PHYSIOLOGY AND MINERAL NUTRITION 113 



analyses of leaves or stems might be best for diagnostic purposes, 

 especially if corrective measures are to be practiced. 



Studies of tissue tests with the peanut are limited, but they seem to 

 merit more attention, especially evaluations for known or controlled con- 

 ditions. Burkhart and Page (20, 61) found variations in mineral content 

 of different parts of the foliage of the peanut and state that the following 

 tissues were most indicative for specific tests: Calcium, lower blades; 

 magnesium, lower petioles ; potassium, top petioles ; phosphorus, top 

 blades; sulfur, lower stems. The lower leaf blades of the peanuts were 

 thought to be the most suitable tissue for determining deficiencies or 

 excesses of all mineral nutrients in the plant. Chemical tests of the lower 

 blades gave results which correlated with response to fertilization of 

 field-grown plants. 



SHEDDING OF FRUIT 



Since the peanut blooms during a period of 2 to 3 months, there are 

 various stages of fruit development as the plant approaches maturity. 

 Many crops of indeterminate growth habit are harvested two or three 

 times during a season. This is impossible with the peanut plant, since it is 

 removed from the soil in the process. If peanuts are harvested early, there 

 will be a large number of immature fruit, and if late, the most mature 

 fruit will be left in the soil by the harvesting process (11, 39, 57, 66). 

 The amount of shedding or fruit loss is undoubtedly related to a number 

 of factors such as the degree of ripeness, amount of disease, insect dam- 

 age, and various cultural treatments. Different seed inoculations ( 1 ) have 

 necessitated harvesting at different times, also applications of gypsum 

 (19) have resulted in early defoliation, making early harvest necessary. 

 Shedding was decreased by sulfur dusting (11, 39) and was also in- 

 fluenced by fertilizer and other treatments (39). The number of fruit 

 shed may be very few, but occasionally, when harvested late or under 

 unusual conditions, as much as 75 percent (39) of all peanuts produced 

 may be left in the soil after harvesting. Therefore, it is quite important 

 in evaluating experimental results to know whether the technique used 

 in harvesting accounts for all the peanuts produced. 



NUTRITIONAL BALANCE 



A lack of balance in nutrient supply (34, 49, 87) frequently accentu- 

 ates nutritional disturbances. Published results ( 10, 19, 37) show that a 

 deficiency of any element to the peanut will quickly produce abnormal 

 plants which deteriorate rapidly. These deficiencies markedly affect the 



