EFFECTS OF ADDING NICKEL (AS OXIDE) TO SOIL ON NITROGEN AND CARBON MINERALIZATION AT DIFFERENT PH VALUES

Nitrogen and carbon mineralisation were measured after adding 50, 250, 1000 and 5000 ppm Ni (as oxide) to a sandy soil at pH levels of 5·8, 6·9 and 7·6 (the last containing 1% calcium carbonate) and incubating aerobically for six weeks at 30°C. Nitrification decreased to a greater extent with increasing Ni at pH 5·8 than at pH 6·9 and 7·6. Nitrogen mineralisation decreased to about the same extent with increasing Ni at all pH levels. Carbon mineralisation decreased with increasing Ni to about the same extent at pH 5·8 and 6·9 but to a lesser extent at pH 7·6. © 1979.