Sweet Pea Diseases 335 



be induced by the excessive use of wood ashes ap- 

 plied with the manure. It is not uncommon for 

 growers to use wood ashes at the rate of 1,500 lbs. 

 to 4,500 square feet of bed space. This would be 

 equivalent to nearly seven and one-half tons per acre. 

 Under such conditions the roots actually bum up 

 because of the strong alkalinity of the soil. More- 

 over, hard-wood ashes contain about 30% caustic 

 lime and from 5 to 12% potash. Both of these ele- 

 ments in excess in soil render it too alkaline for plant 

 growth. To remedy this trouble, acid phosphate is 

 used, followed by a good drenching with water. This 

 will help to neutralize the alkalinity and to restore 

 the balanced ration. 



Malnutrition 

 Cause, physiological. 



Symptoms. The symptoms of malnutrition of 

 sweet peas a-re identical with those of greenhouse 

 cucumbers (see p. 134). 



Cause. Overfertilization may be mentioned as 

 one of the many causes of malnutrition. An analy- 

 sis of an overfed soil will readily show that the solu- 

 ble salts present are in excess of what the plant re- 

 quires and is able to withstand. Table 17 a by 

 Haskins clearly shows that with the exception of 

 nitrogen, the soluble salts were in excess of what the 



♦Haskins, H. D., Mass. Agr. Expt. Sta., Twenty-fifth Ann. 

 Kept.: 76-79» 1913- 



