淹水与非淹水条件下外源水铁矿和葡萄糖对土壤磷有效性的短期影响

Short-term effects of exogenous ferrihydrite and glucose on the soil available phosphorus under waterlogged and non-waterlogged conditions

土壤中活性铁氧化物含量及其对土壤磷生物有效性的影响与施用有机肥有关,但外源添加活性铁氧化物和有机物对土壤有效磷含量的影响并不清楚.通过室内培养实验,研究了在淹水和非淹水条件下外源水铁矿和葡萄糖对土壤中植物有效磷(SAP)含量的影响.利用同步辐射红外显微成像技术原位探索了微域内铁和磷的空间关系.研究结果表明,在培养192 h内无论是添加水铁矿或葡萄糖或二者同时添加均会使SAP含量显著下降且呈持续下降趋势.在淹水和非淹水条件下单施水铁矿处理SAP含量分别下降30.9%和25.8%,单施葡萄糖SAP分别下降40.5%和26.8%,而同时施加水铁矿与葡萄糖处理SAP分别下降61.5%和45.3%.因此,同时施加外源水铁矿和葡萄糖对淹水条件下SAP含量影响更大.同步辐射红外显微成像分析结果表明,无论是添加水铁矿还是葡萄糖或二者同时添加,都会通过改变微区内铁和磷的空间分布打破原来土壤中铁磷相互作用平衡.上述研究结果对于土壤磷养分管理和磷面源污染控制具有重要参考价值和应用潜力.

The contents of active iron oxides in soil and their effect on the bio?availabilty of soil phosphorus were affected by organic fertilizers,but little has been explored about the effect of the application of exogenous iron oxides and organic materials on soil available phosphorus(SAP).In this study,the effects of ferrihydrite and glucose on SAP were studied by laboratory incubation experiments under waterlogged and non?waterlogged conditions.Soil samples were also analyzed by using synchrotron radiation infrared micro?imaging techniques for exploring the spatial relationship between iron and phosphorus in the in situ microsites.The results showed that addition of ferrihydrite or glucose or both could significantly decrease SAP within 192 h.Exogenous ferrihydrite decreased the SAP by 30.9%and 25.8%,while exogenous glucose decreased SAP by 40.5%and 26.8%,respectively,under waterlogged and non?waterlogged conditions.For treatments with both ferrihydrite and glucose amendments,SAP were decreased by 61.5%and 45.3%,respectively,under waterlogged and non?waterlogged conditions.Thus,SAP of waterlogged soil was more affected than that of nonwaterlogged soil.Synchrotron radiation infrared micro?imaging analysis showed that addition of either ferrihydrite or glucose or both could break the balance of interaction between iron and phosphorus by changing the spatial distribution of iron and phosphorus in microsite.The above results have important reference values and application potentials in soil phosphorus nutrient management and non?point source phosphorus pollution control.