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moniiim nitrogen and the total absence of nitrate nitrogen. They 
seem to have proved that ammonium nitrogen and organic nitro- 
gen cannot be converted into the nitrate form in submerged cul- 
tures ; and further have they shown the general instability of 
nitrates in the submerged soil, due to reversion and loss by leach- 
ing, so that very little is available for plant nutrition in this 
supposedly essential form. It has also been found that more 
of the poisonous nitrites are formed m submerged lands than in 
dry lands. In a recent bulletin ‘‘On the Behavior of Nitrate in 
Paddy Soils,” Buis. Imp. Cen. Exp. Sta., Vol. I, No. 2, the con- 
clusions of the two investiagtors above mentioned are summar- 
ized as follows : 
“ ( 1 ) When nitrate is applied to the paddy soil it is reduced 
to some extent, first to nitrite, and then to ammonia and to ele- 
mentary N, the loss of which varies according to the species of 
denitrifying organisms and the amount of soluble organic com- 
pounds present originally in the soil. 
“(2) When nitrate is applied to the paddy soil, together 
with much organic matter in easily available form for microbes, 
such as glycerine, Na-acetate, starch, fresh oil cakes and straw, 
it is destroyed extensively by denitrification, the most part of its 
nitrogen being lost as free N, while only a certain portion of it 
remains in the soil, being partly assimilated by microbes and 
partly absorbed as ammonia by the soil or plants. 
“(3) The question why nitrate is not a favorable manure for 
plants grown in paddy land can be answered as follows : 
(a) The loss of N by denitrification is larger in paddy soil 
than in dry land. 
(b) More of the poisonous nitrites are formed there than in 
dry land.i 
(c) Loss of nitrate takes place easily by the system of irriga- 
tion, practiced with paddy plants, being inevitable in the farm- 
ers’ practice. 
“(4) Dry land surface soil, when no organic manures are 
applied along with nitrate, does not favor denitrification nor 
nitrite-formation, while in the subsoil, reduction occurs to some 
extent. In very moist conditions, however, as in the rainy sea- 
son, and especially when much organic manure is applied along 
with nitrate, 2 some denitrification takes place even in top-soil, 
and the reduction can proceed so energetically in the sub-soil that 
ail the nitrate applied may be reduced within a few weeks. 
“(5) Organic matters easily available to microbes favor deni- 
trification to a large extent; further, straw or fresh rape cake 
1 Young; rice plants placed in a potassium nitrite solution of 0.1% 
died after five days. 
2 According to Anipola, calcium nitrate is less attacked by deni- 
trifying microbes than sodium or potassium nitrate, but in most soils 
calcium nitrate added will surely be changed by alkali-salts, and 
nitrates of sodium or potassium be formed. 
