Conditions Which Affect Fertility.

There are certain conditions which affect soil fertility and of these the most important are:

Texture and Its Relation To Fertility.

By texture is meant the physical condition of the soil. Upon good texture, more than upon any other one thing, depends the productivity of the soil. When the texture is right the soil is fine, loose, and friable; the roots are able to push through it and the feeding area is enlarged. Each individual particle is free to give up a portion of its plant-food, or its film of moisture. The conditions which are found in the woods' soil are almost ideal.

Experiment No. 2.—The importance of good texture may be well shown in the class room. Pots should be filled with a soil which is lumpy and cloddy, and other pots with the same kind of material after it has been made fine and mellow. After seeds are planted in the different pots, a careful study should be made of the length of time required for germination and of the health and vigor of the plants.

Experiment No. 3.—The greater part of our farming lands do not present ideal conditions as regards texture. Clay soils are especially likely to be in bad condition. If samples of the various soils can be collected, as sand, loam, clay, etc., it may be clearly shown how different soils respond to the same kind of treatment. With a common garden trowel, the soils should be stirred and worked while wet, and then put away to dry. After drying, the conditions presented by the soils should be noted, also the length of time required for the soils to become dry. Whereas the sand and the loam will remain in fairly good condition when dry, the clay will have become "puddled," i. e., the particles will have run together and made a hard, compact mass. Thus it is found in practice that clay soils must be handled with far more care and intelligence than is required for the sand and loams, if the texture is to be kept perfect.

Experiment No. 4.—If, in the experiment above suggested, the clay soil is mixed with leaf-mould, or humus soil, from the woods, it will be found to act very differently. The vegetable matter thus mixed with the mineral matter prevents the running together of the particles of clay.

Two principles, both important as relating to soil texture, now have been illustrated. Soils must not be worked when they are so wet that their particles will cohere, and organic matter, or humus, must be kept mixed with the mineral matter of the soil. In practical farm operations, if the soil can be made into a mud ball it is said to be too wet to work. The required amount of humus is retained in the soil by occasionally plowing under some green crop, as clover, or by applying barn manures.