ECONOMY OF FARMING. 73 



to the analysis ofEiNHOFF, they rank in the possession of nutritions matter, as follows : 

 Wheat 78 per cent. ; rye, 70 ; barley 63 to 70 per cent ; oais. 58 per cent. : and con- 

 sequently the exhausting powers of these grains are, wlieat, 13; rye, 10; barley, 7; 

 oats, 5 " 



In the British Husbandry, Vol. II., p. 92 it is said, in view of the above analysis, that 



a bushel of wlieat, weiglung 59 lbs., w^ould absorb about 46 lbs. of nutritive matter. 



'• " rye •' 55 " '• " " 38^ " '• " 



" " barley " 46 " " " " 30 i " " " 



« u oats " 31: " " " " 20 '• " " 



27. The root-vegetables draw from the soil, in proportion to the time 

 which they remain in it, J- to ^ of their weight in humus. 



Turnips on stubble ground which remain in the soil only three months, require sure- 

 ly not more hutnus than the half of the dry product which they have produced in this 

 time ; whilst to carrots, cabbage-turnips, beets, we must allow at least f , since they 

 grow hard longer in the soil. The difference of the product of the succeeding crops 

 will determine for us this question. 



28. Potatoes weaken the soil most of all the root-vegetables, because they 

 must be hoed and hilled ; because they ripen in the soil ; and because their 

 leaves lose the power of absorption before the knobs are formed out. 



It seems to me that we must allow ^ of their dry weight to the estimate of manure, 

 if we would not enfeeble the fields by them. If the summer grains, especially barley, 

 always agree so well after potatoes, as every one sees this is no proof against us ; 

 since, by the culture of potatoes, the old humus, as well as the newly introduced ma- 

 nure, are brought into a very decomposed state ; and the stock remaining in the soil 

 after potatoes, is always large enough to pro, luce a rich harvest of barle)'-. If 250 

 cwt of potatoes are gathered for a yoke ( 1.422 acres), this gives 62 cwt. of dry sub- 

 stance with the stalk; ^ of this is 46.50 cwt. ; and if for 10 cwt. of dry stalk, f be 

 ascribed to the humus, = 6.66, this makes the whole consumption of organic matter 

 to be 53.16 cwt But since we have brought to this fruit, with 300 cwt of manure, 

 150 cwt of organic matter in the soil, there remains of it in the field ^', unless we 

 suppose that by means of hoeing and hilling, a greater escape of the humus takes 

 place than what is allowed in the above estimate, which is not perceptible in the first, 

 but especially in the second and third fruits following the potatoes. 



29. The oil-plants, and the plants which are to be spun, if they are suffer- 

 ed to ripen, must be computed like the ripened culmiferous grains. If they 

 are taken away from the field in a green state, we need only reckon f of 

 their product in dry materials. 



There is no sufficient ground for the conclusion that the oil-plants, and those used 

 for spinning, are as absorbinor as the culmiferous grains; much more is it true, that 

 the latter appropriates to itself more humus than the former plants. The small, low 

 rape and flax plants, which remiin in the soil a shorter time, need not proportionally 

 more for their production, than wheat and rye ; and if the flax and hemp are not left 

 to ripen, certainly less. The notion of some that these plants especially exhaust the 

 soil, rests on the observation that many farms which can yield no sufficient addition 

 for thnt which is wholly taken away from the soil by the oil-plants, and such as are 

 used for spinning, must for a while Iinve their fields withdrawn, as wholly enfeebled, 

 from this culture. But it is clear t!i il iicre the indirect effect is confounded with the 

 immediate one. 



[By the oil-plants, are meant the winter and summer rape-seed, the poppy and 

 dotter. By the spinning-plants, flax and hemp. 



Some particulars n^lating to the plants mentioned in some of the preceding para- 

 graphs may be suitably introduced in this place. 



The following estimates from Burger and Schwertz and from the British Hus- 

 bandry, show the average amount of seed needed, and the average product of the 

 difieront plants. The averagres are of many experiments, made in different countries, 

 with various soils, clim?ites. an 1 modes of culture. Schwertz uses the French meas- 

 ures. It has been necessary to abbreviate in some cases. 



10 



