IRISH POTATOES 239 



land for potatoes is to have legumes precede them. In the South this can 

 be the cow pea the preceding summer and the hairy vetch in winter, the latter 

 to be plowed under for the potatoes. 



MANURIAL REQUIREMENTS OF THE POTATO. 



Analysis shows that the Irish potato consists of 79.75 per cent, of water, 

 0.99 per cent, of ash or mineral matter, and it contains 0.21 per cent, of 

 nitrogen, 0.07 per cent, of phosphoric acid and 0.29 per cent, of potash. 

 Hence it is easy to see that nitrogen and especially potash play the most im- 

 portant part in its growth. Where the crop is planted on a soil abounding 

 in organic matter or humus, there will be little need for an artificial appli- 

 cation of nitrogen, in the northern part of the country, where the potato 

 grows during the greater part of the season when the nitrification of this 

 organic matter is most active. 



But in the South, where the crop is grown in the spring months and 

 earliness is the great point to attain, a more liberal application of immediate- 

 ly available nitrogen is important. In fact, the potato in the South is a mar- 

 ket garden crop rather than a farm crop, as it is in the North, and as the 

 value of this early crop is greater than that grown in the North, it will pay 

 for more liberal fertilization than the farmer in the North usually gives. 

 Any fertilizer mixture for the potato, North or South, must be high in its 

 potash content, while but a moderate percentage of phosphoric acid is needed. 

 The manufacturers make a great many names for their fertilizers and nearly 

 every one of them has a special potato fertilizer, and nearly every one of them 

 makes the phosphoric acid the leading constituent. In fact, if the farmer 

 will take the trouble to examine the tables of analyses of commercial fertil- 

 izers published by the various Experiment Stations, he will find that many 

 of the so-called special fertilizers recommended for different crops are really 

 the same thing, and are probably bagged out of the same pile, and the only 

 difference between them is that one is called "special potato manure" and 

 another is "special manure for cabbage," or some other crop. When farmers 

 learn to buy fertilizers by the analysis and not by the trade brand, or, better 

 still, learn that they can mix their own fertilizers better and cheaper than 

 they can buy them, this humbug will have had its day. 



OTATOES AS A FIELD CROP IN THE NORTH. 



Where the potato crop is one of the regular crops in an improving rota- 

 tion the rule that the application of commercial fertilizers should be to the 



