I tell people to think of soil as a sponge. The idea is to build up the thickest sponge possible, which will be capable of absorbing as much water and as many nutrients as possible. The thick sponge will also hold onto the water and nutrients, whereas a thin, hard sponge won’t do much good at all.

The sponge principle is at the core of why organic gardening is more sustainable than chemical gardening. When you apply chemical products, some of them are absorbed into the plant and the rest of them leach away from or through the soil — or “sponge.” When you apply organic products such as composts, leaf mulches, soil amendments or fertilizers, they actually become part of the soil — therefore increasing the sponge factor incrementally season by season and year by year.

The number one benefit of organic soil management is drought tolerance. In other words, when the rain stops falling naturally, your lawns will stay greener longer when you maintain your lawn organically. In many climates, supplemental water is rarely if ever necessary on a lawn that is maintained organically.

Much of this is related to a phenomenon known as improved soil structure. One of our sponsors, Dr. Earth, has a nice post on this on their web site at www.drearth.com. You’ll find it on the left-hand side of their home page under Projects: Improving Soil Structure.

By Editors of E/The Environmental Magazine

EarthTalk is a Q&A column from E/The Environmental Magazine

Dear EarthTalk: What effects do fertilizers, pesticides and herbicides
used on residential lawns or on farms have on nearby water bodies like
rivers, streams, or even the ocean for those of us who live near the
shore? — Linda Reddington, Manahawkin, NJ

With the advent of the so-called Green Revolution in the second half
of the 20th century — when farmers began to use technological
advances to boost yields — synthetic fertilizers, pesticides and
herbicides became commonplace around the world not only on farms, but
in backyard gardens and on front lawns as well.

These chemicals, many of which were developed in the lab and are
petroleum-based, have allowed farmers and gardeners of every stripe to
exercise greater control over the plants they want to grow by
enriching the immediate environment and warding off pests. But such
benefits haven’t come without environmental costs — namely the
wholesale pollution of most of our streams, rivers, ponds, lakes and
even coastal areas, as these synthetic chemicals run-off into nearby
waterways.

When the excess nutrients from all the fertilizer we use runs off into
our waterways, they cause algae blooms, sometimes big enough to make
waterways impassable. When the algae die, they sink to the bottom and
decompose in a process that removes oxygen from the water. Fish and
other aquatic species can’t survive in these so-called “dead zones,”
and so they die or move on to greener underwater pastures.

A related issue is the poisoning of aquatic life. According to the
U.S. Centers for Disease Control (CDC), Americans alone churn through
75 million pounds of pesticides each year to keep the bugs off their
peapods and petunias. When those chemicals get into waterways, fish
ingest them and become diseased. Humans who eat diseased fish can
themselves become ill, completing the circle wrought by pollution.

A 2007 study of pollution in rivers around Portland, Oregon found that
wild salmon there are swimming around with dozens of synthetic
chemicals in their systems. Another recent study from Indiana found
that a variety of corn genetically engineered to produce the
insecticide Bt is having toxic effects on non-target aquatic insects,
including caddis flies, a major food source for fish and frogs.

The solution, of course, is to go organic, both at home and on the
farm. According to the Organic Trade Association, organic farmers and
gardeners use composted manure and other natural materials, as well as
crop rotation, to help improve soil fertility, rather than synthetic
fertilizers that can result in an overabundance of nutrients. As a
result, these practices protect groundwater supplies and avoid runoff
of chemicals that can cause dead zones and poisoned aquatic life.

There is now a large variety of organic fertilizer available
commercially, as well as many ways to keep pests at bay without
resorting to harsh synthetic chemicals. A wealth of information on
growing greener can be found online: Check out
OrganicGardeningGuru.com and the U.S. Department of Agriculture’s
Alternative Farming System Information Center, for starters. Those
interested in face-to-face advice should consult with a master
gardener at a local nursery that specializes in organic gardening.

In much of the country, though, the opposite problem exists. It’s drier than usual and lawns are frying in the process. This week we’ll dedicate much of our SafeLawns posting to water-saving and drought-tolerance techniques.

For starters, here are some tips from the RainBird company, which has been around for more than 70 years. The company dedicates July to “Smart Irrigation”:

RAINBIRD’S TIPS:

1. Don’t drown
The greatest waste of water comes from applying too much, too often — much of the water is never absorbed. Instead of watering for one long session, water a few times for shorter periods and take 15-minute breaks in between each session. This will allow water to soak in, while minimizing runoff.

2. Watch the clock
Water between 5 a.m. and 10 a.m. — when the sun is low, winds are calm and temperatures are cool. Mid-day watering tends to be less efficient because of water loss due to evaporation and windy conditions during the day. Watering in the evening isn’t a good idea either because leaves can remain wet overnight — an open invitation for fungus to grow. By watering in the morning, leaves have a chance to dry out during the day.

3. Divide by zones
Different plants need different amounts of water. Divide your yard and landscape areas into separate irrigation zones so that grass can be watered separately and more frequently than groundcovers, shrubs and trees. Both sprinkler and drip irrigation can be incorporated to achieve more efficient use of water.

4. Water only things that grow
If you have an underground sprinkler system, make sure the sprinkler heads are adjusted properly to avoid watering sidewalks and driveways. A properly adjusted sprinkler head should spray large droplets of water instead of a fine mist to minimize evaporation and wind drift.

5. Consider dripping
When it comes to watering individual trees, flowerbeds, potted containers, or other nongrassy areas, consider applying water directly to the roots using low volume drip irrigation. This will reduce water waste through evaporation or runoff, and will prevent unwanted weeds from growing.

6. Do routine inspections
Since lawns and gardens should be watered in the early morning hours, a problem may not be discovered until it is too late. Periodically check your sprinklers to make sure everything is working properly. A clogged head or a torn line can wreak havoc on your landscape and water bill.

7. Be rain smart
Adjust your irrigation system as the seasons and weather change. Or better yet, install a shut-off device that automatically detects rain or moisture. These devices are inexpensive and enable you to take advantage of the water without having paying for it.