308 



Report of the Committee on Agriculture. 



Vol. VIII. 



Before this subject was sufficiently inves- 

 tigated, it was common to consider only 

 such substances as furnished vegetable food 

 to plants ''^manures,'''' whilst mineral or in- 

 organic matters, such as lime, potash, &c., 

 it was supposed, entered the plants to act as 

 stimulants, or to have some undefinabie me- 

 chanical action. Some are sufficiently fan- 

 ciful yet to cling to the stimulating theory, 

 but the exact and rigid rules for scientific 

 investigation of the present age permit not 

 the indulgence of fancy, which has been 

 transferred from the more exact sciences to 

 poetry. Each plant always contains certain 

 mineral or organic compounds, (subject to 

 little variation, as will be seen) in whatever 

 part of the world the plant may have its ex- 

 istence. If these essentials be deficient, the 

 plant will languish, and produce a stunted 

 growth : if entirely absent from the soil the 

 plant will die soon after exhausting the min- 

 ute quantity which the seed contained. In 

 order to show what is necessary to some of 

 our most important plants, we will state the 

 quantities and kinds that exist in Tobacco, 

 Wheat and Clover. 



1,000 lbs. of dried Tobacco leaves contain : 



Chloride of potassium, . . .(13 lbs. 



Sulphate of " . . .50 " 



Potassa combined with nitric and malic acids, .91 " 

 Phosphate of lime, . . . 1.66 " 



Litne combined with malic acid, . 2.44 " 



Silica (same as flint or quartz,) . .88 " 



Being about seven pounds. 



-.02 



1,000 lbs. of Wheat and the 2,000 lbs. of 

 Straw that has borne it, contain : 



1,000 lbs. Red Clover when made into 

 contain : 



27.! 

 19. 



Lime, 

 Potash, 

 Soda. 

 Magnesia, 

 Silica, (sand) 

 Sulphuric acid. 

 Phosphoric acid, 

 Chlorine, 



Hay 



80 lbs. 



95 " 



29 " 



,33 " 



,61 " 



,47 " 



57 " 



.62 " 



Besides traces of Alumina and Iron.* 



* These results show that clover contains in equal 

 weights, nearly three times the amount of inorganic 

 matters contained in the whole wheat plant, deduct- 



It has been ascertained, that 1,000 lbs. of 

 maize or Indian corn, contain 15 lbs. of the 

 Phosphate and Sulphate of lime, but a com- 

 plete analysis of the whole plant has not yet 

 been paade, as far as has come to our know- 

 ledge. Every soil depends for its fertility, 

 mainly upon its containing due proportions 

 of certain mineral matters. We find, how- 

 ever, that nature's laws admit plants (in cases 

 where one or more of these are deficient,) 

 to substitute certain others, but this is con- 

 fined within well defined limits. For in- 

 stance, one alkali, or alkaline earth may 

 supply in part the place of another, and some 

 acids may be partly supplied by others, but 

 here those partial substitutions stop. As an 

 instance for illustration, we may give the 

 fact, that where soda and potash are deficient 

 in a soil, t.'ieir place is partly supplied by 

 lime, but if all tliree be absent, the soil will 

 be absolutely sterile, however well we might 

 manage it in all other respects, except in 

 supplying the deficiency. Hence we would 

 remark, that to determine whether lime 

 " acts as a manure," we must know in what 

 sense the term is used. If we mean by ma- 

 nure, such substances as upon being added to 

 a soil, increase the growth of plants therein, 

 it follows that lime as well as many other 

 matters essential to vegetation, act as man- 

 ures only in such soils as do not contain them 

 in due proportion. We shall conclude this 

 branch of our investigation with the follow- 

 ing maxims, viz: 



1. Lime is an essential constituent of 

 plants. 



2. That plants will not thrive when it is 

 entirely absent fi-om the soil. 



3. Chemical analysis has demonstrated 

 that lime exists in all fertile soils that have 

 hitherto been accurately analysed. 



4. In such soils as are absolutely sterile, 

 it has been proven when they have been 

 analysed, that some of the essential inorgan- 

 ic substances are absent ; and that it is lime 

 very frequently. 



Having hitherto treated of lime only as a 

 mineral constituent of plants, we proceed to 

 show that lime and the alkalies serve other 

 important purposes of vegetation. 



ing the roots. If we deduct the silica, which abounds 

 in all soils, we find that clover contains nearly ten 

 times the quantity of minerals as wheat. One great 

 effect of clover is the pumping up, as it were, by means 

 of its long and descending roots, these necessary ma 

 terials, from depths to which tobacco, grains, grasses, 

 &c., do not reach. The crop being allowed to rot on 

 the ground, or fed to stock whose manure is put on the 

 fields, gives a large quantity of mineral matters, which 

 we believe are more effective to the succeeding crop 

 than the vegetable part. 



