Premium
Effect of nitrogen fertilization and irrigation on soil microbial activities and population dynamics — a field study
Author(s) -
Ruppel Silke,
Makswitat Elke
Publication year - 1999
Publication title -
journal of plant nutrition and soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 87
eISSN - 1522-2624
pISSN - 1436-8730
DOI - 10.1002/(sici)1522-2624(199901)162:1<75::aid-jpln75>3.0.co;2-d
Subject(s) - mineralization (soil science) , chemistry , urease , fertilizer , population , nitrification , nitrogen cycle , nitrogen , microorganism , respiration , agronomy , environmental chemistry , zoology , botany , urea , biology , bacteria , biochemistry , demography , organic chemistry , sociology , genetics
In a field experiment, net nitrogen (N) mineralization and immobilization were studied in relation to: 1) population dynamics and activities of N‐metabolizing soil microbial communities, 2) changes in substrate‐induced respiration (SIR) and 3) potential urease acitvity. Nitrogen fertilization (80 kg NO 3 ‐N ha ‐1 ) without irrigation induced additional N mineralization up to 280 kg N ha ‐1 . Net N‐mineralization was weakly correlated to cell numbers of ammonifying and NH 4 + ‐oxidizing microorganisms. Potential urease activity, respiration activity, and substrate‐induced respiration activity were not correlated with the amount of mineralized nitrogen. Irrigation significantly increased potential urease activity of the soil microflora. Substrate induced respiration activity and basal respiration activity of the soil microflora were highest in the unfertilized and non irrigated treatment. But greatest differences were detected between the two sampling dates. NO 2 ‐ ‐oxidizing and ammonifying microbial populations increased, while populations of NH 4 + ‐oxidizing and denitrifying microorganisms decreased with time. The results of this study demonstrate the interaction of nitrogen fertilizer application and irrigation on population dynamics of N‐transforming soil microorganisms and microbial activities under field conditions. Detailed microbiological investigations of this type improve our understanding of nitrogen transformations in soil and suggest possible reasons of nitrogen losses, so that N fertilizer can be used more effectively and N losses be reduced.