植物营养与肥料学报2017，Vol.23Issue(2)：380-388,9.DOI:10.11674/zwyf.16307
长期秸秆还田下土壤铵态氮的吸附解吸特征
Adsorption-desorption characteristics of soil ammonium under long-term straw returning condition
摘要
Abstract
[Objectives] The experiment was to study the effects of long-term straw incorporation on soil ammonium (NH4+) adsorption-desorption characteristics under the surface and subsurface soil level across different cropping systems.Langmuir equation was used to find the maximum adsorption amount (qmax) and adsorption index (b) in order to explore the NH4+ adsorption-desorption difference among different soil types and the relevant impact factors.[Methods] Soil samples of 0-20 cm and 20-40 cm depth were taken from the long-term fertilization experiments in Wangcheng (Hunan Province,double rice rotation),Jinxian (Jiangxi Province,double rice rotation),and Beibei (Chongqing City,rice-wheat rotation) after rice/late rice harvest in October,2015.The treatments included were CK (no fertilization),NPK (chemical fertilizers only) and NPKS (straw returning with chemical fertilization),and soil ammonium N (NH4+) adsorption-desorption experiment using the sampled soils was conducted in the laboratory.For the NH4+ adsorption experiment,different concentrations of NH4Cl solution were added in the soil samples.After oscillation and centrifugation,the amount of NH4+ adsorption was the NH4+ content in the filtrate.The above soil samples were then eluted by anhydrous ethanol until no NH4+ could be tested.Adding 0.01 mol/L KC1 solution with oscillation and centrifugation,and then we analyzed the NH4+ content in the filtrate as NH4+ desorption amount.[Result] Effects of long-term straw returning on soil N adsorption and desorption characters were different across the three sites.NH4+ adsorption difference was mainly detected in the surface soil.There was no difference ofNH4+ adsorption among the treatments and soil layers when NH4+ ＜ 400 mg/L in the balanced solution.However,NH4+ adsorption in the surface layer showed difference among the treatment when NH4+ ＞ 400 mg/L in the balanced solution.At Wangcheng site,N adsorption showed as CK ＞ NPK ＞ NPKS.However,at Beibei,N adsorption showed as CK ＞NPKS ＞ NPK.N adsorption was found significant higher in the purple soil at Beibei than that in the red soil at Wangcheng or Jinxian sites.NH4+ adsorption was not different among the treatments at Jinxian,where was showed the lowest N adsorption among the three sites.Based on the correlation analysis,qmax was showed significant positive correlation with soil pH and soil cation exchange capacity (CEC),but negative correlation with soil organic matter and total nitrogen.Whereas the correlation of b value and soil properties was opposite to qmax~.For the NH4+desorption,there was no significant difference among the samples with different treatment from all three sites.NH4+ desorption was higher than the NH4+ adsorption at Wangcheng and Jinxian,whereas maximum NH4+ desorption (541.89-742.38 mg/kg) was much lower than NH4+ adsorption (1003.83-2014.79 mg/kg) at Beibei.[Conclusions] Long-term straw returning shows different impact on soil N adsorption-desorption in different soil types.As the straw returning increase the organic matter content and decrease the adsorption point of a soil,the N adsorption will be improved by long-term straw returning in purple soil on which there are more adsorption spots and higher potassium ion content,but that will be reduced in the red soil where the soil pH is lower and soil organic matter content is higher.关键词
长期秸秆还田/NH4+的吸附-解吸/双季稻轮作/稻麦轮作/土壤pHKey words
long-term straw returning/NH4+ adsorption-desorption/double rice cropping rotation/rice-wheat cropping rotation/soil pH引用本文复制引用
丛日环,张丽,鲁艳红,黄庆海,石孝均,李小坤,任涛,鲁剑巍..长期秸秆还田下土壤铵态氮的吸附解吸特征[J].植物营养与肥料学报,2017,23(2):380-388,9.基金项目
国家自然科学基金项目(41301319) （41301319）
湖北省自然科学基金项目(2013CFB203)资助. （2013CFB203）
