"4 



THE TROPICAL AGRICULTURIST. 



[August i, 1882. 



generally uuderatootl that clay possess'/a a power of 

 absorbing ammouia from tbe air, but ouly through 

 the influeuce of rain or dews to bring down the volatile 

 carbonute. This la'ter conditiou, however, is not at 

 all necessary. I Snd that clay is so greedy of aiunionia 

 that, if air charged with carbonate of ammonia, so 

 as to be highly pungent, is pasfed through a tube 

 filled with small fragments of dry clay, every piirtiole 

 of the gas is arrest'-d. In the same way, if into a 

 bottle tilled with air similarly impregmted a little 

 dry soil is thrown, and the bottle is then shaken 

 once or twice, all am mouiaeal smell is destroyed. The 

 double silicate of alumina and lime is in tliese cases 

 the cauee of the abforptiou. 



While the principle of ready absorjiition is not dis- 

 puted by Mr. Lawes, Dr. Gilbert, and Mr. Warington, 

 that of refention is entirely disallowed; the theory 

 of these gendemeu, as founded on their experiments 

 at. Rothaiiiated, being that ammonia, however powerfully 

 grasped by the silicates, is extremely liable to be 

 again washed away by being converted into nitric 

 acid by the nitrifying plant, the action of which, 

 under favourable circumstances of heat and aeration, 

 they consider to be very great. Even if this theory 

 be admitted, the question arises, as Mr. Darby put 

 it at the meeting, "Is it no possible that the land at 

 Eothamsted may have this nitrifying ferment in a state 

 of more active working than tlie generality of soils ? " 



A considerable portion of Mr. VVariugton's lecture 

 was devoted to the cunei deration whether India might 

 not be made an extensive nitrate-producing country, 

 owing to its high range of temperature being favour- 

 able, to the working uf this nit^rifyiug principle. It 

 was very conclusively pointed out by hini that nitrific- 

 ation proceeds in English soils far more actively in 

 summer than in winter ; and also ihat active operation 

 only proceeds when the eoil is suffiiiently aerified. 

 The subjoined extract from Mr. Lawes's pamphlet on 

 "Fertility" also teaches very plainly tbat, to proceed 

 actively in the soil, nitrification requires certain 

 mineral constituents to be present in sufficient force. 

 Mr. Lawes says : — 



A short time ago Schlosing proved that nitriticatiou 

 was due to the action of a minute organism which 

 abounds in our soils. Under favourable conditions of 

 temperature and moisture, nitric acid is produced with 

 great rapidity. It h.as been proved, in regard to the 

 yeast plant (which converts sugar into alcohol and 

 carbonic acid), that, like our ordinary crops, its 

 growth depends upon a supply of mineral food. Wa 

 know the nitrifying plant cannot carry on its work 

 unless it is fumished with alkaline substances to 

 to neutralise the nitric acid formed. If, as may be 

 the case, it requires alkalies and phosphates, we can 

 explain why it ii that the water passing through 

 peaty soils dues n^t contiiin nitric acid. 



From all tbis it not only seems possible, but very 

 probable, that this principle nf . nitrifying would not 

 proceed so actively in a great many soils as it has 

 been found to do in that of Ilothamsted. At any 

 rate before conclusions so very startling as those 

 propounded by Mr. Lawes, Dr. Gilbert, and Mr. 

 Waring' on are accepted as forming the new gospel 

 of chemistry, they ought to be confirmed by careful 

 analysis of a doztn or more different soils, especially 

 as they seem to overturn at one fell swoop all the 

 early teachings of the sages. 



The solution of the problem appears to be of the 

 very utmost importance to agriculture, because, if 

 this nitrifying principle have only gentle and slow 

 action — while it may jjrovc a blessing by preparing 

 plant food for crops— in the form brought to light 

 by the Ilothamsted experiments it appears as a de- 

 vastating angel indeed, slumbering beneath the surface 

 of the soil, only to be awakened by the very agencies 

 wh'ch the farmer employs in the vain endeavour to 



increase the earth's fertility, intismuch as the treasures 

 of earth and air would only be brought together by 

 tillage to be a prey for the spuiler's hand. Even 

 the magicians who h.av6 conjured up this phantom 

 seem half afraid of it ; for Dr. Gilbert, speaking at 

 the meeting of the Society of Arts, assured those 

 presmt that ammonia furnished to the soil in a 

 vegetable form would not be liable to the same risk 

 of loss. But although this may relieve anxiety slightly 

 in respect to farmyaid dung, I fear that no similar 

 exemption could c:mdidly be made by him for the 

 large amount of ammonia which must be contained 

 in the urine of sheep that, before consuming green 

 crops, have been highly fed on oilcake. 



A case for more inquiry is certainly then disclosed, 

 the necessity of which appears all the more urgent 

 because the natural inferences to be drawn from the 

 Rothamsted theory, as it now stands, cannot be con- 

 sidered at all favourable to farming enterprise, but 

 as rather calculated to deter everybody from under- 

 taking the task of exciting in the soil a fertility 

 ■which, in addition to the labour and expense required 

 to produce it, is stated to be extremely liable at 

 any time to be washed out of the soil into the drains. 



AORICOLA. 



[We quite agree with our correspondent as to the 

 desirability of carrying out experiments of the same 

 character on different soils ; but, until this is done, 

 we see no reason for concluding that there is any- 

 thing abnormal in the soil hitherto experimented on. 

 IS^o doubt it is easy to answer in the affirmative the 

 question as to the ^oss(ii7(<)/ of the Eothamsted soil 

 having a more powerful nitrifying action than soils 

 in general ; but the same answer could equally well 

 be given were the question put as ti the possibility 

 of the action being less instead of more. In either 

 direction there is a possibility, but the probability 

 seems no greater on the one hand than on the other ; 

 and little harm can be done by .assuming the Rothamsted 

 soil to be of an ordinary character, until there is 

 eividence to prove the contrary. As to Professor 

 Way's writings, wc do not look on them as so 

 diametrically opposed to Mr. Wariugton's statements 

 as our correspondent considers them to bs ; but, even 

 if they were, it is no reproach to Professor Way to 

 say that he could not know twenty years ago what 

 has been subsequently discovered. Prol'essor Way's 

 views, as above quoted, merely indicate that nitrogen 

 wouhl not escape thiough the soil in the form of 

 ammonia ; but he also showed that, although the 

 amount of nitrogen passing off in the form of ammonia 

 is trifling, perfectly oxidised nitrogen (nitric acid) is 

 carried off in large quantitiees in drainage waters. 

 Mr. Warington's investig,ations go to show how readily 

 aommonia is converted into nitric acid while in the 

 soil ; and in estimating the actual amount of nitric 

 acid carried off by the water, he has had recourse 

 to a method of analysis which was not elaborated 

 till long after Professor Way wrote. But the dis- 

 covery of the fact that, under certain circumstances, 

 nitric acid is carried otf more rapidly than has hitherto 

 been supposed, need not lead us to consider the 

 action of the soil as that of a " devastating angel." 

 Mr. Waringlon showed, in the lecture we published 

 a fortnight ago — (1) that nitrates were being continually 

 produced ; (2) that they were easily lost ; and (3) 

 that that loss may be prevented by a crop. No more 

 nitrates are likely to be carried off in the future 

 than have been carried off' in the past, because it 

 is ascertained that the loss is much greater under some 

 conditions than under others. On the contrary, by 

 availing ourselves of the kuowledge now gained, and 

 learning how and when to apply mannres with the 

 greatest advantage, we may hope to save much of 

 tiie waste that has hitherto gone on undetected. — 

 Es.]— Field. 



