MALNUTRITION IN PLANTS.

New Zealand Herald, Volume LX, Issue 18387, 1 May 1923, Page 12

MALNUTRITION IN PLANTS.

EXCESS OF FERTILISERS.

Malnutrition or the. imperfect nourishment of plants may arise either from an insufficiency of plant foods 1 in the soil or from an excess of some particular food, constituent. Just as doctors are continually saying that people as a rule cat too much, especially too much nitrogenous food in the shape of meat, and from this cause become increasingly subject to such complaints as gout, skin diseases, appendicitis, etc., so plant experts point out that in the development of intensive cultivation there is a danger of supplying plants with too much nourishment of a forcing nitrogenous nature, and to this cause is attributed some ot the diseases to which plants are liable to suffer, or if not actual disease, a diminution in the quality of the crop. Thus turnips may develop a dropsical, watery character, potatoes became unsightly from spotty skins, cereals get their tender stems easily attacked by insects. Plants grown in green houses and market garden produce are especially liable to suffer from an excess of nourishment or a supply of ill-balanced plant foods. Crops are grown in quick succession vear after . year on the same soil, continually enriched by large dressings of stable manure and fertilisers, so that the soil beocmes quite surfeited with plant food, and does not get the healthy influence of a period of fallow. An expert of the Massachusetts Agricultural Experimental Station has been devoting a special s'udy tj this subject, in consequence of the attention cf the siV.-oii having been called during the past few years to an increasing number of plant troubles and in a good many cases he has found typical cases of malnutrition, caused by an <;xn.Hs of somo pa:tic substance in the yoil. These troubles, according to his investigation, " all originate from an injudicious use of commercial fertilisers, or from applying certain manures to crops in excess of what they can stand." In some cases an excess of fertilisers causes burning of the roots, which results in the death of the plant, but usually the greater trouble comes from an excess of nitrates in the soil.