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Evaluation of In-Furrow Starter Fertilizer Sources for Corn

Start Date: 2012
Principal Investigator: Dan Kaiser
Organization: University of Minnesota, Department of Soil, Water, and Climate
Status: Complete

Background Info

Placing fertilizer with the seed is typically perceived as a good management practice for the Northern Corn Belt, where soils can remain cool into the early part of the growing season. Placement of fertilizer with the corn seed does pose a potential risk for seedling damage due to salt or high nutrient contents. Traditionally, the salt index of a fertilizer has been thought to be the best way to rank fertilizer sources for seed placement. However, newer research in Minnesota has called into question whether salt index alone is the best indicator. This greenhouse study examines the effects of different fertilizer sources containing nitrogen (N), phosphorus (P), potassium (K) or sulfur (S) on the emergence, early growth and nutrient uptake of corn grown on a silt loam, clay loam and fine sandy loam soil. The resulting data can aid producers in selecting fertilizer and rates that best increase early plant growth and educate them on the risk of seedling damage.

Objectives

Evaluate corn emergence in differing soils following fertilizer applied directly on the seed based on nitrogen or potassium rates

Determine optimum fertilizer rates for promoting top growth and nutrient uptake

Develop models for predicting seed safe fertilizer rates for corn

Develop a new extension publication on fertilizer banded with the seed for corn

Key Findings

The study found that small rates of P applied as starter fertilizer could promote early plant growth and nutrient uptake. Starter N, K, and S seldom affected plant growth except for a sandy soil where small rates of K and S increased plant growth. Fertilizer sources with high salt index values reduced emergence and growth at lower application rates. Sources containing P had the lowest impact on emergence and growth, but also had the lowest salt index values. The fertilizer sources with the highest risk of seedling damage were ATS, AMS, KCl, and urea.

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