The Manuring of Vineyards. 61 



soil will actually lose only the plant-foods contained in the grain, 

 as either the straw or its equivalent in animal manure will be returned 

 to the soil. 



On account of these facts, it is found in the case of grain farm- 

 ing that the composition of the soil is the most important factor upon 

 which to base the composition of the fertilizer used. The chief 

 requirement of a grain fertilizer is phosphoric oxide, and in most 

 cases nitrogen is also needed, but to a less extent. With regard to 

 potash, though the average grain soil does not contain an abundar.ce 

 of this plant-food, its supply is very easily maintained in the soil, 

 smce the grain itself contains very little potash. Thus, as a rule, 

 we find it is not necessary to use a "complete" artificial fertilizer 

 (i.e. one containing nitrogen, phosphoric oxide, and potash), but 

 rather an essentially phosphatic fertilizer, containing also more or 

 less nitrogen. 



In the vineyard, however, we have an extremely exhaustive crop 

 growing year after year on the same soil and always drawing heavily 

 upon the same plant-foods. The problem of maintaining the produc- 

 tiveness uf the soil in this case is different from the above, and needs 

 careful consideration. Experience in this country and in France 

 seems to indicate that a " complete " fertilizer or manure is neces- 

 sary in order to obtain the best results. 



In order to decide how much of each plant-food should be applied 

 to the vineyard per morgen, perhaps the safest general guide in 

 regard to nitrogen and potash is the amount of each of these removed 

 by the crop, viz., approximately 86 lb. per morgen of nitrogen and 

 94 lb. per morgen of potash. The composition of the soil should 

 also be taken into account, for in some cases the supply of either 

 nitrogen or potash, or both, may be so abundant that the quantity 

 used in the manure could with benefit be considerably reduced, at 

 least for a number of years. In other cases the soil may be so 

 impoverished that it will be necessary to apply more than the quanti- 

 ties suggested above. 



A word or two concerning the special functions of nitrogen an I 

 potash in relation to the growth of the vine might not be out of place. 

 Nitrogen appears to be actively associated with the rate of growth 

 of the leaf and vine. A strong vigorous growth of leaves and shoots 

 invariably indicates a good supply of nitrogen. An important point 

 to observe is that an excess of nitrogen must be avoided. Large 

 arid rapid early growth of leaf and vine is to be encouraged, and the 

 nitrogen supply should be adequate for this purpose. But this rapid 

 growth should not be extended through the ripening season, because 

 it is the fruit, not the leaves and wood which constitutes the crop. 

 Too rank a growth and too extended a growing period will render the 

 vines more liable to disease and will produce fruit which does not 

 ripen well. Thus the nitrogenous fertilizer should be such as will be 

 available during the early growing period of the vine. Dark brown 

 and black soils, which owe their colour to the presence of humus in 

 the soil, generally contain a fair supply of nitrogen. Caution should 

 be exercised in applying nitrogen to such soils, as the supply may 

 already be adequate or very nearly so. 



Potash, while absolutely essential, and though taken up by the 

 vine in large quantities, appears to be of relatively less importance 

 than either nitrogen or phosphoric oxide. It is supposed to play a 

 significant part in the formation of sugar in the plant, and it 

 also forms the base of the fruit acids. 



