Abstract
1. The work described in the present series of papers was undertaken with the object of ascertaining the best conditions for the use of calcium cyanamide and of comparing it against older nitrogenous fertilisers. Earlier work has in part been repeated so as to ascertain whether the recent improvements in manufacture have overcome the difficulties encountered with the pre-War product.2. The decomposition of cyanamide to urea can be brought about by a number of minerals likely to occur in the coarser fractions of the soil. The decomposition of cyanamide by soil proceeds according to a logarithmic law such that the rate of disappearance is proportional to the concentration of cyanamide in the soil water.