232 FERTILIZERS. 



coai-ser materials, which are capable of leaving a coat of grit upon the grass, as sometimes hap- 

 pens when meadows are overflowed in great freshets. The adva tages of irrigation are very 

 great, under favorable circumstances. Not only may their depos'ts of mineral matter in a 

 state of fine division be formed, but river water contains a small amount of soluble salts, which 

 supply food immediately to the crop. Besides this advantage the fields are partially indepen- 

 dent of the ordinary rains ; the crops may be advanced at an earlier period in the season, and 

 the soil, instead of growing poorer annually, may in fact become richer. Very few meadows 

 in New-England and New-York, which will not require a preparation of the surface prior to 

 commencing a system of irrigation. Where there are depressions they should be filled, and 

 brought to the general level of the surface ; at least it is desirable to do this. Where much filling 

 up is required the expenses will be too great, if materials are not at hand. Very few improve- 

 ments can be sustained where a transportation of material by carts is required. It is rare that 

 circumstances are sufficiently favorable to admit of carrying sand on to stiff clay soils for their 

 benefit, or clay to sandy soils. In theory this mode of benefiting either kind of soil is often 

 proposed, and the principle is correct enough, yet in practice it is too expensive ; and so it is 

 with many improvements which are proposed ; they look rational on paper, and appear rational 

 when discussed in farmers' clubs, yet in the field, where it becomes a business transaction and 

 the dollars and cents are counted, these measures often fail, or are found unjustifiable from their 

 cost ; and no doubt, in this country irrigation may be found too expensive for our circumstances. 



ON FERTILIZERS. 



The farmer is compelled to employ a class of bodies to restore to his land those elements 

 which he has removed in his crops. The soil is so constituted that at no time can it be re- 

 garded as an inexhaustible store house of food for vegetables. The matters constituting the 

 fertilizers are inexhaustible, but their nature, together with their solubility, prevent large ac- 

 cumulations of any one substance, or group of substances, which are in a condition suitable 

 for the nutrition of plants. These are slowly but constantly prepared from the rocks forming 

 the earth's crust, and hence I have said the aliments which vegetables require are inexhaustible. 

 When plants are cultivated, they take from this store house more nutriment than when they 

 merely vegetate in a wild %tate : the seed and fruit, in the wild stite, contain less of those 

 expensive aliments. But the great reason why fertilizers are required, is in consequence of 

 the removal of the mature crops from the fields, and their consumption elsewhere. Any thing 

 is a fertilizer which can restore one or more of the removed plant- aliments to the soil. Of 

 these bodies the most valuable are those which exist in the smallest proportions in the soil, 

 as the phosphates of lime, magnesia, potash and soda, etc.; the organic salts of lime, as the 

 crenic and apocrenic acids, silicate, and other salts of potash and soda. In all the facts relating 

 to fertilizers we see a special relation and adaptation of the composition of the earth's crust to 

 the constitution of the vegetable and animal kingdoms. Animals, though they can not feed 

 directly on the matters forming the earth's crust, yet they feed no less in reality upon them. 



