The Role of Organic Matter, Especially Manure, in the Nutrition of Rice

Abstract

Rice plants grown in sand or in soln. culture responded to addition of manure with marked increases of growth. This effect of manure could not be duplicated by variations in the composition of the major or minor elements of the nutrient soln. over a wide range. The findings of earlier investigators that rice seedlings utilize ammonium rather than nitrate as a source of N were confirmed. - In addition it was found that ammonium is toxic to the rice seedling at relatively low concs. Manure and other kinds of nitrogenous organic matter can serve as sources of N for cultures of rice seedlings. The N of protein, peptone, and various amino acids is available to rice seedlings. These compounds are probably decomposed by micro-organisms before their N is utilized by the plants since under aseptic conditions the N of protein does not appear to be utilized by rice. The influence of manure on the growth of rice under the conditions used is quantitatively attributable to the organic N content of the manure. This N appears to serve as a supplement to the relatively low concs. of free ammonium salts which are tolerated by the plant.