N-Serve® (Nitrapyrin)

Note about research results available for N-Serve® (nitrapyrin):

Research on N-Serve® was completed on small-plot trials. The majority of studies did not report sufficient information about environmental conditions and practices to enable a full assessment of the nutrient use efficiency benefits possible from using N-Serve®, therefore we report results that suggest the effectiveness of N-Serve® based on yield only.

The intent of the NutrientStar program is to assess whether nitrogen stabilizers and decision support tools improve nutrient use efficiency (NUE). However, few of the trials applied more than one nitrogen rate, which prevented the calculation of NUE. NutrientStar also attempted to analyze the results of trials based on rainfall, but because few of the trials reported daily rainfall after nitrogen application, we were unable to do so, and the yield results were averaged across all the trials.

NutrientStar would be better able to assess the conditions where N-Serve® might be effective as a nitrification inhibitor if rainfall data had been provided. An assessment could then involve separating the trials into two categories: trials where sufficient rainfall occurred in the 30 days after application of N-Serve® to leach nitrate from the root zone, which would greatly increase the chance of N-Serve® improving NUE, and trials where insufficient rainfall to leach nitrate from the root zone occurred in the 30 days after application, which would greatly decrease the chances of N-Serve® improving NUE.

The NutrientStar program is committed to promulgating common standards for research and minimal data requirements that will allow products and tools to be fully assessed for their ability to improve NUE in the future. Information about protocols required to fully assess products and tools is available here.

Product Description and Mode of Action

Nitrapyrin the active ingredient in N-Serve® is a chlorinated pyridine compound that functions as a nitrification inhibitor. It delays the nitrification process by inhibiting the Nitrosomonas spp. bacteria that convert ammonia to nitrite, thus retaining more fertilizer-applied nitrogen in a form readily available to crops. This can prevent the loss of soil nitrogen through leaching or runoff of nitrate (NO3), or gaseous emissions of nitrogen (N2) and nitrous oxide (N2O) gases. For over 40 years, nitrapyrin has been used and studied internationally as a nitrification inhibitor with the goal of increasing crop yields and reducing the environmental impacts of nitrogen fertilizers used in agriculture.

Crops

N-Serve® is labeled for use with anhydrous ammonia on corn and wheat where the ammonia will be incorporated into the soil.

Users

Farmers who apply nitrogen as anhydrous ammonia.

Cost

Varies based on volume.

Form

N-Serve® is an oil based product formulated as an emulsifiable concentrate.

Research Results from Field-Scale Strip Trials

NutrientStar reviewers found no published research results from field-scale strip trials.

Research Results from Chemistry Trials

Note: Chemistry trials can provide information concerning the effectiveness of a product in laboratory and greenhouse settings but do not provide information related to a products effectiveness in the field.

Lab studies indicate that nitrapyrin could also reduce N losses from NO3 leaching by an average of around 11% (Owens 1981; Timmons 1984). These observations were also seen in field lysimeter studies with corn with average NO3 leaching loss reductions ranging from 7 to 28% over 3 and 6-year periods, respectively (Owens 1987; Timmons 1984). Other early studies of nitrapyrin in the field clearly demonstrated nitrapyrin’s ability to conserve soil N under certain conditions (Nelson and Huber 1980).

Research Results from Small Plots
Overview

An intensive and extensive review of the literature was completed to assess the effectiveness of nitrapyrin products to increase yields of corn and wheat. All the research was completed on small plots. Although plot sizes varied considerably, none were greater than ¼ acre in size.

Corn

The average yield increase for nitrapyrin as N-Serve® with anhydrous ammonia in 216 trials when compared to non-treated anhydrous ammonia was 3.5 bushels/acre, with a confidence interval ranging from 2 to 4.9 bu/acre.

The average yield increase for nitrapyrin with urea in 45 trials when compared to untreated urea was 4.6 bu/acre, with a confidence interval ranging from 1.6 to 7.6 bu/acre.

The average yield increase for nitrapyrin as Instinct®II when mixed with UAN or ammonium sulfate in 81 trials was -0.1 bu/acre, with a confidence interval ranging from -2.1 to +2.3 bu/acre.

The Iowa Soybean Association has also published data from trials they have conducted on the economic returns from N Serve.

Wheat

The average yield increase for nitrapyrin as N-Serve® with anhydrous ammonia in 50 trials when compared to untreated anhydrous ammonia was 1.7 bu/acre with a confidence interval ranging from .7 to 2.7 bu/acre.

The average yield increase for nitrapyrin with urea in 54 trials when compared with non-treated urea was 1.4 bu/acre with a confidence interval ranging from 0.4 to 2.4 bu/acre.

The average yield increase for nitrapyrin with UAN or ammonium sulfate in 17 trials when compared to non-treated UAN or ammonium sulfate was 2.4 bu/acre with a confidence interval ranging from 1.1 to 3.7 bu/acre.

For more information about small plot results on the effectiveness of Instinct® II to increase yield please visit the nitrapyrin summary page.