Organic choices for consumers are growing

Nutrition Health Review, Winter, 2002

From apples to zucchini, fresh, attractive, and tasty organically grown produce is bursting forth from supermarkets across the U.S. Americans are choosing appealing organic items from other sections of their supermarkets, too, including breads, and prepared convenience items--even baby foods. In fact, in the year 20001 retail sales of increasingly affordable organic products reached $7.8 billion in the U.S. Today, 25 percent of Americans buy organic products.

From coast to coast, Agricultural Research Service (ARS) scientists are bringing their expertise and advanced technologies to bear in helping organic farmers tackle their toughest problems. Some of their studies are being conducted on ARS-managed research sites that are certified as organic farms. Other experiments are under way on working organic farms ranging from small family operations to large, corporate acreage. For a farm to be certified as organic, each of its products must be grown in accordance with organic standards.

The findings from these ARS studies help organic and conventional farmers alike.

Along California's central coast, Eric B. Brennan has been targeting the organic farmer's single biggest expense--weeds. He is a horticulturist at the ARS Crop Protection and Improvement Unit in the Salinas Valley, the "salad bowl of America." Many conventional and organic growers of broccoli, lettuce, and sweet peppers regularly plant so-called cover crops in their fields after they have harvested their cash crops. Instead of being cut and sold, the cover crops are plowed under to nourish the soil. But weeds make inroads into these cover crop plantings, says Mr. Brennan, and the weed seeds infest the soil for next year's cash crop.

Mr. Brennan has been comparing two different patterns of planting the seeds of cover crops to see which method results in fewer weed seeds. In the traditional pattern of planting, the tractor-drawn seeder is driven back and forth along the field, up and down every row. In the crisscross or crosshatch seeding pattern, the planting rows intersect. He says:

   "Shifting the geometry of the pattern from the traditional to the
   crosshatch may make a significant difference to the grower That's
   because the crosshatch pattern changes the orientation of one plant
   to another. This results in more even distribution of the cover crop
   plants and fewer gaps where weeds may grow and produce seed. The
   cover crop plants might then shade more of the soil surface earlier
   in the season so that the weeds won't produce as many seeds.
   However, crisscrossing the field for planting takes more tractor
   fuel because the field must be covered twice instead of just once,
   and it may increase soil compaction.

   "Even a slight reduction in weed control costs is important. That's
   because the organic farmer today may have to spend up to $1,000 an
   acre to clobber weeds.

   "Conventional farmers spend only about $50 an acre on the herbicides
   that knock out every weed in sight. Organic farmers, of course,
   can't use conventional herbicides."

Mr. Brennan conducted the study on both a U.S. Department of Agriculture (USDA) certified organic field down the road from his laboratory and on a soon-to-be-certified organic field of Takamura & Antle (T&N), one of the nation's largest growers of organic lettuce. For the cover crops in the study, Brennan, along with Mark Mason, T&N's pest control advisor, and Richard Smith, a local University of California Cooperative Extension agent, decided to plant Merced rye and Sudan grass. For each pattern, they used equal amounts of each cover crop seed on each of the plots. They have been sampling the sites for seeds of hairy nightshade, shepherd's purse, burning nettles, and other common weeds.

Small Vegetables Are a Big Hit

Baby salad mixes--the popular blends of Crisp, bite-sized salad greens--are the focus of another of Brennan's studies. These assortments of easy-to-use greens include small, colorful favorites like romaine lettuce, green leaf lettuce, and radicchio. The individual greens that make up these fun medleys are harvested mechanically. They are clipped off at the surface of the field, washed at a packinghouse, quickly sorted into pleasing assemblies, and then shipped to grocers for sale in loose bins or in small, branded retail packages.

Unfortunately, a vigorous cover crop can pose problems later on when the baby greens are harvested. As he points out,

   "Most of the cover crop is plowed under at the end of its season,
   but that practice may leave behind some stems on the surface. And
   the plowing-under process itself brings up roots. If that residue
   has not decomposed by the end of the next growing season, the
   harvester can pick up the cover crop residue along with the baby
   greens. The problem is that the residue is proportionately larger
   than the small greens. This problem does not exist when one is
   harvesting full-sized greens, because they are hand-picked and the
   residue is proportionately smaller."