SOIL FERTILITY 151 



Alabama soils observed marked increases in nut production from the use 

 of magnesium. However, the soils had been subjected to very intensive 

 cultivation prior to planting peanuts, and the responses were undoubtedly 

 exaggerated because of .abnormally low magnesium levels. These workers 

 reported that little benefit was obtained from the addition of minor ele- 

 ments to peanuts. 



VARIETAL DIFFERENCES IN RESPONSE 

 TO FERTILIZATION 



Many studies have" indicated that peanut varieties exhibit marked 

 differences in response to fertilization. Several workers (10, 106) have 

 suggested that the so-called small-seeded types were more responsive to 

 additions of N, P and K, whereas the large-seeded types might be ex- 

 pected to respond more to Ca amendments. However, there appear to be 

 decided differences in the nutritional requirements of varieties within 

 either of the different major types. Such differences might limit broad 

 generalizations regarding the response of any given type of peanut to 

 fertilization. 



McClelland (68), in Arkansas, reported the results of experiments 

 in which a number of different varieties and strains of the major types 

 of nuts were grown with and without additions of limestone. The results 

 are shown in table 7. Strains of Spanish peanuts were found to differ 

 greatly in response to lime. Greater increases in yields of hay and nuts 

 were obtained with improved Spanish and Spanish Selection than with 

 any of the small runner or large-seeded types. The yield of Virginia 

 Jumbo, a large-seeded type, was initially very high and was slightly re- 

 duced by the lime. 



The 5-year average results of an experiment conducted on a Norfolk 

 sand at the Florida Experiment Station (65) are shown in table 8. 

 Several different varieties and strains of both the large- and small-seeded 

 type peanuts were grown with and without additions of 600 pounds of 

 gypsum. The average results show little response of small-seeded varieties 

 or of Virginia Bunch, a large-seeded variety, to this calcium-bearing ma- 

 terial. The yields of Jumbo variety were increased by adding gypsum, 

 while this material tended to decrease the yields of Virginia Runner, also 

 a large-seeded type. Therefore, although one of the large-seeded varieties 

 appeared to benefit from the gypsum, it is not possible to conclude from 

 this experiment that, as a group, the large-seeded peanuts were any more 

 responsive to amendments of calcium than were the small-seeded 

 varieties. 



