This crop of rape is remarkable for the way it fits into the economies of these people. It is a near relative of mustard and cabbage; it grows rapidly during the cooler portions of the season, the spring crop ripening before the planting of rice and cotton; its young shoots and leaves are succulent, nutritious, readily digested and extensively used as human food, boiled and eaten fresh, or salted for winter use, to be served with rice; the mature stems, being woody, make good fuel; and it bears a heavy crop of seed, rich in oil, which has been extensively used for lights and in cooking, while the rape seed cake is highly prized as a manure and very extensively so used.
In the early spring the country is luxuriantly green with the large acreage of rape, later changing to a sea of most brilliant yellow and finally to an ashy grey when the leaves fall and the stems and pods ripen. Like the dairy cow, rape produces a fat, in the ratio of about forty pounds of oil to a hundred pounds of seed, which may be eaten, burned or sold without materially robbing the soil of its fertility if the cake and the ashes from the stems are returned to the fields, the carbon, hydrogen and oxygen of which the oil is almost wholly composed coming from the atmosphere rather than from the soil.
In Japan rape is grown as a second crop on both the upland and paddy fields, and in 1906 she produced more than 5,547,000 bushels of the seed; $1,845,000 worth of rape seed cake, importing enough more to equal a total value of $2,575,000, all of which was used as a fertilizer, the oil being exported. The yield of seed per acre in Japan ranges between thirteen and sixteen bushels, and the farmer whose field was photographed estimated that his returns from the crop would be at the rate of 640 pounds of seed per acre, worth $6.19, and 8,000 pounds of stems worth as fuel $5.16 per acre.
THE UTILIZATION OF WASTE
One of the most remarkable agricultural practices adopted by any civilized people is the centuries-long and well nigh universal conservation and utilization of all human waste in China, Korea and Japan, turning it to marvelous account in the maintenance of soil fertility and in the production of food. To understand this evolution it must be recognized that mineral fertilizers so extensively employed in modern western agriculture, like the extensive use of mineral coal, had been a physical impossibility to all people alike until within very recent years. With this fact must be associated the very long unbroken life of these nations and the vast numbers their farmers have been compelled to feed.
When we reflect upon the depleted fertility of our own older farm lands, comparatively few of which have seen a century’s service, and upon the enormous quantity of mineral fertilizers which are being applied annually to them in order to secure paying yields, it becomes evident that the time is here when profound consideration should be given to the practices the Mongolian race has maintained through many centuries, which permit it to be said of China that one-sixth of an acre of good land is ample for the maintenance of one person, and which are feeding an average of three people per acre of farm land in the three southernmost of the four main islands of Japan.