POTATOES v. WHEAT.

Otago Witness, Issue 4039, 11 August 1931, Page 12

POTATOES v. WHEAT.

LORD BLEDISLOE’S VIEW. The prices at present ruling in the Dominion for wheat, flour, and potatoes suggest that an important reduction in the cost of living to most families can be made by the increased use of potatoes in various ways in partial substitution for bread and other foods made from wheaten flour, with an undoubted gain in nutritive value. The question of the relative food values of wheat and potatoes, both as regards yield per acre and prices, was discussed by no less an authority than his Excellency the Governor-General (Lord Bledisloe) in an important paper on “Potatoes and Pigs with Milk, as the Basis of Britain’s Food Supply,” read by him before the British Association at Edinburgh in September, 1921, and subsequently issued as a pamphlet. As an acknowledged leading authority on farming in Britain and on the problems connected with the national food supplies, Lord Bledisloe’s views and opinions are of considerable value and importance at the present time.

“Potatoes,” says Lord Bledisloe, "provide an immense quantity of starchy food, far exceeding wheat in output per acre. The crop can be obtained at a shorter interval from the time of sowing, and harvested at different periods. Potatoes contain • more vitamins than wheat. Potatoes are relatively deficient in fat and protein, but these can be supplied by bacon. The capacity of pigs for rapid reproduction, large families, high percent-

age of fat yield, and their great variety of by-products, render them invaluable meat providers. “ Large areas of temporary and permanent pasture provide a valuable storehouse of accumulated fertility. No crop thrives better on newly-turned pasture than potatoes. They can be eaten as tubers (preferably in their jackets), or potato flour can be converted into wholesome and palatable scones, cakes, pastry, or even bread. Surplus or unsuitable potatoes can be utilised, both as stock food and as a source of commercial alcohol or starch.

Whatever else may be said for or against the competitive crops of wheat or potatoes,” Lord Bledisloe proceeds, “ the main basis of comparison in time of national emergency must necessarily be their respective nutritive values. According to figures checked for me by the head of the chemical department at Rothamsted, the average net yield of wheat in Great Britain, after allowing for seed, is about four-fifths of a ton, or 17921 b per acre. This would yield 12541 b of wheat flour of 70 per cent, extraction, with an energy value of 1651 calories per lb. This corresponds to 2,070,354, or, say, 2,100,000 calories per acre of wheat. “The average yield of potatoes in Great Britain, after allowing for seed, may be taken as 5.4 tons per acre, which is equivalent to 12.0961 b, with a calorific value (allowing for waste in preparation for cooking) of 427 calories per lb. This corresponds to 5,164.992, or, say, 5,200,000 calories per acre, or more than double the calorific or energy output per acre of wheat. In this calculation no account is taken of the energy value of the 30 per cent, offal from milling, which will normally go into meat production.” These figures are based upon the Royal Society’s report on the food supply of the United Kingdom, 1917. Lord Bledisloe says Dr Plimmcr’s more recent determinations would put wheat at 2,100.000 and potatoes at 4,700,000 calories per acre. The ratio between the two crops in both calculations would work out about the same—between 2.2 and 2.5 in favour of potatoes. Lord Bledisloe goes on to show that the amount of carbohydrate in bread is 218 grammes per lb, as against only 85 crammes per lb in potatoes; but as on an acreage basis there can be produced 12,0961 b of potatoes to 17921 b of bread, an acre of potatoes will yield (allowing 5 per cent, for waste) 1,030,000 grammes of carbohydrate as against 390,000 grammes only in the case of wheat when converted into bread.

As regards price per calory, the Food (War) Committee of the Royal Society pointed out in October, 1917, that whereas potatoes, which yield 427 calories per lb, would at 6d per 71b at that time provide about 500 calories for one penny, bread, which yields about 1176 calories per lb, at a cost of Is per loaf, was only providing about 392 calories for the same price. It was also shown that if potatoes could be supplied to the consumer at 5Jd per 71b, a yield of 540 calories of energy would be procured for a penny, and they would become to the consumer a far more economical source of energy than bread. The Royal Society’s committee further pointed out that “the nitrogenous constituents of potatoes have been found by numerous investigations to hold a very high position as material for repair to the wear and tear of the tissues, and that there is some evidence that they are nearly twice as valuable as the nitrogenous constituents of bread.” The same committee asserted that if the price of bread were three times that of potatoes, the wear and tear of the body could be as well repaired by one penny spent on potatoes as by 1.3 d spent on bread, and that the gain to the nation of available nitrogen by the substitution of potatoes for bread amounted to something like 70 per cent. In the matter of vitamins, bread, potatoes, and bacon are all somewhat deficient, but of these potatoes are the richest in this factor in nutritive values. Potatoes contain a moderate amount of all three essential vitamins (A, B, and C), and one at least of them (C —anti-scor-butic) survives cooking. In any case, if the energy requirements are forthcoming, quite small amounts of milk, fresh vegetables or fruit will supply the Vitamin requisites.

In Germany, with a population of 65,000,000, the total annual potato harvest before the war was 52,000,000 tons, representing 16cwt. per head of population. But for Germany’s potato crop, the war would probably have terminated at least a year earlier. Lord Bledisloe’s figures of the respective average yields of wheat and potatoes in Britain correspond very closely to those in New Zealand. According to figures published by the Government Statistician, the total quantity of wheat (firsts and seconds) threshed in the Dominion during the period January-May, 1931, was 6,660,788 bushels, representing an average yield of 31.92 bushels—or, roughly, fourfifths of a ton —per acre. The figures for the 1930-31 potato crop of the Dominion are not yet available, but those

for the three preceding years compare as follow: — Year 1929-30 1928-29 1927-28 Area (acres) .. 23,214 21,304 21,693 Yield (tons) .. 130,107 123,607 121,402 Average per acre (tons) .. .. 5.60 5.77 5.59 The wholesale value of potatoes at Christchurch on July 22 was Is 104 d to 2s per cwt. The world price of wheat today is about 4s per cwt. In Christchurch the quoted wholesale price of wheat is about 10s per cwt., that of flour about 16s 6d per cwt., and that of bran about 5s per cwt. The figures show a big advantage in value to potatoes, and since the respective yield per acre figures in the Dominion correspond nearly enough to those for Britain quoted by Lord Bledisloe, it follow's that his argument regarding the relative calorific values per acre of wheat and potatoes in Britain applies equally well to the Dominion. Any factors tending at the present time to a reduction of the cost of living are of vital importance to the people, and on the facts and figures quoted a very strong case has been made for cutting dowm household bills by the increased use of cheap potatoes as a foodstuff of a high nutritive value.