1921.] 



34S 



Clover Areas. Failure Areus. 

 A verage A veruge 



for 4 Samples. for 5 Santples. 



Carbonate Nil. Nil. 



Action on litmus Slightly aciilic. Strongly acidic. 



Lime requirement (calculated 



asCaCOs) 0-078 per cent. O'lGO per cent. 



In view of the obvious necessity for increased liming, and of 

 the fact that " Ume " for agricultural purposes may be obtained 

 in at least three forms, viz., burned lime, gi'ound quicklime 

 and ground limestone, it is highly important that farmers should 

 be aware of the conditions under which these various forms of 

 lime may be most profitably used. It is the special object of 

 this article to draw attention to some of the circumstances which 

 may influence the value of ground limestone as a fertilizer. At 

 present there are but relatively few^ farmers who view ground 

 limestone with much favour. There appear to be several reasons 

 for this : — 



(1) Excessive claims made on its behalf have led to the 

 application of dressings much too small to produce appreciable 

 results. 



(2) Its price has often been proportionate to the excessive 

 claims. 



(3) Variability as regards both composition and degree of 

 fineness. This may be exemphfied by the following analyses 

 of samples received at the college laboratory : — 



Ground Ground 



Limestone Limestone 



Xo. 1. No. 2. 



Percentage calcium carbonate ... 94 25 53"11 



♦Percentao-e T Below in, diameter ,,. ... 14-92 3-14 



tineness of J Between in. andg'oin. diameter 73-03 37-05 



particles | v aV in. „ ^^i". lO SO 35 09 



Above 2V in • ^'J^'neter ... ... 1'25 24-12 



(4) Farmers have failed to realise its limitations. Lime- 

 stone is very efficient in correcting sourness and in assisting 

 chemical and bacterial actions, but is very inferior to burned 

 lime for improving the texture of heavy clay soils. It often 

 happens that a farmer's prejudice against ground limestone 

 rests upon failure to secure any benefits from the application 

 of only 4 or 5 cwt. per acre on stiff clay soils. 



Among the reasons whicli may be adviuiced in favour of using 

 ground limestone, the following may be enumerated : — 



® See "Selection of F«>rtilizers," bv J. J. (Jrillitb. University College of 

 Wales, 1915. 



