LTER Biodiversity Weed Harvest Protocol
In use from 2001-01-01 to 2013-01-01
A protocol for a weed harvest to quantify the effect of weed competition on crop yields.
Weeds rooted in a 25 × 100 cm area at two points in each plot are harvested. The sampling locations are approximately 1/3 the distance from north and south borders of the plot. A frame is positioned perpendicular to crop rows and is centered between rows.
In 2001, and 2006-2007 biomass was harvested from all treatments in August – September and separted into two functional groups: weeds (non-crop) and clover
No Data were collected in 2005From 2008-2010, biomass was harvested in October from all treatments and separated into two functional groups: weeds (non-crop) and clover.
In 2011, biomass was harvested from wheat treatments in June and from Corn and Soybean in October and separated into three functional groups, grass, forbs, and clover and bagged separately in the field.
Sometimes clover is a cover crop, other times it is a weed—-separating clover allows it to group as weed if appropriate when data is analyzed. Harvested biomass is NOT sorted to species. No species composition is done.
Weeds are harvested close to the crop harvest date. Weeds in the wheat crop treatments are harvested in late June before the wheat harvest. All other treatments are harvested in the fall.