72 The Bulletin. 



action of the lime on the soil ratber than in supplying lime as plant food to 

 the crop. In addition to supplying plant food and improving the chemical, 

 biological, and physical conditions of the soil, lime hastens the decomposition 

 of organic matter in the soil, liberating much of the inert or locked-up nitro- 

 gen contained in the organic matter of humus. Also, the store of inert potash 

 and phosphoric acid of the soil is acted upon by the lime, and a decidedly 

 larger percentage is brought into an immediately available form annually for 

 plant growth than would have been through ordinary agencies operating in 

 the soils. Hence lime tends to hasten the exhaustion of these constituents of 

 the soil rather than build the soil up, especially when the lime is used alone, 

 continuously, without fertilizer, on poor soil. 



Under poor drainage and aeration poisonous iron salts are developed in cer- 

 tain soils, due to the formation of ferrous compounds. The use of lime on 

 such soils renders these toxic salts insoluble and relatively harmless to ordi- 

 nary fax-m crops. Iron is a common constituent of our soils and is usually con- 

 tained in them in a nonpoisonous form. 



HOW DETERMINE WHEN LIME IS NEEDED. 



If the land contains a large amount of organic matter (usually indicated 

 by dark color of soil) it is fairly safe to assume that such soils, if crops do 

 not yield well on them and they have not received an application of lime or 

 marl in recent j-ears, that they would be benefited by liming or marling. 



If sheepsorrei, buttonweed, and the water grasses are growing in the fields, 

 it will usually be found that such soils will respond favorably to applications 

 of lime. If blackberries, raspberries, or gallberries are growing wild on the 

 same type of soil in close proximity to the field in question, it will generally 

 be found that an application of lime will prove beneficial for ordinary crops 

 like corn and the small grains on such a field. 



If it is an old field that has been robbed of its humus by continuous culti- 

 vation in some clean cultured crop, like cotton, and the soil of which runs 

 together and cements after each rain, it is quite likely to respond profitably 

 to an application of lime, especially for the growth of such crops as clover, 

 vetch, peas, and other legumes. If a heavy growth of some green ci-op is 

 turned under, especially in the spring, an application of lime or marl should 

 be made before turning, in order to prevent the formation and accumulation 

 of a large amount of organic acids in the soil by the rotting of the crop turned 

 under. If the soil has been poorly drained, and has become tight and water- 

 sogged, lime will in most cases prove highly beneficial when applied soon after 

 drainage and before a crop has been put in. If clover, vetch, cowpeas, and 

 peanuts are to be grown upon ordinary upland soils, it will usually pay to 

 make a good application of lime to the soil, the best results usually following 

 with cowpeas, if the application is made to the crop growing previously on 

 the land ; while with peanuts the opposite is frequently true. 



If a soil is quite acid, its presence may be determined by means of litmus pa- 

 per. -Take a portion of the soil to be tested into the hand and make it into the 

 consistency of a mud-pie by adding water and working with the hands. Now 

 take a small strip of blue litmus paper, which may be secured from any local 

 drug store, and bury it in the mud-pie. After remaining for a minute or 

 two, remove the litmus paper and wash in clear water, and if the soil is acid 

 or sour the- color of the paper will have been changed from the original blue 

 to a red color. Of the commonly grown farm crops, probably oats and Irish 

 potatoes are the most tolerant of large amounts of acidity in the soil. 



WHEN APPLY. 



Although conditions and systems of rotation will modify to some extent the 

 time of application, yet usually, the safest time to apply this material to the 

 soil will he during the fall or early winter, especially so if either the caustic 

 or water-slaked form is used. If carbonate of lime be employed it may go 

 on in the spring with less danger of injury to the seed of the crop than when 



