142 



Bulletin 244. 



Sections i and 4 were on land which had been growing beets for 

 the last three years 1902, 1903, 1904; in 1903 the beets suffered from 

 leaf-spot but yielded at the rate of 17 tons per acre. Sections 7 and 

 10 were in corn in 1903. 



So far as could be judged, the plants on all sections had a uni- 

 form start, but those on sections i and 4 soon showed signs of disease 

 and this, with the attack of the flea-beetles, killed many of them or 

 injured them so seriously that the filling in of the blank spaces was 

 almost a second sowing. The plants on section 7 grew vigorously 

 and got ahead of the flea-beetle attack. The same was true of those 

 on Plat 10. The results were as follows: 



YIELD OF FIVE VARIETIES OF MANGELS WITH 

 AND WITHOUT ROTATION. 



Total yield per acre, tons. 

 Dry matter per acre, tons 



Average, 

 sections 

 i^and 4, 

 »i no 1 

 rotation. 



Average, 

 section 



7.. 

 rotation. 



Gain 

 tons. 



24 

 3 



Taking the variety Norbiton Giant, which occurred in all four plats, we 

 find that the results are : 



YIELD OF ONE VARIETY WITH AND WITHOUT 

 ROTATION. 



Total yield per acre, tons. 

 Dry matter per acre, tons 



Average, 

 sections ' 

 I'and 4,' 



no 

 rotation. 



II. 9 

 1.4 



Average, 



sections 



7 and 10, 



'rotation. 



35-1 

 2.9 



Gain 

 tons. 



23.2 

 25 



If we regard the land as fairly uniform, then this would indicate 

 that there is a distinct gain in the rotation of crops, from its influence as 

 an agent in restricting the spread of diseases. 



Results with leaf -spot in sugar-beets: 



In 1904 the leaf-spot disease began its ravages the first week of 

 September and spread rapidly for a few days on the plat which had 

 been in beets without rotation. It was observed that the part which 

 had been under rotation was almost free from leaf-spot and this led 

 to the determination to ascertain its influence. It was presumed that 



