当前位置: X-MOL 学术Soil › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Phosphorus dynamics during early soil development in a cold desert: insights from oxygen isotopes in phosphate
Soil ( IF 6.8 ) Pub Date : 2022-01-12 , DOI: 10.5194/soil-8-1-2022
Zuzana Frkova , Chiara Pistocchi , Yuliya Vystavna , Katerina Capkova , Jiri Dolezal , Federica Tamburini

At the early stages of pedogenesis, the dynamics of phosphorus (P) in soils are controlled by microbial communities, the physicochemical properties of the soil and the environmental conditions. While various microorganisms involved in carrying out biogeochemical processes have been identified, little is known about the actual contribution of microbial processes, such as organic P hydrolysis and microbial P turnover, to P cycling. We thus focused on processes driven by microbes and how they affect the size and cycling of organic and inorganic soil P pools along a soil chronosequence in the Chamser Kangri glacier forefield (Western Himalayas). The rapid retreat of the glacier allowed us to study the early stages of soil formation under a cold arid climate. Biological P transformations were studied with the help of the isotopic composition of oxygen (O) in phosphate (δ18OP) coupled to sequential P fractionation performed on soil samples (0–5 cm depth) from four sites of different age spanning 0 to 100–150 years. The P bound to Ca, i.e., 1 M HCl-extractable P, still represented 95 % of the total P stock after approximately 100 years of soil development. Its isotopic composition was similar to the parent material at the most developed site. Primary phosphate minerals, possibly apatite, mostly comprised this pool. The δ18OP of the available P and the NaOH-extractable inorganic P instead differed from that of the parent material, suggesting that these pools underwent biological turnover. The δ18OP of the available P was mostly controlled by the microbial P, suggesting fast exchanges occurred between these two pools possibly fostered by repeated freezing–thawing and drying–rewetting cycles. The release of P from organic P becomes increasingly important with soil age, constituting one-third of the P flux to available P at the oldest site. Accordingly, the lighter isotopic composition of the P bound to Fe and Al oxides at the oldest site indicated that this pool contained phosphate released by organic P mineralization. Compared to previous studies on early pedogenesis under alpine or cold climate, our findings suggest a much slower decrease of the P-bearing primary minerals during the first 100 years of soil development under extreme conditions. However, they provide evidence that, by driving short-term P dynamics, microbes play an important role in controlling the redistribution of primary P into inorganic and organic soil P pools.

中文翻译:

寒冷沙漠早期土壤发育过程中的磷动力学:磷酸盐中氧同位素的见解

在成土的早期阶段,土壤中磷(P)的动态受微生物群落、土壤的理化性质和环境条件的控制。虽然已经确定了参与进行生物地球化学过程的各种微生物,但人们对微生物过程(例如有机磷水解和微生物磷周转)对磷循环的实际贡献知之甚少。因此,我们专注于微生物驱动的过程,以及它们如何影响 Chamser Kangri 冰川前场(西喜马拉雅山)土壤时间序列中有机和无机土壤 P 池的大小和循环。冰川的迅速退缩使我们能够研究寒冷干旱气候下土壤形成的早期阶段。δ 18 O P与对土壤样品(0-5 cm 深度)进行的连续 P 分馏相结合,这些样品来自 0 到 100-150 年的不同年龄的四个地点。经过大约 100 年的土壤发育,与 Ca 结合的 P,即 1 M HCl 可提取的 P,仍然占总 P 储量的 95%。其同位素组成与最发达地点的母质相似。初级磷酸盐矿物,可能是磷灰石,主要构成这个矿池。可用 P 和 NaOH 可提取无机 P的δ 18 O P与母体材料不同,表明这些池经历了生物周转。的δ 18 ö P可用 P 的大部分主要由微生物 P 控制,这表明这两个池之间发生了快速交换,这可能是通过反复冻融和干燥-再润湿循环促进的。随着土壤年龄的增长,从有机磷中释放的磷变得越来越重要,占最古老地点有效磷的磷通量的三分之一。因此,在最古老的地点与 Fe 和 Al 氧化物结合的 P 的较轻同位素组成表明该池含有有机 P 矿化释放的磷酸盐。与之前关于高山或寒冷气候下早期成土作用的研究相比,我们的研究结果表明,在极端条件下土壤发育的前 100 年中,含磷原生矿物的减少要慢得多。然而,他们提供的证据表明,通过推动短期 P 动态,
更新日期:2022-01-12
down
wechat
bug