Corn School: Don't get knocked out by fertilizer burn

Starter fertilizer can give a corn crop some early-season punch, but if you’re not careful with application rates those new plants could get knocked out by fertilizer burn.

Banding fertilizer in a 2-by-2 band beside the seed promotes early growth and vigour but too much nutrient too close to the seed can injure roots and lead to poor developing and variable stands, says Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) corn lead Ben Rosser.

On this episode of the RealAgriculture Corn School, we catch up with Rosser at the recent FarmSmart Expo at OMAFRA’s Elora, Ont. research station where he offers tips on diagnosing fertilizer burn in a corn crop.

The first red flag is stand variability. Uneven plants and bare spots where seeds have not emerged means there is trouble under ground. Rosser advises growers to dig up the smaller laggard plants and look for tell-tale signs of fertilizer burn. On injured plants, growers will typically notice that seed roots are missing or shorter than they should be. Another clue is black or brown root tips indicating the roots have died because of fertilizer burn. (Story continues after the video.)

When it comes to starter fertilizer, Rosser says it’s best for growers to play it safe. OMAFRA’s guidelines for normal growing conditions are as follows: When using urea-based fertilizer in a 2-by-2 band on 30-inch corn rows, no more than 36 pounds of N per acre (or 71 lb of N + K20 + S). When using non-urea-based fertilizer, no more than 47 pounds of N per acre (or 105 lb of N + K20 + S).

Click here for more Corn School episodes.

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