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There are few soybean soil fertility studies from north central and northwest North Dakota. The objectives of the research were:
1. Determine major nutrient requirements of soybean in north central and northwest North
Dakota.
2. Determine response of soybean to sugar beet waste lime for pH improvement in acid soils of
North-central North Dakota.
3. Determine the starter fertilizer response of soybean in north central and northwest North
Dakota.
4. Determine the foliar fertilizer response of soybean in north central and northwest North
Dakota.
Methods
Over 3 years, there were 6 different locations. The northern sites had pH > 7, the south sites had pH<7. Each site was designed as a randomized complete block. There were 12 treatments with 4 replications.
1. Check (no fertilizer)
2. Bradyrhizobium inoculated at planting
3. 100 pounds per acre of 11-52-0 broadcast (preplant)
4. 3 gallon per acre 10-34-0 (in-furrow at planting)
5. 3 gallon per acre 6-24-6 (in-furrow at planting)
6. 50 pounds of N per acre as urea (preplant broadcast)
7. Sugarbeet waste lime @2 tons per acre (South on acid soils- preplant broadcast)
7. Iron ortho-ortho-EDDHA seed applied (North, high pH-in-furrow at planting)
8. Sugar beet waste lime @ 4 tons per acre (South preplant broadcast)
9. Naked ortho-ortho-EDDHA seed applied (Levesol-North)
10. Foliar 9-18-9 at V5
11. Foliar 9-18-9 with S at V5
12. Foliar 9-18-9 at R2
13. Foliar 9-19-9 with S at R2
Results
There were no significant differences between treatments consistent through years. There was a tendency for seed inoculation to increase yield, but not all sites. There was also a trend for foliar treatments to reduce yields. Lowest P sites were 7 ppm, with no response to P treatment. Soil pH was as low as 5.8, and no response to lime was recorded. In high pH, there was no response to Soygreenâ„¢. IDC does not seem to be an issue in this region even in wetter years. There was no response to N.
There were minimal increases in protein and oil with fertilizer treatments, and differences were inconsistent between years.
Conclusions
This research indicates that soybean would be most profitably grown with minimal fertilizer inputs, monitoring soil test P and pH to ensure that values do not slip into very low ranges. A low P range should be considered as 6 ppm or less. Low soil pH should be considered as values of 5.5 or less.