1 8 HORTICULTURE BY IRRIGATION. 



often results in excessive saturation and caking of the soil and in the 

 injurious deposits of the soluble salts. 



In discussing " Irrigation in Horticulture," Professor Cassiday says : 

 " Surface irrigation, whether practiced out of doors or in the plant house, 

 cannot be too strongly condemned, as it unquestionably induces surface 

 rooting not a desirable result in any climate." Besides promoting 

 surface rooting it induces a continuous evaporation, and refrigeration of 

 the soil, the latter acting as a wick, drawing water by capillary attraction 

 to be absorbed at the surface by the air with which it comes in contact, 

 and depositing at its surface its salts, which, if in too .great quantity, are 

 destructive to all useful vegetation. The " furrow system," although often 

 open to much of the criticisms abo\e, is, nevertheless, when used with 

 care and economy, far less objectionable than is the practice of flooding.* 

 Of course, either natural or artificial drainage should go hand in hand 

 with any system of irrigation. 



Professor Short, in a paper read some three years since before the 

 Colorado State Horticultural Society, said : " When irrigation is properly 

 carried on, it is undoubtedly the best and safest method of furnishing 

 water to plants. I think the method now used throughout the State is a 

 very bad one." 



He then goes on to show that the water used from our mountain 

 streams is laden with the sulphates of soda, magnesia and alumina, which 

 are deposited by irrigating ditches on our lands with the water, and hence, 

 as evaporation takes place, large quantities of these soluble salts remain. 

 After a repetition for several years of this process, a white crust is formed, 

 called "alkali." While a moderate quantity of this so-called alkali is 

 beneficial as plant food, a large accumulation is exceedingly injurious. 

 This is the chief reason that some land, which has been irrigated for 

 several years, will not produce any vegetable growth. As one remedy, he 

 suggests underground 'drainage, by which superfluous water would sink 

 into the soil (with most of the objectionable salts) and be carried off. 

 Fresh water falling would also aid this. Then, concludes Professor Short, 

 with thorough manuring, the lands would be rendered fit for continual 

 use, as the manure furnishes the phosphates and nitrogenous organic food 



*I am aware that frequent and copious flood ings are sometimes recommended 

 for dispersing the accumulated salt from lands, but this plan seems open to 

 serious objections, and should never be resorted to where the under-drainage is 

 not good. 



