Effects of Phosphorus on Nitrification Process in a Fertile Soil Amended with Urea

Jianfeng Ning, Yuji Arai, Jian Shen, Ronghui Wang, Shaoying Ai

Research output: Contribution to journalArticlepeer-review


While the effects of carbon on soil nitrogen (N) cycle have been extensively studied, it is not clearly understood how co-existing macronutrients, such as phosphorus (P), affect the N cycle in agroecosystems. In this study, P amendment effects on nitrification in a fertile agricultural soil were investigated under a typical N-P amendment rate. In a laboratory incubation study, soils were amended with urea, monopotassium phosphate and a mixture of urea and monopotassium phosphate at the same rate. In soils that received no amendments (control), P only, urea only, and urea plus P amendment, nitrification occurred within the first five days, with an average net nitrification rate of 5.30, 5.77, 16.66 and 9.00 mg N kg−1d−1, respectively. Interestingly, nitrification in urea-treated soils was retarded by P addition where a N:P ratio seemed to be a key factor impeding nitrification. This was also supported by the response of ammonia-oxidizing bacteria (AOB), which was more sensitive to P addition than ammonia-oxidizing archaea (AOA). The outcome of this study showed that application of P fertilizer suppressed the nitrification process in urea amended soil, suggesting that a synergistic aspect of N and P nutrient management should be further explored to retard N losses from agricultural systems.

Original languageEnglish (US)
Article number523
JournalAgriculture (Switzerland)
Issue number6
StatePublished - Jun 2021


  • Ammonia oxidizing bacteria/archaea
  • N/P stoichiometry
  • Nitrification
  • Phosphorus
  • Urea nitrogen

ASJC Scopus subject areas

  • Food Science
  • Agronomy and Crop Science
  • Plant Science


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