THE FARMER'S MAGAZINE. 



427 



some way so plentiful a store of nitrogen, that his crops 

 will not bear the slightest addition of it in manure ; and 

 Jie is compelled to be careful how he feeds them even 

 by the mechanical agency of the hoe. There is proof 

 that he is able, as yet, to prepare enough of the aiirial 

 or oreranic nutriment, if the stock of raw material will 

 hold out, or be naturally replenished. According to 

 analysis, there exist about five tons of ammonia per 

 acre in the 20-inch staple — a good capital to fall back 

 upon, in case the annual deposits from the atmosphere 

 should fall short of the drawings taken out by the 

 crops. After a dozen good crops, the soil is thus rich 

 in ammonia — so rich, indeed, that, instead of being less 

 than at first starting, there is every probability (from 

 the fine productive condition of the ground) that this 

 element has accumulated during the period of their cul- 

 tivation. There is, then, as much re-ison for expecting 

 a continuance of food-supply from the atmosphere as 

 from the soil, and no ground for apprehending that the 

 capital is being dissipated from the land, instead of 

 being caught from external sources. I have intimated 

 that the stock of ammonia contained in the soil — and 

 which is equal to the quantity abstracted by 60 good 

 crops— might be had recourse to, and a portion of it 

 be used up, in case enough could not in future be 

 trapped from the air ; but I hope such an expedient 

 will not be found necessary. Indeed, it is very likely 

 that the amount of soil-nitrogen made available by the 

 tillage processes may be in proportion to the total quan- 

 tity of unavailable nitrogen present at one time ; so 

 that, were the bulk reduced, a diminished yield of this 

 constituent in an available form might not be obtained 

 without a much greater and continually-increasing 

 amount of comminution and exposure of the soil. I 

 believe that, so far from the " dormant capital" of am- 

 monia being gradually expended at Lois-Weedon, the 

 supply for each crop is obtained from atmospheric 

 sources year by year ; and that, over and above this, 

 there is an actual augmentation of the permanent store 

 laid up in the land. For the superior excellence of the 

 latest crops betokens it. The land is plainly more pro- 

 lific than it has ever been before. Again, comparing 

 the analysis of this soil, in its present condition, with 

 that of a very good average wheat-soil at Rothamsted, 

 Mr. Lawes finds it to " excel in strength," by 

 reason of its larger proportion of this valuable 

 element ; and if the ten crops grown upon it 

 have removed their ammonia out of the l^nd, without 

 compensation from the atmosphere, Mr. Smith's field 

 must have been (when his cultivation began) the richest 

 wheat-soil ever heard of. But it cannot have been so : 

 the subsoils at Lois-Weedon, at Rothamsted, and else- 

 where, contain only from one-half to one-third as much 

 nitrogen as the surface-soil or staple ; so that instead of 

 Mr. Smith having gradually consumed a store of nitro- 

 gen out of his subsoil, he has replaced a 15-inch stratum 

 of subsoil poor in nitrogen, by a deepened staple rich 

 in this substance, which therefore it can have acquired 

 only from above-ground. 



I ask you, Berzelius, just to consider this fact over 

 again : — Fourteen years ago the clay piece at Lois- 



Weedon had a staple of five inchrs, the subsoil being 

 principally yellow clay, and in some places a mixture of 

 sand, gravel, and clay ; it was under pasture, and not 

 very good land either ; and there is no proof whatever 

 that the subsoil contained an unusual amount of nitro- 

 gen, or even so much as it does now. By gradually 

 sinking spade-work, and elaborate pulverization, the 

 ground for twenty inches in depth has been transformed 

 into a friable mould of good quality, peculiarly rich in 

 nitrogen, yet having less of this element, the lon-er you 

 go for a sample. From whence, then, can the total 

 increase nf nitrogen have come, except from above- 

 ground ? The staple-soil contains more nitrogen than 

 the subsoil ; the staple-s'^il, mire than doubled in bulk 

 upon every acre, has displaced a large amount of sub- 

 soil ; therefore the quantity of nitrogen must have been 

 greatly increased. Q. E. D. 



And you will perceive, also, that, as Mr. Smith's 

 twelve crops without manure have left the land better 

 furnished than before with nitrogen, the perpetuity and 

 even improvement of his yields is a demonstrated cer- 

 tainty—as far as this one element is concerned. And 

 this, I suppose, is the only injredient you ever feared 

 would fall short. B'jt everybody now knows that cereals 

 can be cultivated in successive crops without manure ; 

 all the while abstracting from the soil (or air ?) more 

 nitrogen than has been ascertained to pass into the soil 

 from atmospheric sources. The latest instance is that 

 of Mr. Lawes' barley. In a late " Part" of the Royal 

 Agricultural Society's Jouj-nal, he states that six suc- 

 cessive crops of barley, grown on unmanured ground, 

 contained in grain and straw l70lb. of nitrogen— consi- 

 derably more than the quantity supplied to the soil in 

 rain, and other aqueous depositions in the forms of am- 

 monia and nitric acid. So that, whether the plant itself 

 inhales it from the winds, or the earth arrests it by 

 simple contact with the atmosphere, the precious element 

 does come in ample abundance, in spite of all the rain- 

 water analyses thought to show the contrary. 



Yours, &c. J. A. C. 



RISKS OF HORTICULTURR.— It is very easy for 

 a writer to say that cauliflowers like rather a stiff and 

 heavily-manured loam, and beet a very deep and fipe mould, 

 in which there is no recent manure ; but the fact is, there 

 are many other conditions essential, and we cannot judge 

 fairly of the growth of anything in a soil until that thing 

 has 'actually been tried in it. Tell me where, within a 

 telescopic view of the metropolis, can they grow clover as 

 they do ia Hertfordshire ; or where did you ever see such 

 celery as they raise in the rich loams beside the Thames, a 

 little to the west of London ? The same cart-load of mou'd 

 put down on the Kentish chalk would produce a very 

 different result to what would follow were it shot on the 

 gravel of Hampstead ; and if yoTi get into the Fen country, 

 you might find nnvd?ning quite a different affair to what it 

 would be on the sides of .Malvern Hills. Therefore, before 

 you risk much in seed, and labour, and rent, make a ''air 

 guess as to the nature of the crops best adapted to yoiir 

 position If you grow for market, you must be very nnuh 

 guided by the nature of the demand for certain articles. A 

 man may grow strawberries for Covent-garden, and pet 

 three shillings an ounce one day, and sixpence an ounce the 

 next, and these fluctuations must be taken account of by 

 the man who intends to speculate in allotment and gardtn 

 culture.— Floral World and Garden Guide. 



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