The experiment to be described in this paper was designed with a twofold purpose in view. Firstly, to test on a field scale an original method of using milking cattle for measuring the productivity of grassland, and secondly to make an attempt at determining the potential milk producing capacity of well managed grassland, under practical conditions.The recording of the output of milk from grassland in critical field trials has not been widely practised in Great Britain, and DAVIES and WILLIAMS (6) stress the urgent need for a simple method of assessment. The difficulties of using milk as a yardstick in measuring ihe production of grassland have been discussed previously by the author (5).
EXPERIMENTAL DESIGN AND METHODS
The grasslandThe experimental field, situated at Shinfield, Reading had a free-draining soil of light to medium loam overlying gravel with a series of London clays commencing at a depth of 16 ft. Patches of gravel extended almost to the surface in parts of the field and were vtry evident in dry weather. Tbe results of analyses of soil samples taken on 28 April 194.S and 21 March 1950 respectively, were pH, 5-7 and 7-5, lime requirement 28 cwt. CaO per ac,re and nil, available P^Os, 0-036 and 0'043, and available K2O,0-0I0 and O'OH.