ABSTRACT
The Northwest Region of Cameroon is covered by soils that developed mostly on basalts. They have been weathered, and the nutrients in the soils have been leached by heavy seasonal rain. This has left soils insuf‹ciently fertile enough to yield the crop productivity needed by the population. To help farmers improve soil productivity and develop sustainable land use, powders from different local rocks mixed with green manure were used to improve the growth productivity of carrots and cabbage and to ameliorate plant nutritional quality. The leaves and stems of the carrots and cabbage treated with rock powder showed a signi‹cant improvement over the control soil. Carrot production of 11,666 kg/ha was obtained with basalt and green manure mixture equivalent to the yield treated with tuff powders and green manure. These results were higher than the 8333 kg/ha obtained from the treatment of basalt powder only and 5722 and 4083 kg/ha for the treatments with tuff powder only and the control soil, respectively. While cabbage treated with granite powder yielded 50% increased productivity, soils treated with basalt powders and pyroclastic materials combined yielded also 50% increase versus 0% for the control soil. These ‹eld trials demonstrated that the treatment of local soils with rock powders in combination with green manure is an ef‹cient method to improve productivity on these tropical soils.
