68 MASS. EXPERIMENT STATION BULLETIN 150. 



growth above the average, the drainage from the bogs in the spring was 

 above the average, and in 10 cases the irrigation was high also. On the 

 other hand, bogs lA, IB and llA, in which the water movement was 

 notably slow, yielded the smallest weights of vines when pruned. 



In a large proportion of the bogs the growth of vines appeared to be 

 related to the freedom with which the soil permitted the water to move 

 from bog to drain and back again. Not only was more water evaporated 

 during the summer, but these bogs permitted rapid percolation or seepage 

 in the spring into the small cylinders. The bogs with small vine growth 

 were slow to drain in the spring, and much of the water evaporated from 

 the surface of the bog instead of seeping into the drainage cyhnder. 



In conclusion our observations show that the principal losses of fertility 

 are in the seepage water which may escape from the ditches, and that the 

 vine growth is more influenced by the free movement of water than by 

 fertilizers. 



The assistance of Mr. R. W. Ruprecht in measuring the water, and of 

 Mr. R. L. Coffin in pruning and weighing the vines, is gratefully acknowl- 

 edged. 



