We have inserted in this table, for comparison, the crop of rice, and have increased the crop of potatoes from three hundred bushels to four hundred bushels per acre, because such a yield, like all of those named, is quite practicable under good management and favorable seasons, notwithstanding the fact that much smaller yields are generally attained through lack of sufficient plant food or water. From this table, assuming that a crop of matured grain contains 11 per cent of water and the straw 15 per cent, while potatoes contain 79 per cent and beets 87 per cent, the amounts of the three plant food elements removable annually by 1000 pounds of crop have been calculated and stated in the next table.
Approximate amounts of
nitrogen, phosphorus and potassium
removable annually per 1,0000 pounds of dry crop substance
Nitrogen, Phosphorus, Potassium,
pounds. pounds. pounds.
Wheat 13.873 2.312 8.382 Oats 13.666 2.254 9.580 Corn 13.719 2.149 6.676
Soy beans 30.807 4.070 14.147 Cow peas 25.490 2.745 19.216 Clover 23.529 2.941 17.647 Alfalfa 29.411 2.647 14.118
Beets 19.213 3.462 30.192 Potatoes 15.556 3.210 22.222
Timothy 14.117 1.765 13.922 Rice 9.949 1.129 6.089
From the amounts of nitrogen, phosphorus and potassium applied annually to the cultivated fields of Japan and from the data in these two tables it may be readily seen that these people are now and probably long have been applying quite as much of these three plant food elements to their fields with each planting as are removed with the crop, and if this is true in Japan it must also be true in China. Moreover there is nothing in American agricultural practice which indicates that we shall not ultimately be compelled to do likewise.
IN THE SHANTUNG PROVINCE
On May 15th we left Shanghai by one of the coastwise steamers for Tsingtao, some three hundred miles farther north, in the Shantung Province, our object being to keep in touch with methods of tillage and fertilization, corresponding phases of which would occur later in the season there.
The Shantung province is in the latitude of North Carolina and Kentucky, or lies between that of San Francisco and Los Angeles. It has an area of nearly 56,000 square miles, about that of Wisconsin. Less than one-half of this area is cultivated land yet it is at the present time supporting a population exceeding 38,000,000 of people. New York state has today less than ten millions and more than half of these are in New York city.