Hultgreen: Effect of Seed-Placed Nitrogen and Row Space on Direct Seeded Canola

Date: February 2007
Term: 4 years
Status: Completed
Researcher(s): Gordon Hultgreen, Prairie Agriculture Machinery Institute, Humboldt, SK
SaskCanola Investment: n/a
Total Project Cost: n/a
Funding Partners: n/a

Project Summary

This study developed seed placed fertilizer rate recommendations for use when direct seeding canola with air seeders that have wide distribution patterns of seed and fertilizer. The study results were used to assist in developing guidelines for seed placed rates of fertilizer published in the Saskatchewan Agriculture and Food Farm Facts titled Guidelines for safe rates of fertilizer applied with the seed.

In this study seed placed fertilizer rate recommendations were developed for use when direct seeding canola with air seeders that have wide distribution patterns of seed and fertilizer. Four different designs of air seeder openers were used, with various spread patterns of seed and fertilizer. All openers were placed on 8" centres and spread both seed and fertilizer across the width of the openers to achieve solid seeding.

This project indicated that urea nitrogen may be seed-placed with canola up to 70 lbs/acre of actual nitrogen (152 lbs/ac of 46-0-0) on an 8 inch row spacing, depending on available moisture at the time of seeding and placement of the seed in relation to the fertilizer. However, if the row spacing between the openers is different than 8 inches, then certain guidelines need to be considered.

If the row spacing is greater than 8 inches, the row width utilization (R.W.U.) will be less and therefore the amount of seed placed nitrogen would be higher. If the row spacing between the openers is less than 8 inches the R.W.U. will be greater and therefore the amount of seed placed nitrogen would be less. Altering the row spacing from 6, 8 and 12 inches dramatically affects the R.W.U. with each individual opener. As the R.W.U. decreases with the different openers, a dramatic reduction in plant emergence may occur. This may cause an increase in weed pressure and a reduction in yield.

High rates of seed placed nitrogen can cause increased days to maturity and a reduction in crop quality (i.e. green seed) and a decline in oil content. Emphasis also has to be put on factors such as soil organic matter content, pH, conductivity, soil texture, and cation exchange capacity when determining the amount of urea nitrogen that can be placed safely with the seed.

The study results were used to assist in developing guidelines for seed placed rates of fertilizer published in the Saskatchewan Agriculture and Food Farm Facts titled: Guidelines for safe rates of fertilizer applied with the seed, which has been updated to include many more scenarios with more precise seeding equipment, different soil textures and fertilizers, as well as a variety of crops. Go to:

Website Link: http://www.agriculture.gov.sk.ca/Default.aspx?DN=7aec0e5d-f7f3-47e6- a839-db96986a795c

Full Report PDF: Effect of Seed-Placed Nitrogen and Row Space on Direct Seeded Canola