140 



THE PEANUT— THE UNPREDICTABLE LEGUME 



calcium as was supplied by calcitic lime. Pure magnesium carbonate was 

 found to decrease the yields somewhat. At one location 640 pounds of 

 gypsum appeared to be superior to calcitic lime while at another the lime 

 resulted in higher yields. 



It is obviously very difficult to evaluate the effectiveness of various 

 sources of calcium. In many instances arbitrary comparisons have been 



Table 5. — Yield of Virginia Bunch Peanuts as Affected by Different Calcium 

 AND Magnesium Carriers. Reported by North Carolina Agricultural 

 Experiment Station 1944. (47) 



♦Norfolk sand; pH = 5.0; exchangeable soil calcium = 0.38. 

 **Norfolk loamy sand; pH = 5.0; exchangeable soil calcium = 0.46. 



made between two or more calcium-bearing substances with little effort 

 made to place the materials on a comparable basis . . . that is, to add 

 equivalent amounts of calcium or to use quantities of liming materials of 

 equal neutralizing power. Furthermore, many of the calcium materials 

 are carriers of other elements which may also influence the experimental 

 results. Despite these difficulties, from the existing knowledge of the use 

 of liming materials and of the calcium needs of peanuts, it should be pes- 



