Relationship between soil nitrogen mineralization parameter with several nitrogen forms
JU Xiao tang 1,BIAN Xiu ju 2,LIU Xue jun 1,ZHANG Fu suo 1,MAO Da ru 1 (1 China Agricultural University, Beijing?100094;2 Hebei Agric. Univ., Baoding?071001)
The relationship between soil nitrogen mineralization parameter with NaOH?N, Microbial biomass N, Norg, total?N were studied with long term N, P and manure experiment soils using leaching incubation at intervals. The results showed that the first order dynamic model can excellent fit experimental data no matter incubation temperature was 35℃ or 20℃. N 0 increased through fifteen years applying nitrogen fertilizer or nitrogen fertilizer combining with manure, means soil active organic nitrogen pool increased and k varied from 0 004628 to 0 01348 day -1 , means soil mineralized nitrogen released with average ratio of 0 46%～1 31% every day. Leaching solution had some soluble organic nitrogen (Norg) under 35℃ incubation temperature or 20℃, it was necessary to determine NH 4?N, NO 3?N and Norg at the same time when carried out soil nitrogen mineralization studies. The average percentage of N 0, Norg, NaOH?N and microbial biomass N to total?N were 11 47%±3 50%, 0 355%±0 07%, 6 11%±0 36% and 3 26%±0 91%,respectively and the cv% were 30 4%, 20 0%, 5 8% and 28 8%, respectively. From the average values, we can see: N 0 NaOH?N microbial biomass NNorg and from the c.v%: N 0 microbial biomass NNorg NaOH?N. N 0 was sensitive in expressing soil nitrogen supplying ability although it was much higher than actual mineralized amount in field, therefore, it was expected to get the actual mineralized amount in field through modifying with the field soil temperature and soil moisture. There were different degree correlation between N 0 with NaOH?N, Norg, microbial biomass N and total?N.