Apply the fertilizers and work them in the soil about four inches deep before the crop is planted. Plant the same variety of seed on all the squares at the same time, and carefully cultivate through the entire season, treating all exactly alike. Suppose that potatoes have been used. During the growing season, carefully watch the different plats and notice if any one or more seems more or less thrifty than others. Notice which plat appears to mature first, which blooms first and keep a record of all observations. At the end of the season, carefully dig the crop on each square, gathering all the tubers large and small, and weigh each lot. First weigh the crops on squares 2 and 9. This will serve as a standard of comparison, as it will show the natural condition of the soil. Record the weights in each lot and just for illustration we may say that they run something like this: Average of 2 and 9, 80 pounds; No. 1, 380 pounds; No. 3, 250 pounds; No. 4, 360 pounds; No. 5, 350 pounds; No. 6, 300 pounds; No. 7, 220 pounds; No. 8, 400 pounds; No. 10, 120 pounds. On the particular soil we are supposed to be testing, we can clearly see that the land is benefited in some degree by every element used. Calcium helps, and that means that it should be used on that soil in addition to all of the others. This land plainly needs all four elements and needs potassium especially. What to Do.--After having gone through with Mr. Barnard’s experiments, you will have a practical idea of what your soil is, and what it needs. The only remaining questions then are those of preparing the soil, and obtaining and applying the plant foods and the lime. A cold, wet, clay soil needs to be made warmer and lighter, and a light, sandy soil, being too dry, needs some moisture-retaining substance. If conditions are favorable, it would be well at odd time to put sand on the clay soil and clay on the sandy soil; but in most cases this is too expensive, and therefore not practical. To redeem poor lands then, you will have to depend almost entirely upon green manure and lime. Barnyard manures are, of course, at all times, with all soils, the best of all fertilizers, as they return to the soil by the laws of nature, what has been taken from them, or what it should have. Besides the plant foods, it furnishes additional organic matter or humus, which makes the soil lighter and facilitates plant growth by furnishing food to bacteria essential to plant life. The trouble about barn-yard manure is its scarcity. Every farm needs more plant food and humus than can be supplied with common manure.