INJURIOUS EFFECT OF ALKALINE SOILS. 29 



Five other plants from the same twelve were watered with an alka- 

 line nutritive solution of the following composition : 



-Potassium nitrate (KNO3) 1. gram. 



Magnesium sulphate (MgSOi) 0.4 gram. 



Calcium sulphate (CaS04) 0. 5 gram. 



Potassium diphosphate (KH2PO4) 0. 4 gram. 



Sodium chlorid (NaCl) 0. 5 gram. 



Ferric chlorid (FeCla) Trace. 



Water 1, 000 c. c. 



By the addition of a sufficient quantity of sodium hydrate the re- 

 action of this solution was made alkaline to the degree of 0.006 

 normal. 



Two of the twelve plants were left as checks, being still watered 

 with tap water. 



On March 25, thirty-six days after the watering began, the five 

 plants fed with the acid nutritive solution were restored to a nearly 

 normal green color, and all had begun to put out healthy new growth. 

 The two check plants watered with tap water were still red-purple 

 and stagnant. Of the five plants watered with the alkaline nutrient 

 solution, three were stagnant and somewhat purplish, one was dying, 

 and one was dead. 



Figures 9 and 10, from photographs taken on April 15, 1009, 

 show a typical stagnant plant that had been watered with the alka- 

 line solution, and a typical plant watered with the acid solution which 

 had begun to make new growth from the summit of the old stem and 

 was pushing out a vigorous new shoot from the base. The experi- 

 ment was terminated not long afterwards, but there was every pros- 

 pect that had it been continued the acid-fed plants would soon have 

 made growth comparable with that shown in figure 8 (p. 23). 



Looking toward the aciditv or alkalinitv of the other cultures thus 

 far cited, it may be stated that the rich garden soil described on 

 page 14, which was so remarkably deleterious to blueberry seedlings, 

 was alkaline. The rose cuttings and the alfalfa, which grew so well 

 in that mixture, much prefer a somewhat alkaline soil. Indeed, 

 alfalfa can not be grown with any degree of success in any soil 

 except one with an alkaline reaction. AAlien grown in the humid 

 eastern United States alfalfa is rarely successful, except on calcareous 

 soils, unless the natural acidity of the soil has been neutralized by 

 suitable applications of lime. 



The limed soil, deleterious to blueberry plants, described on page 

 23, gave a neutral reaction with phenolphthalein. 



The heavy clay soil described on page 24, in which blueberry plants 

 made very little growth, Avas neutral. 



The thoroughly decomposed leaf mold described on pages 24 to 2G, 

 which was shown by experiment to be markedly deleterious to the 



193 



