|
| Influence of air drying and freeze drying on cadmium fractions in paddy soils |
| Received:October 18, 2021 |
| View Full Text View/Add Comment Download reader |
| KeyWord:air drying;freeze drying;paddy soil;available cadmium;chemical extraction |
| Author Name | Affiliation | E-mail | | LU Lan | College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China | | | TANG Kaizhao | College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China | | | WU Cong | College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China | | | WANG Shuai | College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China | | | LIAO Wenjuan | College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China | | | YIN Lichu | College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China | | | ZHOU Weijun | College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China | | | CUI Haojie | College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China | hjcui@hunau.edu.cn |
|
| Hits: 812 |
| Download times: 950 |
| Abstract: |
| Chemical extraction of Cd from air-dried soil samples is a commonly applied method used to analyze available Cd in paddy soils. Although during the air-drying process, a range of different physical and chemical properties will contribute to altering the fractions of different Cd species in fresh soils, the characteristics and mechanisms underlying changes in the Cd fractions of paddy soils subjected to different fertilization treatments are still incompletely understood. In this study, using natural air-drying and freeze-drying methods, we investigated the effects of drying on changes in Cd fractions and the content of chemically extractable available Cd in paddy soils that had undergone different fertilization treatments. The results revealed that the contents of chemical extractable available Cd in freeze-dried paddy soils receiving different fertilization were significantly lower than those in naturally air-dried samples. The contents of extractable available Cd in freeze-dried paddy soils that had undergone the long-term application of chemical fertilizer and high-dose organic fertilizer were reduced by 56.5%~69.2% and 50.8%~66.3%, respectively. In contrast, the amount of extractable available Cd in paddy soils with the long-term application of low-dose organic fertilizer was reduced by 16.9%~22.3%. Compared with the naturally air-dried samples, we detected significant changes in the fractions of exchangeable, organic bound, and iron-manganese oxide-bound Cd in freeze-dried samples with long-term application of chemical fertilizer and high-dose of organic fertilizer, whereas the fractions of exchangeable and carbonate-bound Cd showed clear changes in paddy soils that had received long-term application of low-dose organic fertilizer. Differences in the soil particle composition of air-dried and freeze-dried samples were found to have slight effects on the chemical extraction of available Cd from paddy soils. Furthermore, correlation analysis revealed that changes in soil pH and the contents of organic matter, exchangeable iron, and ferrihydrite in soils had a considerable impact on the extraction of available cadmium during air drying and freeze drying. Consequently, with respect to the extraction of available cadmium from paddy soils, attention should be paid to the differences between air-drying and freeze-drying methods. |
|
|
|
