160 L/lme Requirements of New Zealand Soils 



Adopting these standard conditions of experiment, the present 

 writer, with a view to amplifying the practical checks on the accuracy 

 of the method, treated two soils with known weights of calcium carbonate 

 in suspension in known volumes of distilled water, and thereafter 

 determined their hme requirements for comparison with those of 

 untreated samples. The results so obtained are set out in Table VII. 



C. Field Experiments. 



These results are satisfactory, but it is obvious a still more practical 

 test would be to determine the lime requirements 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. To this end a number of farms were visited and samples 

 of soil were collected from adjacent fields, one of which had been limed 

 while the other remained untreated and so served as a check. Some of 

 these soils are typical Hme-requiring soils so far as we meet with such 

 in this country, and the experiments are the more interesting on that 

 account. The results are tabulated below (p. 161). 



Out of these experiments the following conclusions emerge: (1) that 

 an application of lime to a soil in the field is reflected in a diminution 

 of the hme requirement of the soil as indicated by the method under 

 consideration : (2) that the diminution in the indicated lime requirement 

 is not commensurate with the amount of hme added : (3) since it has 

 been found by practical experience that an appHcation of 1 ton of burnt 

 hme per acre is sufficient to convert an unhealthy infertile soil into a 

 healthy fertile one, even in the case of the typical lime-requiring soils 

 of Southland, then either {a) this method for indicating lime require- 

 ments gives excessive values or (6) it gives an optimum value that is 

 greatly in excess of practical, or at all events of economical requirements. 



