GARDENING AS A SCIENCE. 



213 



quence of the clearing of the forests. Of 

 this kind are the grasshoppers and locusts, 

 which, in dry seasons, are very destructive 

 to grass and grain ; the frog-spittle insects 

 (Ctrcopis,) of which several species are 

 found in the fields and gardens, and are 

 very injurious to vegetation; and the lepi- 

 doptera, nearly the whole of which find 

 greater abundance of food, and more favo- 

 rable conditions in the burned barrens and 

 cultivated fields, than in the orrowingr woods. 

 It may be remarked in general, that there 



is no animal, frequenting in Europe the 

 cultivated grounds, and either beneficial or 

 noxious to man, which has not, in the indi- 

 genous species of America, an exact repre- 

 sentative, filling its place in the economy 

 of nature, and often in a natural, historical 

 point of view, closely related to it. This re- 

 sults from a general sameness of arrange- 

 ment in the system of nature in the old and 

 new world ; and if studied in its details, 

 would form a subject of great interest to the 

 zoologist and physical geographer. 



REMARKS ON GARDENING AS A SCIENCE.— No. 5. 



BY DR. \VM. W. VALK, FLUSHING, L. I 



Having adduced the authority of Liebig, to 

 show that the humus of the soil is not taken 

 up by the roots of plants as nutriment, and 

 suggested to the gardener some of the 

 means and experiments by which he may 

 bring the accuracy of the theory to the test, 

 we propose to dismiss the subject, and, at 

 the same time, to lay aside and altogether 

 repudiate the term humus as applied to the 

 garden, leaving the agriculturist to retain it 

 or not, at his pleasure. It matters little 

 what is said or thought of a subject which 

 the mind cannot understand ; and as the 

 horticulturist avails himself of substances 

 little used on the farm, our remarks shall 

 be confined to them exclusively. 



What then is manure, and how does it 

 operate on the produce of the garden ? The 

 questions are by no means easily answered, 

 and they apply in a two-fold direction. Eve- 

 ry one versed in general horticulture must 

 be perfectly aware that the same soil, the 

 same enrichment, (or " dress " of whatever 

 kind it may be,) will operate very different- 

 ly upon plants in the open ground, and 

 when confined in pots. Take, for instance, 

 that staple of the garden, virgin loam, and 

 let us refer to the evidence, on this point, 

 of Mr. James Main in the British Farmers' 

 Magazine, April 1841, p. 93. He says ; 



" Newly reclaimed lands, whether from 

 old pasture, fallen woods, or commons, or 

 fresh loam dug from pits, are all, for a few 

 years, exceedingly productive, without as- 

 sistance from manure or other treatment, 

 save digging or ploughing. This virtue of 

 maiden soil, be it what it may, is at last 

 dissipated by repeated cropping ; and then 

 the land must be refreshed with a dress- 

 ing of some kind of manure. I have never 

 read or heard of any trial having been 

 made by chemists to analyze maiden earth, 

 with a view of ascertaining what that par- 

 ticular quality is that proves so exciting and 

 beneficial to vegetation. Its effects are well 

 known to all cultivators. Trenching and 

 trench plowing are the ordinary means for 

 gaining upon the surface an additional stra- 

 tum of virgin earth ; and the good effects 

 which follow sooner or later, are sometimes 

 attributed to the true cause, namely, the 

 addition of new, untired earth, though, by 

 others, it is said to be owing to the increas- 

 ed depth of the staple." The new stratum 

 is undoubtedly the exciting agent, and elu- 

 cidating his argument by agricultural data, 

 Mr. Main then asks, " What is that property 

 of maiden earth, which z/;Aena<'Va^e6? proves 

 so exciting and nutritive to the roots of 

 plants ? It cannot be humus, that is decay- 



