156 THE IRRIGA TIO X A GE. 



supplied by a change of crops, by what are termed "cover crops,'' and 

 barn manure. Crop rotation is valuable in producing this humus, and 

 for that reason it is well to change your crops from season to season, 

 instead of growing the same thing on the same field year after year 

 until the soil is exhausted and much has to be expended in fertilizers to 

 make it any way productive. 



Certain mineral substances may be applied to the ground with good 

 results, as besides being indirect fertilizers, they are good conservers of 

 moisture. This is true of salt, lime, etc. What is called alkali soil is 

 found in numerous districts of the West and is the cause of many arid 

 places. This alkali is a mixture of potash and soda, the latter being the 

 most injurious to the soil, and is formed from the decomposition of the 

 feldspar in granite. The alkali is washed down by streams from the 

 granite hills into the valleys, where it is. deposited over the surface, 

 making practically a desert if nothing is done to counteract its influence. 

 Here minerals come in good play, though thorough drainage, together 

 with plenty of water judiciously applied will remedy this evil and do 

 away with the obnoxious white deposit. Lime, gypsum and salt, being 

 good conservers of moisture, may be applied to some grounds with the 

 best of results. Quick lime is especially good for heavy clay soils and 

 also on sandy ones. Lime is beneficial on boggy, marshy land, as it 

 helps to act on the animal and vegetable matter remaining decomposed 

 on the soil. 



And lastly, to conserve moisture, select the right crop for your soil. 

 Don't try to grow a crop on a sandy soil that requires a loamy or clay 

 soil to do well. And don't try to grow grain in your orchard. It takes 

 the moisture that should go to the trees, and this robbery has a bad 

 effect on the i'ruit. Then another thing, small grain planted in between 

 the trees prevents a thorough cultivation of the soil, which is so 

 important. 



After the irrigator learns the A. B. C.'s of irrigation to plow and 

 cultivate well before turning on the water and to make his furrows for 

 water straight instead of crooked his next lesson should be to avoid 

 using too much water. There is no need of having a stream run through 

 your fields with such great velocity as to wash up the soil and carry it 

 further down to be deposited as a fine covering which will bake into a 

 hard crust as soon as the water is turned off and the hot sun given a 

 chance to get in its work; for the tender shoots of plant life cannot force 

 their way through this hard upper surface. A gallon of water judic- 

 iously applied is worth a barrel of it put on haphazard, hit or miss 

 fashion. 



The principle of the thing is the same, whether you are watering a 

 small garden patch or irrigating a vast tract of land and the good and 

 bad methods may be exemplified by telling of the two Indiana gardeners 

 who attempted to raise cucumbers last summer. They were next-door 

 neighbors, each having a small garden and each being equally ignorant 



