THE FARMER'S MAGAZINE. 



841 



the soil all the other portions of nutriment necess- 

 ary for their existence. When a manure produces 

 this effect, it is undoubtedly a stimulant, and we 

 should never apply nitrate of soda unless we are 

 sure there is somethinf^ to respond to the demands 

 of the plant — that there is phosphate of lime and 

 other elements present there to satisfy it. It is 

 then the fact that nitrogen exists in various forms 

 in manures. But if we apply lime or strong 

 alkali, it is at once converted into the form of 

 ammonia, and readily escapes. Guano owes its 

 very powerful smell to the quantity of carbonate of 

 ammonia always escaping. Where lime exists in 

 land its ammonia will be developed. Now all land 

 fit for vegetation, in a greater or smaller degree, 

 possesses some lime — in this neighbourhood abun- 

 dance of chalk, probably more than is wished : in 

 others it is deficient, and it is necessary to add it 

 before vegetation can take place successfully. 

 Here is some of the ordinary manure for the wheat 

 crop {exhibits it), which, being used as an autum- 

 nal application, it is necessary should not be too 

 rapid in its action. As the manure passes round 

 it will be found to have little or no smell, and then 

 it will be shown to smell as soon as a little of the 

 alkali — possessing in itself no smell — is added. 

 {This was accordiiujly shown.) Now, it has been 

 pretty well proved, notwithstanding a vast amount 

 of argument to the contrary, that the essential 

 manure for the turnip crop is phosphate of lime, 

 and that the equally essential manure for grain 

 crops is ammonia, or nitrogen, in some form. 

 You are aware that a great and not very good 

 tempered controversy has arisen betwixt Baron 

 Liebig, and Mr. Lawes and Mr Gilbert, on this 

 subject. But it was previously known to the 

 agriculturists of this country that the proper ma- 

 nure for the wheat crop was ammonia, and that for 

 the turnip crop phosphate of hme. It is not a new 

 fact. We were well aware of it 10, 12, or 15 

 years ago, and this it would be easy to prove. 

 But Mr, Lawes has instituted some very laborious 

 experiments, which have set the matter still clearer; 

 for he has well shown that whilst he continued to 

 apply phosphate of lime to the root crops, he suc- 

 ceeded in raising a greater amount of roots year 

 after year; whilst, on land which had no manure, 

 they dwindled, in four years, from 4 tons to 3 tons, 

 then 13 cwt,, and nothing in the fourth. He found, 

 likewise, that he by no means produced the same 

 effect by adding salts of ammonia to a considerable 

 extent. He applied to a crop of turnips, in con- 

 siderable doses, sulphate of ammonia, but, without 

 the phosphates, and had no crop. Professor 

 Voelcker, in the last part of the Society's Journal, 



has given the results of experiments which set this 

 in a yet stronger light. If we adopt these experi- 

 ments as our guide, we should feel almost disposed 

 to say that nitrogen and ammonia are totally 

 useless to the root crops. But there is a drawback 

 to them which I shall mention. It is that in spite 

 of all his endeavours. Dr. Voelcker obtained only 

 a half crop at the best, viz., from 15 tons farmyard 

 manure, 7.16 tons; from nothing, 2\ tons, or 

 rather under 3 ; from 6 cwt. bone ash dissolved in 

 sulphuric acid, from 8 to 9 tons ; from sulphate of 

 ammonia nothing (but as applied there is no doubt 

 its pungency injured the seed), and not more when 

 sulphate of ammonia was added to bone ash than 

 when it was not. We must be cautious, however, 

 in building our superstructure on too narrow a 

 basis; we must repeat these experiments. The 

 following experiment, if I may venture to quote 

 myself, is one which I made and published in a 

 little paper ten years ago : — " I was anxious to 

 ascertain what the eflfect would be of applying to 

 the turnip crop an excess of ammonia. With this 

 view, in the autumn of 1848, I applied to a given 

 space of ground, being a wheat stubble, a liquid 

 preparation of ammonia : I was fearful, if I applied 

 it later, the strength of the application would 

 destroy vegetation ; indeed, it had this effect to a 

 considerable extent on the weeds in the stubble, 

 and also on the worms and other insects, which 

 were found dead on the surface of the land, show- 

 ing that a powerful alkali, such as ammonia, acts 

 as a poison on wireworms and other pests of 

 vegetation — a fact in itself important, and con- 

 solatory to those who cannot divest themselves of 

 the idea, when casting a few hundredweights of 

 Peruvian guano on the surface of the land, that, 

 while the cost of the application is certain, the 

 benefit to be derived is altogether doubtful and 

 hazardous. But to return to our more immediate 

 subject: the stubble thus treated was ploughed 

 and cleaned in the spring, in common with the 

 adjoining land, and, early in June, drilled with 

 Skirving's swede seed, the whole being manured 

 with superphosphate of lime— that is, both that 

 which received the ammoniacal application, and 

 that which did not. The seed vegetated well, and 

 it soon became a good plant throughout the field ; 

 but after a very few weeks, the land which had 

 received the ammoniacal application could be dis- 

 tinguished at some distance by the dark colour 

 and remarkable luxuriance of the greens. This 

 continued throughout the autumn, and, on examin- 

 ing them a week before Christmas, it was found 

 that the luxuriant greens had been the precursors 

 of huge and monstrous necks, twelve to eighteen 



