Nitrapyrin Effects On Nitrous Oxide Emissions From Maize Fields Fertilized with UAN.

Nitrapyrin Effects on Nitrous Oxide Emissions from Maize Fields Fertilized with UAN

In a context of increasing N fertilizer prices and environmental concerns about N fertilizer losses to air and ground or surface water, a higher efficiency in its management is desired. The use of products that delay nitrification may decrease N losses from fertilizer, thus keeping more of it available for plant uptake. Our objectives were to assess (i) if Instinct^TM, a form of nitrapyrin optimized for use with liquid fertilizers, can both delay and reduce N₂O emissions during the growing season after UAN application in a highly productive maize system, and (ii) how Instinct™ impacts soil N cycling processes, mainly by measuring soil mineral N availability and maize plant N uptake. Our field experiment comprises three N rates (0, 90 and 180 kg hectare^-1), two timings (pre-plant banding and side-dress banding) and with or without Instinct^TM. The study was initiated in 2010 on a dark prairie soil near West Lafayette, Indiana (40°28'07'' N, 87°00'25'' W). Preliminary results show a decrease in nitrous oxide fluxes (measured with vented flux chambers at 10-day intervals) when Instinct^TM was pre-plant applied  and data analyzed in a multiple regression model using data from several sampling dates. Instinct^TM effects on N₂O flux with sidedress UAN were less consistent in samplings trough July of 2010. N-rates were positively correlated with N2O emissions. The effects of the treatments on soil nitrate and ammonium concentrations in the upper 30cm were not consistent across sampling dates.

Juan Pablo Burzaco and Tony J. Vyn

Agronomy Department, Purdue University, 915 W State Street, West Lafayette, Indiana 47907-2054, United States

Corresponding author. Tel.: 001-765-496-2221; 765-496-2926

E-mail: jburzaco@purdue.edu; tvyn@purdue.edu