RELATIONSHIPS BETWEEN COPPER CONTENTS, RATES OF SOIL RESPIRATION AND PHOSPHATASE ACTIVITIES OF SOME HISTOSOLS IN AN AREA OF SOUTHWESTERN QUEBEC IN THE SUMMER AND THE FALL

Samples from 17 fields of organic soils (Histosols) were collected on the same day between rows of crops in the summer of 1976 from the environs of Ste. Clothilde, Quebec. Thirty-three properties of the soils were examined for possible correlations. The copper contents of the samples were found to have statistically significant negative correlations with their rates of respiration which were measured as carbon lost as CO 2 upon incubation at 21 ± 2 °C. The acid phosphatase enzyme contents in these Histosol samples at each of three different levels of soil biochemical activity were also similarly negatively correlated with their copper concentrations. The above results were confirmed almost without exception by the data obtained by similar analysis of seven samples collected from the same area in the fall of 1976 when the fields were bare. The results supported an earlier suggestion of Mathur and Rayment (1977) that copper application (at a few quintals/ha) be investigated as a means of mitigating the mineralization and subsidence of some organic soils. Apparently, the added Cu may inactivate some of the exocellular soil enzymes which normally contribute to the degradation and mineralization of organic matter.