34 



BULLETIN 157. U. 



DEPARTMENT OF AGRICULTURE. 



though the yields of the past five years indicate that it is not. An 

 effort was made in 1913 to deter min e the exact extent of the injury 

 to the plants by harrowing with a spike- toothed harrow, the teeth of 

 which were set almost perpendicularly. At this time there was a 

 heavy crust on the ground, which the plants were penetrating with 

 difficulty. 



On May 21. when the plants were from 3 to 4 inches high, four 

 areas were staked off on plat 2 2D, and the plants in each area were 

 counted before the plat was harrowed. Each area was 3.3 feet 

 square, thus containing 4 \, of an acre, so that the total area of the 



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Fig. 17. — Graphs showing the average percentage of moisture in the first 6 feet of soil at the beginning, 

 in the middle, and at the end of the crop season, as found in the spring-cultivation tests of winter 

 wheat at the Nephi substation, 1909 to 1913, inclusive. 



four units equaled 10 1 b0 of an acre. About one week after harrowing, 

 the plants in each area were counted again and the loss due to har- 

 rowing was determ in ed. On the basis of the figures obtained, the 

 stand was 218,000 plants per acre before and 193,000 plants per acre 

 after harrowing, a loss of 25.000 plants, or 11.54 per cent. This loss 

 alone would allow the plants greater freedom for development, and it 

 might be expected to increase the number of culms per plant. 



To determine the effect of harrowing on the production of culms 

 the total number per unit area was deter mi ned just before harvest 

 and the average number of culms per plant calculated. The average 



