Value of Water in the Soil.--The amount of water in the soil each day of the growing season determines in large measure the possibility of securing a profitable crop from land. Observant farmers have noticed oftentimes that the differences in yields on the farms of a region are less in a wholly favorable season than in one of deficient rainfall. The skill of the farmer in conserving the moisture supply in a wet season is less well repaid because it is less needed. The poverty of a worn soil is less marked in a favorable season. The land is accounted poor because the supply of plant-food is inadequate for a drouthy year in which a considerable percentage of the time produces little growth, but most agricultural land has enough plant-food for a fairly good crop when water is present all the time to carry daily supplies into the roots. It is the amount of moisture in the soil that is the limiting factor in the case of most land that is not in a high state of productiveness. The Soil a Reservoir.--The rains of the summer rarely are adequate to the needs of growing plants. Some water runs off the surface, some passes down through crevices beyond the effect of capillary attraction, and much quickly evaporates. The part that becomes available is only a supplement to the store of water made by the rains of the fall, winter, and early spring. If the soil were viewed as a medium for the holding of water to meet the daily needs of plants, and were given rational treatment on this basis, a long step toward higher productiveness would have been taken. As has been stated, rotted organic matter gives a soil more capacity for holding water. It is an absorbent in itself, and it puts clays and sands into better physical condition for the storage of moisture. An unproductive soil may need organic matter for this one reason alone more than it may need actual plant-food. Fall-plowing for a spring crop enables land to withstand summer's drouth if it gains in physical condition by full exposure to the winter's frost. It is in condition to take up more water from spring rains than would be the case if it lay compact, and it does not lose water by the airing in the spring that plowing gives. Early spring-plowing leaves land less subject to drouth than does later plowing. As the air becomes heated, the open spaces left by the plowing serve to hasten the escape of moisture. If a cover crop is plowed down late in the spring, the material in the bottom of the furrow makes the land less resistant to drouth because the union of the top soil with the subsoil is less perfect, and capillary attraction is retarded. It is usually good practice to sacrifice some of the growth of a cover crop, even when organic matter is badly needed, and to plow fairly early in the spring in order that the moisture supply may be conserved.