Abstract
The effect of drying of soil samples at about 20° C on the phosphorus test values estimated by the acetic acid method, the method for adsorbed P of BRAY and KURTZ (1), and the method of TERÄSVUORI (6) was studied. The material consisted of 32 samples of various kinds of soils. Air-drying did not cause any change in the acetic acid P of about one half of the samples and in the adsorbed P of about one third of the samples. A slight increase in the test values was found for a couple of samples. The tendency to a decrease was markedly higher in the values of adsorbed P than in the values of acetic acid P: an average decrease of 28 per cent in 19 samples was found in the former test while the corresponding value in the latter test was 13 per cent in 13 samples. No changes in the test values of Teräsvuori occurred in about one half of the samples, and the fairly low changes in the other half of the material were almost evenly distributed between increases and decreases. No connection between the changes in the test values upon air-drying and the moisture content of the fresh sample, the pH-value, the content of organic carbon, or the contents of iron and aluminium soluble in Tamm’s acid oxalate solution could be demonstrated. The changes in the various test values did not usually go in same direction. The importance of the possible error caused by air-drying is diminished by the sampling errors and by the variation in the soil P conditions.
Highlights
The acetic acid probably extracts some of the phosphorus bound by calcium, while the »exchangeable P» represents most of the fractions of inorganic P bound by iron and aluminium compounds
The effect of drying of soil samples at about 20° C on the phosphorus test values estimated by the acetic acid method, the method for adsorbed P of Bray and
Air-drying did not cause any change in the acetic acid P of about one half of the samples and in the adsorbed P of about one third of the samples
Summary
It is often emphasized that drying of soil samples affects the solubility of soil phosphorus. The use of fresh soil samples is recommended. Since this is not always possible, it would be necessary to know of what order the changes caused by air-drying may be. In a previous work it was found (5) that in several cases, drying carried out at 40° C changed the phosphorus test values more than did drying at room temperature; sometimes the former treatment caused a decrease in the test value while an increase was found as the result of the latter treatment. Some further results are reported of the comparison of data obtained for fresh soil samples and samples dried at about 20° C. The methods used were the following: the acetic acid method (4), the somewhat modified method of Bray and Kurtz (1) for the adsorbed P, and the method of Teräsvuori (6) in which the »exchangeable P», the corresponding P concentration in solution, and an indicator of the phosphate retention capacity of the soil are estimated
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
