210 



THE IRRIGATION AGE. 



Potash combined with Silica 0.120 



Soda combined with Silica 0.025 



Phosphoric Acid combined with Lime 



and Oxide of Iron 0.060 



Sulphuric Acid in Gypsum 0.027 



Chlorine in common Salt 0.036 



Carbonic Acid united to the Lime.... 0.080 



Humic Acid 1.304 



Insoluble Humus 1.072 



Organic substances containing Nitro- 

 gen i.on 



Total Inorganic and Organic sub- 

 stances ioo. 



4,4" + 

 919+ 



2,205+ 



992+ 



1,323+ 



2,941 + 



47,941+ 



39,4"+ 



37,i69+ 



3,676,464 



It should be remembered that these immense quan- 

 tities are contained in only eight inches of top soil, and 

 that twelve inches, or one foot of soil, which is about 

 the depth before reaching the subsoil, woiild contain 

 a total of inorganic and organic matter equal to 5,514,- 

 696 pounds, or 2,757 and one-third tons. 



The calculation is made by multiplying 43,560, the 

 number of square feet in an acre, by 126.6. pounds, the 

 estimated average weight of one cubic foot of wet soil, 

 which gives the weight of one acre twelve inches deep. 

 Then dividing by twelve, we get the weight of an acre 

 one inch deep. To ascertain the weight of eight inches, 

 we have only to multiply by eight inches, and again mul- 

 tiply by the number of parts of any organic or inorganic 

 matter to ascertain the exact weight of that particular 

 matter in the acre, thus : 



43,560x126.6=5,514.696 pounds per acre one foot deep. 



5,514,696+12=459,558 pounds per acre one inch deep. 



459,558x0.120=551.46960 pounds of Potash in one inch 

 acre. 



551.46960x8=4,411 pounds of Potash in acre eight inches 

 deep. 



Five right hand figures must be cut off, three for 

 the decimal places and two more because the calculation 

 is based on a percentage of one hundred parts. 



The average weight of a cubic foot of dry soil, ac- 

 cording to the foregoing estimate, based upon the tests 

 taken in the cases of five hundred soils collected from 

 various places on the globe, is 94.58 pounds, which will 

 make the dry soil acre eight inches deep weigh 2,715,792 

 pounds, a difference in weight between wet and dry soils 

 of 960,672 pounds per acre eight inches deep, which, 

 of course, represents the weight of water. 



This information will prove of value in considering 

 the question of applying water to the soil. As a rule, 

 the proportions of inorganic and organic matter remain 

 about the same, except that the application of water by 

 irrigation adds to the quantity in soluble matter car- 

 ried to the soil, which is greater in the case of irrigation 

 than when rain is depended upon, humus and salts in 

 solution being carried in the ditch water. 



ORGANIC MATTER IN THE SOIL. 



By referring back to the test table of a specimen 

 soil, it will be noticed that the first twelve substances 

 are "inorganic," and the three last "organic." It will 

 also be noticed that the proportion of inorganic matter 

 is vastly greater than that of the organic. It is necessary 

 that this should be so, for the organic matter is the 

 "active" principle, the dynamic force, and the inorganic 

 matter the "passive" principle. If the proportions were 

 reversed, the inorganic matter would react upon and 

 destroy itself, and as it could not be replaced very well, 

 there would soon be an end to the growth of plants. 

 Hence, nature provides a store-house of raw material, so 

 to speak, to be utilized in the manufacture of plant food, 

 and it is practically inexhaustible, the subsoil, for an un- 



limited depth, containing all the ingredients necessary to 

 restore the top soil should it become jaded and unre- 

 sponsive to the demands of cultivation and fertility, if 

 the farmer will take the trouble to dig down after them 

 and bring them to the surface. 



Moreover, the inorganic elements in the soil are 

 permanent. They are insoluble except when acted upon 

 by the acids formed through the chemical action of the 

 organic matter, and the vital force exercised by the 

 growing plant. 



In the table of specimen soil, given on another page, 

 the percentage of inorganic matter passes 95 per 

 centum, while the organic matter is about three and 

 one-half per cent. Yet that particular soil is a fertile 

 one, in which it is possible to produce a good crop of 

 any kind of plant. It is only an analysis, it is true, and 

 a chemical analysis is not always to be depended upon, 

 because there are so many unknown and mysterious ap- 

 plications of the laws of nature, but there are many 

 things to be said in favor of ascertaining what ingredi- 

 ents the soil does contain, approximately, if not with 

 rigorous exactitude. It gives the practical farmer valu- 

 able information in the form of suggestions for the im- 

 provement of the soil. It enables him to remedy the 

 defects in his land by the application of substances it 

 needs, and, what is equally of value, it enables him to 

 avoid adding to the soil what he knows it already con- 

 tains, and will put him upon the search for substances 

 it does need. Moreover, an analysis will indicate to the 

 farmer whether a certain soil is capable or not of pro- 

 ducing a good, profitable crop of certain plants, and 

 save him from losing his time, labor, and money by 

 planting a crop which can not grow to perfection be- 

 cause of some defect in plant food necessary to plant life. 

 In other words, the farmer will know what to do with 

 his land without guessing, or trying expensive experi- 

 ments. This is not "Book farming," it is common 

 sense. 



The reader has already discovered that the inorganic 

 elements consist of decomposed rocks and minerals, 

 which have assumed a variety of forms by combining 

 with one another, and now he has reached a point which 

 is the foundation of plant life, being that other essential 

 in all soils, the organic elements, which must exist in a 

 greater or less proportion. This organic matter con- 

 sists of decayed animal and vegetable substances, some- 

 times in brown or black fibrous particles, many of which, 

 on close examination, show something of the original 

 structure of the objects from which they have been de- 

 rived ; sometimes forming only a brown powder inter- 

 mixed with the mineral matters of the soil, sometimes; 

 entirely void of color and soluble in water. In soils 

 which appear to consist of pure sand, clay, or chalk, or- 

 ganic matter in this latter form may often be detected 

 in considerable quantities. 



In the table already given, the percentage of Humic 

 acid, Insoluble Humus, and organic substances contain- 

 ing Nitrogen, is given as 3.387 per centum, a very small 

 quantity apparently, but really amounting to 124,521 

 pounds or 62/4 tons, in a top layer of soil eight inches 

 deep, covering one acre of land. A quantity sufficient 

 to supply crops with essential matter for plant food dur- 

 ing many years without manuring. 



This vegetable matter is the result of vegetable de- 

 composition, a decay which means fermentation ending 

 in putrefaction, a purely chemical process. Whence it 

 is said : Growth is a living process ; death, or decay, a 



