Studies on soil reaction VIII The influence of fertilisers and lime on the replaceable bases of a light acid soil after fifty years of continuous cropping with barley and wheat (An examination of the Stackyard Field Plots, Woburn Experimental Station) (With two text-figures)

1. At the completion of a 50-year cycle of continuous cropping with both wheat and barley on a light sandy soil at the Woburn Experimental Station, soil samples from all of the plots were analysed for replaceable bases.2. The soil had little or no calcium carbonate originally and comparison with early soil samples showed that the unmanured plots lost about half of their replaceable calcium in the 50 years. The loss of calcium was much greater on plots with ammonium sulphate, and the crops failed completely in about 20 years. Plots with sodium nitrate or farmyard manure retained considerably more calcium than the unmanured plots.3. Plots with mineral manures, essentially superphosphate and potassium sulphate, had less replaceable calcium in the earlier years but more in the surface soil at the end of the experiment than those without mineral manures. The effect of superphosphate was so slight that for practical purposes it may be regarded as without effect on the replaceable bases.

RESP-00791