In-Row Starter Fertilizer?
Saturday, April 15, 2006
filed under: Fertility
Starter fertilizer may be banded 2x2 (two inches beside and below the seed at time of seeding). An in-row starter or ‘pop-up’ fertilizer generally isn’t recommended, since the germinating sunflower seedling is very sensitive to soluble salt in the soil and fertilizer applied in the row at seeding.
Germination conditions (cool, wet or very dry conditions cut availability and uptake of nutrients) and distribution of nutrients in the soil influence the possible need (and safety) for starter fertilizer. North Dakota State University points out that if more than 10 pounds per acre of nitrogen (N) or potash (K2O) is placed in the row under dry conditions, it will usually reduce stands or injure seedlings. Somewhat higher levels of phosphate (P2O5) can be placed with the seed at planting.
The typical recommendation, according to NDSU, is to limit the total amount of fertilizer to no more than 10 pounds of nitrogen plus potassium in seed-placed programs. In dry springs, even this rate may be too high. If you are using pop-up fertilizer, be sure to calibrate each row to make sure that one row is not over applying at the expense of another.
Of course, growers experiment, and the best knowledge about growing sunflower and other crops often comes from the growers themselves. Following is an actual chat room discussion on using starter fertilizer with sunflower from www.notill.org – this is the web site of No-Till on the Plains Inc., a non-profit educational organization providing information to farmers on adopting no-till. See the links to no-till resources and no-till talk, where the following dialogue amongst three sunflower growers was posted:
Sunflower grower #1: Read in the Sunflower magazine not to put fert in row. I was planning to put the 10-34-0 starter in row with Keetons. Is that ok or not??? It of course would be only 5-7 gal per acre.
Sunflower grower #2: No it's not ok. I put a 5 gpa mix down as a popup (mix was 50% of 10-34-0 and 50% water). I still saw problems in places. Where i saw the most problems was in the drier areas of the field. Throw the starter into the N mix and just plant.
Sunflower grower #3: If you go with a lower salt content fertilizer you can do it, and maybe if you just dropped the gallons of fertilizer down. This year we tried it with some knowledge from the people at Assure Crop and we put on 2-3 gal. of 5-20-5 and 2 gal. of water, along with 1 quart of Zinc. That is a 100% orthophosphate fertilizer, and this year we are going to move to using 7-25 blend which is a blend of ortho and polyphosphates. Even used the above mixture on cotton with no observed detrimental effects. Dry soil will increase the risk though. We had plenty of moisture when we were doing this.