AGRICULTURAL LIME.

Northern Advocate, 20 October 1920, Page 4

AGRICULTURAL LIME.

FINE MATERIAL .BEST

line i-act uiat the value oi agricuitui'tii iiuie is 'dependent on the ue-

gree oi lineness co wnich the stone is ijiound ciicsussed in an article in ■Kocx i. roducLs," an American niagaz'lie. Vi\ e arucie, in somewhat shortened xorm, is as follows J —

j£ver since pulverised agricultural limestone nas come into general use :ue question o£ fineness has Jbeen argued pro and con. Whatever may oe the difference of opinion, experiments and practice everywhere, except in the State of Illinois, has shown .that to be really effective ihe limestone must ibe timely ground— at least 50 per cen , .. through 100----iuesh. When quarry screenings are soid for agricultural limestone the;v v.iiuablg only insofar as they c mam the fine material. If these quarvy screenings with material as coarse j;s 4in. mesh, .and with from 10 to 20 per cent, of 100-mesh dust, are worth $1.50 to $2 per ton, it ought not to take very much demonstration :o prove that the same stone reduced to 50 per cent, through 100-mesn. is easily worth more than twice as much.

This fact is indisputable because it io proved wherever both kinds of iunestonie are offered for sale. The farmers know from experience, if they have ever tried the fine ground stuff. The only excuse left for marketing the coarse stuff is that it looks cheap and can be sold to formers who have not had any- experience with fhe fine ground material.

The clearest explanation iof the comparative ineffectiveness of <coarse ground limestone that has come to hand is that contained in a α-ecendy issued 'bulletin of the "Cornell Reading- Course for the Farm," <by Elmer 0. Fip'pin, now secretary of tjhe Nat.onal Lime Association, formerly a professor of agriculture at the New York State College of Agriculture, Cornelll University. Pirof. Pippin

writes

"Tiie fineness of limestone or forms of carbonate of lime is very important in detearmining its .availability and therefore the .quantity that must be applied to the soil in order to secure ithe desired effect. The fineness of lime material is important for two reasons: First, because it determines the solubility of the lime; and secondly, because it deterr.lines the -possibility of distribution through the soil.

• It must ibe remembered that, in the soil, diffusion of material in solution is very slow and not at all eoinpairabie in rapidity to diffusion in a liqaid. Consequently after a granule of lime has neutralised the soil in contact with its surface, the remainder of the granule may remain for a long period practically sealed in a thin shell of alkailine soil while tihe main mass of soil is stnongly acid. This is partly offset by the tendency of the roots of limie4oving plants to concenijrate .arounid the granules of lime. By this .bunching of roots, however, their ability to get other plant nu'trlents iand moisture is reduced, and such a condition is unfavourable f->r th e best growth.

The surface exposed iby the part/icles in a ton of material, assuming they are spheres, increases very rapidly as the size decreases below l-25in. The surface exposed is one measure of th e availability of the material to Solution in soil water.

"In regard to the influence of fineness on availability of limestone, as measured iby ' solubility, availability to plants, and influence on nitrificat'on and isimilar processes, At appeal's that, Iby any method of measurement material 1-20 in. in size or coarses is very s!l | 6 5 w.1y .availaible. The miaterial should ibe of a fineness of from v 3O to 40 meshes to the inch (the openings beihig from/about 1-50 to l-60in v in diameter) in order to ibe available to a roltation. When material is ground ®o as to pass a screen having mieshes of such size that 25 meshes J equal one linear inch, then from 75 to '85 per cent, of the limestone would! pass a 50-mesh screen and approxiniiately would pass a 100-mesh screen. Material of this fineness is reasonably satisfactory and probably will meet all ordinary requirements. However, the proportion of particles of each size in material, all of which will pass a screea Slaving openings l j 2sin. in diameter, will vary with the character (of fehe limestone and the type of mill Us§d to grind it.''

That inoculation alone will not

make clover or alfalfa has been proved ..conclusively in Missouri tests. If the soil is poor in lime these legumes will not grow satisfactory. A farmer near Eagleville had a field, (one-half sown to aflalfa and the other half to' sweet idlover. Both were seeded last year and neither the clover nor ihe alfalfa were 'thriving.

A number of neighbours Who had reported similar experiences were called in and a meeting held by the county agent to determine the trouble. A glance at the field showed stalks Of both clover and .alfalfa to 'be tail and ddark green, while a large majority of them were only Waif as tall and were yellow in colour. The county agent took up a number of the yellow stalks and found no s i- gn of inoculation present. The tall green state were in every instance

found well inoculated. This in spite of the fact that the farmer had inoculated ibo'th the clover and alfalfa before seeding last fall. Since Ms methods of inoculation were in accordance with those 'given 'by the University fof Missouri College of Agriculture the trouble seemed to rest elsewhere. .Soil samples were taken and tested. Every sample showed the soil io ibe extremely sour. The conclusion was readily made that the acidity of the soil had been the limiting factor. The farmers in this community are now planning to secure limestone by tfhe carload to use on the alfalfa land.