J. W. BOULTBEE. CLXXV. 
irrigation raised to 15,000 ibs. per acre, or even less, of saline 
contents. While the above figures are mere approximations, 
obtained under special conditions and varying for different soils 
to a greater or less extent, they are quite sufficient to show that 
the annual addition of, say 5,000 ibs. of alkali salts to any soil 
cannot be long continued with impunity, always supposing that 
the whole of the alkali contained in the irrigating water remains 
upon the land. In many cases, especially where water is scarce, 
this is strictly true, and three years of irrigation has sufficed to 
render land formerly capable of producing all kinds of crops, unfit 
for any save those which, like the beet, the sunflower and others, 
are specially tolerant of alkali salts. It would take but few years 
of such regime to kill out any citrus orchard, and deciduous 
orchards would follow in short order. 
“The subject is really simple enough to be understood by any- 
one capable of doing a sum in arithmetic, and of judging to what 
extent, ifany, his customary method of irrigation relieves the land 
of alkali salts that may have been introduced by irrigation water. 
The principal of the whole matter may be summed up as follows : 
When water containing any considerable amount of alkali salts is 
used for irrigation it should be used very abundantly, at least 
once a year, so as to wash the alkali through into the subdrainage 
if possible. On Jight soils this can be readily done; on heavy 
soils it is extremely difficult to do it without the aid of under- 
drains, and such lands in their natural conditions are, therefore, 
most readily injured by the use of alkaline irrigation water. The 
question is frequently asked, how much alkali in water will render 
it objectionable for irrigation use? From what has been already 
said, it will be easily understood that the question does not admit 
of a definite answer, since both the quality of the saline contents 
and the nature of the soil, together with the possibility of liberal 
and judicious use of the water require to be considered. 
“ Broadly speaking, any water unfit for domestic use on account 
of its saline contents should be used for irrigation only after an 
