80 ECONOMY OF FARMING. 



If any one should suppose that all the product of plants can only be restored again 

 by organic substances, and there must be given back again to the field all that it has 

 yielded in straw and grain, or that it must be replaced by an equal weight of easily- 

 dissolved organic substances ; then in the foregoing case, for the grain drawn from 

 the pro luction of manure 12,280 lbs. are requisite, which must be gathered some- 

 where else in hay from the meadows, and in litter from the woods. But as we know 

 that plants in part draw their nourislmicnt from other sources, the estimate of the 

 need of manure according to our supposition is as follows : 



Potatoes need only f of their dry weight, consequently the saving is 1294 lbs. 



Clover needs only +. and therefore gives a saving of _ _ . 3000 " 



Beans need foi their straw scarcely ■^. and give a saving therefore of 1000 " 



Vetch-mixture green needs only ^, and gives thereibre - . - 1500 ♦' 



Total saving 6,794 « 

 The above mentioned weight in grain and knobs equals - - - 12 280 



Consequently there are needed ___----- 5,486 lbs. 

 But because the mass of manure will be increased by 140 cwt. of green 



vegetable substance, which reduced to dry weight, equals - - 3,500 lbs. 



Therefore the real deficiency in vegetables which needs to be supplied 



for the production of knobs and grain, is only _ _ - - - 1,986 lbs. 



which must be made up by hay or litter, unless potatoes are employed in part for 

 feeding out, in which case the cultivation of the field requires no additional supply, 

 but also can spare 1890 lbs. of dry potatoes as not necessary for the production of 

 manure. 



Here may be introduced the estimates of the need of manure in order to yield a 

 given quantity of production, in § vii. of Vol. II. p. 180, where we must observe that 

 in respect to clover f of its weight of product was assumed instead of ^ as the need 

 of manure, and no account scarcely was made of its roots as manure. For the same 

 object serve also the estimates quoted hereafter § iii. B. 8, seq., what proportions 

 the production of plants tor trade must bear to those tor fodder and the production of 

 litter. 



That the above-mentioned statements must be considered only as probable assump- 

 tions, any one may easily convince himself who knows that the growth of plants 

 depends not only on the quantity, but also the quality of the nutriment furnished 

 them, on their culture and the influences of the weather, &c. The quantity of nutri- 

 ment only can be expressed in numbers, and afterwards verified by experience; 

 therefore I have confined myself thus, in forming an estimate of the proportion be- 

 tween the manure and the product. 



[The estimates to which the author refers as found in Vol. II. p. ISO, occur in the 

 following connexion : "If we take the straw from the field for fodder, then will a con- 

 siderable part of its weight be partly assimilated to the flesh of the animal, partly be 

 dissipated, and the remainder only be applied to the benefit of the manure. If further 

 we take from the field much grain-fruit, if we must repay a proportion of it, and are 

 not in a situation to restore it in the same measure by straw, grain, by wood and bog 

 litter, meadow-growth, manure purchased, &c.. then will the quantity of the manure 

 produced be always smaller, and the harvest from year to year become worse. 



In order to show clearly the value of manure, and the alteration of the power of 

 production of the field, we will quote the product as it really follow^s under certain 

 given circumstances, and show the aids which are necessary to increase the product. 

 The field will be viewed as tilled according to the rules of the Threefield pys- 

 tem, with fallows. Its product per yoke (= 1.422 acres) in grain, the first year, as 

 fallow, was, 



64 " = 103 



