320 



THE GARDENERS' CHRONICLE OF AMERICA. 



LIME AS A SOIL ADJUSTER. 



In man_y States the soil is deficient in lime, and tiiis 

 has caused a number of investigations to be made with 

 good resuUs. 



]\Iany soils are sour. Lime sweetens, sour soils, so 

 that crops such as alfalfa and clovers can be raised 

 that are impossible otherwise. Lime is recommended 

 for the soils in most of the Eastern and Southern 

 States. 



What kind of lime shall be used? Ground marble, 

 or pure limestone, of about the texture of coarse corn 

 meal, is undoubtedly preferable to the burnt lime at 

 the usual price. A fair amount is two tons to the acre. 

 An application lasts several years, depending on the 

 condition of the soil. 



Lime alone is not a fertilizer, but is a "soil adjuster," 

 that is, it neutralizes the acids of the soils, thereby 

 bringing about such conditions that the soil and the 

 fertilizers (materials which contain the food elements 

 required by plants) will readily give up their food con- 

 stituents to the plants. Therefore the lime will not re- 

 place a fertilizer, but it brings about neutrality of the 

 soil, which condition is necessary for rendering the 

 fertility a\ailable for assimilation bv the plant. 



Formerly the lime was added to the soil in the form 

 of burnt limestone, known as burnt lime, or calcium 

 oxide. In contact with the flesh produces irritation 

 and sores and destroys clothing, both of which makes 

 its spreading over the soil a very disagreeable opera- 

 tion. As it must be spread in a pulverized form and 

 being a light material, much dusting occurs, so even 

 with care the persons who are spreading it cannot 

 prevent some of the fine dust entering their eyes, 

 throat and lungs. The result is painful irritation, 

 which may result in bringing about permanent injury 

 to these organs. Furthermore, when the burnt lime 

 is moistened it forms lime-hydrate, more commonly 

 known as slacked lime, which material is rapidly 

 washed away and dissolved by rains, causing loss un- 

 less immediately mixed with the soil. 



These two materials in their pure state are of the 

 same chemical combination, being lime carbonate, a 

 conipound which rapidly and completely neutralizes 

 acids, but which is verj- slightly soluble in water. 

 With these facts in mind, large scale experiments were 

 conducted in several States, the results going to show 

 that pulverized marble dust, or pure limestone, pos- 

 sesses many advantages over burnt lime as a "soil ad- 

 juster." Some of the chief advantages which were 

 ■found are: 1. It is a cheaper material, the actual cost 

 for a given weight of lime equivalent is less than half: 

 2. The material being in fairly large grains is not 

 washed nor dissolved and lost by rains; 3. It is not 

 objectionable nor unhealthy to spread, as it does not 

 dust and does not irritate the flesh; 4. It may be 

 spread easily and uniformly; 5. It does not destroy 

 the vegetable matter of the soil, not being strongl'v 

 caustic, therefore an excess is no injury. 



SUPERIOR ADV.VXTAGES. 



Now as to the advantages of pulverized marble over 

 pulverized limestone. Marble is one of the purest 

 forms of natural calcium carbonate, analyzing 98.0 to 

 99.0 per cent. pure. Limestone on the other hand is 

 composed chiefly of calcium carbonate, in some cases 

 being of as pure a quality as marble, but as a general 

 rule it contains varying amounts of silica, iron oxide. 

 and magnesium carbonate. 



Soil deficient in lime carbonate (sour soils) require 

 an application of a large quantity of fertilizers in or- 



der to raise good crops; whereas soils which contain 

 free lime require less fertilizing and give good returns. 



Charles E. Thorne, director of the Ohio Experi- 

 ment Station, made the following statement in his 

 report on the need of adding lime to soils : "When 

 the land begins to need lime it is a waste of time, 

 energy and money to continue to cultivate it until the 

 need is supplied, for the economical use of every other 

 fertilizing material, including manure, depends upon 

 the lime supply. If it is deficient, everything else 

 must fall short of its possible attainment. 



Pulverized marble alone will not render the land 

 fertile, but if all the plant food elements are present in 

 the soil, then the lime carbonate will adjust the con- 

 ditions so that they will be readily assimilated by the 

 plant. 



TESTS TO DETERMINE NEED. 



The two best methods of determining the need of 

 applying lime to the soil are as follows : 



I. The most practical test is afiforded by laying off 

 a strip in the field which is a fair representative of the 

 whole field. Spread about one pound of the pulverized 

 marble on each square yard on the strip (equivalent 

 to 2 tons per acre) and harrow it into the soil. Sow 

 your regular crop and note if the growth on the test 

 strip is better than the other part of the farm. Test 

 strips of land, to which are also added manure or other 

 fertilizers, together with the pulverized marble, will 

 demonstrate the real need of the soil. 



II. The appearance of a growing field may indicate 

 the need of applying pulverized marble. If the soil is 

 not as productive as it should be, then in most cases 

 the application will prove to be most beneficial. In no 

 case can injury result by applying pulverized marble, 

 even when ajiplied in great excess. 



now TO APPLY IT. 



Tlie most elTective way of applying puiveVized 

 marble to the land is to spread it broadcast, over the 

 plowed surface, then thoroughly harrow it into the 

 soil. In the case of meadows, or other grass lands, a 

 too dressing alone will be beneficial. 



The best time of the vear for making the application 

 is either in the earlv sprin? or in the fall; but still it 

 mav be apolied without doing anv injury at any other 

 time that the land is not occupied by crops and when 

 plowing can be done. The amotmt which should be 

 used is about two tons per acre, which is ample for 

 two to five years, depending on the condition of the 

 soil. 



RESULTS OF USING IT. 



In summarizing; the results of a number of experi- 

 ments on the effect of lime carbonate on soils con- 

 ducted throug-hout the United States, the following 

 show the many advantages gained by the use of pul- 

 verized marble : 



1. The free acid in the soil is neutralized, oroducing 

 sweet conditions, which is essential for fertility. 



2. Hea\-y anrl clayev soils are rendered porous and 

 mellow, thus the maintenance of good tilth is more 

 easy. 



3. Ortjanic nmtter and barnyard manures decom- 

 pose more rapidly and the olant food which thev con- 

 tain becomes more promptly available. Th's is espe- 

 cially so in heavy soils in which decay takes place 

 slowlv. 



4. The capacity of liglit soils to retain moisture is 

 increased when pulverized marble is used in combina- 

 tion with green manuringf or any other org'anic manures. 



.^. It is essential for success with clovers and alfalfa. 

 .\ hea^•v application in this case gives best results. 



