Double crop soybeans in WI may be worth it
The Wisconsin winter wheat crop remains 3 weeks (developmentally) ahead of where we were at this time last year. If this progress continues we can realistically be cutting dry wheat in southern WI by July 1st. Couple that with Nov. CBOT soybean contracts at $12.81 (5/22/12) and though still risky we can start to pencil out a potential profit for WI growers to double crop soybeans in 2012.
The first two questions growers considering double crop soybean will likely ask are “What can be done to expedite wheat harvest” and “Can I apply glyphosate or some other desiccant to my winter wheat to aid in dry down?” First read the label of any product you intend to use to make sure the application is legal. If the product is labeled, read the application timing information and understand how to properly stage the wheat plant prior to application. Below is subsection taken from the Roundup WeatherMax label.
Preharvest (feed barley and wheat only)
USE INSTRUCTION: This product provides weed control when applied prior to harvest of feed barley and wheat. For feed barley, apply after the hard-dough stage and when the grain contains 20 percent moisture or less. For wheat, apply after the hard-dough stage of grain (30 percent or less grain moisture). Stubble may be grazed immediately after harvest.
PRECAUTIONS, RESTRICTIONS: Do not apply more than 22 fluid ounces of this product per acre. Allow 7 days between application and harvest or grazing. Preharvest application is not recommended for barley or wheat grown for seed, as a reduction in germination or vigor may occur.
In winter wheat, the timing for WeatherMax is hard dough (or 30 percent or less grain moisture). An application before this growth stage will not only be off label, it will likely reduce grain yield as the plant is prematurely killed. We do not want to sacrifice any wheat yield in hopes of gaining a few extra days for soybean. In terms of its effectiveness to aid in dry down, I have spoken with many colleagues across the country as well as Canada and the consensus is that the application will not greatly enhance dry down. As you note in the text from the WeatherMax label, the intent of the product is to provide weed control, not increase the rate of wheat drying.
An alternative to herbicide desiccation is to swath the wheat crop when the grain is still wet and let it dry in windrows. This option is risky because rainfall on swathed wheat can lead to sprouting in the head and raking a wet windrowed wheat crop can lead to large shatter losses. Also, an appropriate combine header is needed to harvest swathed crops.