TALKS WITH PRACTICAL IRRIGATORS. 



79 



soil is impoverished to the extent of forty -tour pounds 

 of potash and fifteen pounds of phosphoric acid, and 

 these constituents are not like nitrates, which will 

 increase again, but they are gone forever if they are 

 not put back. It is true many of our soils are rich 

 enough to stand a drain for many years, but it is not 

 good farming and true economy to allow it to be thus 

 impoverished. 



One ton of wood ashes will put into the soil as 

 much potash as five to seven tons of dry alfalfa will 

 take out, or say twenty-five tons of green alfalfa. A 

 good plan is to keep all the farm-yard manure in a 

 pit, watering it from time to time so as to keep it 

 moist but not thoroughly wet, and throw into this 

 manure pit all bones and animal and vegetable refuse 

 of any nature, together with wood ashes. The manure 

 resulting will be invaluable for garden truck of any 

 kind and good for fruit trees or crops. In using it for 

 fruit trees it should be put in a ring around the tree, 

 so as not to come within say a foot of the stem. It 

 should be buried in the ground about three or four 

 inches to prevent its being blown away or dried out. 

 In no case should it be put into the hole with the soil 

 when the tree is first planted. 



Potash is a substance which is very soluble in 

 water, and is thus easily taken into the plant's system 

 by the rootlets. But it is not like a nitrate in being 

 readily washed out of the soil by rains. In this re- 

 spect it resembles phosphoric acid. It is held in the 

 soil by the oxide of iron and alumina, which possess 

 considerable affinity for it. Of all plant foods the 

 only one which need be feared for on account of 

 heavy rains is the nitrate. 



REDUCING EVAPORATION. 



The study of evaporation becomes a very important 

 one in an irrigated country where the loss of water is 

 due to evaporation largely. 



Now, the chief causes which favor evaporation are 

 these : 



First Free access of the water to the air. 



Second Dry air. 



Third Heat. 



Of these we can greatly modify the first two and 

 somewhat modify the third. The first is better ob- 

 tained by putting a layer of dry, loose dirt on top of 

 the moist soil, and this is done .by cultivation at the 

 proper time. The second is lessened by the planting 

 of trees and the keeping of green stuff on the land. 

 The third will be affected in time by tree planting. 



Practically, however, one of our biggest losses of 

 water is due to the quick evaporation set up by run- 

 ning the water into hot earth, and this can and should 

 be much reduced. 



The easiest method of irrigation, perhaps, is by 

 flooding. Its easiness is its only advantage. More 



water is lost by evaporation by this method than by 

 any other. But its worst point is this: The water 

 goes but a short way down, moistening only the top 

 soil. This educates these plants to throw their roots 

 out near the surface; the water evaporates quickly, 

 and the rootlets get harmed by the heat of the sum- 

 mer sun on the earth. 



We want to induce the plant to send its rootlets 

 down for moisture, and the only way to do this is 

 to give it moisture as low down as we can and keep 

 the rootlets from the surface by constant cultivation. 



There are two ways of doing this sub-irrigation, 

 which is expensive in the first outlay, and irrigation 

 by rills. Plow deep furrows some four feet apart 

 and allow the water to trickle through them until 

 the land is well moistened at a spade's depth between 

 the furrows. Before allowing to dry, hoe back this 

 earth into the furrows and cultivate as soon as the 

 land will admit it. By irrigating in this way evapo- 

 ration will be reduced, water will be economized, the 

 earth will be moistened to a depth of at least two 

 feet, and one irrigation of this kind will last as long 

 as two or three by flooding. 



As for the proper times to apply the water, we 

 have to take into account the needs of the plant and 

 of the soil. 



CURING ELECTRICITY BY TREE-PLANTING. 



That electricity is some form of motion is moder- 

 ately well proven. Mechanical motion, heat and 

 electricity are each convertible into the other. In 

 an electric light works, for example, the engine driv- 

 ing the dynamo changes heat to motion, and the 

 dynamo in turn changes this motion to electricity by 

 the simple process of friction. 



Rub a piece of dry paper with rubber; it becomes 

 electrified and will adhere to the wall or the table. 

 Rub glass with silk, it becomes electrified. Evapo- 

 rate water and electricity is produced. In all these 

 cases vibration is set up and electricity results. 



Now, during the spring sandstorms we have violent 

 friction of air, of glass (sand, which is practically the 

 same), violent percussion of substances of different 

 nature (the sand is made up of particles of iron, lime- 

 stone and quartz), and violent evaporation wherever 

 there is moisture; everything combined, in fact, to 

 produce electricity on a huge scale; and the air be- 

 ing very dry at these times the electricity is not 

 easily conveyed to the earth and neutralized. 



Now, what is a lightning conductor? It is a rod of 

 metal which conducts electricity easily and quickly 

 from the air to the earth, and it has been shown that 

 it neutralizes or draws off the electricity from as 

 much space as would be represented by a cone, the 

 top of which was the point of the conductor and the 

 base a diameter equal to the height of the conductor. 



