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Details van artikel 141 van 183 gevonden artikelen
| Titel: |
Potential problems with the determination of Olsen and microbial P of soils due to the instability of 0.5M sodium bicarbonate |
| Auteur: |
Cowling, J. C. Speir, T. W. Percival, H. J. |
| Verschenen in: |
Communications in soil science and plant analysis |
| Paginering: | Jaargang 18 (1987) nr. 6 pagina's 637-652 |
| Jaar: |
1987-06 |
| Inhoud: |
The instability of 0.5MNaHCO3 solution was studied and its consequences for Olsen and microbial-P determinations were examined in a range of New Zealand soils under pasture. Theoretical calculations and experimental evidence showed that storage of 0.5M NaHCO3 open to the atmosphere (the worst possible situation), would result in a rapid increase of pH to a maximum of 10.1. Storage in stoppered vessels resulted in small increases of pH, although experimental data indicated that imperfect seals could allow considerable pH change. Olsen P increased linearly in all soils when extracted at increasing pH in the range 8.5-9.5. These increases were usually large and significant. In contrast, extractant pH had little effect on the Piflush (CHCl3 treatment-control, i.e. microbial P) and no effect on Ptot flush. This was because the increases in P extracted by increasing extractant pH observed for control samples were usually matched by identical increases in fumigated samples. Recommendations concerning preparation and storage of 0.5M NaHCO3 and measurement of Olsen and microbial-P are made. |
| Uitgever: |
Taylor & Francis |
| Bronbestand: |
Elektronische Wetenschappelijke Tijdschriften |
Details van artikel 141 van 183 gevonden artikelen
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