)16 



THE FARMER'S MAGAZINE. 



tion to farming, their labours will be of little direct utility 

 to the agriculturist. We understand in England better 

 than in any other country the division of labour, and this 

 circumstance is highly favourable to the development of agri- 

 cultural chemistry, for greater opportunities are offered thau 

 in any oiher country to men trained in scientific matters 

 to apply their scientific knowledge to special purposes. I 

 might take up any subject to illustrate the intimate couuec- 

 tiou of scientific labours with practical matters ; but I believe 

 there-is none better CAlcuiated to sho',v more the direct bear- 

 ing of chemistry upon agriculture thau the cultivation of root 

 crops. In cultivating root crops the farmer is directly thrown 

 in contact with chemistry, for few farmers at thepreseat time 

 can produce sufficient natural manure to satisfy their expecta- 

 tions of grovTing large crops of roots, and hence they are com- 

 pelled to employ artificial manures. From the first period 

 when the seed is put in the ground, or the soil itself is cul- 

 tivated, to the very last moment when the roots are consumed 

 on the farm, the farmer meots with many matttrs iu which a 

 knowledge of chemistry is extremely useful to him, Take, for 

 instance, the mechanical cultivation of the'^soil. He is at oace 

 shown the reason why it is of the utmost importance to work 

 the land properly, to subdivide it, to cultivate it deep. By 

 this mechanical means he liberates mineral food for the use of 

 root crops, which are specially benefited by readily available 

 mineral food ; for, like all quick-growing plants, roots require 

 their food to be prepared before-hand. Hence, if on stiflf lands 

 you neglect the mechanical preparation of the soi), you have 

 not a sufficient amount of available food to satisfy the imme- 

 diate wants of the growing rcot crop. Then again, in putting 

 the seed into the ground, the intelligent agricu turist is re- 

 minded of various purely chemical matters ; and the question 

 occurs to him, " Can I hasten the germination of my seed by 

 the application of csrtain salts, or by soaking it in certain 

 dilute acids ? or can I use any other chemical preparation to 

 make the seed germinate, and bring up the young plant more 

 rapidly ?" But in no time in the cultivation of root crops is a 

 knowledge of chemistry of greater utility than whan the far- 

 mer has to decide what manuring substances he ought to apply 

 in order to obtain a goui crop of mangolds, swedes, or tur- 

 nips. Perhaps he is told he ought to use super-phosphate, or 

 guano, or a tnix'ure of the two, or a special turnip manure : 

 how is he to decide what super-phosphate he is to select, if he 

 does not understand the character of the ingredients that 

 enter into the compasitiGn of super-phosphates or guano ? and 

 how can he understand the chemical composition ,of super- 

 phosphates if he dojs nut understand chemical terms ? If 

 he look at an analysis like that before me, he may glance over 

 it ; but if he does not understand what the meaning of the 

 term " soluble phosphate," for iustaace, is, he ruiis the risk 

 of selecting an inefficient manure, which he buys simply be- 

 cause an analysis has been oflsreJ him. It never enters his 

 mind that a man who has to sell a very inferior article would 

 have it analyzed, and to issue the analysis with all the im- 

 purities which the manure contains ; hence, he is satisfied 

 with simply seeing the analysis. It is, therefore, of 

 great utility to understand the chemical terms for the sub- 

 stances tlrit enter into the composition of those manures 

 which are most frequeaily used fyr agricultural purposes. 

 But, in the first place, it is of great importance to be able to 

 select those manures which are best adapted to the cultivation 

 of roots. Let us take, for example, the cultivation of swedes. 

 We hear constant discussions as to whether guano is better 

 than supci-phosphate, or v/hether a mixture of guano and 

 auper-phosphate should be used; and these discussions are 

 never brought to a succ-ssful issue, simply because we require 



to ascertain, first, whether ammoniacal matters can be dis- 

 pensed with in the cultivation of root crops, or not, and what 

 the conditions are under which we can dispense with ammonia, 

 a very expensive manuring constituent. The question of the 

 superiority of guano or super-phosphate mainly hinges upon 

 this: " Can I dispense with the expensive ammonia, and yet 

 grow a good crop of roots ?" Now, I have no hesitation in 

 saying that there are many instances in which roots may be 

 grown with great advantage without tho direct application of 

 ammoniacal manures ; and that in all these instances a great 

 deal of the moat useful constituent of guano is, comparatively 

 speaking, lost, and that guano is therefore to a great extent 

 misapplied. Now, before I allude to some experiments which 

 I made some years ago, and which I hope the Society will 

 enable me to c^rry on for years to come (for it is only by a suc- 

 cession of experiments that truth is gradually established), I 

 would simply mention the practical experience of many farmers 

 who have found that a mixture of super-phosphate and guano 

 has answered much better thau guano alone ; and likewise the 

 fact that inferior guanos, rich in phosphates, but, comparatively 

 speaking, poor in ammonia, have answered better, practically, 

 than the best Peruvian guano. I might also appeal to the 

 experience of many farmers who apply nothing else in tho 

 cultivation of their roots but super-phosphates prepared from 

 bone-ash alone. Moreover, it is the tendency of the present time 

 to produce super-phosphates compar.itively poor in nitrogen. 

 It is not likely that an intelligent class of men like the artificial 

 manure makers would shorten the supply of ammonia in arti- 

 ficial manures if they did not find that it answered their pur- 

 pose. If they could satisfy their customers without going to 

 the expense of using much ammonia in the composition of arti- 

 ficial manure, they were evidently the gainers. I would not, 

 however, have you to understand that I think that ammonia 

 can be dispensed with even in the cultivation of root crops. 

 I know that it cannot be. There are many soils on which the 

 very cheapest manure that you can possibly use is guano. 

 There are many soils in which ammoniacal matters are 

 beneficial to the root crops; but the instances are far more 

 numerous in which phosphates are more beneficial. With 

 a view of throwing some light on the action of ammonia on 

 root crops, more especially on turnips, I some years ago 

 instituted some experiments which were purposely made 

 on extremely poor land — very thin and exhausted land. 

 They were not made with a view of ascertaining how large 

 a crop of turnips I could obtain by the application of certain 

 mixed manures, but more especially for the purpose of 

 ascertaining whether on our soils and the soils in our neigh- 

 bourhood wa could dispense with the use of ammonia or 

 not, and what manuring constituents were likely to be of 

 till! greatest benefit to the root crops. I used for this pur- 

 pose several simple salts — like sulphate of ammonia, sulphate 

 of potash, sulpbate of soda, sulphate of lime — besides phos- 

 phate in a soluble and most available condition, alone, and 

 mixed with ammonia. That the soil on which the experi- 

 ment was carried on was extremely poor is shown by the 

 result embodied iu tlic diagram to which I direct j'ouv 

 attention. The natural produce of the land in one part was 

 about 3 tons, and in another part 2 tons 11 cwts. 10 lbs. 

 Tliat is the difference between the middle of the field and 

 the outside ; it is too small to be taken into account. And 

 allow me to observe that I think that all.difFerences in prac- 

 tical experiments amounting to no more than half a ton 

 ought to be dismissed altogether as accounted for by natural 

 variations in the soil, or by accident. You should not 

 dwell upon these minute differences, and draw nice distinc- 

 tions as to the n'.'tiou of uilfcrcnt manuring matters. And 



