SOIL FERTILITY 



139 



of Spanish and runner peanuts grown in a rotation with vetch. The lime 

 materials were applied broadcast at two rates, 1,500 and 3,000 pounds 

 per acre, to a Norfolk sand. The results are shown in table 4. All of the 

 calcium sources were found to be approximately equal in value except the 

 calcium silicate slag which gave profitable increases over no lime but was 

 inferior to other liming materials. Dolomitic limestone was found to be 



Table 4. — Peanut Yields as Affected by Kinds and Rates of Lime and Growth 

 OF Vetch as a Green Manure Crop, Auburn, Alabama.* (95) 



Lime treatment 



Kind of lime 



Pounds 



per acre 



applied, 



1941 



Soil 

 pH 



Sept. 



1945 



Yields of 

 vetch 

 turned 

 under, 

 pounds 

 per acre 

 1942-45 



Yields of 



Spanish 



peanuts, 



pounds per 



acre 



1943-45 



None 



Calcic limestone (Av. of 3 sources) . 



Dolomitic limestone (Av. of 3 

 sources) 



Oyster shell 



Paper mill waste 



Blast furnace slag 



T.V.A. Ca-silicate slag 



1,500 

 3,000 



1,500 

 3,000 



1,500 

 3,000 



1,500 

 3,000 



1,500 

 3,000 



1,500 

 3,000 



5.3 



5.3 



5.5 



5.3 

 5.6 



5.3 

 5.6 



5.3 



5.7 



5.2 

 5.6 



5.4 

 5.6 



5,766 



14,720 

 16,701 



16,073 

 18,615 



16,874 

 16,894 



18,743 

 16,757 



13,243 

 15,694 



14,822 

 15,341 



1,093 



2,073 

 2,307 



2,165 

 2,633 



1,871 

 2,242 



2,203 



2,415 



1,666 

 2,198 



1,978 

 1,732 



♦Maximum response to lime obtained in these tests in small plots by turning under vetch each year 

 as a green manure crop, close spacing of plants, and fertilizing both vetch and peanut crop with 300 

 pounds per acre of 0-14-10. Peanuts were planted and dug each year from these plots on Norfolk loamy 

 sand since 1942. (The 1942 crop was lost after harvesting.) 



superior to calcitic lime oh an intensively cropped Norfolk sand but was 

 not significantly better in larger-scale field tests on sandy loam soils. 



Experiments were conducted in North Carolina (47) to compare the 

 relative values of dolomitic and calcitic limestone and gypsum, applied at 

 diflferent dates and in different manners. The results are shown in table 

 5. Calcitic limestone was found to be distinctly superior to dolomitic 

 limestone, regardless of the time of application. Furthermore, almost 

 twice as much dolomite had to be applied' to furnish the same amount of 



