Fertilizer Placement Risk Management

I have been farming with my brother Glen in the Carrot River Valley region of North-Eastern Saskatchewan since 1980.

From the years 1990 through 1994, I served as the Soil Conservation Specialist for the S.S.C.A. for North-Eastern Saskatchewan.  I had the great fortune to be involved in extension work during the early days of direct seeding and observed the many “Farm Shop” concepts designed to place the seed and all of its nutrient requirements into the soil in a single pass. Virtually all of these concepts involved side-banding, where 1 or 2 rows of seed were placed approximately 1.5” to the side and approximately 1” above the nitrogen band. Many of these concepts were taken to market, and a few are still available today.  However, during my term with SSCA, I observed every one of these side-band concepts severely damage or kill a crop somewhere every year. Many of us in the agronomic community were convinced that the problem lay with excessive soil disturbance causing the seed and fertilizer to mix, and excessive evaporation. 

Starting in 2008, small plot fertility trials were established to try and establish safe distances of N fertiliser from the seed row in one-pass seeding systems using a Fabro disc plot drill. Phosphorous placement strategies were also included in these trials. All sites were randomized and replicated 4 times. Wheat and canola were the crops used in the trial. The trials are done in cooperation with the University of Saskatchewan and  North Dakota State University.

After over 2600 plots resulting in 8 station years of data, we are observing that ammonia based nitrogen fertiliser is causing a problem for the germinating seeds and subsequent root growth.  It appears that the nitrogen fertiliser conversion reaction in the soil; from the initial NH₃ form to NH₄, then finally to NO₃ (nitrate), the ammonium (NH₄) is hurting any germinating seeds closer than about 2 inches from a nitrogen band and that subsequent root growth will damaged or succumb to NH4 encroaching on the seed row. This might explains why side-banding seeders manufactured today that achieve excellent seed and fertilizer placement with less seed bed disruption are causing similar damage to crop growth that I observed during my extension tenure with SSCA.

Stabilizing the Nutrient sources in adverse soil conditions is also a consideration; and may be influenced by factors such as placement fertilizer sources and the presence of stabilizers in the nutrient band. Ensuring that the crop has enough available nutrient through the growing season to maximize yield and quality with a one pass seeding system can be influenced by several management strategies.

As a farmer and an agronomist, I have always believed that seeding equipment should be designed to deliver an agronomic package that a crop needs.  Stand establishment is critical, and a zero-till seeding tool must have the ability to place the seed at the desired depth, adequately separated from the nitrogen band to ensure vigorous growth in a wide range of conditions. 

History has taught many of us in the agronomic community that a crop that establishes quickly, and has it’s nutrient band far enough away so as not to reduce the crop’s vigor will be a competitive crop, will make weed control an easy task and make harvest a bountiful experience…most of the time!