Wednesday, November 15, 2006

Cover Crop, Amendment, and Tillage Effects on Collembolans and Nematodes in an Organic Vegetable System.

Douglas Collins1, Craig G. Cogger2, Ann Kennedy3, Tom Forge4, and Andy I. Bary2. (1) Washington State Univ, - REC, 7612 Pioneer Way East, Puyallup, WA 98371-4998, (2) WSU - REC, 7612 Pioneer Way East, Puyallup, WA 98371-4998, (3) USDA-ARS, WSU USDA-ARS, 217 Johnson HallPO Box 646421, Pullman, WA 99164-6421, (4) AAFC, 6947 Highway 7, Agssiz, BC V0M 1A0, Canada

Soil organisms are sensitive indicators of changes in soil properties.  This study reports the effects of different organic management practices on soil collembolans and nematodes.  Cropping systems in the experiment vary the cover crop species, tillage frequency, and planting time.  The two organic amendments are relatively nitrogen-rich chicken manure compost and relatively carbon-rich yard waste and dairy solids compost.  Tillage treatments include intensive conventional plowing and rototilling and a less intense low-speed spader.  Collembola were isolated by Berlese-Tullgren funnel and identified to the family level at 3 separate dates in 2005.  Cropping system significantly affected total collembolan populations only at the post harvest sampling.  Amendment did not significantly affect collembolans but the low carbon amendment favored higher collembolan populations early in the season (p>0.09) while the high carbon treatment favored higher collembolan populations mid season (p>0.13).  Tillage intensity did not significantly affect collembolans, though the low intensity spader favored higher collembolan populations than rototilling at each date tested.  Nematodes were sampled once, post harvest, and isolated with a modified Baerman funnel and total nematodes were counted.  There were no significant tillage, crop rotation, or amendment effects on total nematode populations.