Yield Penalty from Second Year Soybean

John Grove, Agronomic Soil Scientist and Director, Research and Education Center, University of Kentucky

Growers are considering planting soybean after soybean, especially full season soybean after full season soybean, over some acreage in 2017. Many growers have little experience with second year full season soybean, having kept with their existing crop rotations. Other growers, experiencing problems like soybean cyst nematode in some fields, have avoided soybean after soybean on all acres they manage. I observed two extension agricultural economics presentations modeling profit/loss to different crop rotation options, and where second year soybean yield loss relative to first year soybean was set at either 5 or 10 %, in the absence of field data.

Field Day and Workshop for Herbicide Resistant Weeds in Kentucky

University of Kentucky Extension Weed Specialists are hosting a a Herbicide Resistant Weeds Workshop and Field Day on August 6, 2014 from 8:30 am to noon (eastern) at the University of Kentucky Research Farm in Woodford County. The plots and field is located at the corner of US 60 and US 62.

Participants will view field research plots on Marestail (Horseweed) control. The workshop will include discussions on Palmer Amaranth as well as other herbicide resistant weed species.

Pesticide Education Credits: 2 General & 1 Specific
CCA Credits: 3 Pest Management

For more details contact:

J.D. Green jdgreen@uky.edu or James R. Martin james.martin@uky.edu

CCA Credits: 3 Pest Management

Burndown Weed Control for Corn and Soybeans

Jim Martin and J.D. Green, Extension Weed Scientists, University of Kentucky

The status of weedy vegetation in corn and soybean fields ranges from very clean to very weedy. Burndown treatments applied last fall or during the last few weeks have created a clean seedbed. Burndown treatments that had a soil-residual herbicide look cleaner compared with those that did not have a soil-residual herbicide. This is especially true with marestail. However, do not expect these fields to remain clean for long since the warm temperatures will likely degrade soil-residual herbicides sooner than normal and allow weeds to emerge.

The amount of weedy vegetation in fields that have not yet received a burndown will vary depending on weeds present. With the warmer temperatures cool-season broadleaf weeds such as henbit, purple deadnettle, and common chickweed are maturing earlier than normal and will soon dieback and not likely to be a significant factor unless cooler weather conditions return. However, such weeds as marestail, giant ragweed, ryegrass, and volunteer wheat are growing well and need to be monitored. This may motivate growers to apply burndown treatments earlier than normal in order to manage weeds before they become too large.