straw mulch which holds them from the moist soil and acts to conserve water by diminishing evaporation and, through decay from the summer rains and leaching, serves as fertilizer for the crop. In Fig. 155 the view is along a pathway separating two head ditches between areas in watermelons and taro, carrying the drainage waters from the several furrows into the main ditches. Although the soil appeared wet the plants were vigorous and healthy, seeming in no way to suffer from insufficient drainage.
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Fig. 155.—Looking along a path between two head ditches separating patches of watermelons and taro, Japan.
These people have, therefore, given effective attention
to the matter of drainage as well as irrigation and are
looking after possible losses of plant food, as well as ways
of supplying it. It is not alone where rice is grown that
cultural methods are made to conserve soluble plant food
and to reduce its loss from the field, for very often, where
flooding is not practiced, small fields and beds, made
quite level, are surrounded by low raised borders which
