控制光照条件下生物炭对水稻土中铁还原过程的影响  

Effect of biochar on iron reduction in paddy soils under controlled illumination condition

作　　者：游萍[1] 贾蓉[1] 曲东[1] 唐珺瑶 

机构地区：[1]西北农林科技大学资源环境学院,陕西杨凌712100

出　　处：《农业环境科学学报》2016年第1期101-108,共8页Journal of Agro-Environment Science

基　　金：国家自然科学基金面上项目(41171204)

摘　　要：为探究生物炭的添加对淹水稻田体系中蓝藻等光合微生物生长及稻田土水界面氧化还原平衡的影响，选择3种水稻土样品，采用土壤泥浆厌氧恒温培养方法，在控制光照条件下研究添加不同粒径生物质对光合细菌生长及Fe（Ⅲ）还原过程的影响。结果表明，避光条件下添加生物炭可以促进水稻土中铁还原过程，但不同粒度生物炭对铁还原的促进作用差异不显著。光照条件下添加不同粒度生物炭使天津（TJ）、宁夏（Nx）和四川（sc）水稻土中叶绿素a（Ch]a）含量分别降低35．63％～67．47％、39．66％～70．56％和46．82％，生物炭粒度对Chla累积量的影响因土壤不同而存在差异。光照刺激下光合微生物的大量生长并产氧，引起了Fe（1I）的氧化，使Fe（Ⅱ）累积量降低了6．009~6．415mg·g-1（TJ）、1．473～2．058mg·g-1（Nx）和3．037—3．693mg·g-l（sc）。光照条件下，添加生物炭在三种水稻土中均对铁氧化过程有促进作用，且增加量与水稻土来源和生物炭粒度有关：TJ和sc水稻土中〈0．25mm处理和0．25～O．5mm处理对铁氧化的促进作用高于O．5~1．0mm处理和1．0~2．0mm处理；NX水稻土中，不同粒度生物炭对铁氧化的促进作用差异不明显。表征光合微生物生长的Chla含量、体系pH的改变量及Fe（Ⅱ）的氧化量之间存在显著的相关性。Photosynthetic cyanobacteria in paddy soils influence soil redox and thus iron oxidation-reduction via their oxygen-producing process. Biochar may affect the habitats for these microorganisms. Here the effects of biochar additions on photosynthetic cyanobacterial growth and redox balance at soil-water interface in paddy soil system were investigated. Three types of calcareous paddy soils amended with biochar with different particle sizes were anaerobically incubated with or without illumination at constant temperature（ 30 ℃ ）. Fe（ Ⅱ） con- centration, pH, and chlorophyll a（Chl a） content were determined during incubation. Results showed that under no illumination, microbial iron（ Ill ） reduction was promoted by biochar additions, but the particle size of biochar did not show significant effects. However, under illu- mination, Chl a content in TJ, NX and SC paddy soils was reduced by biochar by 35.63%~67.47%, 39.66%-70.56%, and -46.82%, re- spectively, while light stimulated photosynthetic microorganism growth, thus causing Fe（ II ） oxidation by 6.009-6.415 mg· g-l, 1.473~ 2.058 mg· g-i and 3.037~3.693 mg· g-1 in TJ, NX and SC paddy soils, respectively. Moreover, biochar also promoted the iron oxidation under illumination, but such promotion varied with different soil types and biochar particle sizes. Biochar with 〈0.25 mm and 0.25~0.5 mm parti- cles showed greater promotion on iron oxidation than that with 0.5-1.0 mm and 1.0-2.0 mm in TJ and SC paddy soils, whereas the iron oxi- dation by biochar was not obvious in NX paddy soil. Significant correlations existed between chlorophyll a, pH change and oxidized Fe（ Ⅱ ）.

关 键 词：生物炭 光合微生物 Fe(Ⅲ)还原 

分 类 号：X71[环境科学与工程—环境工程]