From three to eight core holes were made per sampling. 

 This number did not prove to be adequate because of Inherent 

 variability of the soils. 



During analysis of data collected during the 195:? season, 

 it was determined that observation holes should have been main- 

 tained at all plots to determine if water table conditions existed. 

 Through observation holes on a few of the plots, and examination 

 of soil samples taken from the lower profiles, it was found that 

 water tables did exist on some plots where they were not expected. 

 When a water table is present in or near the root zone, there is 

 a probability that the crop will utilize some of this source of 

 moisture. It is impossible to determine this amount. 



The greatest problem, however, was that irrigation in 

 some cases added too much water, and in other cases was too in- 

 frequent or too little. As previously mentioned, when too much 

 water is applied, downward moisture movement continues for a con- 

 siderable length of time. A series of field moisture measurements 

 will include both moisture movement, or change, due to plant ex- 

 traction and evaporation. If too little water is applied, the 

 soil moisture may become critically short, and crop growth may 

 be affected. If the soils become very dry, the evapotranspira- 

 tion rate may also be affected. 



For the next several seasons, work was concentrated on 

 fewer plots, and more detailed observations were made of crop 

 growth, presence of water tables, and other conditions. As the 

 need for irrigation control became recognized as being critical 



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