128 WHEAT 



and well adapted for green manuring have not 

 yet been fully determined. 



INCREASING THE YIELD BY BETTER CULTURE 



Deep plowing compared with shallow plowing 

 for wheat at the experiment station farm at 

 Davis, California in forty trials gave an average 

 increased yield of 37.4%. At the San Joaquin 

 valley station it was found that adding humus to 

 the soil by green manuring with rye and vetch 

 increased the average yield 244%, compared with 

 growing wheat after wheat, and the green ma- 

 nuring plot gave 62% greater yield than the bare 

 summer fallow. 



The relative yields were given as follows:* 



Yield per Acre, Bushels, 

 Treatment Average for 1909 and 1910 



Wheat after wheat 15.7 



Bare fallow 33.3 



Rye and vetch (turned under) 54.0 



Rye alone (turned under) 52.3 



Professor Shaw concludes from these and other 

 experiments that by means of deeper plowing and 

 better culture methods, together with the growing 

 of green manuring crops during the winter, the 

 average acre yield of wheat in California may be 

 doubled and at the same time the soil rendered 

 more fertile. The use of commercial fertilizers 

 did not as a rule give much benefit in the_Cali- 

 fornia experiments. 



"California Experiment Station Bulletin No. 211. 



