February, 1921. 



SCIENTIFIC AGRICULTURE. 



OV 



lime comiug from a kiln, for felling the forest and for 

 plowing matches. The i^rizes were all such agricultural 

 implements as drill plows, harrows, etc. In view of the 

 present interest in the application of lime it is of in- 

 terest to quote from the Lime Competition the follow- 

 ing: "It is expected that enterprising farmers will strain 

 at burning a thousand bushels wliich %vill be barely 

 adequate for ten acres of summer fallow." Valuable 

 strains of seed were imported and at a later dater ship- 

 ments of improved live stock were brought over from 

 Great Britain and the United States. 



These are the outstanding features of the work of 

 this wonderful man whose influence is felt in the Pro- 

 vince of Nova Scotia even to the present day. The 

 genei'al readei', however, will be more interested in the 

 content of the letters than in the local history and so 

 we will include in this article a brief review of Agri- 

 cola 's views in respect to Agricultural science and prac- 

 tice. It must be of interest to those whose knowledge 

 of the chemistry of plant growth antedates the time of 

 Bousignault, Leibig, Lawes and Gilbert and others, to 

 read the views of this early writer whose knowledge of 

 these principles was based upon the work of Priestley, 

 Ingenhousz, Woodhouse, DeSaussure and Sir Hum- 

 phrey Davj-, particularly the latter. To be accurate in 

 this respect we will quote from his letters. 



To begin with he enumerates the elements of vegeta- 

 tion as follows: "The elements which constitute the 

 greatest part of organized vegetable matter are oxy- 

 gene, hydrogene and carbon, with, in some of the pro- 

 duets, a little of azote (the then name for nitrogen). 

 But in addition to these, chlorine, sulphur, phosphorus, 

 calcium, magnesium, silicon, aluminum, potassium, and 

 sodium, with small portions of iron and manganese, 

 enter, either in their simpler or more complicated ar- 

 rangements, into the fibre and texture of plants, or 

 into the agents which operate on them." In a note on 

 the preceding excerpt he says that Sir Humphrey Davy 

 enumerates only twelve elements, leaving out chlorine, 

 potassium and sodium as being essential to agriculture ; 

 and from the fact that Agrieola subsequently finds 

 difficulty in working these bases into his scheme, it is 

 clear that his knowledge on agricultural chemistry is 

 based largely upon the work of Sir Humphrey Davy. 



In discussing the means by which plants take these 

 elements into their system he sa.vs "The conclusion of 

 the whole- matter is that plants feed on decayed animal 

 and vegetable remains and that, in addition, the.v must 

 have, for the free exercise of their functions, a regular 

 supply of water and air." In further elucidation of 

 this point he adds "All the present experiments, which 

 have been conducted with accuracy, seem to verge 

 toward one point, tliat oarbon, oxygene, hydrogene and 

 azote, with their combinations, form the principal in- 

 gredients in the sustentation of plants and that these 

 principles are introduced chiefly by the roots." Later in 

 discussing the function of leaves in breathing carbonic 

 acid from the air he is clearly worried in making a satis- 

 factory explanation. I quote his conclusion: "Carbon, 

 therefore, which is unquestionably a prime ingredient 

 of vegetable food is supplied by the leaves from the 

 atmosphere and by the roots from the earth. It is owing 

 to this capacitv of the plant to take in carbonaceous 

 matter either above or below that so many species can 

 be turned upside down : the roots growing into branches 



and the branches into roots." Had he written at a later 

 date he would, of course, have understood carbon nutri- 

 tion as well as adventitious roots, better. 



In reading Agrieola 's chemistry of the soil, the 

 modern student would be struck with the fact that he 

 had not present day knowledge of chemical and physical 

 principles, including them both in one category. For 

 example, he states "that soils consist of only four 

 simple and primitive earths, clay, sand, lime and magne- 

 sia." He describes a soil as defective in so far as it 

 lacks one or other of the foregoing four principles. Con- 

 cluding a discussion on this point he observes, "From 

 all this reasoning it seems deductible that sand and clay 

 in almost any proportion, with a quantity of lime laid 

 on with judgment but not in excess, constitute the best 

 and most fertile soil: and that the only mode of im- 

 provement is to supply whatever sort of these original 

 and elementary ingredients is deficient in the composi- 

 tion. But all this will be far from besto^^ing lasting 

 fertilities unless to the mass be added decayed animal 

 and vegetable substances which uuquestionabh- minis- 

 ter to plants their principal food and nourishment." 



In connection with the foregoing the reader must re- 

 member that practically aU that now constitutes the 

 chemistry of agricultural fertilizers was unkno\vn and 

 that knowledge which today is possessed by almost 

 every one was not then in the grasp of even the most 

 enlightened. This point will be all the more impressed 

 upon tlie reader as we present Agrieola 's views on man- 

 ures and their uses. 



lie diviiles manures into two classes, the first com- 

 prehending all animal and vegetable decomposed mat- 

 ter, which is principally instrumental in feeding the 

 plants, and second, fossil manures, in which class is 

 included lime, marl, gj'psum, sand, gravel and clay. 

 The function of the .second class he describes to be 

 a very humble kind and mainly confined to indirect 

 action, although he says that even in respect to the 

 direct support of vegetable life fossil manures are not 

 altogether useless. 



That part, however, of his discussion of manures 

 which bore the most practical fruit was that which had 

 to do with the care of barnyard manure. He refers 

 to "The stream of rich putreseible matter which issues 

 from all barnyards," and also to the escape of vapours 

 which is "the most wasteful prodigality." To control 

 waste from the first source he strongly recommends the 

 construction of "dunp-pits" and he gives detailed in- 

 struction as to how these should be made. In respec' 

 to fermentation he says "Sir H. Davy contends tha* 

 the smallest degree of fermentation is aceompanie' 

 with setting at liberty the elementai-y principles." Da-«) 

 therefore holds that manure sliould be plowed into the 

 ground in a fresh state so that all vapour might be ab- 

 sorbed by the earth and no loss occur. In opposition 

 to this he quotes "the conductor of the Farmers' Maga- 

 zine" (an English publication") that "unless a certain 

 degree of putrefaction comes on in the barnyard no 

 subsequent fermentation vnl] take place in cold and 

 claye.v soils." This editor therefore recommends the 

 thorough fermentation of manure before appl.ving i{ 

 to the land. Agrieola in discussing these two extreme 

 views sa.vs that the proper course lies between these 

 extremes. Briefly he recommends that manure be 

 mixed in alternating layers with loam or waste veget- 



