Transformation of Phosphorus Pools in an Agricultural Soil: An Application of Oxygen‐18 Labeling in Phosphateстатья из журнала
Аннотация: Core Ideas Transformation of P pools in soils can be tracked by 18 O labeling of phosphate. A suite of HCl‐extractable P i with different δ 18 O P values can be precipitated in soil over time. An interplay of biological and abiotic cycling of P could be better analyzed using δ 18 O P values. P hosphorus is a key ingredient of fertilizers, and there is no other substitute for P in sustaining life and food production. Excess P in soils may be fixed and become agronomically inactive or removed as a result of leaching and soil erosion. In this research, we aimed to explore how a particular P pool transforms into another pool by applying 18 O‐labeled phosphate in an agricultural soil. We analyzed the changes in concentrations and phosphate O‐isotope ratios (δ 18 O P ) of four inorganic P (P i ) pools (H 2 O‐P i , NaHCO 3 –P i , NaOH‐P i , and HCl‐P i ) along with soil chemistry to understand the roles of different biogeochemical processes changing isotope composition. By monitoring δ 18 O P values of four P pools, an active transformation from H 2 O‐P i and NaHCO 3 –P i to NaOH‐P i and HCl‐P i was identified. Transformation of originally bioavailable P to unavailable P such as HCl‐P i allowed us to conclude that a suite of HCl‐P i with different δ 18 O P values could be precipitated from the originally biologically cycled or bioavailable P pools. Thus, the isotope technique allowed tracking of short‐term transformation of readily bioavailable P to a less or non‐bioavailable P pool and to discriminate biological and chemical reactions during transformation. These findings support the burgeoning applications of δ 18 O P as a tracer of P cycling in soil and are expected to be useful for fertilizer application as well as nutrient management in soils.
Год издания: 2016
Авторы: Sunendra R. Joshi, Xiaona Li, Deb P. Jaisi
Издательство: Wiley
Источник: Soil Science Society of America Journal
Ключевые слова: Soil and Water Nutrient Dynamics, Phosphorus and nutrient management, Soil Carbon and Nitrogen Dynamics
Открытый доступ: closed
Том: 80
Выпуск: 1
Страницы: 69–78