Alabama

Alabama tests included no-till, non-irrigated cotton and corn with evaluations of ammonium nitrate, urea, urea-AS blend, UAN solution, Agrotain, Nutrisphere, Nitamin Nfusion, ESN, poultry litter and calcium chloride.

Controlled release nitrogen and nitrogen stabilizer products did not show any yield advantage compared to more conventional nitrogen sources such as urea, ammonium nitrate, UAN solution, or the urea-ammonium sulfate blend, which is being sold as a substitute for ammonium nitrate. Agrotain did not reduce ammonia losses in general but did reduce losses when both urea and UAN solutions were applied to a high residue cover.

Poultry litter results in very high ammonia losses when applied as a sidedress to both cotton and corn. For the relatively low, non-irrigated yields represented by this study, the newer, controlled-release nitrogen products failed to produce a consistent yield advantage over traditional nitrogen materials such as urea, UAN solutions, or a urea-ammonium sulfate blend.

Arkansas

In Arkansas, researchers looked at conventional-tilled, non-irrigated corn and cotton. ESN was compared to urea at five rates of application, plus no nitrogen as a control.

The 2010 summer was drier than normal, making fertilizer nitrogen losses from denitrification less likely than in wet years. Corn yields, averaged across all nitrogen rates, were numerically greater by 10 percent when ESN was applied pre-plant compared to urea applied pre-plant. Yields of cotton treated with urea and ESN were not significantly different at one site, but were significantly different at another site.

These results indicate that ESN is a suitable, alternative nitrogen fertilizer (to urea) for both crops. Use of ESN as the pre-plant nitrogen source does not necessarily guarantee greater corn and cotton yields than urea under all conditions but likely helps reduce the risk of losing greater amounts of nitrogen in wet years. ESN should be considered a tool that can enhance nitrogen management and crop uptake. Additional research, encompassing several years and various field and weather conditions common to Arkansas, is needed to determine the frequency and magnitude of yield increases and whether other crop management benefits may be realized when ESN is used in place of urea for pre-plant nitrogen applications.

Florida

Florida studies included tomatoes and bell peppers, irrigated and under plastic mulch. Research looked at three products: New Suryamin, Megacal, and BioPotash. The products did not show any effective yield or quality advantages in 2009 as nutrient requirements of both green bell peppers and tomatoes were more than adequately met through both pre-plant soil application and supplemental nitrogen fertigation. However, in 2011, as the treatment combinations were changed appropriately to document the effects, yields and performance in both crops were significantly lower in absolute control and with product sprays alone indicating the need for regular fertilizer applications.

In tomatoes, application of the product spray resulted in significant yield increases over both absolute control and the standard recommendations, indicating that under intensive nutrient management practices foliar spray may help tide over nutrient stresses, particularly with regard to highly leachable and mobile nutrients such as nitrogen and potassium.

A 25 percent savings in fertilizers was realized without yield reductions when fertilizer was applied at standard recommendations in combination with the product spray. In green bell peppers, a 25 percent savings in fertilizer was possibly derived by the 75 percent SRP and 25 percent product spray combinations.

Also, the granular and foliar spray combination at 50 percent dosages produced significantly higher yields, suggesting that if the dosages of the product combinations of soil and foliar applications were increased to 100 percent, the potential is to increase yields or to achieve the highest yields. Foliar applications of nitrogen and potassium products at 100 percent labeled dosages could sustain the supply to meet all the crop nutrient requirements.