SOIL FERTILITY 



153 



Stokes and Camp (104), working in Florida, have reported that 

 gypsum gave profitable increases in yields of Florida runner and a Jumbo 

 variety, but not of the Spanish, Valencia and Virginia Bunch varieties. 



Experiments conducted at several locations by workers at the North 

 Carolina Station (46) show considerable differences in response of the 

 large- and small-seeded type peanuts to additions of lime and gypsum. 

 On soils extremely low in calcium, the Virginia Bunch variety, a large- 

 seeded type, was found to respond more to additions of gypsum than a 

 small runner and White Spanish varieties. On soils high in calcium the 

 response was quite erratic and no general trends were observed. 



A detailed study by Middleton, et al. (74) of the behavior of four 

 varieties of peanuts as affected by calcium and potassium variables re- 

 veals some interesting variety-fertility interrelations. Some of the results 

 of this study are shown in figure 10. It is evident that the relative behavior 

 of the four varieties depended upon the fertilizer treatment. For example : 

 Without treatment the Spanish varieties yielded highest and the Virginia 

 Bunch yielded lowest. However, when all varieties received gypsum, the 

 yield of Virginia Bunch was the highest. The authors concluded that the 



YIELD EXPRESSED IN POUNDS PER ACRE 

 SHELLING 60 PER CENT 



GK 



356 





i 



te 



L.SDC05) ;§| 



11 



VIRGINIA 

 BUNCH 



G = 400 POUNDS OF GYPSUM 



GK = 400 POUNDS OF GYPSUM PLUS 45 

 POUNDS OF KgO 



N. C. 

 RUNNER 



SPANISH 

 2 B 



GK 



WHITE 

 SPANISH 



Figure 10. — The relative yields of four varieties of peanuts grown with and without 

 amendments of gypsum and potash. Gypsum applied to foliage at early bloom- 

 ing; potash applied as top dressing at emergence. Soil, Norfolk sand; pH = 

 4.6; 0.54 m.e. exchangeable calcium; 0.04 m.e. exchangeable K. Source: Middle- 

 ton, Colwell, Brady, and Schultz (74). 



