154 Irrigation and Drainage 



practice which is equivalent to it in effect, will be found 

 to give better results than steady cropping, either with 

 or without catch crops. 



INFLUENCE OF SUMMER FALLOWING ON SOIL MOIS- 

 TURE AND ON PLANT -FOOD 



In a study on the influence of summer fallowing on the water 

 content of the soil, it was found that the effect still showed, even 

 at the end of the following season, after a crop had been matured 

 on the ground. In order to show how great this influence may 

 be, the results of the study are cited here, giving first the con- 

 dition of the soil in the spring, when the fallowing experiment 

 was begun. The results cited are from three adjacent plots, the 

 middle plot being the one bearing the crop. The table which 

 follows shows the water content of the plots as given by three 

 determinations, on May 22, June 11, and June 17, the averages 

 being given in every case, and the data from the two fallow 

 plots being combined: 



Mean 19.20 18.92 



Here it will be seen that there is a slight tendency for the 

 ground left fallow to be a little wetter than that which was to 

 bear the crop, but this difference is not as large as the table 

 shows, because the fallowing effect had begun to show its in- 

 fluence somewhat when the last two sets of samples were taken, 

 corn having already begun to grow upon the intervening plot. 



At the end of the growing season, August 24, the difference 



