In Situ Nitrogen Mineralization, Nitrification, and Ammonia Volatilization in Maize Field Fertilized with Urea in Huanghuaihai Region of Northern China.

Zhang, X., Wang, Q., Xu, J., Gilliam, F.S., Tremblay, N., and Li, C. (2015). "In Situ Nitrogen Mineralization, Nitrification, and Ammonia Volatilization in Maize Field Fertilized with Urea in Huanghuaihai Region of Northern China.", PLoS ONE, 10(1: e0115649), pp. 15 pages. doi : 10.1371/journal.pone.0115649  Access to full text

Abstract

Nitrogen (N) fertilization potentially affects soil N mineralization and leaching, and can enhance NH3 volatilization, thus impacting crop production. A fertilizer experiment with five levels of N addition (0, 79, 147, 215 and 375 kg N ha-1) was performed in 2009 and 2010 in a maize field in Huanghuaihai region, China, where > 300 kg N ha-1 has been routinely applied to soil during maize growth period of 120 days. Responses of net N mineralization, inorganic N flux (0–10cm), NH3 volatilization, and maize yield to N fertilization were measured. During the growth period, net N mineralization and nitrification varied seasonally, with higher rates occurring in August and coinciding with the R1 stage of maize growth. Soil NO3−-N contributed to more than 60% of inorganic N flux during maize growth. Cumulative NH3 volatilization increased with N additions, with total NH3 volatilization during maize growth accounting for about 4% of added N. Relative to the control, mean maize yield in the fertilizer treatments increased by 17% and 20% in 2009 and 2010, respectively. However, grain yield, aboveground biomass, and plant N accumulation did not increase with added N at levels > 215 kg N ha-1. These results suggest that the current N rate of 300 kg N ha-1 is not only excessive, but also reduces fertilizer efficacy and may contribute to environmental problems such as global warming and eutrophication of ground water and streams.

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