I 78 POTATOES 



abundantly supplied with humus. A young clover field 

 in which a second cutting of clover has been turned under 

 in the fall offers fine conditions for potato planting the 

 following season. If land is plowed in the early fall and left 

 in the rough during the winter, it can readily be put in good 

 tilth by disking in the spring. The fine-tooth harrow should 

 be run at weekly intervals after disking to prevent baking, 

 loss of moisture, and for the purpose of killing weeds. A 

 deep, mellow seed bed well supplied with fertility is essential 

 for large yields of good-sized potatoes. Potatoes should 

 not be planted on heavy clay lands that are not properly 

 drained and filled with humus. Light sandy soil, low in 

 fertility and humus content, should also be avoided. 



The plowing under of clover or vetch with the heavy 

 application of barnyard manure will soon enable one to 

 grow potatoes to advantage on light, sandy soil or on the 

 heavy clays, provided the drainage is good. One should 

 never attempt to grow potatoes on creek or river bottoms 

 that overflow periodically, or on marsh land where the 

 ground-water line is only a few feet beneath the surface. 

 Peaty marsh lands should be avoided as they lack uniformity 

 in character and the soil is too loose. The land should be 

 uniform in tilth and fertility in order to assure an even 

 growth and a good yield. 



Diseases. Chief among -the diseases that affect po- 

 tatoes may be mentioned early and late blight, scab, and 

 black leg. 



Both early and late blight in their first stages affect the 

 leaves of the plants and later the stems and tubers. These 

 diseases are controlled by spraying at intervals with Bor- 

 deaux mixture. This mixture is made as follows: dis- 

 solve 5 pounds of high-grade stone lime in 50 gallons of 



