82 



tivated and shallow plats were cultivated four times during the season, 

 others twelve times i. e., three times as often as usual. 



In each of the eight plats under experiment every other row was root 

 pruned with a knife, which cut the roots about 3 inches deep and about 

 6 inches from the center of the hill, which is as close as a cultivator 

 ordinarily runs. 



As general results of the experiments it appears that (1) as to fre- 

 quency of cultivation, there was practically no diflereuce in the yield 

 whether cultivated four, six, or twelve times; the onlj'^ benefit from 

 the extra cultivation was that the land was kept much freer from weeds ; 



(2) as to depth of cultivation, the largest yield was with shallow culti- 

 vation (1 inch) and the smallest with deep cultivation (3 inches); the 

 yield without any cultivation was less than with the shallow and more 

 than with the deep cultivation ; the weeds were more effectually destroyed 

 by the dee[) than by the shallow cultivation ; (3) as to the effect of prun- 

 ing, no difference was observed between the pruned and unpruned rows 

 in regard to size, vigor, or stage of maturity. 



The yield of corn per acre was, on the average, 4 bushels more from 

 the unpruned than the pruned rows. In no plat was the difference in 

 favor of the pruned portion. The effect of pruning was greatest where 

 the plats were cultivated least, and was least marked on those which 

 had tlie most cultivation. 



As to the general application of the above results, it is to be observed : 

 (L) That in these experiments the soil was very fertile, being "newly 

 broken sod, which is generally conceded to require less cultivation than 

 old land;" (2) " that the season was unusually favorable for corn," and 



(3) that there was considerable rain during the time of cultivation and 

 pruning, which may have helped the corn to recover from the injury of 

 root pruning. "Final judgment may, therefore, be wisely delayed until 

 the experiment can be repeated several years on the same land." 



Experiment No. 54. — Corn, root growth (pp. 113-115). — The particular 

 object of the inquiry was to ascertain the number of the roots and their 

 depths at the points where they are likely to be disturbed b^^ cultivation ; 

 what proportion of all the roots was sufficiently near the surface to be 

 so injured; and whether by root-pruning 3 inches deep, as in Experi- 

 ment No. 10, enough roots would be cut so that any considerable effect 

 should be exj^ected therefrom. To this end a few hills were examined 

 just as they were found growing in the field by digging a trench beside 

 the hill and washing the vertical side with water. Four hills were ex- 

 amined. They grew on a black prairie loam, which is 1^ to 2 feet deep, 

 and is underlaid with permeable yellow clay. These investigations are 

 as yet too limited to allow any general conclusions, but they will form 

 the basis of future work in this line. Three-fourths of the roots would 

 not have been broken by root- pruning or cultivating 3 inches deep; but 

 all but one would have been at 4 inches deep. 



Experiments No. 11 and No. 24. — Comparison of effects of fertilizers on 



