SOILS ADAPTED TO POTATOES. 323 



the potato wlien the dog-star rages, in the latter part of July 

 and daring August. The engorged state of the plant, and its 

 soft vascular tissues, especially when grown in rich soil, render 

 it liable to disease when the hot, moist days are succeeded by 

 cool nights, or a sudden change of the weather checks the flow 

 of sap. The cells may burst, from an excessive flow stimulated 

 by heat, moisture and nitrogeneous manure, or they may collapse 

 by the sudden check of the sap by cold. In either case putre- 

 faction ensues. If the potato has great constitutional vigor it 

 may resist these changes. The Garnet Chili, the Harrison and 

 Gleason seem to possess this vigor, and we trust the Rose has it 

 also, but its character is not yet fully established. We have the 

 past summer raised the Gleason on very rich garden soil, and 

 while other varieties planted by their side rotted, the Gleasons 

 came out sound and in great abundance. The potato loves a 

 rich soil, and large crops can be raised in no other, and one 

 great advantage in planting vigorous varieties is that we can 

 plant them in such a soil. For many years after the disease 

 made its appearance it was supposed that little, if any, nitroge- 

 neous manure could be applied to the potato patch, as it so 

 greatly enhanced the tendency to rot, and we were content 

 to raise light crops on poor, light soil. The yield fell oflf from 

 an average of three hundred bushels to the acre to less than 

 one hundred. Since new and healthier varieties have been 

 introduced the yield is again on the increase, partly because 

 we find that these vigorous kinds can resist the tendency to 

 disease which manure induces. The Garnet Chili, one of the 

 earliest introduced by Mr. Goodrich, and one of the most vigor- 

 ous, has evidently lost something of its original constitutional 

 power, and in a hot, damp time decays when planted on fresh, 

 unfermented manure. 



The soil best adapted to the potato seems to be a sandy loam, 

 well drained, in case the subsoil is of clay. Clay soils, if the 

 season is unfavorable, are peculiarly prejudicial to the health of 

 the potato, as they envelop the tuber closely and prevent the 

 access of air, light and heat. If the surface of the unripe tuber 

 is kept constantly wet, as it is apt to be in a wet season, on clay 

 soil, decay will be likely to ensue, even when morbid matter 

 has not been conveyed from the vine to the root, which seems 

 to be the usual mode. The inverted sod of an old pasture is 



