Ramsey County Ag Column

By Bill Hodous

June 29, 2009

Howdy!!!

Well it finally felt a lot like summer this past week and if we would take a look at the NDawn GDD’s we would find that we actually gained ground from the the previous reading of 125 days behind normal.  This morning we are at 548 Growing degree units for the year (based on May 1 date) but still about 100 GDD’s behind, this week sounds cooler in both nights and days.  Where we really make up our units is warm uncomfortable sleeping nights.  Rain amounts varied significantly around the county with amounts ranging from 2 inches up to 5 plus and some of you had an additional upto .7 inch of rain on Saturday to include a little hail.

The Ramsey County and Towner County Crop Improvement association will be holding its annual field days coming up in July.  The tour will be held at the site west of Starkweather along hwy 17.  This site is approximately 8 west of Starkweather right along the highway.  We planted a corn strip trial, soybean trial, small grain variety performance trial and also a edible bean trial.  We have several companies entering the plot this year, in all crops.  We also have Marcello Carena (NDSU corn breeder) in the plot doing corn research.  This plot was developed to enhance the economic value of the farming community.  Stop by and take a look.

NITROGEN AND NODULATION IN SOYBEAN

Soybeans are legumes that form a beneficial relationship with specialized bacteria to fix atmospheric nitrogen (N) making it available to the soybean plant. In North Dakota soybeans do not normally require N fertilizer because of this relationship with beneficial bacteria. The nitrogen-fixing bacteria colonize host roots and form nodules (small swellings) on the root system (see picture). These nodules are pink or red inside when they function properly. Nodulation is decreased when Nitrogen is available in the soil. Limited nodulation may also occur in fields where there is no previous soybean cropping history (limited numbers of beneficial bacteria). Other factors that may reduce nodulation are wet conditions early in the season or dry soil conditions. The presence of root rots may also inhibit the ability of the bacteria to form nodules. It is recommended to check roots for nodules. Carefully dig up plants to avoid sloughing off the nodules and wash them in a bucket of water. Check a number of locations in each field. Jay Goos did a demonstration on nodulation and fixation of nitrogen from a soybean plant with the demonstration clearly showing that the Nitrogen available to the plant resulted in lower numbers of nodules and smaller nodules. Most fields will have some residual nitrogen at the beginning of the growing season and soybean plants will use this Nitrogen. In North Dakota, we do not recommend the application of Nitrogen fertilizer if the plant is able to normally nodulate and provide the needed Nitrogen to the plant from the symbiotic relationship with the beneficial bacteria.

Hans Kandel
Ext. Agronomist
hans.kandel@ndsu.edu
 

R. Jay Goos
Professor - Soil Science
rj.goos@ndsu.edu

524 4th Ave #5, 2nd Floor Ramsey County Courthouse
Devils Lake  ND  58301
701-662-7027
email - NDSU.Ramsey.Extension@ndsu.edu