FERTILISED SOIL AND ACID.

Putaruru Press, Volume IV, Issue 147, 26 August 1926, Page 6

FERTILISED SOIL AND ACID.

U.S.A. EXPERIMENTS. Laboratory studies are now being made at tl:e Ohio Agricultural Experimental Station of soils that have been receiving regular treatments with various fertilisers sir.*2e 1594. Contrary to popular opinion, these analyses show that acid on superphosphate has not increased the acidity of the soi : i. In fact, none of the common ingredients of commercial fertilisers either increased or the soil’s need for lime appreciably, except sulphate of ammonia, whose use in rather liberal quantities 'increased the soil acidity. This effect of sulphate of ammonia was not 'large enough to be of ‘consequence on limed land, and not cn un-

limed land unless the application given considerably more than what would be carried in a normal application of commercial mixed fertilisers. Basic slag phosphate measurably reduced the soil's acidity. Here again I the effect was too small to be of much j practical importance. Basic s r ag j phosphate is not considered a sa.Mst factory substitute for limestone on ) soils which fail to grow good clover. ! j An application of 1G stone of barnI yard manure made during each fivej year rotation neither appreciably ini’ creased nor decreased the soil’s acidj ity as shown by chemical tests. The 1 fact that cCov.er on sour soil often \ does better after manuring is explainI ed by as increased tolerance for acid , due to a more adequate supply of plant food elements.