Get to know soil

May we never refer to it as dirt again…

There are a couple ways to look at soil: one is as a static, inert growing medium and the other is as a dynamic, living environment of its own that affects the environment above ground. It is the latter context that scientists use mostly today. Understanding soil basics first facilitates better understanding of this much grander context.

World Soil Day is December 5, 2018

What is soil?

Unweathered geological material, mineral, or organic matter is the original source of soil, referred to as its “parent” material. Over time, and with the effects of climate and biological activity, the parent material breaks down to make up about half of the total mass of soil. The other half is made up of varying proportions of air and water. The specific qualities of a given soil—along with climate and surface features (slope or rock, for example)—determine what thrives in it.

It can take up to 200 years to produce
1 cm of soil.

According to the National Resources Conservation Service, there are over 1300 different soil types in Texas, and they vary widely throughout the state.

Capture

The General Soil Map of Texas  shown above, is the go-to for an overview of soil types. The Woodlands, for the most part, sits in area 51, which is a small portion of the Western Coastal Plain and Flatwoods region. This area covers about 16.1 million acres, dissected by many streams. It has many kinds of upland soils, which tend to be deep, light-colored, acid sands and loams over loamy and clayey subsoils that support pine-hardwood vegetation characterized by the ubiquitous loblolly pine.

Breaking it down

By simple observation, many clues can be gleaned about a particular soil’s properties.

Color. A soil’s color helps determine how much organic material it has, the various minerals present, and its ability to drain. The darker the soil, the more organic material it has. Darkness can also indicate slower drainage. Conversely, lighter soil is an indication that it’s lower in organic content and more highly leached.

Color can also give clues to the soil’s mineral content. Iron minerals are by far the greatest contributor to soil color variation, creating yellow, red, grey, black or brown hues.

Texture. Soil texture is important because it determines how well (or not) water drains through it and if it creates pockets of air. Texture is defined by the relative mix of three components:

  • sand, being coarse;
  • silt, being fine; and
  • clay, being finest.

The degree of coarseness or fineness provides clues to soil’s productivity. The coarser the soil:

  • the faster it drains;
  • the less water and more air it holds;
  • the faster it warms; and
  • the more easily it can be worked or penetrated by roots.

Depth. More can be learned from the soil’s “horizons.” Horizons are simply layers of differing composition. If there are key things to note about horizons, it’s that the A horizon, or surface, is the most fertile and has the best structure of all the other horizons., making it vital for plant life. Its depth can vary between just 2 inches to more than 12 inches thick. The B horizon, or subsoil, dictates how well water drains. Its depth too, varies between 2 and 12 inches. A subsoil of mostly clay will impair drainage and root growth. And these issues only increase the more shallow the surface soil is above it.

Soil Horizons

If there’s good news for the gardener who has less-than-ideal conditions in surface soil and subsoil horizons, it’s that improvements can be made by adding organic material, especially compost.

The value of loam

The relative proportion of sand, silt and clay gives soil what is referred to as its class. If there is a “perfect” soil class, it would be what’s called loam. Generally, loam is made up of equal parts sand, silt, and clay.

The best soil texture for growing plants is
what is called “loam.”

Loam = (<52% sand) + (28-50% silt) + ( 7-27% clay)

Loam soils are best for plant growth because the different-sized particles leave spaces in the soil for air and water to flow and roots to penetrate. The roots then can feed on the minerals in the suspended water. It retains enough water to keep the soil moist, but its texture is porous, allowing water to flow through slowly enough for the plants to access it, but fast enough to keep soil from getting waterlogged.

Tiny air pockets in soil are critical to support the animals that live in the soil, like worms and many types of bacteria. And one of the ways that plants get air is by absorbing it through their roots. Without air at a plant’s roots it would suffocate.

Deep sands do not hold moisture well and are often infertile. Clay holds moisture better than sands and may be more fertile, but they tend to swell when they get wet, which may limit the movement of water and roots. Clay cracks when they dry and the clods become very hard and difficult to penetrate.

Soil is alive

The key to understating soil’s properties is that they can determine the life it holds. Soil is a dynamic, interconnected, living thing—there’s a whole universe of life underneath our feet. It’s a web of energy conversions that fuels and makes possible life above ground. How big and diverse that universe is, is an easy measurement of how healthy the soil is.

As a living thing, soil quality is referred to as its “health.” The healthier the soil, the more it can:

  • Sustain plant and animal productivity and biodiversity;
  • Maintain or improve air and water quality; and
  • Support human health and habitation.

Healthy soil teams with life and supports its own food web as shown in the chart and illustration below, both from Soil Biology Primer, by Soil and Water Conservation Society.

Soil organisms

The Soil Food Web

Billions of bacteria, fungi, and other microbes that live within soil are the foundation of an elegant symbiotic ecosystem.  Healthy soil makes possible clean air and water, bountiful crops and forests, productive grazing land, diverse wildlife and beautiful landscapes.

Keep soil alive with organic material

Organic material in soil not only greatly improves its structural qualities it also helps create the right conditions for the life it supports. By helping maintain favorable temperature and moisture in the soil, earthworms, insects, bacteria, fungi and other organisms thrive. These in turn, break down the organic material into nutrients that make plant life flourish.

Up to half our household waste could be composted to nurture the soil.

Tips for maintaining healthy soil:

  • Disturb it less
  • Minimize compaction
  • Diversify soil biota with plant diversity
  • Keep roots growing in it year-round
  • Keep it covered
  • Compost, compost, compost

To learn more about soil, check out these great resources:

Healthy Soils Are… PDF series of fact sheets

Soil Biology Primer, by Soil and Water Conservation Society

 

Healthier lawns, cleaner streams

One thoughtful action can help promote both: Think before you fertilize. All too often, lawns are fertilized too heavily, at the wrong time, or when they don’t need it at all—thanks to the formidable marketing efforts by fertilizer companies. Instead of automatically reaching for your spreader, consider what your lawn really needs and the consequences of over-fertilization.

blade-blooming-blossom-5865

Know what your lawn needs

Timing. The time to fertilize a lawn is when it’s growing more roots than blades; and to know when that is, know the type of grass in the lawn. Grass can be categorized in two ways: warm-season or cool-season. These terms refer to the weather in which the grass has adapted to grow. Turf grasses most common in our area, St. Augustine, Zoysia and Bermuda, are all warm-season grasses and start their growth in spring, making that the best time for fertilization.

Fall is when these grasses go dormant making fertilizers moot. Fertilizing at the wrong time can actually be harmful. Feeding your warm-season turf nitrogen in fall can force new top growth making the lawn susceptible to frost, shock and disease. What’s more is that this takes away energy from root growth, leading to weak, thin lawns.

No matter what, always follow a fertilizer’s instructions exactly when it comes to application.

Test it. Having said all this, don’t assume you need to fertilize every spring. The only way to know what nutrients your soil is lacking is to have your soil tested. Instructions for how to take a soil sample and the form for sending it to Texas A&M for analysis can be found with this link: Soil Test Form.

Go organic. If you find your soil needs supplemental nutrients for turf grass, consider using organic instead of synthetic fertilizers. Unlike synthetic fertilizers, organic fertilizers don’t create high levels of salts which kill beneficial soil organisms—the key to good soil health. And organic fertilizers work slowly, wasting nothing. They also improve soil texture making it easier for air to get to the roots and helping the soil retain water longer.

Organic forms of fertilizers include:

  • Alfalfa meal
  • Bat guano
  • Fish emulsion
  • Cotton seed meal
  • Seaweed
  • Manure
  • Compost

Refer to Best Organic Fertilizers for a full list of organic fertilizers and what they specifically offer.

How does this affect the quality of streams?

When quick-release synthetic fertilizers are over used, the chemicals are washed from our lawns in a downpour. The polluted run-off is channeled into the nearest waterway via storm drains, untreated and unfiltered. This water in turn contaminates our creeks, rivers and groundwater. High concentrations of nitrogen in water can also lead to an algae overgrowth, threatening the health of aquatic life.

Pond-LVphoto

Currently, over 80% of waterways in Texas are listed by the Texas Commission on Environmental Quality as “impaired,” creating poor habitat for aquatic organisms such as fish and turtles. High bacteria levels are another culprit and may lead to restrictions on water-contact recreation, such as  swimming and wading, fishing, and kayaking.

Other ways to help keep our water clean:

  • Pick up pet waste—it’s the number one source of bacteria in our waterways.
  • Maintain cars so they don’t leak oil and other chemicals onto driveways.
  • Compost, compost, compost.
  • Never flush unwanted or out-of-date medicines down the toilet or drain.
  • Minimize areas of turf grass and pavement while increasing areas of native plants
  • Install a rain garden

For more information about lawn care, download Guide to Yard Care, by Texas Commission on Environmental Quality.

To learn more about water conservation in The Woodlands, visit The Woodlands Township’s Water Conservation webpage.

Water Conservation Yard Sign 3

Add beauty and manage rain with a rain garden

Rain gardens are simple landscaping features used to slow, collect, infiltrate and filter storm water. They offer a great way to turn a landscape “problem” into a real benefit. Rain gardens are planted areas—best added to a low lying area that collects rain water—that include deep-rooted native plants and grasses that are designed to thrive in wet soil, soak up excess rain water, and withstand intermittent dry periods.

There are aesthetic benefits to rain gardens as well, transforming a bare, wet area into a green, blooming habitat that provides food and shelter for birds, butterflies, and other wildlife. Amphibians such as frogs and toads will be attracted to this naturally wet area.

The problem

Increased stormwater runoff is the real problem. Add soil erosion to that and the result is vulnerability to flooding. Rain gardens help prevent both, helping to conserve water and soil.

Water Cycle

Consider the water cycle shown above and then add human development to the picture. Humans create stormwater runoff when natural areas are developed, replacing them with a sea of impervious surfaces fragmenting our green spaces.  Within a developed residential area, pollutants such as fertilizers, herbicides, pet waste, and oil are washed from lawns, streets, and parking lots into local streams and drainage systems.

Polluted runoff is the number one water
quality issue in the United States. 

How rain gardens help

While a single rain garden may seem inconsequential, it has great value, and several in a neighborhood collectively can produce substantial benefits. They slow the water down and let it collect in the garden’s depression, settling soil, silt and organic material that are washed by the water from higher ground. Water slowly filters back into the soil where it is needed most.  The deep rooted plants and grasses in the rain garden hold of the soil, keeping it in place. Rain gardens can also be designed to divert run off from sewer systems.

Plants within the rain garden increase the infiltration of water, giving the natural process that removes pollutants time to do its work. Naturally purified water then recharges the groundwater system. The end result is that by adding a rain garden to the landscape is a strategy that makes a difference.  Flooding is reduced.  Pollutants are filtered from the water. Runoff is diverted from streets and storm sewers.

Concern that a rain garden might serve as a breeding area for mosquitoes is not valid when they are sited correctly. Following a rain, ponding should last no longer than approximately 72 hours. This is a much shorter time frame than the 7 to 14 days required for most species of mosquitoes to develop and hatch from eggs laid in standing water.

texas rain garden

Rain garden basics

Choose a site. Locate your garden in a low lying area of your landscape that tends to collect rain water at least 10 feet from your foundation. Choose a sunny or partially sunny spot. Also consider how it can be incorporated into your existing landscape replacing an area of traditional turf grass where the lawn slopes toward the street. An area that would catch roof run off or water from a down spout is perfect. If the rain garden is located on a slope, create a berm on the low side to retail water and soil.

Compared to a patch of lawn, a rain garden allows 30% more water to soak in the ground.

Test drainage. Test the location’s drainage before you create the bed. Dig a hole 8 to 12 inches deep and fill the hole with water. The water should soak in within 48 to 72 hours. Soils heavy in clay will drain much more slowly than soils heavier in loam, silt or sand. Amend sites heavy in clay with organic compost to improve the soil and help drainage. If the site doesn’t drain within 72 hours, choose another site.

Start digging. Rain gardens can be any size, but a typical residential rain garden ranges from 100 to 300 square feet. The depth of the garden can range between four and eight inches. Anything too deep might pond water too long and if too shallow, it will require greater surface area to effectively manage water.

Add plants. Choose a variety of native forbs and grasses, planting those with higher water tolerance in the middle of the garden. Include plants of varying heights and bloom times to maximize the garden’s depth, texture and color. Plant in groups of three to seven plants of a single species.  Go for diversity. In natural areas, a diversity of plant types not only adds beauty, but also creates thick underground root network that keeps the entire plant community in balance.

The chart below includes plants for our area suitable for a rain garden. Planting zones are indicated as:

Margin: the high edge around the rain garden that is the driest zone
Median: the area between the margin and center
Center: the middle of the garden that is deeper and will stay wet longest

Rain garden plant listHelp it flourish. Rain gardens can be maintained with little effort after plants are established. Weeding and some watering during dry periods will be needed the first two years.

Attend the upcoming rain garden class

Join Patrick Dickinson, Texas A&M Water University horticulturist on Saturday, October 27, 2018 from 9:00 a.m. to noon as he presents Gardening 102:  Rain Gardens.

Register here.

Resources

Refer to Harris County AgriLife Extension gardening fact sheet, Rain Gardens, for more details about planning a rain garden and for a full plant list.

Check out WaterSmart, a presentation by Chris LaChance of Texas AgriLife Extension, for good information and nice photos of various rain gardens.

This how-to manual on Rain Gardens by the Wisconsin Department of Natural Resources may have plant lists that aren’t suitable for this area, but it’s a good guide to creating a rain garden no matter where you live.

Backyard birds

Whether you have a home with a backyard or an apartment with a balcony, the fun of birding can be enjoyed by all. There are over 800 bird species in North America, and as many as 500 can be found in Texas alone. This rich diversity of birdlife is a testament to Texas’s diversity of habitat.

The state’s biodiversity is easily grasped when the high number of ecoregions in Texas—ten to be exact—are taken into account.

An ecoregion denotes a geographic area of similarity in its mosaic of flora, fauna, and ecosystems.

Gould ecorregions of texas

 

Texas’s geographic location is a crossroads where eastern habitats meet western ones and southern subtropical habitats meet northern temperate ones. Adding to the state’s super-birding aspects is the fact that it’s situated smack dab in the central flyway. During the spring and fall migrations, birders are apt to see species that aren’t generally seen otherwise. The Woodlands is situated in the Piney Woods ecoregion.

Attract birds to your landscape

By providing the essentials:

  • feeders and native food-producing plants,
  • water, and
  • shrubs, trees and birdhouses for nesting and shelter

in home landscapes, backyards can be transformed into bird wonderlands.

What’s growing in a backyard is key, and there are many native plants you can add to your property to attract birds and other wildlife. Here’s a short-list of some excellent ones for the Piney Woods. And remember—the best habitats address all four layers of your landscape—canopy, understory, high ground, and ground.

Plants for Birds Chart

Birds of the Piney Woods

Here’s a look at some common and less-common birds that visit The Woodlands backyards—either year-round or seasonally during migration. See how many visit your backyard feeder this season.

Backyard Bird chart.page 1

Backyard Bird chart.page 2

Backyard Bird chart.page 3

Backyard Bird chart.page 4

Especially for birders…

For aspiring and dedicated citizen scientists of all ages, take part in this year’s Project FeederWatch, developed by the Cornell Lab of Ornithology at Cornell University. The project kicks off in November. FeederWatch data help scientists track broad-scale movements of winter bird populations and long-term trends in bird distribution and abundance.

Another great resource for birders is also brought to you by the Cornell Lab of Ornithology, eBird, where bird enthusiasts can connect to and contribute to the world of birding.

 

 

The way of the future: sustainable landscapes

Community resilience. Sustainable landscapes. These terms are becoming more commonplace and heard more often. Why? Because our collective and growing knowledge and experience tells us that global climate change is the impetus for increased catastrophic weather events.

What do these terms mean, exactly?

Taken one at a time, community resilience is the ability to anticipate risk, limit impact, and bounce back rapidly through survival, adaptability, evolution, and growth in the face of turbulent change, as defined by the Community and Regional Resilience Institute.

Turbulent change can include severe threats such as sea level rise, hurricanes, wildfires, drought, economic down-turns, social unrest, and other disruptions.

Environmental threats make up just one component—though significant—to the whole of turbulence that impacts resiliency, and designing landscapes that are sustainable is one way to help manage them.

The American Society of Landscape Architects defines sustainable landscapes best: “Sustainable landscapes are responsive to the environment, re-generative, and can actively contribute to the development of healthy communities. Sustainable landscapes sequester carbon, clean the air and water, increase energy efficiency, restore habitats, and create value through significant economic, social and, environmental benefits.”

It’s worth noting too, that a sustainable landscape is designed to be both attractive and to require minimal resources in terms of cost and ongoing maintenance.

Attend The Woodlands Township’s upcoming event:

Walk in the Woods Nature Lecture Series 

Thursday, October 11
6:00 p.m. to 7:30 p.m.
at HARC, 8801 Gosling Rd, The Woodlands
Lisa Gonzalez, President and CEO of HARC, will present:

Working with Nature to Build Resilient Communities

Registration is required.

A sustainable landscape can include:

  • Reduction of stormwater run-off through the use of bio-swales, rain gardens and green roofs and walls
  • Reduction of water use in landscapes through design of water-wise garden techniques (sometimes known as xeriscaping)
  • Bio-filtering of wastes through constructed wetlands
  • Landscape irrigation using water from showers and sinks (known as gray water)
  • Integrated Pest Management (IPM) techniques for pest control
  • Creating and enhancing wildlife habitat in urban environments
  • Energy-efficient landscape design in the form of proper placement and selection of shade trees and creation of wind breaks
  • Permeable paving materials to reduce stormwater run-off and allow rain water to infiltrate into the ground and replenish groundwater rather than run into surface water
  • Use of sustainably harvested wood, composite wood products for decking and other landscape projects, as well as use of plastic lumber
  • Recycling of products, such as glass, rubber from tires and other materials to create landscape products such as paving stones, mulch and other materials
  • Soil management techniques, including composting kitchen and yard wastes, to maintain and enhance healthy soil that supports a diversity of soil life
  • Integration and adoption of renewable energy, including solar-powered landscape lighting

That’s a lot. Let’s take a closer look at just two aspects of a sustainable landscape.

FIRST: Enhancing wildlife habitat.  Habitat loss, and the corresponding loss of biodiversity, can be curbed when we connect properties into networks of attractive, wildlife-friendly neighborhoods, cities, and regions. Starting with the home landscape, fragmented habitats can be rewoven together, creating spaces that are not only healthier for wildlife but also for people.

Watch this informative, short (4-minute) video produced by American Society of Landscape Architects, Designing Neighborhoods for People and Wildlife.

 

 

SECOND: Reduction of stormwater run-off.  In many communities, rain water flows into combined stormwater and sewer systems, which channel both sewage and rainwater together through underground pipes to central treatment facilities. Storms can quickly overrun these combined systems, leading to flooding with pollutant-laden water and even backed up sewage.

Watch this informative, short (4-minute) video produced by American Society of Landscape Architects, Leveraging the Landscape to Manage Water.

 

When these approaches are viewed with a wide scope and on a large scale, the potential impacts of sustainable landscaping are pretty powerful. At the same time, it’s important to recognize that change often starts on a small scale. And there might be no better place to start than in your own back yard.

For further reading, that’s as fun to read as it is informative, get Bringing Nature Home: How You Can Sustain Wildlife with Native Plants, Doug Tallamy, Timber Press, 2009.