialties at The Kestrel Design Group is designing urban tree systems (especially designing urban tree systems to maximize stormwater benefits). One question we are regularly asked on urban tree projects is whether or not soil organic matter will become too low or depleted when trees are surrounded by pavement and leaves are no… More
In October, I wrote about some of our concerns with Philadelphia’s highly-lauded green infrastructure plan, now codified in their Green Streets Design Manual. This plan has received more praise and recognition than any other citywide green infrastructure policy that I’m aware of (here are a few examples). I’m thrilled to see a major green infrastructure… More
Last year, Jim Urban wrote a post for this blog entitled Against Mulch. The principle reasons he cited for his position were: 1) Mulch floats and can clog drains and releases “lots of phosphorus” as it breaks down, and 2) work by Gilman et al. that suggest that mulch does not reduce evapo-transpiration. We discussed… More
We love trees. We also love woodies. For those of you who have been reading this blog for a while, you will know that we promote large volumes of non-compacted, biologically active loam as essential for street tree health and longevity. There are other plants which require soil volume and need attention as well. Vines,… More
Soil. Stormwater. Sustainable Infrastructure.
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