摘要
利用15N分别标记有机肥和化肥,通过小麦盆栽试验,研究了外源氮素在典型潮土中向土壤有机氮和无机氮(铵态氮、硝态氮)各形态的转化与分配。结果表明:(1)土壤全氮受有机肥影响显著。有机肥处理土壤全氮显著提高24.8%(P<0.05),其中铵态氮和硝态氮分别增加了59.0%和120倍;有机无机肥配施处理土壤全氮提高13.7%,其中硝态氮增加了84.5倍,均达到显著水平(P<0.05);化肥处理对土壤全氮包括土壤硝态氮和铵态氮含量有一定提高,但差异性检验不显著。(2)外源氮对土壤有机氮影响明显。与对照相比,不同施氮处理均提高了土壤各形态有机氮的含量,有机肥处理土壤酸解性有机氮和酸解性铵态氮显著增加(P<0.05),分别提高了25.3%和39.3%;不同施氮处理各形态有机氮占全氮的比例变化较小,处于动态平衡中。(3)来自不同肥料的外源氮对土壤有机氮含量变化的贡献不同。外源化肥氮直接影响土壤酸解性铵态氮和非酸解性有机氮含量的变化,残留化肥氮分别占这两种形态有机氮含量的7.8%和5.2%;外源有机氮对土壤非酸解性有机氮和酸解未知氮含量的变化起主导作用,残留有机肥氮分别占这两种形态有机氮含量的5.0%和4.5%;有机无机肥料配施情况下,在土壤酸解未知氮含量的变化中有机肥氮起主要作用,残留有机肥氮占酸解未知氮含量的18.0%。(4)土壤铵态氮和硝态氮的变化均主要由外源氮转化而来。在化肥处理中分别有27%的土壤铵态氮和硝态氮来自外源化肥氮的转化,有机肥处理中分别有8%的土壤铵态氮和硝态氮来自外源有机肥氮的转化,有机无机肥配施处理中分别有5%的土壤铵态氮和硝态氮来自外源有机肥氮的转化。(5)有机无机肥配施可提高土壤有机肥氮素的残留并促进其向土壤酸解性铵态氮和酸解未知氮、铵态氮和硝态氮等有效形态转化,从而提高有机肥的有效性,减少环境风险,表明有机无机肥配施是土壤培肥的有效途径。
Using ^15N labeled organic manure and urea, a pot experiment was conducted to investigate the effect of organic and inorganic fertilizer on nitrogen(N) pool and distribution of residual N fractions in fluvo-aquic soil under the winter wheat system. The results shown:(1)The effect of organic fertilizer on soil total N was significantly(P〈0.05):Soil total N increased by 24.8%, ammonium N and nitrate N of which increased by 59.0% and 120 times respectively in OM* treatment(application of 15N labeled pig manure totally); soil total N increased by 13.7%, nitrate N of which increased by 84.5 times in OM*+CF treatment(application of 15N-labeled pig manure with common urea); the effect on the content of soil total N, nitrate N and ammonium N was not significantly performed in CF* treatment(application of 15N labeled urea only). (2)Compared to the non-fertilizer(CK) treatment, the application of N fertilizer increased the contents of different fractions of organic N in soil, especially the contents of hydrolysable organic N and hydrolysable ammonium N in OM* treatment were significantly increased by 25.3% and 39.3%, respectively(P〈0.05), the proportion of organic forms accounted for total N was in dynamic balance.(3)The contribution of exogenous nitrogen to the nitrogen contents in different fractions varied with fertilizer forms. The content of hydrolysable ammonium N and non hydrolysable N was significantly influenced by the application of the chemical fertilizer respectively, and the content of non-hydrolysable N and hydrolysable unidentified N by the application of the organic fertilizer significantly, and the content of hydrolysable unidentified N by the application of the organic fertilizer significantly.(4)As the transformation of exogenous inorganic nitrogen, 27% of soil ammonium N and nitrate N respectively, derived from the application of chemical fertilizer in CF* treatment, and as that of exogenous organic nitrogen, 8% and 5% from the application of organic fertilizer in OM* and OM*+CF treatment respectively.(5)Ammonium N and nitrate N, hydrolysable ammonium N and hydrolysable unidentified N were available N; the present results indicated that the chemical fertilizer combined with organic fertilizer is a practical approach for promoting the transformation and distribution of organic fertilizer to available N, increasing the availability of organic fertilizer, reducing environmental risk and maintaining the sustainability of soil.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2013年第6期1185-1193,共9页
Journal of Agro-Environment Science
基金
国家重点基础研究计划"973"课题(2013CB127406)
农业部公益性行业科研专项(201103007)
关键词
15N
潮土
有机氮
无机氮
氮残留形态
^15N
fluvo-aquic soil
organic nitrogen
inorganic nitrogen
residual N fractions