SOILS AND FERTILIZERS 225 



are the depth of eyes, the shape of tubers, the color of skin and 

 flesh, and period required for maturing the crop. Farmers most 

 commonly classify potatoes as early or late. 



Common early varieties in order of earliness are: Early Rose, 

 Early Ohio, Triumph and Irish Cobbler. The time for producing 

 potatoes with these varieties varies from sixty to one hundred 

 days. Early potatoes are usually harvested and marketed as 

 soon as they are large enough not always waiting for them to be 

 thoroughly mature. Late potatoes are allowed to remain in the 

 ground until they are thoroughly mature. They will keep much 

 better and may be stored and sold, or used much later. So-called 

 late varieties would include Rural New Yorker, Burbank, Sir 

 Walter Raleigh, and Carman No. 3. Green Mountain is a variety 

 which will keep fairly well and is usually considered of the late 

 type. It will produce a crop in about one hundred days. Other 

 late varieties mentioned usually require a little longer. 



The keeping quality of potatoes depends not only upon the 

 variety, but also upon the maturity of the crop and season of 

 harvesting. Early varieties may be grown late in the season, and 

 keep well for winter and spring use. The late grown crop is often 

 called the second crop, but it is seldom grown on the same field 

 where the first crop was harvested. Two crops of potatoes in one 

 season are frequently grown in southern latitudes. 



In the selection of varieties for market purposes a study 

 should be made of the market requirements. Potatoes of white 

 flesh and Avhite skin usually bring a better price than the red 

 varieties. The tubers should be smooth not rough; the eye 

 should be shallow not deep; the tubers should be round and 

 somewhat flat, rather than long or irregular. In size they should 

 not be too large nor too small. Those of medium size are always 

 preferred. 



Soils and Fertilizers. Rich sandy loams produce a better 

 quality of potatoes than heavier soils. Early potatoes are not 

 quickly produced on heavy soils, but late varieties may be grown 

 on clay loams if there be plenty of organic matter present. Po- 

 tato soils can usually be much improved by the use of green manure. 

 The heavier soils are also much benefited by drainage. The use 

 of barnyard manure will help to increase the amount of humus 

 present, but it should be applied on the field for the preceding crop 

 in the rotation, as fresh manure upon potato soils increases the 

 development of the disease known as potato scab. For early 

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