20 
In pot experiments conducted some time ago for the purpose of 
studying the nutritive value of different forms of nitrogen it was 
found that in every instance the addition of nitrate to submerged 
soil resulted in the formation of comparatively large amounts of 
nitrite within a few days after the time of application. In sand cul- 
tures similar effects were observed except where complete steriliza- 
tion was effected. Furthermore, wherever any considerable amount 
of nitrite was formed, more than 5 to 6 parts per million, toxic effects 
were produced, while still greater amounts caused the rice to turn 
yellow and later to die. 
Nitrite, however, was not produced to any considerable extent 
when organic ammoniacal nitrogen was the only form of combined 
nitrogen present, A further objection to the use of nitrates as fer- 
tilizer for rice is found in the fact, therefore, that nitrates become 
reduced to nitrites, which are extremely poisonous to rice. Nitrate, 
then, is unsuited to the nutrition of rice, and in turn may give rise 
to a substance that is distinctly poisonous. 
THE MANAGEMENT OF RICE SOILS. 
During the past few years an increasing amount of study has been 
given to the question of soil management and cultural methods, the 
rotation of crops, and various methods of soil treatment are coming 
to be viewed in their relation to this general question. Investiga- 
tions on special phases of this subject have thrown new light on the 
important question of soil fertility in general and on that of sub- 
merged soils in particular. 
In an investigation on the solubility of the island soils 1 some 
data of interest in this connection were recently obtained. Likewise 
Coleman and Ramachandra Rao 2 studied the effects on the yield of 
rice of aerating the soil. 
The solubility of substances in submerged soils has been found to 
be abnormally high, the amounts of the several mineral constituents 
going into solution in water having been found to be considerably 
greater than were obtained from any of the dry-land soils of the 
islands. 1 After the wet soil was allowed to thoroughly dry out, 
however, the solubility in water was found to be greatly decreased, 
falling to about the same degree as that of dry lands. Similar data 
have also been obtained by Coleman and Ramachandra Rao, in 
Mysore. 2 This seems referable in the main to soil colloids and the 
formation of soil films in the air-dried state. The overcoming of 
film pressure and diffusion of dissolved materials upon resubmerg- 
ence require considerable time, so that the amount of soluble plant 
1 Hawaii Sta. Bui. 30. 
2 Dcpt. Agr. Mysore, Gen. Ser. Bui. No. 2, 1012. 
