418 



FORESTRY AND IRRIGATION 



September 



The waste during the month of 

 July was greater than any other 

 month. This occurred while we 

 were irrigating the lower tier of 

 plats, and no opportunity was af- 

 forded whereby we could again use 

 the waste. The farm consists of 40 

 acres, and being an experimental 

 farm, there are a great many differ- 

 ent crops grown, requiring water at 

 different times and in varying 

 quantities. 



The evaporation almost equaled 

 the amount of water applied during 

 this month, less the waste and evap- 

 oration as shown by the evaporating 

 tank. 



Assuming that the evaporation 

 from the water-free surface in the 

 tank was equal to the amount evap- 

 orated from the ground, plus the 

 amount used by the crops, we can 

 have some idea of the amount of 

 water actually required. 



No doubt if less water had been 

 applied, the results, as far as the 

 crop production is concerned, would 

 have been the same or greater, as 

 was indicated by some tests made 

 by Mr. Nelson, showing that the 

 third foot of soil lost much less 

 moisture in a given time than the 

 first or second foot. The roots of 

 certain crops penetrate to a depth 

 where they would be able to draw 

 upon the moisture to a greater depth 

 than the shallow rooted ones. 



If all the crops grown had been 

 of the kind that could have been 

 cultivated, thus conserving the mois- 

 ture, I am sure much less water 

 would have been required. 



Taking the four months, or 122 

 days as the irrigating season, we 

 used water 24 days, 9 hours in May, 

 26 days in June, 22 days 9 hours in 

 July, and 23 days and 2 hours in 

 August, leaving 26^ days during 

 the irrigating season when water 

 was not used. 



These results show that 1-80 of 

 a cubic foot per second continuous 

 flow is more than necessary at Twin 

 Palls, where the soil is very deep. 



I believe if the land were given 

 a thorough irrigation late in the fall, 

 thus storing the moisture in the soil 

 for use the following year, it would 

 be a great saving of time and labor, 

 and materially lessen the amount of 

 water used during the irrigating sea- 

 son, besides being more economical, 

 and as the surrounding areas be- 

 come moistened through irrigation, 

 with proper cultural methods, less 

 and less water will be necessary 

 each year until half the amount used 

 this year will be sufficient. 



Just what the duty of water will 

 be on the Twin Falls tract a few 

 years hence, I am unable to say, but 

 I believe that it will be far greater 

 than now, as the people are becom- 

 ing educated in the use of water, and 

 find that less water and more atten- 

 tion to the soil give greater and 

 more beneficial results. This fact 

 was demonstrated this year on a 

 portion of the experiment farm, 

 where last fall it was irrigated late, 

 and only one irrigation was required 

 this season to produce 70 bushels 

 of wheat to the acre and 96 bushels 

 of oats. 



The character of the soil and the 

 lay of the land should indicate the 

 best method of applying water. 



Two methods have been tried on 

 the Twin Falls tract flooding, and 

 by furrows or corrugations. After 

 a thorough trial, the corrugation 

 method has been given the prefer- 

 ence, and fully 90 per cent of the 

 farmers have adopted this method. 



I believe that it is the better of 

 the two, especially when annual 

 crops are grown, such as grain, etc. 

 While it is true that some others 

 claim that the duty of water is 

 greater by flooding than by corru- 

 gation, that has not been by experi- 

 ence in the portion of the arid dis- 

 trict where I am located. 



As it is understood that water 

 only goes into the soil under pres- 

 sure, and that plants practically stop 

 growing when the air is excluded, 

 which is done by flooding, this is 

 objectionable. 



