IRRIGATION AND SOIL FERTILITY 71 



stem and roots if the soil be prone to bake. On larger scale work 

 it has been fully demonstrated that for productiveness a small piece 

 of ground thoroughly soaked with water and then as thoroughly 

 cultivated on the surface to kill weeds and prevent the waste of 

 moisture into the air by evaporation, is preferable to twice the sur- 

 face only half watered. One very thorough wetting, with good 

 cultivation, will produce better results than several superficial water- 

 ings. And in this way the water can be used the most economi- 

 cally by accomplishing the most good with the least labor. 



Another very important point is to keep the moisture supply 

 always adequate. One who waits till the plants show distress has 

 lost his chance. One of our experienced growers very pertinently 

 says : "If we allow our ground to get the least bit dry the vege- 

 tables are stunted in growth, and then it takes several days to catch 

 up again if it ever does. I hold that a stunted vegetable is as bad 

 as a stunted calf or pig. It is never as good as if it was pushed 

 right along from the beginning." 



RELATION OF IRRIGATION TO SOIL FERTILITY. 



It must always be borne in mind, however, that adequate moist- 

 ure must always be accompanied by adequate supplies of plant food 

 in the soil. The gardener who keeps his soil rich gets the greatest 

 return from the water he uses, and attention must be paid to the 

 suggestions in the chapter on Fertilization. This has always been 

 demonstrated by experience, and an interesting measure of the fact 

 has been deduced from experimentation by Dr. J. A. Widtsoe of the 

 Utah Agricultural College. He shows that a given amount of moist- 

 ure will produce at least 30 per cent more crop on rich soils than on 

 poor ones, and the crop grown on the rich soil will contain at least 

 45 per cent more food value than that grown on the poor one. In 

 other words, the moisture that would produce 100 pounds of crop 

 on a poor soil would produce at least 130 pounds on a rich soil, and 

 the crop raised on the rich soil would contain on an average 45 per 

 cent more protein, which would still further increase the food-value 

 of the crop grown on the rich soil to the equivalent of 188 pounds 

 grown on poor soil ; almost twice as much food value on the rich soil 

 as on the poor one from the same amount of moisture. Then again 

 the rich soil will hold more moisture, and if there is plenty of 

 moisture the rich soil can grow two or three times as much crop as* 

 the poor soil and with a food value that is higher. 



