Abstract
Two experiments to investigate the requirements of sorghum and groundnut grown on Malaysian peat soil for Cu, Mn, Zn, Fe, Mo and B are described. The first experiment showed that only Cu was needed when growing sorghum and groundnut on peat. Plant survival and seed and total dry matter yields were greatly improved by fertilizing with 20 kg/ha of copper sulphate. Application of Cu also enhanced the absorption of Cu, Fe, Zn and Mn. The second experiment showed that 10 kg/ha of copper sulphate produced the same effects on crop yields as 20 kg/ha. The sorghum leaf Cu content was increased from about 16 p.p.m. to about 28 p.p.m. by the addition of 10 or 20 kg/ha of copper sulphate. Groundnut leaf Cu content was similarly increased from 3·6 p.p.m. to about 4·5 p.p.m. In both experiments, each crop of groundnut or sorghum only recovered about 20 to 30 g/ha of the applied Cu.
