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作 者 ：巨晓棠1;2;刘学军1;张福锁1

期 刊 ：植物营养与肥料学报 2002年 8卷 3期 页码：259-264

关键词：N肥；NH4+-N；NO3--N；固定态铵；微生物N；

Keywords:nitrogenfertilizer, NH4+-N, NO3--N, soilfixedammonium, soilmicrobialbiomassnitrogen,

摘 要 ：应用盆栽试验和¹⁵N标记技术研究了小麦苗期施入N肥后土壤不同N库的动态。结果表明 ,施肥后 28d ,作物所吸收的土壤N占总吸N量的 58.1% ,吸收的肥料N占 41.9%。作物对肥料N的利用率达到 55.3% ,N肥在土壤中的残留率为 24.3% ,损失率为 20.4%。施肥后短期以NH₄⁺-4 N存在的肥料N占施N量的 50.5% ,随着硝化作用的进行和作物的吸收 ,土壤中的NH₄⁺-N显著下降。NO₃^--N在第 7d达到高峰 ,表现为先升高后降低的趋势 ,说明施肥后在 7d以前有强烈的硝化作用发生。施肥后 2d ,以固定态铵存在的肥料N占 33.7% ,至 28d ,仅占施入N量的 2.4% ,说明前期固定的铵在作物生长后期又重新释放出来供作物吸收。在施肥后第 7d ,肥料N以微生物N存在的量占施肥量的 15.2% ;至 28d来自肥料N的微生物N也几乎被耗竭 ,仅占施N量的 2.4%。随作物生长 ,肥料N在各个土壤N库中的数量均显著下降。在其它N库几乎被耗竭的情况下 ,至施肥后 28d主要以有机N的形式残留。在不种作物的条件下 ,土壤N素的矿化量很低 ,作物的吸收作用导致土壤有机N库不断矿化 ,施入N肥后 ,土壤N素的矿化量增加 ,表现为明显的正激发效应

Abstract:The dynamics of various soil nitrogen pool after nitrogen fertilizer application at wheat seedling stage was studied by pot experiment and 15N trace technique. The results showed that soil nitrogen of crop uptake was 58.1% of total nitrogen of crop uptake, and fertilizer nitrogen was 41.9% of that at 28th day after N application. Fertilizer nitrogen recovery rate, residual rate and losses rate were 55.3%, 24.3% and 20.4% respectively. The NH + 4-N was 50.5% of applied nitrogen fertilizer in short time after application. NH₄⁺-N in soil sharply decreased with nitrification and crop uptake afterwards. NO₃^--N in soil increased in short time after application and decreased afterwards. High NO₃^--N in soil appeared at 7th day after N application, which means strong nitrification before that time. The fixed NH₄⁺ fertilizer nitrogen was 33.7% of applied nitrogen at second day after N application and 2.4% at 28th day, which showed that the fixed NH + 4 from fertilizer nitrogen at early period could be used by crop at late period. The microbial biomass N was 15.2% from fertilizer nitrogen at 7th day after N application and 2.4% at 28th day. The fertilizer nitrogen in various soil nitrogen pool significantly decreased with crop growth. Fertilizer nitrogen mainly existed as organic form when other soil nitrogen pools almost was exhausted at 28th day after N application. Soil nitrogen mineralization was low without crop system, and high in crop system. Soil nitrogen mineralization increased with nitrogen fertilizer application which showed positive priming effect.

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