398 Journal of Agriculture, Victoria. [10 July, 191 2. 



practice, yet there is no danger of giving foo mucli of tlie substance at one 

 time. Indeed, tlie lieavier application (No. 2) was better than the lighter 

 (No. 3), which, however, was also, good. The beneficial action of mild 

 lime on nitrification is not new, but it is very clearly demonstrated in these 

 results. 



Tables 11. and III. show that about 93 per cent, of the ammonia 

 nitrogen given was nitrified after using carbonate of lime within three 

 weeks. This is probably as large an amount as will ever be recovered 

 in practice.* The final analysis shows a higher figure, but the bottles 

 of Nos. 2 and 3 were emptied by mistake, and refilled at the t"me of the 

 second analvsis, and these particular results are therefore nitrated. 



Increased production of nitrates following upon the use of carbonate- 

 of lime is one of the chief, if not the chief, reason for its beneficial effect 

 on crops. The results obtained in this experiment may be confidently 

 expected in the field where the land is deficient in lime, and sufficiently 

 dry. When two soils in Trinidad were limed, and subsequently examined, 

 a striking increase in the percentage of nitrates was shown over similar 

 unlimed land.f 



Caustic Lime (Nos. 8 and 9) had a bad effect in the fresh state, and 

 practically stopped all nitrification. The larger application did most harm. 

 There was some unavoidable loss of ammonia in filling and aerating these 

 bottles, but as care was taken to wet the .soil before adding the ammonia, 

 the loss was only partial, and cannot be held to explain the result. Table 

 III. shows clearly the folly of applying hot lime with, or .shortly before, 

 the seed of any crop, as thereby the nitrate factory is effectively closed 

 down. Table IV. indicates that the smaller application was beginning 

 to recover at the end of fifty-one days, but the large one was not. The 

 lesson is that hot lime should be appled some months before seeding, and 

 the heavier the dressing the longer the time should be. When hot lime 

 lies a few months in the soil, it unites with carbonic acid, and is then 

 present as carbonate of lime. The beneficial effects of carbonate of lime- 

 have already been noted. Any injurious effect of applying hot lime at 

 the wrong t'me may be expected to disappear by the second year. 



Hot lime eventually will stimulate nitrification just like mild lime, 

 because it will be converted into mild lime. Using small quantities, it may 

 indeed give a better re.sult the second year, because it will be better dis- 

 tributed over the soil particles. For the same reason, its effect would 

 be sooner expended. 



Gypsum hadi a moderate effect in encouraging nitrification, but was not 

 at all equal to carbonate of lime. The heavier application (No. 6) was a 

 trifle better than the smaller (No. 7), but nothing to abide by. It is 

 suflficient to group the results, and note that gypsum has certainly been 

 of benefit, but that it was slow (Table III.) in beginning to act. Gypsum 

 contains lime, but in union with sulphuric acid, and on this account 

 gypsmia will not generally repair the defic'encies of a soil requiring lime 

 as quickly as the other forms, hot or mild. 



Carbonate of Magnesia (Nos. 4 and 5) seems to behave in a curious 

 manner. It was intended to apply the neutral carbonate, but by mistake 

 the " magnesii carbonas levis " of the pharmacopceia was used. This con- 

 tains hydrate as well as carbonate of magnesia, and is weakly alkaline. At 

 the first period, therefore (Table III.), this material delayed nitrification 



* Die Stick-stoffd'imun'j cler Ir-nduK. Kulturpflamyen, by Dr. Paul Wagner, Berlin, 1892. 

 t Bui. Depl. Aji-lc. Trinadad 9 (1910), No. 66, pp. 239, 240. 



