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Experiment Tests Crab Claws, Shredded Plastic, Manure on Corn

May 6, 1994

BELTSVILLE, Md. (AP) _ The cornfield of the future may be strewn with little bits of crab claw, tiny scraps of plastic bags and clumps of yesterday’s news.

Scraps of this and that turn up in dirt-like compost being applied on an experimental cornfield at the Beltsville Agricultural Research Center. Various city and rural waste products were being slung by spreaders onto strips of land Thursday.

The land will be tilled and planted with corn next week. When harvest comes around in October, researchers will have a better idea of how 11 different kinds of composted sludge, waste and other gunk work on corn, a crop that takes lots of nitrogen and other fertilizer to grow.

″This is under sort of the umbrella of sustainable agriculture, and the definition of sustainable agriculture is to grow crops with a reasonable yield and using less inputs into the system,″ said Larry Sikora, microbiologist at the Agricultural Research Service.

Approaching the site from downwind, it was easy to tell what one of the piles contained - good old-fashioned cow manure. The flies liked it best.

The smorgasbord of soil enrichers also offered composted crab chum from Maryland’s Eastern Shore, which is broken down enough to look like regular dirt except for points of claws that look like giant thorns. A good close sniff revealed a slightly briny tang.

Municipal trash compost from the city of Baltimore, slightly redolent of rotten food, with little strips of plastic bags and wet clumps like papier- mache, held the least promise.

″We’re probably more curious about the refuse,″ Sikora said. ″The refuse hasn’t got a lot of fertility because there’s so much paper in there.″

In fertilizer terms, that means a high carbon-to-nitrogen ratio. To get the nitrogen up, the refuse is blended with the cow manure in one test strip.

That’s where the notion of ″co-composting″ comes in: mixing two kinds of waste, especially farm and urban or industrial. The pressure is on both sides - for agriculture needing to use fewer chemicals and find safe ways to dispose of manure and for cities running out of landfill space or finding that certain wastes are now banned.

The experiment is designed to be as close to real life as possible, with plots large enough to test real farm equipment. Some of the material works in spreaders and slingers; some doesn’t.

The lime-containing residue washed off cement mixers was still so moist it gummed up the slinger, a tractor-drawn version of the broadcast spreader used on lawns.

It’s a small experiment, not enough to yield the kind of data that scientists share in journals.

But Sikora hopes that this season’s results will lead to larger experiments that answer some bigger questions.

The materials have to be economical for farmers. Waste is cheap, but it takes a lot more waste than commercial products to enrich soil, with a lot more pressure on equipment and compaction of fields.

Then there are problems with buildup from dangerous metals like cadmium in sewage sludge.

So, what might scientists learn in the short run?

″Some things may die,″ Sikora said. ″Some things may work better than others.″

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