With the early grain harvest this year, soil testing is already in high gear in many areas. The early trend in soil nitrate levels is higher than last year. AGVISE has already tested over 5000 soil samples from wheat fields in the northern region. The data below represents the percentage of wheat fields testing in each range for soil nitrate (0-24” samples).
Soil Nitrate Range % of fields % of fields
0-20 lb/a 25% 49%
21-40 lb/a 43% 34%
41-60 lb/a 17% 10%
61-80 lb/a 7% 4%
81-100 lb/a 3% 1%
Over 100 lb/a 4% 2%
Soil Samples tested as of August 24, 2015
Why are more wheat fields testing higher in soil nitrate this year?
- Many growers applied higher rates of N fertilizer this year to reduce chance of lower protein wheat like they had last year.
- Wheat yields were not quite as high as expected this year, so the total N uptake by the crop was a less than last year.
- A warm summer may have resulted in increased N mineralization from the soil after the wheat crop stopped taking up N (warm July and August).
- Most areas did not lose N from the soil profile to leaching or denitrification during the growing season like the previous year.
Please give our staff of Soil Scientists a call if you have any questions.
Bob Deutsch or John Lee – Soil Scientists, AGVISE Laboratories – 701-587-6010