MODERN FARMING

Hawke's Bay Tribune, Volume XXVI, Issue 231, 12 September 1936, Page 11

MODERN FARMING

Are Methods Reducing Soil Fertility?

FAILURE TO PLOUGH

With the introduction of artificial manures, the partial scrapping of the plough, and so on, there has accurred a great change from the oldtime farm practices, when the rotation of crops, the ploughing in of legumes, the application of farm manures together with liming, all combined to maintain and improve soil fertility. Touching on these matters, Mr J. A. Bruce, Inspector of Fertilisers, said that a careful examination of certain small farming and cropping lands in this country at the present time would produce evidence that, despite the comparatively large amounts of artificially made commercial fertilisers that are being employed annually, there is a tendency to decrease, rather than increase, soil fertility. “This tendency,” Mr Bruce added, “is by no means the fault of the artificial fertiliser. The one should be used as a complement to the other.” The reasons were insufficiency of organic matter in the soil, absence of farm manure, as well as failure to plough in leguminous crops, fairly general lime deficiency and, in some cases, injudicious and haphazard use of artificial fertilisers. ORGANIC MATTER DEFICIENCY. “The grower is frequently placed in a quandary for supplies of farm manures, Science has tried to come to his aid, but various methods of making up deficiencies of organic matter have not yet taken on very well. Peat of special type is specially treated in other countries, notably in U.S.A, and Russia, and its use is showing some promise of expansion in horticulture. Undoubtedly this organic material (which is really well rotted vegetation) should in the future be used to much greater advantage for the improvement of horticultural soils.

■‘The real effects of manuring can only be judged over a period of years, but some farmers and growers occupied with the immediate return are very aptly to overlook the fundamentals of soil fertility. ... It is quite safe to say that present day manuring paye far too much attention to the chemical and physical and far too little to the biological conditions. Hitherto the value of fertilisers has been judged too much by their effects on crop yield. An ideal manure should, however, promote disease resistance and should maintain quality. By quality is meant the nutritional value expressed not in calories or units of heat energy, but more in terms of vitamin content. ASSESSING PHOSPHATE VALUE. “The trade description 44-46 per cent, water soluble as applied to superphosphate sold to-day is somewhat confusing,” said Mr Bruce. “For comarative purposes, for assessing the value of phosphate fertiliser, it may be said that phosphoric acid has approximately 2 l-sth times the value of tricalcium phosphate. . . . Phosphoric acid is the standard term not almost universally adopted for expressing the amount of phosphate plant-food in a fertiliser. The necessity of having a standard description is obvious when there are several different forms in which phosphates occur in fertilisers.”