College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi Province, China.
Sci Total Environ. 2018 Jan 15;612:223-230. doi: 10.1016/j.scitotenv.2017.08.126. Epub 2017 Sep 1.
The surplus of exogenous and endogenous phosphate in submerged paddy fields could increase the risk of algal blooms, the photosynthesis of which might further influence the redox processes of iron. This work investigated the effects of biochar on photosynthetic microorganism growth and iron redox under different phosphate (P) levels to understand the dynamics of P and thereby control non-point source pollution by biochar addition. Paddy soils were incubated anaerobically with phosphate and biochar addition under controlled illumination conditions to determine the variation in chlorophyll a (Chl a), ferrous iron [Fe(II)], soil pH and water-soluble phosphate (W-P) with incubation time. Biochar addition significantly inhibited the photosynthetic microorganism growth, with Chl a decreased by 4.74-15.78mg·g when compared with the control. Fe(III) reduction was significantly stimulated in response to biochar addition, while Fe(II) oxidation was inhibited because of the suppression of photosynthetic microorganism growth. The enhanced Fe(III) reduction and suppressed Fe(II) oxidation decreased the P solubility in the tested soils. These findings provide a cost-effective approach for inhibiting photosynthetic microorganism growth in paddy field and valuable insight into the effect of iron cycling on P retention for further management of eutrophication from exogenous and endogenous P loading.
在淹水稻田中，过量的外源和内源磷酸盐会增加藻类大量繁殖的风险，而藻类的光合作用可能会进一步影响铁的氧化还原过程。本研究探讨了生物炭在不同磷酸盐（P）水平下对光合微生物生长和铁氧化还原的影响，以了解 P 的动态，从而通过添加生物炭来控制非点源污染。在受控光照条件下，将稻田土壤进行厌氧培养，并添加磷酸盐和生物炭，以确定培养时间内叶绿素 a（Chl a）、亚铁[Fe（II）]、土壤 pH 值和水溶性磷酸盐（W-P）的变化。与对照相比，生物炭的添加显著抑制了光合微生物的生长，Chl a 降低了 4.74-15.78mg·g。生物炭的添加显著刺激了 Fe（III）的还原，而由于抑制了光合微生物的生长，Fe（II）的氧化受到抑制。增强的 Fe（III）还原和抑制的 Fe（II）氧化降低了测试土壤中的磷溶解度。这些发现为抑制稻田中光合微生物的生长提供了一种具有成本效益的方法，并深入了解了铁循环对磷固定的影响，以进一步管理外源和内源磷负荷引起的富营养化。
