Old System of Intertillage 161 



Table showing the distribution of moisture in a potato patch, June 27 



0-18 20.99 19.31 18.24 20.97 



At the time these determinations were made, the 

 potato vines were about one -half full size. It will be 

 seen that the moisture had been withdrawn from the 

 soil more completely at 18 inches directly below the 

 center of the hill than it had at 18 inches on either 

 side. It does not follow from this, however, that the 

 plants were not receiving important additions of soil 

 moisture from the soil in the center of the row. In 

 our work in irrigating potatoes, where the rows were 

 30 inches apart, and where ridge culture was adopted, 

 the water being applied in furrows about 9 inches 

 wide, it was found that on the boundary between the 

 irrigated and non- irrigated areas, the second row of 

 potatoes from the last water furrow had its yield 

 increased on the average, in 1897, 7.9 bushels per 

 acre, or 3.2 per cent of the yield of merchantable 

 tubers grown on the land not irrigated. That is to 

 say, the lateral capillary movement of the water in 

 irrigation influenced the yield to that extent through 

 a distance of about 40 inches. 



In the case of corn, the second rows beyond the 

 last irrigating furrow showed the influence of the 

 water to the extent of 2.2 per cent of the non- 

 K 



