Soils, Fertilizers and Irrigation 187 



times of the year. The range would be from, say, ten acre inches 

 for irrigation of deciduous fruits, which need moisture supplementary 

 to rainfall; twice or thrice as much for citrus fruit trees; four or 

 five times as much for alfalfa where a full number of cuttings are 

 required. These are, of course, only rough estimates which would 

 have to be modified according to local rainfall and soil character. 

 Water should be applied frequently enough to keep the lower soil 

 amply moist. A color of moisture is not enough and a muddy condi- 

 tion results from too much water. One has to learn to judge when 

 there is moisture enough, and a good test of this to take up a handful 

 of soil, squeeze it and open the hand. If the ball retains its shape 

 it is probably moist enough. If it has a tendency to crack upon 

 opening the hand, it is too dry. This test, of course, is somewhat 

 affected by the character of the soil, but one has to form the best 

 judgment possible how far allowance has to be made for that. 



Sewage Irrigation. 



What is the usefulness or harmfuhicss of the outflozu from septic 

 tanks for use on fruits and vegetables? 



There is no question as to the suitability of the affluent from 

 a septic tank for irrigation purposes. Waste waters are sometimes 

 injurious when they are loaded with antiseptics, but the septic tank 

 will not work unless it has a chance for free fermentation in the 

 absence of antiseptics, therefore, this objection against waste water 

 does not hold with the out-flow from septic tanks. It has the ad- 

 vantage over straight sewage irrigation because fermentation in the 

 septic tank is believed to free the water from many dangerous germs, 

 though not all of them. 



Creamery Wastes for Irrigation. 



Will the zvaste zvater from a creamery, pumped into a ditch and used 

 for irrigating sandy loam orchard land, or nursery stock, in any zvay 

 be injurious to the land or the trees? 



It will depend upon the amounts of salt and alkaline washing 

 materials which it carries. This would be governed, of course, by the 

 amount of fresh water used for dilution in the irrigation ditch. There 

 are two ways to determine the question. One would be to make an 

 analysis of a sample of the water taken when it contains the largest 

 amount of these materials after the dilution with ditch water. Another 

 wa-" would be to plant some corn, squashes, barley and other plants, 

 so that they would be freely irrigated by the water during one grow- 

 ing season. This would be rather better than an analysis, because 

 everybody could see whether the plants grew well or not, and would 

 be apt to be better convinced by what they see than by an opinion 

 which a chemist might give on the basis of an analysis. The use 

 of this water on a sandy loam would obviously be less injurious 

 than upon a heavy retentive soil. 



