A generation later, Charles Mitchell still recalls the discarded gum wrapper floating down the irrigation ditch in a carefully tended vegetable garden located at a on the campus of a Chinese agricultural college he was visiting in 1987.

In fact, for Mitchell, a soil scientist, the sight was a bit of an epiphany. The night before, he had casually flushed this discarded wrapper down the toilet of his living quarters, located only a stone's throw away from the garden.

The waterborne wrapper was a quaint reminder of the indispensable role waste — not only livestock but human waste — has played in fertilizing crops throughout four millennia of farming.

Now, after a long hiatus and in the midst of one of the most serious energy crunches in history, some farm observers believe that farmers in the United States and the rest of the West will soon view manure with the same respect as their counterparts in the East.

To and increasing degree, they already are, contends Gene Logsdon, author of "Holy Sh*t: Managing Manure to Save Mankind."

Indeed, as Logsdon sees it, the title of his book precisely expresses what Western farmers must learn to do over the next few decades: use and manage manure as a critical source of soil fertilizer.

The era of cheap manufactured and mined fertilizers is drawing to a close. Farmers, however reluctantly, will be dragged back to the future, back to a time when animal and even human manures comprised the primary sources of fertilizer, he maintains.

As a prime example, Logsdon cites ammonium polyphosphate, which climbed $1,000 a ton while he was writing the book. The rising costs of natural gas, the major source of nitrogen fertilizer, is also complicating matters as more people turn to it as a fuel substitute.

For these reasons, the day may be fast approaching when farmers will have to rely on animal and even human waste to maintain the necessary soil fertility levels, he says.

Logsdon and others even contend that a book, F.H. King's "Farmers of Forty Centuries," outlining Chinese and Korean practices for securing, managing and applying manure will be the manual of farming in the 21st century.

Other sweeping changes will follow, Logsdon contends.

For example, as costs of commercial processed fertilizers spike, he foresees that a growing number of row-crop farmers, desperate for manure, will augment their farms with concentrated livestock operations. Meat production will only be a secondary concern, Logsden contends.

For many Western row-crop farmers, this raises the inevitable question: Will things really get this bad?

For his part, Mitchell is a true believer in the value of animal manure. He's been preaching its merits to farmers for years, occasionally expressing frustration over farmers' reluctance — up to now, at least — to make greater use of it.

But while a true believer in the value of animal manure, he isn't willing to go as far as Logsden.

Commercial fertilizers still command focus

Granted, animal wastes will acquire a growing niche among farmers, he says. Even so, he believes that commercial fertilizers, which have been the standbys of Western farming for more than a century, will continue to command center stage.

Mitchell sees a kind of ebb-and-flow effect at work in the future, as row-crop farmers make greater use of animal manures to compensate for spiking costs of commercial fertilizer.

"First of all, there is going to be a gradual decline of commercial fertilizer use, not a precipitous one," Mitchell says. "But manufactured and mined sources are going to get more expensive and that's going to make manures more attractive."

Even so, manures are no panacea, he stresses. They are hamstrung by a few limiting factors, notably the excessive levels of phosphorus that build up as manure is applied season after season.

"Yes, you can put on excessive rates of chicken litter, for example, and produce a beautiful crop of cotton , corn or wheat," Mitchell says. "But if you do it year after year, the phosphorus levels build up and you will end up dealing with environmental issues."

Back to that ebb-and-flow effect, Mitchell says.

"We're going to use manures where we can and supplementing them with expensive synthetic fertilizers, especially on our nonlegume crops — crops such as wheat, grains, corn, forages, pasture grasses and hayfields."

He also foresees closer integration between row-crop and livestock operations, though not to the degree Logsden foresees.

"In the South, especially in Georgia, we're seeing more poultry farmers locating to areas of intensive row cropping," Mitchell says, adding that a similar effect is occurring in the Midwest as more feedlot operations locate near areas of intensive row-crop farming.

Even so, in as specialized a field as agriculture, Mitchell expresses doubt that large feed operators would want to become involved in row-crop production or vice versa.