10 



BULLETIN 33, U. S. DEPARTMENT OP AGRICULTURE. 



CONDITIONS OF THE PLAT EXPERIMENTS. 



DIMENSIONS OF THE PLATS. 



Most of the field tests were conducted on tenth-acre plats. These 

 plats are mostly 21 feet wide by 181.5 feet long, though a few are 

 33 feet wide and 132 feet long. In some years, on account of lack 

 of space or seed, the plats were one-twentieth acre in size, measuring 

 12 by 181.5 feet or 16.5 by 132 feet, The plats lay side by side in 

 series, which extend both north and south and east and west. They 

 are separated within the series by 3-foot alleys, while the series arc 

 separated by 16.5-foot roads. Each plat is thus bounded on the sides 

 by a 3-foot alley and on the ends by a 16.5 foot road. A general view 

 of the plats is shown in figure 3. 



Fio. ?,. — General view of the varietal plats of cereals at the Dickinson substation in 



1910. 



TREATMENT OF THE PLATS. 



For the first year's planting the land had been broken from virgin 

 soil the previous spring and backset or else worked down well- with 

 disk and harrow and kept free from weeds throughout the season. 

 The following spring most of the land was double disked and har- 

 rowed. In all cases, sufficient spring cultivation was given to put the 

 land in good tilth and keep down the weeds. The treatment of the 

 plats for each succeeding year is given in the discussion of each crop. 

 Cultivated crops (corn or potatoes) are grown in alternate years on 

 the plats used for the experiments with cereals. This system gives 

 nearly as good results as would be given by a system of alternate 

 cropping and fallowing, and much better results than continuous 

 cropping to cereals. For the cultivated crop the land is spring 

 plowed to a depth of about 8 inches, disked, and harrowed. The 

 plats are harrowed at least once after planting to corn or potatoes, 

 and frequent cultivations are given during the season, thus keeping 

 them free from weeds. After removing the crop in the fall the land 

 is usually harrowed. 



