Starter Fertilizer Role in Increasing Corn Yield

From AgVenture's Seeds for Success Agronomy Update, February 2016

Starter fertilizers can provide essential nutrients to young corn plants during early season growth periods. While it is difficult to predict exactly if yield response will occur, under some conditions, starter fertilizers can greatly improve the potential for yield response. According to University of Illinois research, starter fertilizers provided benefits:

  • Where phosphorus (P) availability is low – readily available P is essential early in the growing season. Young corn seedlings need P near the row on soils testing less than 20 pounds P per acre. However, University of Illinois indicates that even on medium- to higher-testing soils, starter will increase yield potential if the soil remains cool for several weeks after plant emergence. High pH soils (>7.3) often respond well to starter fertilizer since high pH reduces P availability.
  • Cool soil temperatures – in reduced tillage systems, where residue reduces soil temperatures, root growth can be slow, and thus is the nutrient uptake near the seed. Cool soils also reduce the rate of microbial release of nitrogen (N) from soil organic matter. Starters help provide N near the seed. U of I research shows significant corn yield increase 90 percent of the time in no-till situations, but roughly 30 percent of the time in conservation tillage systems. N combined with P gave better responses.

University of Minnesota research rigorously tested starter fertilizers in a variety of growing environments over several years. Results of their studies show that starter fertilizers containing N, P, and Sulphur (S) increased early growth and reduced plant variability of continuous corn with reduced tillage. Yield responses were inconsistent but were more likely on poorly-drained and glacial-till soils. Where starter fertilizers were used containing N, P & S, grain moisture at harvest was also reduced. Potassium (K) starters are important especially in reduced tillage or low K soils. Complete NPK starters typically provide more consistent responses. Always start with your soil test. Consult your AgVenture Yield Specialist.