旱地土壤氮素矿化参数与氮素形态的关系

Relationship between soil nitrogen mineralization parameter with several nitrogen forms

应用间歇淋洗培养方法 ,以长期不同培肥定位试验土壤为研究对象 ,求得土壤氮素矿化参数 ,并探讨氮素矿化潜势 (N0 )、碱解氮、微生物氮、可浸提易矿化氮、全氮之间的关系。结果表明 ,在 35℃和 2 0℃条件下培养 ,一级动力学模型能够很好的拟合试验数据 ,模拟方程和模拟参数均达到极显著水平。经过 15年的培肥和轮作 ,无论是单施氮肥区 ,还是氮肥与有机肥配合施用区 ,N0 均有不同程度的增加 ,这标志着土壤活性有机氮库增加。k值变化范围在 0 0 0 4 6 2 8～0 0 1314 8d- 1之间 ,说明可矿化氮以每天 0 46 %～ 1 31%的平均速率矿化释放。而且 ,在本试验条件下 ,淋洗液中均含有一定数量的可溶性有机态N ,因此进行氮素矿化研究时 ,同时测定NH4 N、NO3 N和Norg的含量是必要的。 35℃下 ,N0 占全氮的比例为 7 2 3%～ 17 36 % ,变异系数 30 4% ;易矿化有机态氮占全氮的比例为 0 2 7%～ 0 48% ,变异系数 2 0 0 % ;碱解氮占全氮的比例为 5 55%～ 6 54% ,变异系数仅 5 8% ;微生物氮占全氮的比例在 2 16 %～ 5 18%之间 ,变异系数 2 8 8%。从几种指标测得的平均值看 ,N0 >碱解氮 >微生物氮 >易矿化氮 ,而变异系数是N0 >微生物氮 >易矿化氮 >碱解氮。虽然N0 的绝对值远高于田间实际矿化量 ,?

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 N>Norg and from the c.v%: N 0> microbial biomass N>Norg> 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.