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Indiana University Studies 



effects pass away very slowly. On the other hand, when a sandy 

 soil is dressed with ground limestone, the soil becomes more 

 compact and has a greater ability to retain moisture. This 

 effect of ground limestone is readily shown by the appearance of 

 the soil after a long drought. On fields that have been treated 

 the soil is markedly more moist than on fields that have not been 

 treated. This is well shown by a series of experiments which 

 have been carried on by Mr. Perry Blackburn on his farm near 

 Oolitic, Ind., during the last two years. The writer visited the 

 farm early in June after that section of country had undergone 

 a severe drought, and examined a field which had received a partial 

 dressing of rather coarse limestone early in the spring. The line 

 of division between the dressed part of the field and the portion 

 which had received no limestone was very marked, as shown in 

 the picture. The clover on the part of the field that received the 

 limestone dressing was on an average 6 inches taller, the roots were 

 on an average 4 inches longer, and the soil markedly more moist 

 than on the portion which had been left without dressing. In the 

 picture it will be seen that the part of the field on the left which 

 received no limestone is hardly covered by the crop and the 

 clover present is short and undeveloped, while on the right where 

 the limestone dressing was applied the clover is much thicker, 

 taller, and more advanced in its growth. 



The statements of those interested in commercial fertilizers 

 that lime and limestone are not fertilizers have tended to keep 

 many farmers from the use of these soil correctives. In the strict 

 sense of the word limestone is not a fertilizer, since it does not 

 contain any one of the three essential foods of plants: phosphorus, 

 nitrogen, or potassium. Materials that act in a secondary way 

 have been called soil amendments by Professor Vivian in his 

 work on The Fundamentals of Soil Fertility. The chief value of 

 these amendments lies in their ability to correct conditions in the 

 soil that keep plant foods from becoming available. The condition 

 most easily observed and the most widespread is soil acidity, 

 which causes the death of the nitrifying bacteria. Probably no 

 one man has done more toward the development of the theory 

 of raw fertilizers than Professor C. G. Hopkins, and the results 

 of his experiments in the use of ground limestone and ground 

 rock phosphate leave no doubt that the grinding of limestone 

 and rock phosphate will soon become a great industry. The 

 results of these experiments are published in pamphlet form and 

 can be obtained from the Illinois Experiment Station. Some of 



