For most frequent yield per acre of crops in China to-day, vide J. L. Buck
: Land Utilization in China ( Chicago, 1937): 224-225. According
to his survey ( 1929-1933), the average yield of rice per acre in the rice
region is 67 bushels (approximately 500 catties per mow); that of the
Yangtze Rice-Wheat Area, 63 bushels (approximately 470 catties per
mow); that of the Szechwan Rice Area, 75 bushels (approximately 560
catties per mow); that of the South-western Cropping Rice Area, 97
bushels (approximately 770 catties per mow). Moreover, he adds (p.
233): 'The range in yields is very great. For instance, wheat varies from
5 to 67 bushels per acre, rice from 22 to 169 bushels per acre.'

In terms of yield, it may be calculated that the 'superior-superior'
land, according to this way of distribution, produces 1,200 catties; the
'superior-medium', 1,210 catties; the 'superior-inferior', 1,200 catties;
the 'medium-superior', 1,215 catties; the 'medium-medium', 1,200
catties; the 'medium-inferior', 1,225 catties; the 'inferior-superior',
1,200 catties; the 'inferior-medium', 1,200 catties; the 'inferior-inferior',
1,200 catties. The lands are thus slightly unequal in terms of yield.