The amount of manure produced must be considered in planning a cropping system for a farm. If one wishes to manure one-fifth of the land every year with 10 tons per acre, there would have to be provided two tons per year for each acre of the farm. This would require about one cow or horse, or equivalent, for each six acres of land.
Naturally there is great variation in manure according to the animals it is made by, the feeding and bedding material, and the manner in which it is kept. Different analyses naturally shows different results and the tables here given serve only as a guide or index to the various kinds. The manure heap, by the way, is no place for old tin cans, bottles, glass, and other similar waste material.
The essential requirements of a soil upon which to grow onions profitably are a high state of fertility, good mechanical condition, properties – that is, if it contains sufficient sand and humus to be easily worked, is retentive of moisture and fertilizers, and is capable of drainage – all other requirements can be met.