216 DURATION OF ORGANIC MANURES. 



manure in the soil is not taken away in part, by the growth and 

 removal of every crop, but that such waste is continually compen- 

 sated by new acquisitions. And whether such new supplies of 

 alimentary matter be furnished in part during every day, or in 

 every year, or only during the one term of rest in the whole course 

 of crops, the practical result is the same, of the natural or original 

 amount of alimentary manure remaining finally undiminished. 



So far as to the absolute permanency of putrescent or alimentary 

 manures supplied by nature. Next let us see whether the same 

 reasoning, and also experience, so far as yet obtained, do not in 

 like manner prove the permanency of putrescent manures applied 

 after calcareous manures. The poor soil just adduced for illustra- 

 tion, while having its natural alimentary ingredient and its natural 

 supply of lime thus balanced and proportioned to each other, was 

 supposed to produce at the rate of 10 bushels of corn to the acre, 

 and to remain at or near that rate of productive power. Suppose 

 then marl to be applied in such quantity as would give enough cal- 

 careous earth to combine with twice as much new alimentary mat- 

 ter as the soil before held. Suppose further, that the soil so marled 

 is not left to draw and store up this now needed stock of alimentary 

 manure by its newly increased poweiv, (and as would be done in 

 sufficient time, if under favourable circumstances of tillage), but 

 that so much putrescent manure is applied to the soil, gradually 

 and judiciously, as can be combined with and held by the supply 

 of calcareous earth ; and that such addition of manure gives to the 

 soil a power to produce 30 bushels of corn. As soon as this com- 

 bination is completely made, the soil is in precisely the same con- 

 dition as to its newly increased rate of product of 30 bushels, as 

 before to that of 10 bushels ; and the new and larger supply of 

 putrescent manure must be as permanent as was the natural and 

 smaller supply. 



But it is not contended that the mere application of vegetable 

 or other putrescent manure, under such circumstances, secures the 

 permanency of effect of all thus applied, but only of so much as 

 can be and is combined with the calcareous earth. And many cir- 

 cumstances may and do usually obstruct the immediate and com- 

 plete combination from taking place. To insure the perfect and 

 full result, the intermixture of the calcareous and the putrescent 

 matters, and in due proportions, must be perfect, and no excess of 

 the latter must remain anywhere in the soil ; the putrescent mat- 

 ter must also be in the particular state of decomposition (whatever 

 that may be) to enter into combination ; and moreover there must 

 be enough and equally diffused moisture, without which no chemi- 

 cal combination can take place. Now, as some and probably all 

 these conditions must necessarily be deficient in every case of ap- 

 plying putrescent matters to marled land, it must follow that much 



