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average of ninety-nine American analyses of silage, thirty-five of maize fodder and sixty of maize stover:
The average composition of the water-free substance of the sixty samples of maize stover is almost identical with the average composition of sixty-eight samples of timothy hay except a somewhat higher percentage of fat in the latter and a corresponding decrease in the nitrogen-free extract.
233. Water.—The per cent of water in both the grain and stover of maize when field cured is extremely variable. When the ears have dried in a crib for a year, the grain will contain under ordinary conditions from ten to eleven per cent of water, but at the time of husking it contains very much more. For example, the Illinois Station found, during 1888, 1889 and 1890, the average per cent of water in varieties of different maturities to be as follows:
No. of varie Av. per cent ties tested
of water Early maturing varieties
36.8 On this basis 1,000 bushels of medium maturing maize would lose, upon becoming thoroughly air-dry, a weight of water equivalent to 115 bushels of shelled maize. If this 1,000
bushels of shelled maize could be sold for fifty cents when gathered, it would be necessary to get fifty-seven cents a bushe when thoroughly air-dry in order to get the same amount for it
Different varieties vary greatly in regard to the percentage of moisture which they contain. Two varieties of maturing maize, have been grown the same season which contained sixteen and thirty-four per cent of water respectively. In the former case, 1,000 bushels of shelled maize when husked would make 945 bushels when ,air-dry, while in the latter case 1,000 bushel: would make only 740 bushels when air-dry. In the first it would take seventy pounds of ears as husked to make a bushel of air-dry shelled maize, while in the last instance it woult take ninety-seven pounds of ears to make a bushel when air dried. The weight of maize as husked does not, therefore, indicate accurately its food value.
The per cent of water in field cured fodder has been foun, to vary from twenty-three to sixty per cent and in field cureil stover from fifteen to fifty-seven per cent, thus greatly modifying: the pounds of dry substance per ton and consequently the feeding value per ton of field cured substance. At the Cor. necticut Station field cured maize fodder was placed in thr: barn giving perfect shelter November 11th, when it containel twenty-seven per cent of water. On February 8th, after much warm and damp weather, it contained fifty-four per cent of water. Thus maize fodder which weighed five tons when put in storage in November weighed eight tons three months later. This is probably unusual, but it shows the possibility of varia: tion of weight due to atmospheric conditions.
The water in silage has been found to vary from 62.4 to 87.4 per cent. In the first instance a ton of silage would contain more than three times as much dry matter as the latter. When the practice of putting maize in the silo was first started, it was the custom to harvest at a much earlier period of growth than at present. The average of 79.1 per cent of water in silage • 1 Conn. Rpt. 1878, p. 64.
given in table (232) is based entirely upon analyses made prior to 1890. It is probable that much of the silage at the present time contains seventy per cent or less of water. Silage at the Wisconsin Station? in 1893 contained 64.3, and in 1894, 70.7 per cent of water. In an experimental sample the per cent of water in the maize plant when it was put into the silo was 68.9, while when taken out it was 71.2 per cent. It thus appears that the loss of dry matter in silage is greater than the loss of water.
234. Ash.--The maize grain is characterized by a comparatively low percentage of ash. The ash appears to be principally phosphates of potassium and magnesium. The ash contains approximately fifty per cent of phosphoric acid (P,03), thirty per cent of potash (K,O), and fifteen per cent of magnesia (MgO). The extremely small amount of lime (CaO) present, about two per cent, has an important bearing upon the feeding value of maize when fed to growing pigs exclusively or only in connection with milk. Schweitzer found that the maize plant removed from an acre of land 2 19 pounds of ash and 135 pounds of nitrogen. One-fourth the ash and one-half the nitrogen was removed by the ear.
The Massachusetts Station has found the fertilizing constitvents in air-dry substance to be as follows:
235. Protein. In the analyses of the 208 air-dry samples including all varieties, the protein (N x 6.25) was found to vary from seven to 15.3 per cent. The usual limit of variation lies between eight and twelve per cent."
Osborne' has studied the proteids of the maize grain and has distinguished them according to their solubilities as follows:
"a Proteid, soluble in pure water, having some of the properties of proteose. * Globulins, insoluble in pure water, but soluble in salt solutions.
“c Proteid, insoluble in water and salt solutions, but soluble in alcohol of 60 to 99 per cent.
"d Proteid matter, insoluble in water, salt solutions and alcohol, but soluble in dilute alkalies and acids.”
The most important of these compounds, both on account of its quantity and because it is a characteristic of the maize grain, is the proteid soluble in dilute alcohol, called zein.
No proteids are found in the maize grain which give to its meal the properties which gluten (mixture of gliadin and glutenin) gives to wheat flour. Zein in maize corresponds in some of its chemical properties to gliadin in wheat, but it is neither sticky nor plastic.
236. Carbohydrates.—The chief constituent of the carbohydrates of the maize grain is starch, which may constitute sixty-five per cent of the total dry substance. In the manufacture of starch, fifty-five per cent of commercial starch may be obtained from the water-free grain. Besides the starch, the carbohydrates consist of two per cent of fiber, five per cent of gum (pentosans), and small quantities of sugar (sucrose and dextrine).
237. Fat.—The fat of maize is fluid at ordinary temperatures, solidifying at -36° F., and is hence known in commerce as corn oil. It is composed principally of linolin and olein and has a specific gravity of about .925.3
1 U. S. Dept. of Agr., Yearbook 1901, p. 304. 2 Conn. Rpt. 1896, p. 391. 8 III. Bul. 53 (1898), p. 170.
CLASSIFICATION AND VARIETIES 238. Species.—No wild species belonging to the genus Zea having with certainty been identified, all the knowledge we have of maize is obtained from its cultivated types, all of which have been considered as coming from one species (Zea mays L.). Apart from pod maize, there are five types or classes which are readily recognizable and when kept pure breed true to type. Although the different types cross readily, intermediate types are not common. The difference in these types is due primarily to the arrangement and character of the endosperm, although accompanied with and resulting therefrom are marked variations in the shape of the grain. (226)
If a dent maize grain is split through its two longest diameters, the endosperm will appear to consist of two parts. In the central part the endosperm will appear white, while on either side it is glossy or corneous (horny). Sturtevant first pointed out the relation between the character of the endosperm and the five types of maize. The several types he has called agricultural species and proposed Latin names for them as follows:
1. Pod maize (Zea tunicata).
In this book these proposed species will be referred to as the types of maize, and variations within these types will be called varieties.