Influence of biochars and silica on K fractionations and release into CaCl2, HCl and oxalic acid in a calcareous soil
Abstract The amount of potassium (K) in arid calcareous soils is sufficient; however, insufficient K fertilization, along with competition between K and calcium (Ca) for absorption has led to reported deficiencies. This study investigated the effect of sheep manure and rice husk biochars produced at...
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| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Nature Portfolio
2025-07-01
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| Series: | Scientific Reports |
| Subjects: | |
| Online Access: | https://doi.org/10.1038/s41598-025-07686-z |
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| Summary: | Abstract The amount of potassium (K) in arid calcareous soils is sufficient; however, insufficient K fertilization, along with competition between K and calcium (Ca) for absorption has led to reported deficiencies. This study investigated the effect of sheep manure and rice husk biochars produced at two different temperatures (300 and 500 °C) and sodium metasilicate on various forms of K, the soluble cations and their ratios, K release to 0.01 M CaCl2, HCl, and oxalic acid solutions, and K re-fixation. The addition of different biochars increased various forms of K, with a more pronounced increase observed for sheep manure biochars. The addition of sodium metasilicate enhanced the contents of soluble Ca and sodium (Na), exchangeable K and Na, Ca to K ratio, KSP, and ESP. However, it decreased the soluble K content, and the ratios of Ca to Na and K to Na. Oxalic acid initially extracted less K than CaCl2 and HCl, but it released more K during the second release stage compared to other extractants. The addition of all biochars increased K release. The amount of K re-fixation following K release ranged from 198 to 285 mg kg−1, with soils treated with CaCl2 fixed more K than those treated with HCl and oxalic acid. |
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| ISSN: | 2045-2322 |