J. W. Robertson Scott, The foundations of Japan
“ Page 70 Just one-half of the cultivated area of Japan is devoted to paddy, but there is to be added to this area under rice more than a quarter million acres producing the upland rice, the yield of which is lower than that of paddy rice. The paddy and upland rice areas together make up more than a half of the cultivated land. The paddies which are not in situations favourable to the production of second crops of rice (they are grown in one prefecture only) are used, if the water can be drawn off, for growing barley or wheat or green manure as a second crop [63] . ”
