Anil Shrestha, with the Department of Plant Sciences at California State University Fresno, talked about research he has been conducting on use of recycled paper mulch for weed control in the establishment of blackberries.

Shrestha said organic growers face special challenges because there are few registered chemicals for berry production.

He and others conducted research on the mulching in a transitioning organic plot at Fresno State. They found that weed biomass around the mulched plants was between 49 and 51 percent lower than around non-mulched plants.

Soil temperature was higher around the plants with no mulch, and soil moisture similar in the mulch and no-mulch plots. Lower soil temperatures in summer may have helped the plants and moisture was retained.

Shrestha said research with paper mulch in strawberries showed slower plant growth due to lowered temperature of the soil, but the mulch helped cut down on nutsedge growth.

He said controlling weeds organically has a range of costs – as much as $350 per acre with herbicides, about $150 for propane burning, steam in about that same range and cultivation at less than $100 an acre.

“Nothing beats iron,” he said, a reference to use of a French plow or a cultivator called the Bezzerides.

Sajeemas “Mint” Pasakdee, advisor to the student-run Fresno State organic farm, talked of research on various brassica plants as a forage crop for grazing lands during transition to organic cropping.

She and other researchers, including Shrestha, evaluated the use of the plants as a winter cover crop to augment growers’ incomes while building soil fertility and improving soil health.

Researchers looked at six varieties: Forage brassica, two varieties of forage turnips, tillage radish and canola. The idea was to test for reduction of soil-borne disease and weed population.

Pasakdee said researchers saw high weed pressure on a one-acre test plot only from broadleaf weeds, but not from grasses.

Earlier, Pasakdee talked of the importance of organic matter for the soil, saying “a good soil is a live soil” and adding that earthworms are “major decomposers of dead and decaying organic matter.”