Wild. — Lime Requirements of certain SoiU. 



51 i 



These results are very satisfactory ; l)ut it is obvious that a more 

 practical test of the method would be to determine by it the lime require- 

 ments of two similar and adjacent soils, one of which had received a known 

 dressing of lime at a sufficient length of time previously to allow of its 

 being incorporated with the soil. Unfortunately, such conditions do not 

 obtain on the College farm at the present time ; for, though a good deal 

 of liming has been done on grass land during the past winter (1915), it is 

 certainly not yet incorporated with the soil, owing to the abnormally low 

 rainfall. However, the following trials were made with such material as 

 was available : — 



(1.) A sample was collected from field 21, consisting of thirty -three 

 cores taken 4 in. deep, the assumption being that the 3 in. of rain received 

 since the field was limed in June had distributed the lime through that 

 depth of soil. Determinations were made on this sample, and, for com- 

 parison, on one collected from the same field before the application of 

 the lime. 



(2.) It is known that the east end of the College playing-field was heavily 

 dressed with air-slaked lime about ten years ago, with a view to the eradi- 

 cation of rushes. Samples were therefore taken 6 in. deep from the east 

 end, from the west end, and from among a patch of cushes in the north- 

 west corner. 



(3.) A determination was made on a soil from Weka Pass, formed from 

 limestone rock, and obviously containing a high percentage of calcium 

 carbonate. The results of this set of trials are shown in Table C. 



Table C. 



Soil. 



Requirement of CaO indicated. 



Percentage. i Pounds per Acre. 



2,887 

 2,398 

 2,586 

 2,450 

 3,267 

 -680 



These results presented several interesting features. First, the difference 

 in lime requirement of the two samples from field 21 is about 4| cwt., while 

 the amount of lime actually applied was 5 cwt. or 6 cwt., so that the agree- 

 ment is fairly close. There is practically no difference in the indicated re- 

 quirements of the two ends of the football-field ; one must assume, therefore, 

 that ten years is sufficient time to neutralize the effect of a dressing of lime 

 in the top 6 in. As was expected, the corner of the ground covered with 

 rushes showed a markedly high requirement. The limestone soil was able 

 to give lime to the solution. 



III. 



Early in the course of the work it was noticed that the determinations 

 made at different times on the same soil gave different results. Thus the 

 following figures for the percentage lime requirement of field 21 have been 

 obtained on different occasions : 0-14, 0-15, 0-17, and 0-18. Expressed in 



17* 



