In this system of combined intertillage and multiple cropping the oriental farmer thus takes advantage of whatever good may result from rotation or succession of crops, whether these be physical, vito-chemical or biological.  If plants are mutually helpful through close association of their root systems in the soil, as some believe may be the case, this growing of different species in close juxtaposition would seem to provide the opportunity, but the other advantages which have been pointed out are so evident and so important that they, rather than this, have doubtless led to the practice of growing different crops in close recurrent rows.

XII

RICE CULTURE IN THE ORIENT

The basal food crop of the people of China, Korea and Japan is rice, and the mean consumption in Japan, for the five years ending 1906, per capita and per annum, was 302 pounds.  Of Japan’s 175,428 square miles she devoted, in 1906, 12,856 to the rice crop.  Her average yield of water rice on 12,534 square miles exceeded 33 bushels per acre, and the dry land rice averaged 18 bushels per acre on 321 square miles.  In the Hokkaido, as far north as northern Illinois, Japan harvested 1,780,000 bushels of water rice from 53,000 acres.

In Szechwan province, China, Consul-General Hosie places the yield of water rice on the plains land at 44 bushels per acre, and that of the dry land rice at 22 bushels.  Data given us in China show an average yield of 42 bushels of water rice per acre, while the average yield of wheat was 25 bushels per acre, the normal yield in Japan being about 17 bushels.

If the rice eaten per capita in China proper and Korea is equal to that in Japan the annual consumption for the three nations, using the round number 300 pounds per capita per annum, would be: 

             Population.  Consumption. 
   China 410,000,000 61,500,000 tons
   Korea 12,000,000 1,800,000 tons
   Japan 53,000,000 7,950 000 tons
               -----------------------
   Total 475,000,000 71,250,000 tons

If the ratio of irrigated to dry land rice in Korea and China proper is the same as that in Japan, and if the mean yield of rice per acre in these countries were forty bushels for the water rice and twenty bushels for the dry land rice, the acreage required to give this production would be: 

Area. 
Water rice,     Dry land rice,
sq. miles.       sq. miles. 
In China        78,073            4,004
In Korea         2,285              117
In Japan        12,534              321
-------           ------
Sum             92,892            4,442
Total           97,334

Our observations along the four hundred miles of railway in Korea between Antung, Seoul and Fusan, suggest that the land under rice in this country must be more rather than less than that computed, and the square miles of canalized land in China, as indicated on pages 97 to 102, would indicate an acreage of rice for her quite as large as estimated.