Variation in Speciation and Availability of Phosphorus in Paddy Soil

• 作者: Haruhiko Horino Shinji Sakurai Takao Nakagiri Yasuaki Nishiura
• 来源期刊: 土壤科学期刊(英文)
• 学科: 医学
• 关键词: PHOSPHORUS AVAILABILITY Chemical Form SEQUENTIAL Extraction INCUBATION Experiment
• 年，卷（期）: 2018,（9）
• 页码范围: 213-224
• 页数: 12页
• 分类号: R73

摘要

There is a global concern about the depletion in phosphorus (P) resources in the near future. Some attempts for effective reuse of P, including recovery from municipal wastes, have been conducted. However, a strong sorption of P onto some minerals may result in low P availability for crops. Therefore, it is necessary to understand the speciation of the chemical forms of P and to elucidate the relationships between P availability and chemical forms of P in soil. This study focuses on the variation in P speciation and the chemical forms of available P in a paddy soil. Incubation experiments with/without drainage, simulating the situation in a paddy field, were performed at a laboratory scale to evaluate the variation in speciation and P availability in soil. The speciation of P was analyzed according to Wilson’s sequential extraction method and measured using Bray No. 2 and Truog methods. Two kinds of chemical forms, i.e. , Fe and Mn (oxy)hydroxides (Fe-Mn-P) and organic and biogenic P (Org-P) were predominant in the soil, and they were easily interconverted by changing soil redox conditions. Available P using the Bray No. 2 method was increased in 21 days owing to the anaerobic condition;thereafter, it reached a constant value by the end of both the incubation experiments. However, a drastic decrease was detected in available P, using Truog-P. It occurred owing to the drying of soil, which suggested that some chemical form(s) of P other than Truog-P might be generated. A comparison between the concentrations of available P and that of each chemical form showed that available P included some Org-P, which might be less absorbed by plants compared to the exchangeable and pore water fraction (Ex-P) and Fe-Mn-P. We conclude that anaerobic soil conditions play an important role in the efficient consumption of P.