INFLUENCE OF SUPPLEMENTART CALCIUM AND MAGNESIUM FERTILIZERS UPON NUTRITIVE VALUE OF KALE ¹

Abstract

It has been repeatedly observed that at times it is difficult, if not impossible, to produce experimental rickets in rats by feeding the Steenbock and Black (1925) rachitogenic ration. Since this ration contains 76 per cent yellow corn meal, Holmes and Tripp (1933) studied the influence of the composition of yellow corn on the effectiveness of a rachitogenic ration and found that the calcium-phosphorus ratio of samples of corn grown in the Midwest varied from 0.06 to 0.75 part of calcium to one part of phosphorus. I n a review of papers published between 1844 and 1898 they found the calcium-phosphorus ratio varied from 0.017 to 0.230, and in papers published since 1909 the calcium-phosphorus ratio was found to vary from 0.04 to 0.45. These observations have raised questions concerning the effect of various factors upon the nutritive value of plants used for human food, and the present study was undertaken to accumulate data regarding the influence of supplementary calcium and magnesium fertilizers upon the dietary constituents supplied by kale.For a long time kale (Brassica oleracea) has been used as a human food. It is classified as a green leafy vegetable and it is frequently considered with such plants as spinach, endive, lettuce, mustard greens, and turnip and beet tops. Since kale has relatively few insect enemies and can be grown on many types of soils, it is widely distributed throughout this country in home gardens and in commercial market gardens.

Chloroplast Pigments in Relation to Magnesium Deficiency

“…darner and associates (16).were the first to report magnesium deficiency In tobaooo. Since the disease occurred frequently in sandy areas in fields it was given the name " sand drown11.…”

“…The study of Eisentnenger and Xucinski(12) concerning the relation of the order of plant development to the need of magnesium was based on observations made of plants grown on these plots. These plots were also used byHolmes and Crowley(17) and Holmes, Crowley and Xuzmeskl(16) in their study on the carotene, calcium, magnesium and phosphorus content of Boston head lettuce and kale.It should be noted that in the earlier studies of Jones(20) andBeaumont and Snell (2) dealing with these plots the same letters A, B, C, and D were used to designate them by starting at the north side with Plot A. In the later reports(16,17) they were designated by starting with Plot ▲ at ths south side.…”

“…These plots were also used byHolmes and Crowley(17) and Holmes, Crowley and Xuzmeskl(16) in their study on the carotene, calcium, magnesium and phosphorus content of Boston head lettuce and kale.It should be noted that in the earlier studies of Jones(20) andBeaumont and Snell (2) dealing with these plots the same letters A, B, C, and D were used to designate them by starting at the north side with Plot A. In the later reports(16,17) they were designated by starting with Plot ▲ at ths south side. Thus the placements of lime and magnesium have not changed in the twenty-seven years during which they have been used, but the letters ussd to designate the plots were changed.…”