Fosforista eräitten luonnontilaisten soitten eri kerroksissa

In the present paper results are reported concerning the total content as well as solubility of organic and inorganic phosphorus in 122 peat samples which were collected from various depths of 30 peat lands. The total phosphorus content of all the samples was rather low and no regularity in the influence of the depth upon this quantity could be demonstrated. There seemed to be some tendency to an increase in the P-content with increasing depth in the peat lands of lower quality. In peat lands of higher quality the opposite often held true. A large part of the phosphorus occurred in organic form, and, almost without exception, this percentage of total phosphorus increased with the depth: in undecomposed plant material this proportion was about 50—60 per cent, in the surface layers 70 per cent, on the average, in deposits deeper than 50 cm seldom less than 80 per cent and it could even reach 95 per cent. 1he amount of organic phosphorus expressed as a percentage of organic dry matter was low in most of the samples and although it tended to increase with the depth only in 11 of all the 122 samples values higher than 0.1 per cent were obtained. Even if an allowance is made for the conditions prevailing in peat lands these low percentages of organic phosphorus indicate that, from the microbiological point of view, no rapid mineralization of the organic phosphorus compounds is probable. The inorganic phosphorus content was low and tended to decrease from the surface to deeper layers. The solubility of inorganic phosphorus, however, dropped much more drastically. Thus in the deeper layers the amount of easily extractable inorganic phosphorus could be negligible. The solubility of organic phosphorus also impaired with the depth. The phosphorus economy of peat lands was discussed on the basis of the results obtained.Tutkimuksessa selvitettiin 30:ltä luonnontilaiselta suolta kerätyn 122:n turvenäytteen perusteella eri kerrosten fosforin pitoisuutta ja fosforin liukenevuutta. Todettiin, että orgaanisen fosforin osuus kokonaisfosforista on tavallisesti sitä suurempi, mitä syvemmältä näyte on otettu: elävässä kasviaineksessa orgaanista fosforia oli noin 50—60 % kokonaisfosforista, pintakerroksessa keskimäärin 70 % ja 50 emi syvemmällä harvoin alle 80 %. Sekä orgaanisen että etenkin epäorgaanisen fosforin liukenevuus oli suhteellisesti suurin pintakerroksessa ja aleni syvemmälle mentäessä hyvin nopeasti. Orgaanisen fosforin prosenttinen osuus orgaanisesta kuiva-aineesta kasvoi yleensä syvempiin kerroksiin siirryttäessä, mutta oli ainoastaan 11 näytteessä suurempi kuin 0.1 %. Tämä viittaa siihen, että syvempienkin kerrosten orgaanisen fosforin mineraloituminen tapahtuu hitaasti ja että etenkin pintakerroksissa fosforin biologinen pidättyminen on mahdollista