EXPERIMENTS WITH SOOT CROPS.

Otago Witness, Issue 2456, 17 April 1901, Page 6

EXPERIMENTS WITH SOOT CROPS.

The results of most field experiment.-- involving the growth of loots aie given on the assumption that one ton of 100t — be they turnips, or swedes, or mangeU — is as good as another. When, for example, the tin nip crop is gro-.vn in order to test the effects of different maiiures-j and the different mixtiucs of manures, the weight of roots jielded per acre is commonly taken as the pole indication of the comparative values of the several maminol dressings in the circumstances under which thoy aie applied. We have, on more than one occasion, suggested that the root.T them s elve» should be tefated— \haj, their sjjeuiic should fee

ascertained as well as the percentage and composition of the solids in their expressed juice — but it is not possible to refer to any, rccont experiments where this has systematically been done. That ioot3 vary in the percentage of water which they contain "is well known, and it is at least possible that of two turnip ciops the one giving the^ greater weight of roots per acre may actually contain less solid matter per acre than, the apparently lighter crop. For feeding purpo-cs the latter is the moie valuable, and yet the manure that grew the bulkier crop would be regarded as better than thajjs which grew the one returning a .smaller gross weight per acre. Sheep-feeders have been told time after time that to give their animals a laige quantity ot watery turnips is aj phy=iolog;cal blunder, because all the vater in the roots has to be raised to tho temperature of the blood of the sheep w Inch, consume them. But what effort has beer* made in the many field experiments which county council grants ond other sources of income have rendeied possible during the last decade to determine the pcicentages of water contained in turnips of the same variety grown under different conditions, manurial or otherwise? If httlo has been done to determine the percentage of water, still le^s has been done to control it. The high practical importance of the question is obvious when it is considered that a difference o£ 1 per cent, m the total solids of a crop of, say, 30 tons of roots per acre means a difference of 6721b per acre in the quantity of: fohd matter elaborated from the air and the soil — m other word 5 , 6721b of water of no nutritive value is ioplited by 6721b of solid matter of veiy considerable feeding value. Reflections Mich a? these are suggested by a perusal of the striking essay with which Messrs James Carter and Co., 237 High Holborn, London, preface their new annual list; of farm seeds, and, to mark the beginning of another centurj', they describe in some detail their "new method in the selection of root crops for seed." The work has been m progress for a number of years, but the publics am ouncement of the method followed and of results obtained has been reserved till the present as an appropriate occasion. They point out that mangels, for example, contain of water from 85 to 94 per ecnt. As the 94 pet cent, coexists with 6 per cent, of solids, and the 85 per cent, with 15 per cent, of solids, it is obvious that a given weight of the one lot of roots would contain two and a-half times as much solid matter as the same weight of the other lot, and their feeding value would be enhanced accordingly, though not necessarily in the =ame ratio. Swedes have 86 to 92 per cent, of water, yellow tuimpo 90 to 92. white turnips 92 to 95, cauots 85 to 92, and Kohl rabi 86 to 92 per cent, 'ihese figures ins^eate the difference m value between loots of close, firm, hard texture, on the one hand, nnd soft, spongy, watery loots on the other. As lllustranng- what it is in the power of the cultivator to effect by long continued selection, associated with chemical analysis of the roots, the case of the sugarbeet is taken. In tins plant, which is clo«ely allied to the mangel, the proportion of sugar in tho roots has been increased from 5 per cent. to a po c sible 20 per cent. It is true that Continental growers v,:ere occupied upon this; work throughout {he nineteenth century, but to mciease the saccharine matter fourfold is a great result to .it! am. After desenbing their own experiments Me-srh Carter enunciate tho following conclusions: — (1) All roots have a tendency to contain an excess of water, which in iUclf is valueless. (2) Some varieties contain water to a harmful degree. (3) A «mall deviation in the percentage of water alters matenally the value of the crop in feeding piopertics. (4) Five tons of one crop may contain as much solid -food as ten tons of another. (5) The obvious necessity arises of ascertaining tb3 weight of solids in any rcot crop. (6) The specific gravity of a root is a guide to its keeping quality. (7) The specific gravity of the juico is a guide to its fe n dmg quality. (8) When the density is highest in both the juice and the whole root, the value of tho stock is mater : ally increased. (9) The increase of saccharine matter in mangels, and all other loots goes hand in hand with the increase of feeding matter. (1C) The quantity of dry matter is not necessarily a determinating factor in the feeding value of loots. The nature of the te-tmg ppparatm employed and the meiii3 whereby strains of roots of superior feeding value are fixed and perpetuated are described in sufficient detail in the essay. The great object in view — and it is one that deserves every encouragement — is to inciease the quantity of available food produced per utra bj the growth of roou crops. — London Times.