Plant and Soil

, Volume 199, Issue 2, pp 239–250

Denitrification and total N losses from an irrigated sandy-clay loam under maize–wheat cropping system

Authors

  • T. Mahmood
    • Soil Biology DivisionNuclear Institute for Agriculture and Biology
  • K.A. Malik
    • National Institute for Biotechnology and Genetic Engineering
  • S.R.A. Shamsi
    • Department of BotanyUniversity of the Punjab
  • M.I. Sajjad
    • Pakistan Institute of Nuclear Science and Technology
Article

DOI: 10.1023/A:1004335132617

Cite this article as:
Mahmood, T., Malik, K., Shamsi, S. et al. Plant and Soil (1998) 199: 239. doi:10.1023/A:1004335132617

Abstract

Denitrification and total N losses were quantified from an irrigated field cropped to maize and wheat, each receiving urea at 100 kg N ha-1. During the maize growing season (60 days), the denitrification loss measured directly by acetylene inhibition-soil cover method amounted 2.72 kg N ha-1 whereas total N loss measured by 15N balance was 39 kg ha-1. Most (87%) of the denitrification loss under maize occurred during the first two irrigation cycles. During the wheat growing season (150 days), the denitrification loss directly measured by acetylene inhibition-soil cover and acetylene inhibition-soil core methods was 1.14 and 3.39 kg N ha-1, respectively in contrast to 33 kg N ha-1 loss measured by 15N balance. Most (70-88%) of the denitrification loss under wheat occurred during the first three irrigation cycles. Soil moisture and NO3--N were the major factors limiting denitrification under both crops. Higher N losses measured by 15N balance than C2H2 inhibition method were perhaps due to underestimation of denitrification by C2H2 inhibition method and losses other than denitrification, most probably NH3 volatilization.

acetylene inhibitiondenitrificationirrigated fieldmaize15N balancewheat
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© Kluwer Academic Publishers 1998