In another plan winter wheat or barley may grow side by side with a green crop, such as the "Chinese clover" (Medicago denticulata, Willd.) for soil fertilizer, as was the case in Fig. 144, to be turned under and fertilize for a crop of cotton planted in rows on either side of a crop of barley. After the barley had been harvested the ground it occupied would be tilled and further fertilized, and when the cotton was nearing maturity a crop of rape might be grown, from which "salted cabbage" would be prepared for winter use. Multiple crops are grown as far north in Chihli as Tientsin and Peking, these being oftenest wheat, maize, large and small millet and soy beans, and this, too, where the soil is less fertile and where the annual rainfall is only about twenty-five inches, the rainy season beginning in late June or early July, and Fig. 145 shows one of these fields as it appeared June 14th, where two rows of wheat and two of large millet were planted in alternating pairs, the rows being about twenty-eight inches apart. The wheat was ready to harvest but the straw was unusually short because growing on a light sandy loam in a season of exceptional drought, but little more than two inches of rain having fallen after January 1st of that year. The piles of pulverized dry-earth compost seen between the rows had been brought for use on the ground occupied by the wheat when that was removed. The wheat would be pulled, tied in bundles, taken to the village and the roots cut off, for making compost, as in Fig. 146, which shows the family engaged in cutting the roots from the small bundles of wheat, using a long straight knife blade, fixed at one end, and thrust downward upon the bundle with lever pressure. These roots, if not used as fuel, would be transferred to the compost pit in the enclosure seen in Fig. 147, whose walls were built of earth brick. Here, with any other waste litter, manure or ashes, they would be permitted to decay under water until the fiber had been destroyed, thus permitting it to be incorporated with soil and applied to the fields, rich in soluble plant food and in a condition which would not interfere with the capillary movement of soil moisture, the work going on outside the field where the changes could occur unimpeded and without interfering with the growth of crops on the ground. 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.