FOR BETTER CROPS IN THE SOUTH 27 



It will be seen that previous to the beginning of this soil 

 treatment, the last five plots yielded no more than the first five ; 

 but after four years of soil treatment, the yield of clover was 

 only 1.23 tons without phosphorus, while 3.12 tons of well field- 

 cured clover hay were produced where phosphorus had been 

 applied. The effect of potassium was slight. 



Of course this increased crop of clover means a larger yield 

 of corn to follow, and both clover and corn mean more farm 

 manure for further soil improvement or maintenance. 



As an average of the three years, 1907 to 1909, plots six and 

 seven produced seventeen and one-half bushels more corn, seven 

 bushels more oats, 1720 pounds more clover hay, and forty-three 

 pounds more clover seed, per acre, than plots four and five; 

 these increases being due to the application of phosphorus. In 

 the later years the use of limestone is also producing profitable 

 increases on the older prairie lands of the corn belt. 



Soils Deficient in Both Phosphorus and Lime — Soils on 

 which clover can not be grown successfully even before they are 

 badly worn are usually acid and consequently deficient in lime- 

 stone, but as a matter of fact such, soils are usually deficient in 

 both limestone and phosphorus. 



The effect of limestone and of limestone and phosphorus in 

 connection with legume treatment on the University of Illinois 

 soil experiment field, will serve to demonstrate the need of both 

 limestone and phosphorus on such soils as are commonly called 

 "clay land," which refuses to grow clover. 



Wheat Yields in Soil Experiments 

 Typical Wheat Belt Prairie Soil in "Egypt," near Odin, 



Illinois 



Soil Treatment Applied 



None 



Legume.. 



Legume, limestone . 



Legume, limestone, phosphorus 



Legume, limsetone, phosphorus, potassium 



Yield per Acre 



Average fo 



Eight Years 



11 bu. 

 12» bu. 

 17 bu. 

 26 bu. 



28 bu. 



Gain for legume, limestone, phosphorus treatment 15 bu 



On similar soil in Wayne county in southern Illinois, an 

 experiment field was started on forty acres of land in 1905. A 

 four-year rotation of wheat, clover, corn, and cowpeas (or soy 

 beans) is practiced on four ten-acre fields, so that each crop may 

 be represented every year. Two tons of ground limestone and 

 one ton of fine ground raw rock phosphate, per acre, are applied 



