Following last summer’s devastating hail event on our Morgan field we were advised to plant Liberty Link soybeans this year to give us later season options for weed control. Driving by the field one week prior to planting made our stomachs turn. The weeds had grown very quickly this spring and were threatening to make planting difficult. We sprayed a burn down herbicide on the field and, after working it with our vertical till machine a week later, the planting went quite smooth.
Spraying Liberty Link Soybeans
A pre-emerge herbicide was applied after planting and again about a month later. Two weeks after that, we had a lot of grass laughing at us as it continued to emerge and flourish. An application of Liberty was applied and now we are preparing to cultivate the field on Monday, July 17. A lot of extra effort and money has been spent on this field due to last June’s hail. We expect our efforts to pay off by keeping the weeds from seeding. This should make the future years of weed control a little more normal.
Weed control in soybeans is a summer long effort. In early July, we made our 3rd pass with the sprayer. The first pass was right after planting and consisted of a herbicide to burn down existing weeds as well as one that gave us about 1 month of control for emerging weeds. The second pass was similar but using chemicals with different modes of action to circumvent weeds becoming resistant to the few chemicals we have left. For the 3rd and final pass we use Roundup and a grass control herbicide. The grass control herbicide controls the volunteer corn. The Roundup will control some weeds that aren’t resistant. We will use hand weeding as a follow up to control weeds that are Roundup resistant.
Early in spring, pre-emerge herbicide was applied to our corn fields. This picture shows how necessary that is. These 12 rows are in a location that we cannot get to with our field sprayer and no herbicide was applied early. You can see the weed pressure that exists in this part of the field. Those weeds will quickly rob the corn of it’s full yield potential.
Post emerge spraying will clean up weeds that come through the early application. Later we will cultivate these fields and build ridges in the corn that will serve as the seedbed for next year’s soybeans.
As planting nears, we need to be assured that our liquid handling systems are working well. It’s a tricky call as to when we can put water in these systems and not risk having them frozen and cracking components. Once testing is done the equipment is stored in a closed machine shed during freezing nights yet to come.
April 1 and 2 were the days we felt comfortable with this call. The planter handles liquid fertilizer, specifically Ammonium Thio Sulfate (ATS), that is banded as a narrow stream over the seed once the furrow is closed. The rain will then take the nitrogen (N) and sulfur (S) down to the roots. We apply 8.3 gallons/acre to get a total of 24 #/Acre of S on the field. The N is just an added bonus to the S application and is subtracted from the total N we put on our fields so we don’t over apply our nitrogen. The fertilizer application is controlled by our John Deere GS3 monitor mounted in the cab. We also have a controller for insecticide application using the Smart Box system as well as a Precision Planting 20/20 monitor system tied to an iPad for precise monitoring of seed placement.
Our Top Air sprayer handles the bulk of our chemical applications for weed control. It needs to be in top notch condition for application of herbicides soon after planting. The soybean pre-emerge herbicide has a 3 day window to be applied so it won’t damage emerging seedlings.
The time has come to do our post-emerge application of Roundup on our soybeans. This spring we used a pre-emerge herbicide on our our fields. The soybean fields looked so clean we delayed longer than usual with our post emerge application. When we started spraying we realized the mistake we had made. The remaining weeds were 1 foot or taller. Too large for Roundup to do significant damage to. Many will burn down and then come back. Scouting the field one week later we already saw signs of new growth on waterhemp that looked dead from a distance. We also found 1 1/2 foot tall waterhemp than had little or no damage to the plant from our Roundup application of 38oz/acre.
On two fields we chose to take more drastic measure and hired migrant workers to hoe out our resistant weeds. They showed up two weeks after spraying and spent a few days walking the fields.
We also dug our old bean rider out of the shed and did some field border spraying from that.
Not to leave any weed patches untouched, we finally brought out our own hoes and went after some stray weeds with them.