DO FERTILISERS FEED?

Dominion, Volume 1, Issue 258, 24 July 1908, Page 3

DO FERTILISERS FEED?

. One has scarcely had time to master fully the great fact..iHat.fertilisers feed the crops,, when' new . experimenters arise who tell, us that they .do nothing of. the sort—or, at least, that that is not tho chief cause pf their good, effects. ' ■ The United.States Department of Agriculture announces, as a'result of many : experiments and deep observation, that ■" whilo manure and fertilisers may often increase crop yields as a result, of a direct supply of plant food or as'a stimulant to the plants, there, is now abundant , evidence that their effect is rather the:result.of _a. direct, action upon the soil, thereby changing,its relation .tb. plants. Complex .and _ imperfectly understood as. is this action, it. is a more satisfactory explanation of the benefits derived from fertilisers than the idea that the inconsequential amounts of/nitrogen,;:, potash, and phosphorus applied, as: compared with the larger stores of.tHose elements'already in the soil, should be directly responsible for such marked increaso .in growth /as .frequently follows the application of, fertilisers. Other investigators throw some degree, of support upon these announcements'independently by the contention that " roots possess well-defined oxidising powers, • due principally to enzymes. Certain substances used as fertilisers promoto the activity of roots, and root oxidatiou is more active in fertilo.than in unproductive soils." , Tho practical meaning of all this is'that we may yet discover that wo can leave'off our feverish clamour for nitrogen, phosphorus, and potash, and stir up our crops just as successfully with applications of cheaper and less bulky substitutes. The drain of the soil's chief plant-food can .meanwhile bo rectified by ploughing deeper.':