106 THE PEANUT— THE UNPREDICTABLE LEGUME 



(42) by the drip-culture method (76). The deficiency was corrected 

 quickly by spraying iron on the plants. 



Boron. A deficiency of boron affects the growing tissues, similar to 

 that of calcium, resulting in death or growth abnormalities. The mobility 

 of calcium is related to the boron supply. A boron deficiency for peanuts 

 (19) resembles a calcium deficiency except that the necrotic areas are 

 localized near the leaf margins. : i , 



Manganese. Manganese is in some way related to chlorophyll produc- 

 tion since a deficiency results in a chlorosis of J)lants. It seems to play a 

 |)art in oxidation and reduction processes possibly through its effect on 

 enzymes. Shear and Batten (71) reported that when peanuts were grown 

 on heavily limed soils the foliage was chlorotic and yields were reduced 

 due to the unavailability of the manganese. 



Copper and Zinc. A deficiency of copper results in chlorosis, prevents 

 nitrogen from functioning normally (32, 35), and reduces yields. Harris 

 reported that in copper deficiency the bud area of the peanut was affected, 

 the terminal leaflets were chlorotic, small and distorted, a few yellowish- 

 white spots appeared on many leaves, and the yields were greatly reduced 

 (figures 5, 6) . The pattern was much the same as that reported by Allison 

 et al. (2) when peanuts were grown on soils in the Everglades and was 

 similar to that attributed to thrip injury by Shear and Miller (72) and 

 to leaf hopper injury by Metcalf (53). It is quite possible that such char- 

 acteristics are similar to those resulting from insect injury. However, the 

 symptoms described above did not occur when copper was applied to the 

 soil before peanuts were planted. 



Zinc-deficiency symptoms of the peanut have not been described, 

 although some workers (2, 6) have reported that applications of zinc 

 have increased yields. 



Molybdenum. Molybdenum is considered an essential element for 

 some plants (82, 86). The foliage of the peanut plant had a dark green 

 color when a small amount of molybdenum was applied to the soil, and 

 shoot growth was increased by its addition to nutrient solutions (37). 



CHEMICAL COMPOSITION 



The data of mineral analyses of various parts of peanut plants as 

 compiled from several sources (26, 33, 43, 48, 83) are given in tables 

 4 and 5. Few values for sulfur were found, and it would appear that the 

 evaluation of this element would merit more attention. The results given 

 in these tables merely indicate the mineral content of plants when grown 

 under various conditions. Therefore, caution should be used in drawing 



