10 BULLETIN 151/ U. S. DEPARTMENT OF AGRICULTURE. 



SUMMARY. 



(1) Tests of biennial cropping in comparison with annual cropping 

 have been carried on at the San Antonio Experiment Farm for 

 three years. 



(2) The yields of corn and cotton have been less on biennially 

 cropped land than on annually cropped land. The yields of winter 

 oats have been somewhat larger on the biennially cropped land. 



(3) Soil -moisture studies made in connection with these tests do 

 not show any important differences in the amount of soil moisture 

 present in fallowed land and in continuously cropped land at planting 

 and harvest time for corn and cotton. In the plats used for oats 

 there was more moisture present at planting and less at harvest time 

 on the biennially cropped land than on the annually cropped land. 

 In other words, the oats grown biennially used more water and made 

 less vegetative growth, but gave larger yields. 



(4) Observations made after heavy rains show that in most cases 

 the proportion of run-off from heavy rains was greater on land which 

 had been fallow for several months than on land which had been 

 fallow for a comparatively short time. The run-off from an oat plat 

 was less than from any of the fallow plats. 



(5) Considering both crop yields and cost of production, the results 

 of these experiments indicate that biennial cropping, at least for 

 corn, cotton, and oats, is not to be recommended for the San Antonio 

 region. 



WASHINGTON : GOVERNMENT PRINTING OFFICE \ 1914 



