The condition of the food may likewise alter its facility of digestion and nutritive properties, this depending upon its mode of growth, care in collecting and preserving, cleanliness, and freedom from animal and vegetable parasites. If the land on which the food is grown be poor in quality, the produce will be in a similar condition; it will be poor in its chemical constituents, particularly those on which its nutritive value depends. Oats, manured with cows' dung, will produce sixteen bushels for every bushel of seed sown, while on unmanured land there will be only five bushels produced for every bushel of seed. The formation of the soil affects to a considerable degree the produce and quality of the food. Oats reared on clay land are superior to any other. Rye flourishes better on a light, sandy soil. A stiff clay produces a coarse barley; a light chalk a light grain; and a loamy land a full, plump grain; these are only a few examples of many which might be quoted. The time of cutting influences the nutritive value of a food; hay cut late has lost much of its properties; if cut too early it is prevented from reaching the full extent of its nutritive matters. Wheat cut about a fortnight before it is ripe contains the most starch and gluten; the bushel weighs heavier, and the straw contains its greatest nourishment; cut late, the ear contains more cellulose, consequently an increased production of bran, and a diminished proportion of flour.
The season affects the quality of the forage; for instance, in very wet years, and especially when lands have been flooded, parasitic diseases of plants are most common. The age of grain and forage, up to a certain time, enhances their value and quality. Old hay is preferable to, and more valuable than, new; and the same applies to oats, beans, wheat, etc. Food badly saved and stored undergoes deterioration, which may range from slight diminution in nutritive principles, or sourness, to mouldy, decomposing, and offensively smelling material.