Influence of Added Aluminum on Carbon Dioxide Production in Tropical Soils1
- V. K. Mutatkar and
- W. L. Pritchett2
Aluminum added to a yellow-brown Latosol, as Al2(SO4)3, at rates of 6.6, 16.5, and 33.0 meg /100 g of soil decreased soil pH from 5.9 to 4.6, 4.0 and 3.8, respectively. Carbon dioxide production during 35 days of incubation decreased with increases in H-ion concentration. In an attempt to separate the effects of H-ion displacement from that of Al-ion hydrolysis on microbial activity, Al-treated soils were left unadjusted, or adjusted to pH 4.0, 5.5 or 6.5 before incubation.
Carbon dioxide production decreased with increases in added Al when the soil pH was maintained below about 4.0. Aluminum precipitated rather rapidly in soils with a higher pH and the Al had little influence on CO2 production. Less than 1 ppm of Al was extracted by 1
In a second experiment, a highly significant negative linear relationship was found between CO2 production and increasing percentages of Al in mixtures of Al- and Ca-saturated Everglades muck. Furthermore, when Ca-saturated muck was adjusted to pH 4.0 with HCl, and incubated, the production of CO2 was significantly greater than in Al-saturated muck adjusted to pH 4.0. Since exchangeable Al did not increase when the Ca-saturated muck was adjusted to a lower pH, but did increase when the pH of the Al-saturated muck was lowered, it appeared that Al had an influence on CO2 production in these acid soils.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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