21 April 2010

Old News Can be Worth Reading

The American Society of Landscape Designers sends out a monthly email called
The Dirt with links to stories of interest. Through a series of clicks I found a link to a Sept. 23, 2009 New York Times story that is perfect for the Earth Day thoughts we are all having.

In the Garden, by Ann Raver, "The Grass is Greener at Harvard"

Follow the link above to read the entire piece. Here are a few excerpts to help you think Earth Day thoughts.

There is an underground revolution spreading across Harvard University this fall. It’s occurring under the soil and involves fungi, bacteria, microbes and roots, which are now fed with compost and compost tea rather than pesticides and synthetic nitrogen.

Our goal is to be fully organic on the 80 acres that we maintain within the next two years, said Wayne Carbone, Harvard's manager of landscape services.

The lumps of soil showed how grass grew when treated with chemical fertilizers and how it looked when treated organically, she said. You could really see the root systems and how different they were.

The organically grown grass on campus is now green from the microbes that feed the soil, eliminating the use of synthetic nitrogen, the base of most commercial fertilizers. No herbicides or pesticides are used, either. Roots reach eight inches into soil that was once so compacted the trees planted in it were dying.

Soil tests show the presence not only of beneficial bacteria and fungi but also of the micro-organisms that feed on them, recycling nitrogen back into the soil.

And the 40-year-old orchards at Elmwood, which have been treated with compost tea, are recovering from leaf spot and apple scab, two ailments that had afflicted them.

Mr. Van Valkenburgh, who grew up putting DDT on the family’s vegetable plot, had seen how Mr. Fleisher's use of compost and teas had improved Battery Park City's 36-acre landscape, which thrives, despite heavy foot traffic, without the use of pesticides or synthetic fertilizers.

An organic approach requires a radical change in thinking.

This is not a product-based program, it's knowledge-based, Mr. Fleisher said...

When the project started, Mr. Fleisher said, the soil was so compacted, we could not dig past three inches.

But when Mr. Clyne stepped down on his spade this day, it went through the grass like the proverbial knife through butter. He made a core sample, a square of turf and soil as wide and deep as his spade, then lifted it gently and laid it on the grass. The soil was dark and crumbly; the roots were six to eight inches long.

Healthy soil is a mixture of sand, silt and clay particles held together by the gums and gels formed by bacteria as well as by fungi and plant roots. These micro-organisms, as well as insects and earthworms, create the spaces through which air and water can trickle.

Organic growing techniques are so simple that any homeowner can get the hang of them. But to do so, it’s necessary to learn some basic facts about the structure and biology of your particular soil. In an organic approach, one bag of chemicals does not fit all. And timing is key.

Without good drainage, water and air cannot be properly absorbed by plant roots.

There’s a give-and-take between fungi and plants, as the fungi consume carbohydrates exuded by plant roots and give back water, phosphorus and other minerals. Bacteria also consume carbohydrates. And they in turn are eaten by protozoa and other creatures that convert the bacteria’s protein into nitrogen, which feeds the plants.

Adding compost to soil gets that biological community cooking.

To help laypeople unravel the mysteries of the soil in their own yard, Harvard has posted a kind of mini-course on its Web site www.uos.harvard.edu/fmo/landscape/organiclandscaping. It includes simple directions for building a compost pile hot enough to eat weed seeds, building a compost tea brewer, and brewing teas particularly suited for grass, perennials or woody plants.

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