EXPERIMENT STATION BULLETINS. 



343 



CULTURAL TESTS. 



Methods of cultivating the potato crop are effected by the type of soil, 

 drainage, presence or absence of noxious weeds and way of planting. The 

 comparisons made were based on the methods in use on farms in this terri- 

 tory. The experiments were conducted on a calcareous sandy loam soil 

 with more than the usual amount of rock present. 



Seed Treatment : — Seed potatoes have been handled in four ways to de- 

 termine the effect on the ensuing crop. (1) Treating with corrosive subli- 

 mate; (2) with formaldehyde; (3) leaving the potatoes in the ground 

 over winter and digging them in the spring and then green-sprouting them 

 for seed, using no treatment; (4) planting the ordinary cellar storage po- 

 tatoes. 



With the above methods the most favorable results have been obtained 

 with corrosive sublimate, old style treatment. By this treatment the po- 

 tato seed piece is freed from the scab and Rhizoctonia (Black Scurf) organ- 



Fig. No. 16. Digging potatoes at the Chatham Station in 1920. 



isms, thus getting a better start for the young plants. Corrosive sublimate 

 plats out-yielded and gave a better quality of potatoes than the other plats, 

 though Scab and Black Scurf of the potato was prevalent on all plats at 

 digging time. The soils of the Chatham Station are high in lime content 

 and appear to be natural harbors for scab and Rhizoctonia organisms, even 

 on new soils recently brought under cultivation. 



Time of Planting — Two varieties. Green Mountain and Rurals were used 

 in this experiment. The earliest planting was made on May 19th and a 

 plat planted every week until June 30th, making seven different dates of 

 planting. 



Time of planting potatoes in the Upper Peninsula is influenced by the 

 growing season. Late potatoes planted early in the spring just so as to 

 escape the late spring frosts will have a sufficiently long growing season to 

 develop and mature a crop before the early fall frosts. The character of the 

 average growing season is such that it allows for the continuous development 

 of the potato plant. The plantings made the last two weeks in May gave 



