The canalization of fifty thousand square miles of our Gulf and Atlantic coastal plain, and the utilization on the fields of the silts and organic matter, together with the water, would mean turning to account a vast tonnage of plant food which is now wasting into the sea, and a correspondingly great increase of crop yield.  There ought, and it would seem there must some time be provided a way for sending to the sandy plains of Florida, and to the sandy lands between there and the Mississippi, large volumes of the rich silt and organic matter from this and other rivers, aside from that which should be applied systematically to building above flood plain the lands of the delta which are subject to overflow or are too low to permit adequate drainage.

It may appear to some that the application of such large volumes of water to fields, especially in countries of heavy rainfall, must result in great loss of plant food through leaching and surface drainage.  But under the remarkable practices of these three nations this is certainly not the case and it is highly important that our people should understand and appreciate the principles which underlie the practices they have almost uniformly adopted on the areas devoted to rice irrigation.  In the first place, their paddy fields are under-drained so that most of the water either leaves the soil through the crop, by surface evaporation, or it percolates through the subsoil into shallow drains.  When water is passed directly from one rice paddy to another it is usually permitted some time after fertilization, when both soil and crop have had time to appropriate or fix the soluble plant food substances.  Besides this, water is not turned upon the fields until the time for transplanting the rice, when the plants are already provided with a strong root system and are capable of at once appropriating any soluble plant food which may develop about their roots or be carried downward over them.

Although the drains are of the surface type and but eighteen inches to three feet in depth, they are sufficiently numerous and close so that, although the soil is continuously nearly filled with water, there is a steady percolation of the fresh, fully aerated water carrying an abundance of oxygen into the soil to meet the needs of the roots, so that watermelons, egg plants, musk melons and taro are grown in the rotations on the small paddies among the irrigated rice after the manner seen in the illustrations.  In Fig. 153 each double row of egg plants is separated from the next by a narrow shallow trench which connects with a head drain and in which water was standing within fourteen inches of the surface.  The same was true in the case of the watermelons seen in Fig. 154, where the vines are growing on a thick layer of 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.