Published on 06/30/97

Waste Now Building Up, Not Just Filling Up, Soil

In the landfills, waste just fills up a hole in the ground. But some products that normally end up there are finding new life in the land as nutrients for crops.

"We've found a way to use things like wallboard, fly ash and composted yard trimmings on row crops," said Glen Harris, a University of Georgia Extension Service scientist.

"It's really a win-win-win situation," said Harris, who specializes in environmental soils and fertilizer. "The people who have this 'waste' are happy to be rid of it, taxpayers don't have to pay for it in the landfill and farmers can get it for a competitive price."

As Georgia landfills quickly fill, the cost to dispose of construction and other waste keeps rising. New Georgia laws ban yard trimmings from landfills, too.

Harris, working with UGA engineer Mark Risse and a number of county agents, private companies and local governments, is finding answers to these problems. The waste products, he said, can be useful as soil amendments, fertilizers and liming material.

"We're working with 10 products that can be used in commercial agriculture and home gardens," he said.

All types of crops require calcium, potassium, nitrogen, phosphorus and many other nutrients. Composted yard trimmings are very rich in organic matter. Construction wallboard is made from the same gypsum that peanut farmers use to supply calcium to their crop.

Newspaper recycling fly ash is the ash that flies up with the smoke when wood and coal are burned in a stage of the recycling process. The fly ash, Harris said, is another good source of calcium.

Wood ash from the tree limbs, bark and "junk wood" pulp and paper mills can't process is good, too, he said. It's rich in potassium and organic matter.

But don't rush out to the landfill for these nutrient sources for your garden or farm, Harris said.

"You have to know what's in it," he said. Harris answers these questions before he tests products as a soil amendment:

* What is the nutrient and how concentrated is it?

* Is it safe -- does it contain heavy metals or other toxins?

* How does it fit into your fertilization plan?

* How much does it cost, compared to other sources of the same nutrient?

"All these questions have to be answered before the product is ready to use as a soil additive," he said.

Harris said some of the reclaimed nutrient sources are more ready for farmers to use than others. Fly ash, for instance, can go straight into the spreader.

"But we're still working on how to sift the paper coating out of the crushed wallboard," he said. "We hope to have that method ready for the 1998 crop season."