16 
lished the results of experiments conducted at the Hawaii station 
which showed the great superiority of ammonium sulphate over 
different nitrates. 
Notwithstanding these facts some American writers continue to 
recommend sodium nitrate for rice and to discuss rice soils from the 
same standpoint as dry lands. 
It is not necessary to go into a theoretical discussion of this ques- 
tion at this time further than to state that abundant experimental 
evidence has already been brought forth in various parts of the 
world to prove that nitrate is not the only form of nitrogen available 
to plants. Results obtained at the Hawaii station show that nitrate 
can hardly be considered to be the principal source of combined 
nitrogen for many plants when grown in the state of nature. It is 
known that nitrates are ill suited to assimilation by rice. 
To study the practical effects produced on the growth of rice by 
ammonium sulphate and nitrate nitrogen, respectively, a series of 
plats was arranged alongside of those used in the experiments dis- 
cussed above. To one plat ammonium sulphate and to another nitrate 
of soda was applied before the time of planting. To other plats 
ammonium sulphate and sodium nitrate were applied in smaller 
quantities, the same being repeated at intervals of 10 days until 
six applications had been made. To each plat the total amount of 
nitrogen applied per acre was the same, and the experiments were 
repeated for three successive crops. The results follow: 
Comparison of ammonium sulphate and sodium nitrate on rice. 
Nitrogen applied. 
Fall crop, 1909. 
Spring crop, 1910. 
Fall crop. 1910. 
Straw. 
Paddy. 
Total. 
Straw. 
Paddy. 
Total. 
Straw. 
Paddy. 
Total. 
Ammonium sulphate (ap- 
plied before planting) 
Sodium nitrate (applied be- 
Lbs. 
3,168 
1,881 
2,475 
2,277 
Lbs. 
4,603 
2,475 
3,465 
2,623 
Lbs. 
7,771 
4,356 
5,940 
4,900 
Lbs. 
3,316 
2,029 
2,772 
1,633 
1,930 
Lbs. 
3,564 
2,128 
3,078 
2.079 
2,178 
Lbs. 
6,880 
4, 157 
5,850 
3,712 
4,108 
Lbs. 
2,920 
2,227 
2,722 
1,831 
2, 145 
Lbs. 
4,010 
3,312 
3,762 
2, 427 ' 
2, 762 
Lbs. 
6,930 
5,539 
6,484 
4,258 
Ammonium sulphate (ap- 
plied in six applications) . . . 
Sodium nitrate (applied in 
Check 
4.907 
From the above yields it is -apparent that nitrate of soda pro- 
duced only slight increases either when applied before transplanting 
or at intervals during the growth of the crop. Ammonium sulphate, 
on the other hand, brought about notable increases in every instance, 
the larger harvests having been obtained from the single application 
before planting. The repeated applications were made for the pur- 
pose of guarding against the loss of nitrate through leaching, but 
this appeared to have no advantage over the single application. 
