We were unable to secure definite data as to the chemical composition of these composts and cannot say what amounts of available plant food the Shantung farmers are annually returning to their fields.  There can be little doubt, however, that the amounts are quite equal to those removed by the crops.  The soils appeared well supplied with organic matter and the color of the foliage and the general aspect of crops indicated good feeding.

The family with whom we talked in the village place their usual yields of wheat at 420 catty of grain and 1000 catty of straw per mow,—­their mow was four-thirds of the legal standard mow—­the grain being worth 35 strings of cash and the straw 12 to 14 strings, a string of cash being 40 cents, Mexican, at this time.  Their yields of beans were such as to give them a return of 30 strings of cash for the grain and 8 to 10 strings for the straw.  Small millet usually yielded 450 catty of grain, worth 25 strings of cash, per mow, and 800 catty of straw worth 10 to 11 strings of cash; while the yields of large millet they placed at 400 catty per mow, worth 25 strings of cash, and 1000 catty of straw worth 12 to 14 strings of cash.  Stating these amounts in bushels per acre and in our currency, the yield of wheat was 42 bushels of grain and 6000 pounds of straw per acre, having a cash value of $27.09 for the grain and $10.06 for the straw.  The soy bean crop follows the wheat, giving an additional return of $23.22 for the beans and $6.97 for the straw, making the gross earning for the two crops $67.34 per acre.  The yield of small millet was 54 bushels of seed and 4800 pounds of straw per acre, worth $27.09 and $8.12 for seed and straw respectively, while the kaoliang or large millet gave a yield of 48 bushels of grain and 6000 pounds of stalks per acre, worth $19.35 for the grain, and $10.06 for the straw.

A crop of wheat like the one stated, if no part of the plant food contained in the grain or straw were returned to the field, would deplete the soil to the extent of about 90 pounds of nitrogen, 15 pounds of phosphorus and 65 pounds of potassium; and the crop of soy beans, if it also were entirely removed, would reduce these three plant food elements in the soil to the extent of about 240 pounds of nitrogen, 33 pounds of phosphorus and 102 pounds of potassium, on the basis of 45 bushels of beans and 5400 pounds of stems and leaves per acre, assuming that the beans added no nitrogen to the soil, which is of course not true.  This household of farmers, therefore, in order to have maintained this producing power in their soil, have been compelled to return to it annually, in one form or another, not less than 48 pounds of phosphorus and 167 pounds of potassium per acre.  The 330 pounds of nitrogen they would have to return in the form of organic matter or accumulate it from the atmosphere, through the instrumentality of their soy bean crop or some other legume.  It has already been stated that they do add more than 5000 to 7000