The Manuring of Vineyards. 59 



THE MANURING OF VINEYARDS. 



By J. C. Ross, Ph.D., Research Chemist, Elsenburg School of 

 Agl'icultiire, and S. W. van Niekerk, Government Viticulturist. 



The Requirements of the Vine. 



The vine, in common with all farm crops, takes from the soil 

 certain chemical substances termed plant-foods, which are 

 indispensable to its proper growth and development. The average 

 soil contains all the essential plant-foods, though not always in 

 sufficient amount or in proper form for the production of the best 

 crops. The problem of manuring consists in adding to the soil, in 

 a form which is easily available to the crop, those plant-foods of 

 which it shows a deficiency, or which are present in a form not suit- 

 able for the use of the crop. Fortunately, there are only a few 

 plant-foods whose supply is liable to be insufficient to meet the 

 requirements of the crop. These are iiifrogen, phosphoric oxide, and 

 potash, and occasionally lime. 



It is obvious that the ideal system of manuring will be one in 

 which provision is made for returning to the soil at least as much of 

 each of the important plant- foods as is removed by the crop. In this 

 way the fertility of the soil will be maintained from year to year, and 

 may even be gradually increased. If adequate provision is not made, 

 the store of plant-foods in the soil becomes less and less, until finally 

 a point is reached where it fails to produce a profitable crop. To 

 improve such a depleted soil will be a far more costly business than 

 the taking of proper precautions in the first place to keep up its 

 fertility from year to year. 



In order to maintain fertility, there are two important factors 

 to be considered: — 



(1) The plant-foods removed by the crop. 



(2) The plant-food content of the soil. 



Unfortunately we have no local data as to the plant foods 

 removed by the vine, but the following figures are stated by Dr. A. I. 

 Perold to represent the average per morgen for the vineyards of 

 France (according to M. Miintz in his '' Les Vignes," 1895): — 



Nitrogen. Phosphoric Oxide. Potash. 



Vine leaves 55 lb. 9.5 lb. 48 lb. 



Vine shoots 13 lb. 3.7 lb. 22 lb. 



Grape crop 18 lb, 5.8 lb. 24 lb. 



Whole vineyard 



Wine produced from the 

 grapes 



