CULTURAL CARE. 145 



potassic salts. Sulphate of potash diffuses better than any 

 other, and has so far given the best results in comparative 

 experiments ; it promotes better fructification and greater 

 richness in sugar. In calcareous soils we should only use 

 superphosphates, as neutral phosphates do not produce any 

 effect. 



Chemical manures are generally absorbed the first year. 

 It is, therefore, better to alternate their use with stable 

 manure. 



Commercial fertilizers are mixtures of different fertilizing 

 matters prepared by manure manufacturers. The variations 

 existing in their composition from the point of view of pro- 

 portion and the forms under which the matters composing 

 them are found prevents the expression of a general opinion 

 on them. One should always ask for a guarantee of the 

 composition of the fertilizer, specifying the proportion of 

 matters in a soluble state, with the method of analysis used. 



(B.) MEANS OF IMPROVEMENT. 



The means of improving the soil of vineyards are similar 

 to those used for other plants : drainage, which is outside 

 the scope of this work; addition of lime, marl, gypsum, 

 paring and burning the sward, and sometimes the addition 

 of coal ashes and hammerslag. 



Lime (carbonate of lime) and marl help to modify the 

 physical properties of the soil as well as its chemical com- 

 position. Their use seems to ameliorate the quality of the 

 wine, giving it a better colour. 



Gypsum (sulphate of lime) exerts a more favorable action 

 on the fructification of vines when the soil is naturally rich. 

 Used in quantities of J to 1 tons per acre it increases the 

 yield in a proportion which seems to increase with the 

 quantity used, and which may reach half or more of the usual 

 crop. 



Raw gypsum, evenly crushed, or burnt gypsum, are used 

 indifferently. It is applied broadcast in March or April, 

 and ploughed over. 



Paring or burning the sward renders clayey soils very 

 permeable, enables them to get warm easily, and, according 

 to Page'zy's experiments, the yield in sugar is increased. 

 This seems due to the transformation of certain mineral 



10890. K 



