Given the importance of weed suppression to organic production, this is one of our most complete and involved data sets. Six transects were sampled in each plot during each vegetable rotation. Sampling included plots still in bahiagrass to more fully understand effects of bahiagrass on weed suppression. Over 140 species of weeds were identified and quantified throughout the study.
It will take us a while to sort through all of this laboriously collected data. This will be analyzed as a biodiversity study as well as integrated with other data to assess potential effects on yield, insects, etc.
Our preliminary examination of this data show how important weed control is in understanding our data as a whole. A very pronounced increase in number, coverage and diversity of summer and autumn weeds in 2012 and 2013 was well correlated with the decrease in broccoli yields in these years.
This data was collected in November of each year and is consistent with our observation that broccoli seedlings often had difficulty at this time becoming established because of weed pressure in 2012 and 2013, thus perhaps contributing to decline in broccoli yields. Synthesis of all data should clarify contributing factors.
