Three New Zealand coals, ground to pass a 150 ,urn sieve, were evaluated as a source of -ulphur for ryegrass in a factorial pot experiment on two sulphur-responsive soils. All coals examined supplied useful amounts of sulphur to ryegrass. Sulphur uptake over a 90-day period. by ryegrass supplied with Webb coal, was similar to uptake from gypsum at 40 ppm S, and higher than uptake by ryegrass supplied with Pirongia or Waimumu coals. The Pirongia coal, in common with other Waikato coals, contains relatively high levels of boron which, in This study, caused boron toxicity in ryegrass.
MATERIALS AND METHODS
Rothbaum 1969). In the same field experiment a lignite (6.3% S) applied at the same rate of sulphur per hectare failed to give a response. Apart from this study there does not appear to be any published work on the use of coal as a source of sulphur for plant growth.This paper reports the results of a pot experiment designed to evaluate three representative New Zealand coals as a source of sulphur for the growth of perennial ryegrass (Latium perenne L.) .