(Pennisetum purpureum). Lime greatly increased the Total mineralization and uptake of peat and the consequent growth of the grass by a factor of about 4. A comparison of lime and calcium sulphate showed that the effect was due to pH rather than to the addition of Ca. However, this increase accounted for only about four per cent of the total peat N and most of this became available relatively soon after treatment, later N uptake and growth being reduced. The most likely explanation of this declining growth response and uptake by the plant is that, under the conditions of the experiments, easily decomposed nitrogenous components of the peat are mineralized first, leaving forms of organic N that are not easily decomposed.