Ma nee: Quarry Industry of Southern Indiana 129 



the results of these experiments are outhned below for the benefit 

 of those who may be unable to obtain the circulars mentioned. 



In November, 1903, a farm of about 300 acres in Illinois was 

 purchased at less than $20 per acre. It was abandoned prairie 

 land, which was thought to be almost worthless, but by scientific 

 emplo3aiient of a small quantity of farm manure and ground 

 rock fertilizers it was brought back to a point where the yield of 

 wheat on a 40-acre field was 353^2 bushels per acre. During the 

 10 years that the experiment was in progress a 6-year rotation 

 system was used; 1 year each of corn, oats, and wheat, and 3 

 years of meadow and pasture with clover and timothy. During 

 the 10 years 2 applications of 2 tons per acre of ground limestone 

 and 2 applications of 1 ton each of ground rock phosphate were made. 

 These applications of fertilizer occupied 12 years and cost $18 

 per acre, or a cost of $1.50 per acre per year, and this outlay re- 

 sulted in an increase of 24 bushels per acre over the amount that 

 was raised on an adjoining strip of land with liberal applications 

 of farm manure. The differences in the clover crops were even 

 more marked than the differences in the wheat crops. The fol- 

 lowing are given as the best directions for the southern counties 

 of Illinois, and most of Southern Indiana closely resembles 

 Southern Illinois in the conditions of its soils. The directions 

 are as follows: 



First, apply 2 to 5 tons per acre of ground limestone. 



Second, grow clover or cowpeas. 



Third, apply from 1,000 to 2,000 pounds per acre of very 

 finely ground natural rock phosphate, to be plowed under with 

 the clover or cowpeas. 



During the last 8 years 318 tests to determine the effect of 

 the lime or ground limestone on crop yields in Southern Ilhnois 

 were made. These included 79 tests on legumes (clover, cow- 

 peas, and soy beans), 122 tests on corn, 55 tests on oats, and 62 

 tests on Avheat, these crops being grown in the rotations usually 

 practiced. As an average of all tests the yield per acre was in- 

 creased by }/2 ton of hay, 5 bushels of corn, 6.6 bushels of oats, 

 and 4 bushels of wheat. The data at hand and here reported 

 are amply sufficient to justify the conclusion that, in practical 

 economic systems of farming on the common prairie and timber 

 soils of Southern Illinois, limestone at less than $1 per acre per 

 year will produce 3^2 ton more of clover or cowpea hay, 5 bushels 

 more corn, 6 bushels more of oats, and 4 bushels more wheat 

 than would otherwise be obtained. The only reason that the 



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