52 CALCAREOUS MANURES— THEORY. 



states, while the successive crops of several years' grrowth, in the different 

 stages of their slow decomposition, may be always found on the acid wood- 

 land of lower Virginia. 



The presence of acid in soils, by preventing or retarding putrefaction, 

 keeps the vegetable matter inert, anS even hurtful on cultivated land ; and 

 the crops are still further injured by taking up this poisonous acid with 

 their nutriment. A sufficient quantity of calcareous earth, mixed with such 

 a soil, will immediately neutralize the acid, and destroy its powers ; and the 

 soil, released from its baneful influence, will be rendered capable, for the 

 first time, of using the fertility which it really possessed. The benefit 

 thus produced is almost immediate ; but though the soil will show a new 

 vigor in its earliest vegetation, and may even double its first crop, yet no 

 part of that increased product is due to the direct operation of the calca- 

 reovts manure, but merely to the removal of acidity. The calcareous earth, 

 in such a case, has not made the soil richer in the slightest degree, but has 

 merely permitted it to bring into use the fertility it had before, and which 

 was concealed by the acid character of the soil. It will be a dangerous 

 error for the farmer to suppose that calcareous earth can enrich soil by 

 direct means. It destroys the worst foe of productiveness, and uses to the 

 greatest advantage the fertilizing powers of other manures ; but of itself it 

 gives no fertility to soils, nor does it furnish the least food to growing 

 plants.* 



These two kinds of action are by far the most powerful of the means 

 possessed by calcareous earth for fertilizing soils. It has another however 

 of great importance — or rather two others, which may be best described 

 together as the poiver of altering the texture and absorbency of soils. 



At first it may seem impossible that the same manure can produce 

 such opposite effects on soils as to lessen the faults of being either too 

 sandy or too clayey — and the evils occasioned by both the want and the 

 excess of moisture. Contradictory as this may appear, it is strictly true 

 as to calcareous earth. In common with clay, calcareous earth possesses 

 the power of making sandy soils more close and firm — and in common 

 with sand, the power of making clay soils lighter. When sand and clay 

 thus alter the textures of soils, their operation is altogether mechanical ; 

 but calcareous earth must have some chemical action also in producing 

 .such effects, as its power is far greater than that of cither sand or clay. A 

 very great quantity of clay would be required to stiffen a sandy soil per- 

 ceptibly, and still more sand would be necessary to make a clay soil much 

 lighter — so that the cost of such improvement would generally exceed the 



* Perhaps it may be considered that there are exreptions lo the above dorlrine in fhe 

 well established facts that certain plants will not grow well, it at all, in soils containing 

 so little lime as to be classed as acid soils, no matter how rich they may be made for the 

 time by putrescent manures. Among trees, locust, papaw, and hackborry have been 

 already named as plants of this kind ; and red clover is as remarkable among grasses for 

 requiring lime in fhe soil. Sainfoin is still more remarkable, and cannot be produced 

 to profit, even if it will live, except on a highly calcareous .soil. Lime then is certainly 

 a. spi'cijic manure hv these plants; that is, lime promotes tiieir growth in a remarkable 

 and peculiar degree, and they can scarcely live without a considerable quantity in the 

 soil. Still it may be doubted whether it is that they require the lime as food, or for 

 some other unknown purpose, no less indispensable. Except as to sainfoin, (of which 

 I have no practical experience,) a moderate proportion of lime in a soil, such as will 

 merely make it neutral, seems to add as much vigor to the growth of the plants named, 

 as if it be given in ten-fold quantity. This would seem to contradict the supposition 

 of the lime serving as Ibod, tliough it may be as indispensable to these plants as is their 

 food. It is certain that dung, or other rotten vegetable matter, acts as tbod to all crops 

 which it benefits ; and therefore it is, that, in every case of its use and benefit, a large 

 quantity will always produce effects perceptibly better than a small quantity. 



