SURFACE IRRIGATION 15 



the soil is available and effective, and, assuming that the ground 

 is already well drained naturally or artificially, the conditions 

 are the best. The shallow-rooted plants are always directly 

 benefited, while the deep-rooted ones derive some good. 

 They, however, are not always in as great need of moisture 

 even in dry weather. Good results from surface irrigation 

 also depend upon the surface soil ; purer sandy soils are not 

 retentive of moisture, while the stiff clays are particularly so ; 

 therefore soils such as the loams are much preferable. 



Figure 3 and the frontispiece show sections of both flori- 

 cultural and olericultural or vegetable gardens on the col- 

 lege grounds, which have been watered for the most part by 

 surface irrigation. In Fig. 3 the average depth of soil was not 

 over six inches on account of underlying ledge, but by proper 

 fertilization and irrigation through a net-work of small ditches 

 made and manipulated by Mr. Hunt, the assistant horticulturist, 

 the beautiful effect here shown was accomplished. In the 

 frontispiece, the conditions were about the same except that the 

 soil was very much deeper. The outer rows, or the rows next 

 the fence in this cut, show very plainly the effect of lack of 

 irrigation. The lower ends of these rows together with the 

 rest of the section were watered by surface irrigation. The 

 furrows for the distribution of water were shaded bv the foliage 

 in both of the cuts and, too, at the time when the sun was 

 hottest and the drouth severest, and evaporation was thus 

 partially prevented. 



There are many instances where surface irrigation will be 

 found the most economical, not only where plenty of water is 

 to be had, but where economy of water is necessary. There 

 are more advantages in favor of this method than are attributed 

 to it. After having experimented with sub-irrigation at various 

 depths and upon different soils, I would recommend caution 

 before going into irrigation on a very extensive scale, believing 

 that the extra expense in purchasing and laying tiles will 

 more than offset the expense of labor in surface irrigation. 

 Figure 4 shows the method of surface irrigating or flooding in 

 the West. 



