IRRIGATION OF FIELD CROPS. 239 



they did not put on the water and a pradlically com- 

 plete failure if they did so. 



The moment the growers get done planting nowa- 

 days, if the ground is too dry to germinate the seed, 

 and if the prospe<5l of copious rainfall is not extremely 

 favorable, no one fears and very few hesitate to furrow 

 out the ground and turn on the water at once. If the 

 seed is in fair condition it is the uniform experience 

 that the young plants will push themselves through 

 the earth in an astonishingly short time and grow vig- 

 orously after they come up. Two irrigations were 

 formerly considered sufficient under ordinary circum- 

 stances as to the rainfall to mature an average crop 

 and three irrigations under the conditions of extreme 

 drouth. As the country grows older and improved 

 methods of cultivation supersede the first primitive 

 efforts, as the soil increases in humus by liberal coatings 

 of manure, or by the turning under of masses of green 

 alfalfa, rich in nitrogen and other plant-foods, more 

 and more water is necessarily required to produce the 

 best results. 



In many instances the potatoes are irrigated from 

 four to eight times, and when there is sufficient supply 

 of water the growers do not hesitate to run water down 

 the potato rows once every week from the time it first 

 becomes necessary or advisable to irrigate until the 

 growth of tubers and vines is completed. It must be 

 understood, however, that this condition prevails only 

 when the soil is well drained, thoroughly enriched 

 with manure or alfalfa, and cultivation is thorough. 

 The strong point in the whole business is to keep the 

 ground at an even, moist temperature. In very dry 



