LIMITS OF ENDURANCE OF DIFFERENT FARM CROPS. 197 



None of the above germinated, and the pots were resown 



on July 3rd with soil No. 2 (no manure added). 



Pot 28, *001 per cent. NH 4 ONS 



„ 29, -003 



„ 30, '005 



„ 31, -01 



On July 24th, Pot No. 28 had germinated well, but growth 

 was retarded, the plants were poor in colour and the 

 tips of the leaves were becoming yellow. 



Pot 29 had germinated but the plants were growing very 

 feebly. 



Pot 30 had germinated, the plants were very feeble and 

 apparently dying. 



Pot 31 had hardly germinated, and the plants had died. 

 On August 26th— 



Pot 28 had recovered, and the plants were growing fairly 

 well. 



Pot 29 had also recovered and was growing fairly. 



Pot 30, all the plants were dead. 



The conclusions drawn are the following : — *01 per cent, 

 of ammoniun sulphocyanide in the soil prevents germination, 

 quantities as small as '001 per cent, seriously affect the 

 growth of the plant, which however, under favourable con- 

 ditions may recover. *005 per cent, is fatal to the growth 

 of the plant. 



Experiments with sodium chlorate. 

 This ingredient is sometimes present in nitrate of soda. 

 The following experiments were carried out to ascertain 

 the proportion of this substance which the wheat plant 

 can tolerate without being injuriously affected. 



The following pots were prepared, filled with soil No. 1 



and sown on June 3rd : — 



Pot 32, *01 per cent. Na01O 3 



,, oo, "05 ,, 



,, 34, -10 



,, o5, *50 ,, 



