FALLOW (AS. feels, yellow, ]eel. folr, OFIG. Palo, Ger. fall; connected with Lat. pallidus, pale, Gk. roM6s, polios, gray, Skt. imilita, gray). Waste, unfilled land; also land that is plowed, and otherwise stirred, for a season without being cropped. Most of the wheat raised by the Ro mans was sowed after the land was followed; in deed, the usual rotation was fallow and wheat al ternately. It was only fertile soils that could long support such an exhausting system: hence re sulted the decreasing produce which the later Boman agricultural authors so often speak of and lament.
The fallowing of land was introduced into all the countries which fell under the dominion of the Romans. During their sway, Great Britain exported large quantities of wheat ; and for cen turies after the Romans left it. no other mode of cultivating the land was followed. It may here be observed that wherever the system of fallowing, without giving manure to the crops, is practiced, it necessarily supposes that the soil is at least moderately fertile. This system is most successful on argillaceous soils, which are retentive of organic manure. It must be borne in mind that the chief use of fallow is to liberate material from which plants may derive their food, and which is already stored up in the soil as organic matter, although the weathering which the soil undergoes assists in rendering the min eral substances it contains more available. The plowing and stirring, by admitting air, promote decomposition and nitrification, and at the same time destroy insects and weeds that impoverish the soil and choke the crops. With improvements in the plow and other tillage implements and the rapid increase in use of manures and fertilizers during the last half-eentury, the practice of fal lowing has been largely abandoned; hut it could doubtless be revived with advantage in many cases. For summer fallow, the land should be plowed deeply about the last of Alay, and the surface put in fine tilth. When the weeds spring up, they should be destroyed by surface tillage. If the land is to be seeded to wheat or rye, the last stirring of the soil should be given not later than the middle of August. The number of
plowings and the amount of surface tillage re quired will depend upon a variety of conditions, but in some eases one deep plowing and one sur face tillage will accomplish the deSired purpose of destroying the weeds and preparing the soil for the succeeding crop by improving the tilth and increasing the supply of nitrates and other available plant-food. For winter fallow, the land should receive a deep plowing in autumn. Ex posure through the winter allows the frost to pulverize the surface. In the spring, when the weather becomes dry. the cultivator or the plow opens up the soil and the process of extirpating the weeds goes on. In old cultivated countries. land is commonly so ninth reduced in its organic matter that fallows receive dressings of farm yard manure, guano. etc.. to increase fertility.
Since the general introduction of green manur ing crops, the term fallow has departed some what from its original meaning. These crops are sown on what was formerly the fallow, and are styled fallow crops. Green fallow is espe cially applicable to light, poor soils. It pro tects the soil from washing and loss of nitrates by leaching, chokes out weeds, improves the tilth, and, if leguminous plants are grown, it enriches the soil in nitrogen gathered from the air by these plants, while some mineral matter is brought to the surface from the subsoil by the roots of the plants. (See Gatxx 1)1Asracce.) In dry climates, however, green fallow land is more likely to suffer from drought in autumn than is bare fallow. Bastard fallowing is a term applied in Scotland to the practice of plowing hay-stubble at the end of smuttier, freeing from weeds, and sowing with wheat in autumn. A similar practice, known as short fallow in Amer ica, consists in plowing the soil innnediatcly after removing a crop of grain, clover, etc., and keep ing the soil well stirred until grain or grass is seeded in the fall. This treatment is very bene ficial, and the period is so short that there is not much danger of loss of nitrogen by leaching. Con sult: Roberts. The Fertility of the Land (New York. 1897) ; Storer, Agriculture (7th ed., New York, 1897).