306 



Value of Chalk as a Dressing. 



[JULY, 



the plants will be weakened and the succeeding crop much 

 diminished. Mr. Wing states that he has observed the ill- 

 effects of cutting lucerne too early in England, and suggests 

 that the lucerne ought to be cut as soon as the shoots or 

 buds appear without regard to the flowering of the plant. 



With reference to this point, Mr. Martin H. Sutton informs 

 the Board that experiments made by him for many years 

 have shown the statement to be perfectly correct so far as the 

 first season of growth is concerned. Lucerne should never 

 be cut until the first buds have formed at the base of the 

 plant, as if the crop is cut too soon the result is a definite 

 retarding of growth. This, however, is only found to apply 

 to the first year. After the first year the plant is well estab- 

 lished; no ill-effects have been noticed from cutting early. 

 When once the plants are well established new buds are form- 

 ing almost continuously, and there is, therefore, no risk in 

 cutting early in the second and succeeding years. 



Observations on the agricultural value of chalk, with special 

 reference to particular kinds of soil requiring lime in a mild 

 form, have recently been made by Mr. 



^essin C fo^Li a ht J ° hn Hu £ hes ' Agricultural Analyst for 

 Soils Herefordshire. Chalk is but slightly 



soluble in cold distilled water — very 

 much less so than caustic lime. It was found that while 

 i part of caustic lime dissolves in 833 parts of water, 1 .part 

 of chalk only dissolves in 22,222 parts of water — the relative 

 solubility being, therefore, about as 1 to 27. Under soil 

 conditions, however, the solvent is not pure water, but "soil 

 water," which contains various vegetable acids exerting a 

 considerable solvent action on plant foods. It is usual, 

 therefore, to make comparisons by the use in chemical prac- 

 tice of a 2 per cent, solution of citric acid, originally sug- 

 gested by Wagner as a standard solvent for estimating the 

 probable availability of phosphate of lime in basic slag. Such 

 a solution, however, is far stronger than the sap acidity of 

 plants, and in order that an acidity or solvent action less than 

 that possessed by the sap of farm crops should be represented, 

 Mr. Hughes tried a o'i per cent, solution of citric acid. With 

 such a solution he found that 1 part of caustic lime was dis- 



