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  • From: "Lawrence F. London, Jr." <lflj@intrex.net>
  • To: permaculture <permaculture@lists.ibiblio.org>
  • Subject: [permaculture] The potential for growing food from perennial crops
  • Date: Tue, 04 Dec 2007 12:30:58 -0500


<http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2007/11/24/HOFKT0670.DTL>
Article:The potential for growing food from perennial
crops:/c/a/2007/11/23/HOFKT0670.DTL
San Francisco Chronicle
The potential for growing food from perennial crops
Deborah K. Rich, Special to The Chronicle
Saturday, November 24, 2007

Alfalfa fields, as seen on this property near Interstate ...
home and garden

Perennial crops have great potential. Yet they hardly figure in the world's
calorie consumption.

The world's major grains, food legumes and oilseeds - including all of its wheat, rice, corn, barley, soybeans, cottonseed and dry beans - are annuals. These crops covered 80 percent of harvested cropland in 2004.

A food system based upon plants that start each growing season anew from
seeds is inherently risky.

Farmers' efforts to reduce the risk often degrade soil and water and
accelerate the buildup of greenhouse gasses.

Many crop seeds won't germinate if the soil is too hot, cold, wet, dry, crowded or full of clods. With plow and disc, farmers clear the soil of weeds and debris and slice it into a fine crumb. If it's a spring planting, they wait for the soil to warm. For a fall planting, they wait for it to cool. In the arid West, farmers "irrigate up" before planting; in the changeable Midwest, they squeeze in planting between thunderstorms.

Weeds enjoy the farmers' carefully prepared seedbed just as much as crops. Farmers cultivate, spray herbicides or hoe to keep weeds under control while their crops get established.

There is a beginning for perennials as well, complete with seedbed and coddling of seedlings. But the initial soil disturbance and fieldwork pay off for several years.

Alfalfa, a legume grown for animal feed, often produces for five years or more. Without the need to disc and plant each year, tractor use is less, fuel use declines and the soil suffers less degradation.

Agroecologist Jerry Glover of the Land Institute demonstrates the power of
perennial plants.

Arms outstretched, he holds up a clump of annual wheat in one hand and a handful of wild perennial wheatgrass in the other. While the slender roots hanging from the clump of wheat fall barely to Glover's elbow, the boisterous tangle of wheatgrass roots tumbles down to his feet.

"You can visualize roots as a series of safety nets for the soil," he says. "Safety nets not only with depth, but extending over time."

Within the first year of planting, the roots of perennial crops leave little room for weeds. Glover thinks that a reduction in herbicide costs of four to 8 1/2 times is a conservative estimate.

"I have 5-year-old wheatgrass plots that are weed-free and have never had herbicides," says Glover. That saves money, reduces tractor passes and benefits environmental health.

Perennial crops extend the growing season, partly by already being in the ground as winter is ending. In states such as Kansas, where the Land Institute is located, it isn't unusual for only half the days in a month to be suitable for planting.

Perennials start growing first. "Root activity can take place at much cooler temperatures than seeds can germinate," he said.

They also stretch out the growing season. In late September, Glover's wheatgrass had already regrown 4 to 6 inches after being harvested in August while he waits to reseed his wheat field.

"Our annual winter wheat won't do well at all in July or August," says Glover. "It doesn't even matter if we can get the seed to germinate; the winter wheat just can't grow in those temperatures, and the surface of the soil is too dry for the seedlings. Yet our perennial wheatgrass, because its roots are deep down, is able to reach where the soil is more buffered against extremes in temperature and moisture."

Reaching deep into the soil year-round, perennial roots make more efficient use of nitrogen inputs, half of which can leach out of the root zone before plants can make use of it.

"Nitrogen in the soil typically moves with water," says Glover. "You don't want to have water flowing through the system unused. Picture Iowa in April or May. There's no crop growing because it's too cold, but yet they're getting a lot of rainfall."

Not only are nitrate losses a waste of an expensive input - the price of nitrogen is on the rise along with the price of oil - nitrates draining into waterways fuel the spread of coastal dead zones.

Spring and summer nitrate flows out the mouth of the Mississippi River cause massive algae blooms that rob the water of oxygen and create dead zones in the Gulf of Mexico.

The perennial web of roots holds onto more than nitrogen.

The roots anchor the soil and reduce erosion. A study begun in 1888 at the University of Missouri measured the depth of topsoil remaining after 100 years of continuous farming.

Topsoil under plots of perennial timothy grass (a crop cut for hay) was more than two times deeper than the topsoil remaining under annual corn, and almost 1 1/2 times deeper than the topsoil remaining under a six-year rotation of corn, oats, wheat, clover and timothy grass.

With the world's population growing, agriculture must anchor all the soil it can as ever more marginal land is pushed into production.

"We get away with a lot here in North America because our soils are so rich, fertile and deep. The thinner or more poor your soils are, the more you need perennials there to safeguard them," says Glover.

Conversion to perennials cannot happen overnight.

The Land Institute began its perennial breeding programs in 2000. Today it has four breeders and total funding of approximately $2 million.

Glover estimates that the institute is probably at least 25 years out from having a high-yielding perennial substitute for a major grain. The world may come asking for seed sooner.

"How far out we are from having a product partly depends on expectations," says Glover. "Our wheatgrass, for example, right now out-yields some of the world's minor annual crops, such as Ethiopian teff, in a good year. Also, for some of the non-food-crop oilseeds, you don't have all the taste and handling requirements that you have for wheat. You want a very consistent bread, but for oil you're more flexible. And how far we are from a commercially viable crop will partly depend upon world resources."

This article appeared on page F - 9 of the San Francisco Chronicle




  • [permaculture] The potential for growing food from perennial crops, Lawrence F. London, Jr., 12/04/2007

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