40 



Journal of Agricultural Research 



Vol. XX, No. i 



EFFECT OF COMPOUNDS OF LIME IN INDUCING CHLOROSIS 



To see whether lime salts in general induce chlorosis in certain plants, 

 experiments have been conducted with calcium carbonate, sulphate, 

 phosphate, and silicate. The effects of these compounds on the growth 

 of lupines have been determined by Heinrich {23), Pfeiffer and Blanck 

 (35), and Creydt (5). The calcium sulphate did not induce chlorosis 

 but depressed growth considerably, although much less than the calcium 

 carbonate, while calcium phosphate and silicate were markedly toxic. 

 The toxicities of the latter two substances were attributed to their acid 

 and alkaline reactions, respectively. 



Large quantities of gypsum depressed the growth of pineapples about 

 20 per cent but did not cause chlorosis (12). Various experiments were 

 conducted to determine the effect on rice of large amounts of assimilable 

 lime in the form of gypsum. 



Experiment II. — In this experiment, rice plants were grown from 

 December 17, 1912, to May 20, 1913, in small brick compartments, with 

 24 plants to each compartment. Each compartment held about 200 

 pounds of soil fertilized with 30 gm. sulphate of ammonia, 20 gm. nitrate 

 of soda, 30 gm. acid phosphate, and 18 gm. muriate of potash added in 

 two applications. The results are shown in Table II. 



Table II. — Effect on the growth of rice of adding gypsum to the soil 



Test 



No. 



Kind of soil. 



Loam. 



...do 



Clay . . 



do 



Gypsum 



(CaSO<. 



2H2O) 



added. 



Per cent. 

 O 



o 

 IS 



Green weight of plants per compartment. 



Series A. Series B. Series C Average 



Gm. 



I, 218 

 312 



936 



Gm. 



1,229 



446 



808 



958 



Gm. 



1,452 

 382 

 840 

 842 



Gm. 



1,300 

 380 

 824 

 912 



During the first four weeks the plants were all of good color, but later 

 the plants in the loam soil containing gypsum became yellow, though not 

 typically chlorotic. 



Experiment III. — A second experiment was conducted to see whether 

 large amounts of gypsum would depress the growth of rice if the plants 

 were sprayed with ferrous sulphate. The compartments contained about 

 200 pounds of a sandy soil and received 45 gm. sulphate of ammonia, 

 30 gm. acid phosphate, and 18 gm. muriate of potash. In each compart- 

 ment 22 plants were grown. The plants treated with ferrous sulphate 

 were sprayed twice with a 0.1 per cent solution, five times with a 0.15 

 per cent solution, once with a 0.2 per cent solution, three times with a 

 0.75 per cent solution, and seven times with a 1 per cent solution. The 

 results are given in Table III. 



