i82 Bulletin 156. 



does not seem to have produced the marked results that were 

 shown in the previous experiments and this was probably due to 

 excessive droughts preceded and followed by excessive rains. 

 When a study is made of the table giving yields, a study should 

 also be made of the table showing what crops have been produced 

 on each plat during the past five years. All of these crops 

 have been well above the average and the annual drain 

 upon the soil has been greater than upon ordinary soils. To 

 explain the uniformly high yield we must then make a study of 

 the treatment which all plats have received. It is probable that 

 frequent and deep plowing has done much to bring and keep the 

 land productive. So far as the plowing is concerned all plats 

 have received the same treatment. The land has been turned 

 from two to three times each year, and the pulverizing which has 

 resulted therefrom has liberated sufficient plant food to mature 

 large crops. In addition to the plowing the land has been fre- 

 quently harrowed and cultivated and the intensive culture which 

 has been given has liberated all the plant food that could be used 

 by the growing crops with the amount of moisture that was 

 present. 



Plats 30 and 32 were not sprayed. Paris green was applied 

 with plaster to kill the Colorado potato beetles. The potatoes 

 grown on Plat 32 were the same variety as those grown upon Plat 

 2 1 which was kept well sprayed. It is not probable that the spray- 

 ing alone was responsible for the wide difference in yield as the 

 land becomes more gravelly in texture and hence more leachy as 

 it approaches Plat 32. The variety, Mill's Endurance, is said to 

 be blight proof and it does seem to possess to a remarkable degree 

 qualities which enable it to resist blight. Plat 32, though it was 

 not sprayed, remained in fairly good condition until killed by 

 frost. On Plat 21, the same variety which was spra3^ed with Bor- 

 deaux mixture, the foliage remained remarkabl}' healthy and 

 vigorous, and even though the variety seems to be exceedingly 

 hardy, yet the effect of the spraying was very marked. 



On Plat 31 the variety, Rose of Sharon, seemed utterly unable 

 to resist the blight. It was sprayed seven times with Bordeaux 

 mixture and finally succumbed to blight in the early part of the 

 season. The varieties which have with us proven most satisfac- 



