100 Maine Agricultural Experiment Station. 1920. 



effect on the seed-piece, since there was a marked absence of 

 decay in the latter where fertilizers were used which contained 

 it in considerable quantities. 



Plants which survived till the middle of the summer usu- 

 ally began to put forth roots from the stem close to the surface 

 of the ground or in the region most remote from the point of 

 application of the fertilizer.* These plants, if they had not 

 been too severely injured, then began to grow fairly rapidly as 

 the result of the partial establishment of a new root system in 

 the hilled-up soil, out of contact with the fertilizer. As has 

 already been stated the yellowing and other evidences of injury 

 disappeared more or less completely with the new growth. This 

 belated or secondary growth of the injured plants tended also 

 to obscure the number of missing hills and thus improved the 

 appearance of the affected fields generally. Such of these fields 

 as it was possible to observe from time to time during the season 

 proved very deceptive to those who were not familiar with their 

 history. The yields of tubers were far from what might be 

 expected from the appearance of the partially recovered plants. 

 One field in particular, which the writer had under observation 

 during the latter part of the growing season, showed marked 

 improvement during August and September, but the owner ob- 

 tained only about one-third of a normal yield. The fertilizer 

 used carried 0.88 per cent anhydrous borax and at the rate used 

 was equivalent to an application of 17.6 pounds of anhydrous 

 borax per acre. 



The above description of the injury to potatoes in the field 

 and attributed to the presence of borax in the fertilizer used, 

 applies more particularly to the severe cases. All gradations 

 between this and fairly normal plants might be found on the 

 same field. A few mild cases of injury were seen where it was 

 rather difficult to decide whether or not the trouble was due to 

 the presence of borax in the fertilizer. Some of these were 



*For the benefit of those who are not familiar with the cultural 

 practices followed with potatoes in Maine it may be said that it is cus- 

 tomary to cover the plants with a horse hoe as soon as they begin to 

 break ground. This is repeated when the plants begin to appear a sec- 

 ond time. Hence a considerabe ridge or hill is already formed from 

 the surface soil, well above the seed-piece and fertilizer, before the plants 

 finally come up. 



