Manure on Grass.--When the crop-rotation embraces two or more years of grass, or one of clover followed by only one of grass, it is better practice to use the manure to thicken the sod. The object in view is the largest possible amount of crops, and the maximum amount of organic matter for the soil. Grass is a heavy feeder, like corn, and makes good use of nitrogen. Its roots fill the soil so that no loss attends the use of manure. When the supply is given the grass, after the harvest of the second crop of clover and during the winter, the timothy can make a rank growth. The part of the plant above ground has corresponding development below ground. Not only does a large increase in the hay crop result, but the heavy mass of grass roots, the aftermath, and the remains of the manure provide a great amount of fertility for the corn which follows. The increase in hay permits a corresponding increase in the manure supply the next year, if it is fed, and if it is sold on account of a market price greater than its value for feed and manure, it adds to income materially--and that is one reason for farming. Manure on Potatoes.--There are excellent cash crops that may get more than their fair share of the farm supply of fertility, and against the interest of fields in the farm not adapted to cash crops. The justification is found in the farm ledger. In some regions potatoes are the best crop in point of net income per acre, where the acreage is kept restricted so that there may be plenty of organic matter to help in conserving moisture. It is not good practice to use fresh manure, and especially that from horse-stables, for potatoes. A heavy application makes an excessive growth of vine, and the yield of tubers suffers. A stronger deterrent is the effect that fresh manure has on the development of the spores that produce the disease known as potato-scab. Rotted manure is less dangerous, and few crops repay its use in higher degree than the potato. Some growers prefer to make heavy application of fresh manure to grass for corn, and follow with potatoes so that they can profit by the rotted organic matter that remains. In this way the physical condition is made excellent, moisture is well held in a dry season, and commercial fertilizers can supplement the plant-food left in the manure.