Soil Compaction in the Landscape

Soil Compaction in the Landscape

One big goal of establishing a home lawn and landscape is to enjoy an attractive setting for family and friends, while also helping manage healthy soils and plants.  Soil compaction at these sites can cause multiple problems for quality plants establishment and growth.  Soil is an incredibly important resource creating the foundation for plants and water absorption.

Photo courtesy: Stephen Greer, UF IFAS

Soils are composed of many different things, including minerals.  In Florida, these minerals often include sand of differing sizes and clay in the northern area of the counties in the panhandle of Florida. Soil is also composed of organic matter, nutrients, microorganisms and others.  When soil compacts, the air spaces between the sand or clay are compressed, reducing the space between the mineral particles.  This can occur anytime during the landscape and lawn construction phase or during long term maintenance of the area with equipment that could include tractors, mowers, and trucks.

What can be done to reduce soil compaction?  There are steps that can be taken to help reduce this serious situation.  Make a plan on how to best approach a given land area with the equipment needed to accomplish the landscape of your dreams.  Where should heavy equipment travel and how much impact they will have to the soils, trees, and other plants already existing and others to be planted?  At times heavy plywood may be needed to distribute the tire weight load over a larger area, reducing soil compaction by a tire directly on the soil.  Once the big equipment use is complete, look at ways to reduce the areas that were compacted.  Incorporating organic matter such as compost, pine bark, mulch, and others by tilling the soil and mixing it with the existing soil can help.  Anytime the soil provides improved air space, root will better grow and penetrate larger areas of the soil and plants will be healthier.

Even light foot traffic over the same area over and over will slowly compact soils.  Take a look at golf course at the end of cart paths or during a tournament with people walking over the same areas.  The grass is damaged from the leaves at the surface to the roots below.  Plugging these areas or possibly tilling and reestablishing these sites to reduce the compacted soils may be necessary.

Photo courtesy: Stephen Greer, UF IFAS

Water absorption is another area to plan for, as heavy rains do occur in Florida.  Having landscapes and lawns that are properly managed allow increased water infiltration into the soil is critically important.  Water runoff from the site is reduced or at least slowed to allow the nutrient from fertilizers used for the plant to have more time to be absorbed into the soil and taken up by the plants.  This reduces the opportunity for nitrogen, phosphorus, and other nutrients to enter water areas such as ponds, creeks, lagoons, rivers and bays.  Even if you are miles from an open water source, movement of water runoff can enter ditches and work their way to these open water areas, ultimately impacting drinking water, wildlife, and unwanted aquatic plant growth.

Plan ahead and talk with experts that can help with developing a plan.  Contact your local Extension office for assistance!

 

Now is Time to Use Solar Power Against Soil Pests

Now is Time to Use Solar Power Against Soil Pests

North Florida vegetable gardeners have made it to summer and now the plants and gardeners are starting to give in to the heat and humidity. The squash has likely succumbed to squash vine borers, many of the tomato varieties are having trouble setting fruit, stink bugs are all over, and gardeners easily wilt by noon. This is a good time to use our oppressive heat to your advantage in the vegetable garden by solarizing the soil.

Graph of annual temoerature

We have reached the peak of heat. Use it to your advantage in the garden. Source: National Weather Service.

Soil solarization is a method of pest control that creates a greenhouse to heat up the soil in an effort to drive away pests. Pests that can be reduced with soil solarization include weeds, various soil-borne fungal pathogens, and nematodes. Weed seeds can actually be killed by the increased temperatures, sometimes as high as 140 degrees Fahrenheit, while fungi and nematodes are merely driven deeper into the soil layer as they try to escape the heat. Although they are not killed, this can help vegetable gardeners as it may take these organisms 3-4 months to repopulate in high enough numbers to cause damage. Soil solarization can be considered another tool in your integrated pest management (IPM) toolbox, along with other cultural, physical, and chemical means of pest control.

Picture of raised bed garden covered in plastic.

A raised bed being solarized over the summer. Source: Evelyn Gonzalez, UF/IFAS Master Gardener Volunteer.

To properly execute soil solarization, the site should be in full sun and the existing vegetation removed, either by hand or with a tiller or other implement. Tilling can help loosen the soil surface and allow heat to penetrate deeper in the soil horizon. Before being covered with plastic, the area should receive rainfall or be irrigated, as the water will help conduct heat to greater depths. The next step is to cover the area with plastic. Note that this can also be done over raised beds! Clear plastic is best for maximum solar radiation penetration. Black plastic will heat up mostly on the surface and opaque plastic sheeting may not let enough light in to get temperatures high enough. The plastic should be slightly larger than the area covered, as the edges will need to be buried to create an air-tight seal. It’s recommended to leave the plastic in place for at least six to eight weeks, just in time to begin fall gardening preparations.

It’s important to monitor the site while it’s “cooking” to look for any holes that might appear. Small holes can be repaired with duct tape, while large holes or rips in the plastic may require starting over. Overlapping strips of plastic is not recommended since too much heat will be lost.

You may be wondering what happens to all of the good soil microbes. Well, unfortunately, they are also either killed or suppressed. Fortunately, researchers have found that they are able to repopulate quicker than the pest organisms, especially in soils with a good amount of organic matter.

Much more information on soil solarization can be found in these two documents:

Introduction to Soil Solarization – https://edis.ifas.ufl.edu/pdffiles/IN/IN85600.pdf

Solarization for Pest Management in Florida – http://edis.ifas.ufl.edu/pdffiles/IN/IN82400.pdf

Also, please contact your local county extension office for more gardening tips.

Phosphorus – Know Your Soil

Phosphorus – Know Your Soil

In our area of Florida, soils will vary in the amount of nutrients they hold. In general, we think of our soils as nutrient poor because sand is often the highest component. Sandy soils have large pore spaces and the particles themselves do not ‘attract’ many of our nutrients. Therefore needed plant nutrients can leave a sandy soil quickly, especially when rainfall or irrigation is prevalent.

There are areas along the Panhandle that do have more quality soils that have the ability to retain some nutrients. Also, frequent fertilizer or lime applications in home landscapes can create soils with abundance of certain nutrients over time .

One nutrient that may become prevalent in routinely fertilized soils is phosphorus. We know that phosphorus is one of the big three nutrients needed by plants in order to grow and flourish. When we routinely apply phosphorus to garden beds or lawns, it can build up. Phosphorus is a nutrient that does not leave the soil as readily as other nutrients. It binds to other elements to hang around. If we keep adding phosphorus to the soil, even though there is plenty there, problems can occur. One negative impact is the potential for soils with phosphorus to wash away and pollute local water systems.

Phosphorus is absolutely necessary for plant growth. It is needed for the energy transfer which is involved in plant growth functions. Phosphorus is also important for flower and fruit formation, and root growth.

Flowering plants benefit from fertilizer but make sure your soil needs the nutrients before an application.  Photo:  Beth Bolles, UF IFAS Escambia Extension

Flowering plants benefit from fertilizer but make sure your soil needs the nutrients before an application. Photo: Beth Bolles, UF IFAS Escambia Extension

There can be too much of a good thing. The key to remember, as with any nutrient, is make sure it is needed before applying it to your soil. Plant growth will not be improved beyond what is normal by adding more of any nutrient. Before you grab the bloom promoter or starter fertilizer with high phosphorus, run a soil test to accurately determine what is really needed in your soil.