BULLETIN 210. IMPERIAL VALLEY SETTLERS' CROP MANUAL. 



197 



even bear heavy crops so long as the layer of soil in which the roots 

 lie is kept moist. This requires numerous irrigations throughout the 

 growing season. The omission of one irrigation may seriously damage 

 or kill vines in this state of unstable equilibrium. Even when the 

 irrigations are not neglected the conditions are not favorable for the 

 best results. Where the roots are confined to the upper twelve inches 



Fig. 27. Vine with shallow horizontal root system, very objectionable. 



of soil they are subject to constant changes in moisture and tempera- 

 ture. This condition is unfavorable to the proper development and 

 nourishment of the fruit and does not tend towards the production of 

 grapes of the highest eating or shipping qualities. 



With a deep root system penetrating six, eight, or more feet in 

 depth, the growth of the vine is more regular, the grapes ripen more 

 regularly, are firmer and of better flavor. Moreover, fewer irrigations 

 are needed and the omission of one will not have such serious con- 

 sequences.. 



The position of the main roots of the vine is fixed by the growth 

 of the first year. Where this growth will be is determined by the soil 

 conditions and not by the length or position of the cutting. The roots 



