Pedosphere 30(2): 272--284, 2020
ISSN 1002-0160/CN 32-1315/P
©2020 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Air-drying changes the distribution of Hedley phosphorus pools in forest soils |
Jipeng WANG1,2, Yanhong WU1 , Jun ZHOU1, Haijian BING1, Hongyang SUN1, Ji LUO1, Shengyan PU2 |
1Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041 (China);
2State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu 610059 (China) |
| ABSTRACT |
| Hedley labile phosphorus (P) pools in soil tend to be several times larger than annual forest requirements, even in highly weathered soils characterized by P limitation. The discrepancy between plant and soil P status could be partly attributable to the frequently adopted air-drying pretreatment that tends to increase soil P solubility. In this study, the effects of air-drying on the distribution of Hedley P fractions were examined using soils collected under 4 forest types at Gongga Mountain, southwestern China. The results showed that the microbial biomass P (Pmic) in the organic horizon decreased markedly after air-drying. The concentrations of Hedley labile P in the air-dried samples were 31%–73% more than those in the field-moist samples. Consequently, the air-drying-induced increments of Hedley labile P pools in the surface soil horizons were 0.8–3.8 times the annual plant P requirements. The organic horizon was more susceptible to the air-drying-induced increases in Hedley labile P than the mineral horizon, probably because of the stronger release of Pmic and disruption of soil organic matter. The quality of P, indexed by the ratio of Hedley labile P to slowly cycling P, shifted in favor of the Hedley labile fractions after air-drying, further revealing that air-drying changed the distribution of Hedley P pools in forest soils. These indicated that the effects of air-drying could not be ignored when interpreting the discrepancy between the P status of plants and the Hedley labile P pools in forest soils. To more efficiently evaluate the P status in forest soils via the Hedley fractionation procedure, the use of field-moist soils is recommended. |
| Key Words: Hedley fractionation,labile phosphorus,microbial biomass phosphorus,phosphorous limitation,slowly cycling phosphorus,soil pretreatment |
| Citation: Wang J P, Wu Y H, Zhou J, Bing H J, Sun H Y, Luo J, Pu S Y. 2020. Air-drying changes the distribution of Hedley phosphorus pools in forest soils. Pedosphere. 30(2): 272-284. |
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