There are many foliar applied nitrogen products available on the market which claim to, among other things, increase plant nutrient uptake, reduce fertilizer volatility, and in the case of some products, cause nitrogen to be available to the plant longer through slow release technology.

The NutrientStar program conducted a search of the peer-reviewed scientific literature for data on the effectiveness of slow-release and foliar applied nitrogen products such as methylated urea and urea triazone, and found insufficient data exists to adequately assess the efficacy of these products when used on commodity crops, particularly corn.

The NutrientStar Science Review Panel discussed the status of such products and concluded that field-scale, replicated strip trial data are needed to document the effectiveness of foliar applied nitrogen products. Of specific interest is their ability to increase uptake of N and the resulting benefits either to grain yield, grain quality, and/or nutrient use efficiency, such that smaller total N application rates can give the same yield level as obtained when N fertilizer is applied via conventional soil-based application methods. Before using these products on crops, farmers and advisors are encouraged to conduct field-scale, replicated strip trials to evaluate product effectiveness.