Published online by Cambridge University Press: 27 March 2009
Field experiments were carried out in central Scotland to assess the lime and fertilizer dressings required for the establishment and growth of grasses and clovers on deep acid peat. Without lime, the sown grasses and clovers failed when ammonium sulphate and mono-ammonium phosphate were used, but with Nitro-Chalk and single superphosphate a poor establishment was obtained. With adequate P, lime at rates as low as 0–25 metric ton Ca per ha produced a marked improvement. The yields obtained with 1, 2 or 4 metric tons Ca per ha were similar, but the herbage from the last treatment contained the highest Ca percentage.
Even with adequate lime, the grasses and clovers failed in the absence of applied P. Superphosphate and basic slag gave similar establishments but the former produced higher yields. Ground mineral phosphate was inferior to basic slag in the first and second years but in the fourth, fifth and sixth seasons it was equal to superphosphate and superior to slag. After establishment the 98 kg P rates were always better than the 49 kg levels. The 490 kg P treatment of superphosphate did not produce a bigger yield than the 98 kg rate, but it did give a higher percentage of P in the herbage.
Dressings of N and K had appreciable effects on establishment and growth, especially on the botanical composition of the sward and yield of herbage produced in the second year.
The effects of treatment on the pH value of the peat and on the Ca, P and K extracted by 2·5 % acetic acid were measured. To get a satisfactory establishment of grasses and clovers on deep acid peat it is suggested that about 3 metric tons Ca, 35 kg N, 100 kg P and 140 kg K per ha should be applied.